Biology Lab Gene Expression

/in /by

To delve a bit deeper into our topic this week, we are going to spend some time using Phet’s Gene Expression Simulation, as well as work through the effects of various mutations on gene expression.  To access the simulation, you can either click on the Gene Expression Simulation Link below (recommended) or use the version that is embedded in each of the parts below.

HERE IS THE LINK TO THE  Gene Expression Simulation (Links to an external site.)

https://phet.colorado.edu/sims/html/gene-expression-essentials/latest/gene-expression-essentials_en.html

Gene Expression Lab Simulation worksheet adapted by L. McPheron & Shannon Nixon; Phet Simulation by Elizabeth Hobbs; Mutation worksheet by Eliza Woo

Objectives:

● Identify the roles transcription factors, RNA polymerase, ribosomes, and mRNA destroyers have on transcription and translation.

● Distinguish between the location and function of regulatory regions compared to transcribed regions of DNA.

● Predict the effects of concentration, affinity, and degradation rates of transcription factors and RNA polymerase on gene expression.

● Identify the effects of mutations on gene expression. Background: Transcription​ is the process of making mRNA from DNA. This is a highly regulated process that our cells complete in preparation to make a protein. ​Translation​ is the process of making a protein from a piece of mRNA.

DNA ——————–> mRNA ——————–> protein transcription translation

Not all regions of DNA are used to make mRNA – only the parts of DNA that correspond to genes. Even then, not all gene regions are transcribed all the time. When genes are transcribed into mRNA depends on the needs of the cell. Once mRNA is made from DNA, it is translated into protein. Translation is an energy expensive process (it requires LOTS of ATP) which is one reason the cell only completes the process when the protein product is needed. This week’s “Reading and Lesson” explains many of the details of these highly complicated processes, transcription and translation. Please review the lesson for a deeper understanding of the concepts in this lab activity. Procedure: Click the Play arrow on this ​Gene Expression activity​ to complete the simulations. (The simulations are also embedded in the Canvas lab assignment page.) You will complete 3 simulations: 1) Expression, 2) mRNA, and 3) Multiple Cells.

Part 1: Expression Simulation

Click “Expression” to start that simulation. Notice the molecule that spans across the screen, from left to right. Answer the following 2 questions:

1. What is this molecule that spans across the page that is shown in red and blue?

2. What do you think the different colors (red and blue) of the molecule represent?

 

1

 

 

 

Now, start the process of transcription.

For transcription, you need these things to happen. First, most genes require 1 or 2 “transcription factors” to bind to the area in front of the gene (called the “regulatory region”). Second, an RNA polymerase (an enzyme that makes mRNA from DNA) needs to be present in order for transcription to occur.

1. Drag one Positive Transcription Factor and one RNA Polymerase from the box called Biomolecule Toolbox to the regulatory region on the DNA molecule. This should start TRANSCRIPTION.

2. Now, drag a ribosome next to the mRNA, in order to do TRANSLATION. 3. The mRNA is eventually broken down by an mRNA destroyer protein. Drag one of these next to the

mRNA when it is done making a protein. 4. Put the protein in Your Protein Collection. 5. Stop the gene from working by dragging the Negative Transcription Factor to the Regulatory Area, and

remove the Positive Transcription Factor by dragging it out of the way.

After you have made 1 protein, answer these 5 questions. HINT: Think about what/where things are at the start, and what/ where things are at the end of the process.

1. What does the “Positive Transcription Factor” do?

 

 

2. What does the “RNA Polymerase” do?

 

3. What does the “Ribosome” do?

 

4. What does the “mRNA destroyer” do?

 

5. What does the “negative transcription” factor do?

 

2

 

 

 

Click the yellow “Next Gene” box to begin working on the second gene. Can you remember the steps in order from your first trial? Try to see if you can! (HINT: There is one small difference between the transcription of gene 2 versus gene 1 – the difference is not in the order of steps but in the amount of something!) If not, not to worry, we are still learning… As a reminder, the steps are:

1. Drag Positive Transcription Factors and one RNA Polymerase from the box called Biomolecule Toolbox to the regulatory region on the DNA molecule. This should start TRANSCRIPTION!

2. Now, drag a ribosome next to the mRNA, in order to do TRANSLATION! 3. The mRNA is eventually broken down by an mRNA destroyer protein. Drag one of these next to the

mRNA when it is done making a protein. 4. Put the protein in Your Protein Collection. 5. Stop the gene from working by dragging the Negative Transcription Factor to the Regulatory Area, and

remove the Positive Transcription Factors by dragging them out of the way.

After you have made the second protein, answer these 2 questions.

1. What is one difference you noticed that was required to initiate the transcription of gene 2 versus gene 1?

2. What could be an advantage of multiple positive transcription factors versus only one?

 

 

Now, put all of your items back in the Biomolecule Toolbox and begin again, and answer the following 2 questions.

1. What happens if you add 2 RNA Polymerases (one after the first, before transcription is complete), and then 2 ribosomes (one for each mRNA)?

 

 

2. What would be the benefit of working this way versus adding RNA Polymerase one at a time?

 

 

Click the yellow “Next Gene” box to begin working on the third gene. Can you remember the steps in order from your first trial? Try to see if you can!

 

 

3

 

 

 

Additional 4 Questions from the Expression Simulation:

1. What is gene expression?

 

 

2. What molecules are involved in gene expression? List them all and state the role of each.

 

 

 

 

 

 

3. What is the difference between the “regulatory region” and the “transcribed region”?

 

 

4. A student says that “ALL DNA codes for proteins.” Do you agree with her? Why or why not? Give evidence to support your answer.

Part 2: mRNA Simulation

At the bottom of the simulation page, click on the next simulation (it’s greyed out) called mRNA.

You should see a strand of DNA with a bunch of RNA Polymerases floating around. (If the RNA Polymerases are not moving, click the Play button.) Answer the following 7 questions.

1. Is mRNA being made?

 

2. In the Positive Transcription Factor box, slide the Concentration slider from NONE to just a tad (a couple millimeters or so) away from NONE. What do you notice is happening in the simulation now?

 

 

4

 

 

 

3. Move the Concentration slider all the way to HIGH. How does this affect what is happening in the simulation?

 

 

4. Leave the Concentration slider on HIGH but move the Affinity slider all the way to LOW. What happens? Move the Affinity slider to a midway setting? What happens now? Based on these observations, what do you think ​affinity​ means in this simulation?

 

 

 

 

 

 

5. Place both sliders in the Positive Transcription Factor box on the HIGH setting. ​Predict ​what will happen to the simulation if you were to move the RNA Polymerase affinity slider to the LOW position. Record your prediction.

 

 

 

6. Now, move the RNA Polymerase affinity slider to the LOW position and record your observations. Was your prediction correct?

 

7. Place all the sliders in the HIGH position. Check the box to add Negative Transcription Factors and place the concentration and affinity sliders on HIGH. How does this change transcription compared to without Negative Transcription Factors?

 

 

 

Continue to play around with the sliders until you can accurately predict how the change will affect transcription each time.

 

 

5

 

 

 

Additional 3 Questions from the mRNA Simulation:

1. What circumstances make the most mRNA? (What slider positions?)

2. What circumstances make the least mRNA? (What slider positions?)

 

3. Why would a cell need the option to make or not make a protein?

 

 

 

 

Part 3: Multiple Cells Simulation

At the bottom of the simulation page, click on the next simulation (it’s greyed out) called Multiple Cells.

Watch the generation of the graph called Average Protein Level vs. Time when one cell is working. If the graph does not automatically begin, then click the Play button at the bottom of the page. Answer the following 4 questions.

1. On the right side of the page, there are controls for Concentration, Affinity, and Degradation. (You need to click the green + to see the sliders.) Predict where you need to place each of the 3 sliders to achieve lots of protein. Record your predictions here:

a. The Concentration slider should be on LOW or on HIGH to achieve lots of protein?

 

b. The Affinity slider should be on LOW or on HIGH to achieve lots of protein?

 

c. The Degradation slider should be on LOW or on HIGH to achieve lots of protein?

 

6

 

 

 

2. Now, move the sliders into the positions you predicted to see if your predictions were correct. (NOTE: Each time you click “Refresh” to restart the graph, all of the sliders reset themselves to their original setting.) Then, explain why each setting – concentration, affinity, and degradation – makes sense for making lots of protein.

 

 

3. Why would a protein need to be degraded?

 

 

 

4. Think back to last week’s lab – Lactase Enzyme Lab. Give an example from that lab of a time when it would be necessary to make a lot of one type of protein.

 

Part 4: Effects of Mutations on Gene Expression You have learned this week that cells use the two-step process of transcription and translation to transform a protein-coding DNA sequence into a chain of amino acids that makes up a protein. The resulting chain of amino acids will fold into a three-dimensional protein structure that defines the phenotype. Imagine that the following DNA sequence is part of a protein-coding gene. Use this sequence to answer the questions that follow.

… G G A T G C C G C T C T G C A A C T A C…

A) What is the ​complementary DNA sequence​ to the DNA sequence above? ​Hint: look back to your reading and lesson notes to recall the pairing rules for nucleotides A, T, G, and C if you need to!

 

 

B) What is the ​mRNA sequence​ transcribed from the DNA sequence from ​Part A​? ​Hint: your answer below should start with the letter ​G​ and not ​C​!

 

 

C) What ​corresponding amino acid sequence​ is translated from the mRNA sequence from ​Part (B)​? Use the genetic code from the lesson or the one posted in the lab. ​Remember that your amino acid sequence should always start with the ​START codon​!

 

D) For the following scenarios (i)-(iii), identify the type of mutation that has occurred (single base-pair substitution or frameshift mutation) to our original sequence AND the new amino acid chain that results

7

 

 

 

from such a mutation. Complete the same sequence from complementary DNA sequence, then mRNA sequence, and then corresponding amino acid sequence like what you did in Parts A, B, and C above!

(i) The 4​th​ C in the original sequence is mutated to a T:

… G G A T G C C G C T ​T​ T G C A A C T A C …

Type of mutation:

New amino acid chain:

 

(ii) An extra C is inserted into the original sequence:

… G G A T G C C G C ​C​ T C T G C A A C T A C …

Type of mutation:

New amino acid chain:

 

(iii) The 5​th​ C in the original sequence is mutated to A:

… G G A T G C C G C T C T G ​A​ A A C T A C …

 

Type of mutation:

New amino acid chain:

 

E) At the end of translation, an amino acid chain will subsequently fold into a protein with a specific structure and function.

 

(i) Of the three mutations described in part (D), which mutation will cause the ​least ​change to protein function? Briefly explain your reasoning.

 

(ii) Which mutation would you expect to significantly alter protein function? Briefly explain your reasoning.

 
"Looking for a Similar Assignment? Get Expert Help at an Amazing Discount!"

Marine Biology 180

/in /by

How to Effectively Write a Fact-supported Essay

1. University standard. Write a 10-15 sentence, fact-supported, essay answer to your assigned weekly question(s).

2. How to determine your assigned weekly essay question(s)? You will be answering the “Study Guide Questions” (found under Course Content), for the assigned weekly textbook chapters listed in your Class and Assignment Schedule. These are excellent questions representing the most important concepts in our course. Therefore, if you cut-and-paste your classmates’ correct answers to these weekly questions, you will have created an excellent Study Guide (questions plus answers) for studying for your final exam. To determine your assigned question(s), go to the Navigation Bar, Roster, select the Students tab, alphabetize by student’s last name, then count down the list of students to your name. That number is your student number. You only need to check this number once each week, as students will drop the class, causing your number to change. Now, go to the last paragraph in this document and use your class Week number and your student number to determine your assigned essay question(s) to answer. Don’t be concerned that more than one student does the same question(s), as student numbers will change when students drop the course.

3. Mechanics a. Your discussion directions will direct you to submit your work by selecting Start a New Thread. Do not use attachments. b. After the week is over, the discussion is closed to further input so that we can move forward to the next week’s discussions. I will not respond to every discussion that is made, but will be following your submissions and responses, and interjecting when I feel it is appropriate. c. I will interact weekly with each student using a completed discussion grading rubric, so be sure to read them for my feedback. The last paragraph explains where to find them in LEO.

4. Expectations a. Your submission must be thorough, concise, positive, and in essay form using effective writing, with a length of one or two single-spaced paragraphs totaling 10-15 sentences (not including the question(s) or references). Question(s) should be in bold font. Answers should discuss the concept in DETAIL to show your understanding of the topic. If you need more scholarly information on your topic, consider an internet search or a second textbook. b. Your submission must be paraphrased (as explained in UMUC’s “How to Avoid Plagiarism” self-study module), i.e. written in your own words. Do not copy or cut-and-paste from any source. Do not use direct quotes. The reason I insist on this is because (1) student comprehension is significantly increased by paraphrasing instead of copying verbatim material, and (2) UMUC considers copying-and-pasting another author’s work to be plagiarism. Paraphrasing also allows me to identify, and subsequently correct, any misconceptions a student may have with the course material. I will not give credit to an input that gives little detail, or uses verbatim text from an internet site, our course materials, or other source. c. Use APA in-text and reference list citations, which are explained on UMUC’s APA Citation Examples web page, as well as in UMUC’s “How to Avoid Plagiarism” self-study module. Liberally use in-text citations to cite material which is not your own. Use our course materials as your primary reference. You may use other scholarly, peer-reviewed references in addition to our course materials. 1) If using an electronic textbook, use the provided physical textbook page numbers for your citations. 2) If you wish to add an internet reference, be sure to use a paragraph number in its in-text citation if the reference has no page number. The internet address should also be a “hot link” which allows the reader to click on it and be taken directly to the page where you found the information. 3) Use only scholarly references, dated no older than 10 years. Do not use dictionary references. Do not cite commercial web sites (URL ending in “.com”) since they are not scholarly (i.e. peer-reviewed). d. I will evaluate effective writing based on the Maryland Statewide English Composition standard for undergraduate writing which states that writing should be “substantially free of errors in grammar, spelling, punctuation, and mechanics” to earn a “C” grade. e. I will grade your first submission of that week; therefore, submit only final, not draft, versions of your work. For effective writing assistance, you may wish to have UMUC’s Effective Writing Center review your work before submission. f. No late submissions are accepted. Before the deadline, use the “Edit” function to correct errors that I bring to your attention.

5. Discussion example with errors. To read error comments, you will need to use Microsoft Word and select View => Print Layout. Paragraph 5 provides a corrected version.

Discussion subject line: Jones Comment by Dennis Whitford: Missing question number

2. Differentiate between marine biology, biological oceanography, and oceanography. Comment by Dennis Whitford: Did not bold question number and question

Marine biology is closely related to both oceanography and biological oceanography, a subset of oceanography. (Castro & Huber, 2013, p. 2) If you were studying marine organisms, and how they interact with their environment and other marine organisms, you would be studying marine biology (Begin et al., 2014, p. 2). However, if you were studying the ocean from the perspective of one, or many, natural sciences, such as biology, geology, etc., you would be studying oceanography (Begin, Wurzbacher, & Cucknell, 2014, p. 2). Comment by Dennis Whitford: End-of-sentence punctuation comes after the in-text citation Comment by Denny Whitford: Format: first use in a paragraph of a multi-author reference must use all author’s names. Comment by Denny Whitford: 2nd and subsequent use in a paragraph of multi-author ref can use all authors or use the shortened “et al.” version.

Castro & Huber (2013) explain that marine biology is the study of biology applied to the sea, and that scientific study of the ocean is oceanography (p.2). Oceanography, being a broad area of study, are split into many branches, including biological oceanography (Castro & Huber, 2013, p. 2). Often, marine biology and biological oceanography are hard to set apart from each other. However, there are a few dissimilarities that can be pointed out. Castro & Huber (2013) explain that marine biologists focus their examination to marine organisms which live closer to the shoreline (and sometimes on terrestrial organisms), while biological oceanographers spend their attention on organisms in the deep, open ocean (p. 2). Meteorologists study the weather and climate. Marine biologists focus their attention on the roles and life cycles of the organsm, while biological oceanographers focus their attention on the effects of the organism on the ocean as a whole (Castro & Huber, p. 2). More specifically, marine biologists show interest in the reproduction, physiology, or biochemistry specific to the marine organism which they are studying (Marine Biology & Biological Oceanography, 2010, para. 1). On the other hand, biological oceanographers focus on the ecological effects of the organisms they study; especially taking into account the different physical characteristics of the ocean environment they live in (Marine Biology & Biological Oceanography, 2010). However, these distinctions are not very easy to draw, and there are many exceptions, meaning that some scientists consider these two branches to be the same (Castro & Huber, 2013, p. 2). Comment by Dennis Whitford: Missing blank space Comment by Dennis Whitford: Ineffective writing (grammar) Comment by Dennis Whitford: Irrelevant statement Comment by Dennis Whitford: Ineffective writing (spelling) Comment by Dennis Whitford: Missing year

References:

Bégin, C., Wurzbacher, J., & Cucknell, M. (2014). BIOL 181: Life in the oceans – Lecture notes. Posted in University of Maryland University College (UMUC) BIOL 181 online classroom, archived at UMUC, Adelphi MD.

Castro, P., & Huber, M. E. (2013). Marine Biology (9th ed.). New York: McGraw-Hill Higher Education Comment by Dennis Whitford: Incorrect capitalization and missing italics Comment by Dennis Whitford: Missing ending period

(2010). Marine Biology & Biological Oceanography. Retrieved June 5, 2010, from http://www.lifesci.ucsb.edu/eemb/programs/graduate/research/marine_biology/marine_biology.html . Comment by Dennis Whitford: Incorrect reference list citation format for an Internet citation Comment by Dennis Whitford: Missing hyperlink

Errors Not shown:

Essay did not answer question that was asked

Verbatim copying of any material from textbook or another source

Failure to use any in-text citations Use of quotations rather than mandatory paraphrasing

 

5. Same discussion example, with all errors corrected. This submission scores 100%.

Discussion subject line: Jones, Question #2

2. Differentiate between marine biology, biological oceanography, and oceanography.

Marine biology is closely related to both oceanography and biological oceanography, a subset of oceanography (Castro & Huber, 2013, p. 2). If you were studying marine organisms, and how they interact with their environment and other marine organisms, you would be studying marine biology (Begin, Wurzbacher, & Cucknell, 2014, p. 2). However, if you were studying the ocean from the perspective of one, or many, natural sciences, such as biology, geology, etc., you would be studying oceanography (Begin et al., 2014, p. 2).

Castro & Huber (2013) explain that marine biology is the study of biology applied to the sea, and that scientific study of the ocean is oceanography (p. 2). Oceanography, being a broad area of study, is split into many branches, including biological oceanography (Castro & Huber, 2013, p. 2). Often, marine biology and biological oceanography are hard to set apart from each other. However, there are a few dissimilarities that can be pointed out. Castro & Huber (2013) explain that marine biologists focus their examination to marine organisms which live closer to the shoreline (and sometimes on terrestrial organisms), while biological oceanographers spend their attention on organisms in the deep, open ocean (p. 2). Marine biologists focus their attention on the roles and life cycles of the organism, while biological oceanographers focus their attention on the effects of the organism on the ocean as a whole (Castro & Huber, 2013, p. 2). More specifically, marine biologists show interest in the reproduction, physiology, or biochemistry specific to the marine organism which they are studying (UCSB, 2010, para. 1). On the other hand, biological oceanographers focus on the ecological effects of the organisms they study; especially taking into account the different physical characteristics of the ocean environment they live in (UCSB, 2010, para. 1). However, these distinctions are not very easy to draw, and there are many exceptions, meaning that some scientists consider these two branches to be the same (Castro & Huber, 2013, p. 2).

References:

Bégin, C., Wurzbacher, J., & Cucknell, M. (2014). BIOL 181: Life in the oceans – Lecture notes. Posted in University of Maryland University College (UMUC) BIOL 181 online classroom, archived at UMUC, Adelphi MD.

Castro, P., & Huber, M. E. (2013). Marine biology (9th ed.). New York: McGraw-Hill Higher Education.

UCSB (2010). Marine biology & biological oceanography. Retrieved June 5, 2010, from http://www.lifesci.ucsb.edu/eemb/programs/graduate/research/marine_biology/marine_biology.html

6. If you are assigned more than one question, divide your submission into smaller parts:

Question A

Answer A

Question B

Answer B

Question C

Answer C

Note the 10-15 sentence requirement applies to your entire submission, and not to each of the multiple questions.

 

7. Your discussion grading rubric template is provided in LEO with the discussion directions. After the discussion due date, you can read the completed (1) rubric feedback and score and (2) grade feedback by going to: My Tools, User Progress.

 

8. Now, go to the tables below and use your student number and class Week number to determine your assigned essay question(s) to answer. Don’t be concerned that more than one student does the same question, as student numbers may change in the middle of a week.

 

 

.

 

 

 

2

 

BIOL 181 Week 1BIOL 181 Week 3

Student

chques

Student

chques

Student

chques

Student

chques

Student

chques

Student

chques

#

##

#

##

#

##

#

##

#

##

#

##

1111225231116112732384

2121326241226213742485

3131427251336314752586

4141528261446415762687

5151629271556516772788

61617210281666617782861

71718211291776718792962

821192123021868197103063

92220213312296920813164

1023212143223107121823265

1124222153324117222833366

BIOL 181 Week 4BIOL 181 Week 5

Student

chques

Student

chques

Student

chques

Student

chques

Student

chques

Student

chques

#

##

#

##

#

##

#

##

#

##

#

##

191129122311211211213123141

292131012411321221313224142

393141022511431231413325143

494151032611541241513426144

59516104279151251613527145

69617105289261261713628146

79718106299371271813729147

89819107309481281913830148

99920108319591292013931149

10910211093296101210211310321410

11911221113397111211221311331411

BIOL 181 Week 6 (if SG questions are assigned)BIOL 181 Week 7 (if SG questions are assigned)

Student

chques

Student

chques

Student

chques

Student

chques

Student

chques

Student

chques

#

##

#

##

#

##

#

##

#

##

#

##

11511215122317311811219423206

2152131612417421821319524207

3153141622517531831419625208

4154151632617641841519726209

5155161642717751851619827211

6156171652817861861719928212

7157181662917971871820129213

81581916730171081881920230214

9159201683115191912020331215

1015102117132152101922120432216

1115112217233153111932220533217

 
"Looking for a Similar Assignment? Get Expert Help at an Amazing Discount!"

Which of these would be a valid hypothesis?

/in /by

MULTIPLECHOICE SECTION INSTRUCTIONS: Read all instructions carefully. Please answer all questions. Each question is worth 0.5 points. The Multiple Choice section is worth 40 points.

 

**Do not enter your answers here.** Type in the letter you select as the best answer on the Answer Sheet provided by your instructor.

 

1. Which of these would be a valid hypothesis?

A) Human history is determined by a series of supernatural events.

B) Humans should help in the conservation of other animal species.

C) Humans are controlled by forces beyond our understanding.

D) Humans and bacteria share a common genetic code.

 

2. In the scientific method, a hypothesis .

A) is a statement of fact

B) can only be tested once

C) is usually proven to be correct

D) is a proposed explanation based on observations

E) none of the above

 

3. What is the correct sequence of steps in the scientific method?

I. State the problem

II. Analyze and interpret the data

III. Share the results with other scientists

IV. Develop a hypothesis

V. Design and perform an experiment to test the hypothesis

 

A) I → II → III → IV → V

B) III → I → V → II → IV

C) V →IV → III → II → I

D) I → IV → V → II → III

E) V → II → I → III → IV

 

 

 

 

 

 

4. To test a hypothesis about a given variable, experimental and control groups are tested in parallel. Which of the following best explains the dual experiments?

A) In the experimental group, a chosen variable is altered in a known way. In the control group, that chosen variable is not altered so a comparison can be made.

B) In the control group, a chosen variable is altered in a known way. In the experimental group, that chosen variable is not altered so a comparison can be made.

C) In the experimental group, a chosen variable plus all other variables are altered.

In the control group, the chosen variable is altered; however, all other variables are held constant.

D) In the experimental and control groups, two different variables are altered.

E) Experimental and control group experiments are identical and run in parallel to get repeatable results.

 

5. Which of the following can be considered definitions of “theory”?

A) A theory can be an explanation of scientific laws

B) A theory is a widely accepted integrated explanation of numerous hypotheses, each supported by a large body of observations and experiments

C) A theory is a condensation and simplification of many data that previously appeared unrelated

D) A theory is a prediction for new data suggesting new relationships among a range of natural phenomena

E) All of the above

 

6. You have formulated a hypothesis that light is not necessary for seed germination.

 

To test your hypothesis, one set of maple seeds is placed in light with warm temperatures and adequate moisture. Another set of identical seeds is placed in the dark under the same set of conditions. The control in the experiment is

 

A) seeds in the dark

B) seeds in the light

C) warm temperature

D) adequate moisture

E) germination rate

 

7. A newly discovered multicellular organism obtains food by digesting dead organisms. Such an organism is most likely a member of the kingdom .

A) Plantae

B) Fungi

C) Protista

D) Animalia

 

 

8. Which of the following structures can perform all the activities required for life?

A) organelles

B) nuclei

C) DNA molecules

D) cells

E) plasma membrane

 

9. A group of medical researchers recently tested the effects of a cholesterol- lowering medication, Drug A, on women who had high blood levels of cholesterol. The researchers did the following experiment and obtained the indicated results. One group of 150 women took a tablet containing 40 mg of Drug A for 90 days; 120 of this group decreased their blood levels of cholesterol by at least 10%. Another group of 150 women was given a tablet with no added Drug A for 90 days; 25 of these women decreased their blood levels of cholesterol by at least 10%.

Which of the following is the most reasonable and accurate conclusion based on results obtained in this experiment?

 

A) Drug A is good for women.

B) Drug A is found in the blood of women.

C) Women taking tablets supplemented with Drug A will show a decrease in cholesterol levels in the blood.

D) Women taking tablets supplemented with Drug A will show an increase in cholesterol levels in the blood.

E) Blood levels of cholesterol are not affected by oral supplementation of Drug A.

 

 

 

10. Using the branching tree of life for bears depicted in the accompanying figure, choose from among the following bear species the one that is most closely related to the polar

bear.

 

 

 

 

A) brown bear

B) sun bear

C) spectacled bear

D) giant panda

 

 

 

 

 

 

 

 

Page 4 of 25 © UMUC

 

 

 

 

 

11. What are the products in the following chemical reaction?

C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O

A) CO2 and H2O

B) C6H12O6, H2O, and O2

C) O2 only

D) C6H12O6, H2O, O2, CO2, and H2O

 

12. Relative to a pH of 3, a pH of 7 has a .

A) 400 times lower H+ concentration

B) 10,000 times lower H+ concentration

C) 4 times higher H+ concentration

D) 10,000 times higher H+ concentration

 

13. A substrate binds to an enzyme by interacting with amino acids in the ?

A) dehydration reaction

B) binding site

C) hydrolysis site

D) denaturation portal

 

14. Which component of the following reaction is the substrate, and which is the enzyme? sucrose + sucrase + water → sucrase + glucose + fructose

A) sucrose is the substrate, and sucrase is the enzyme

B) sucrase is the substrate, and sucrose is the enzyme

C) glucose is the substrate, and water is the enzyme

D) fructose is the substrate, and glucose is the enzyme

 

 

 

15. If one strand of a DNA double helix has the sequence AGTACTG, what will be the sequence of the complementary DNA strand?

A) GACGTCA

B) UCAUGAC

C) GUCAUGA

D) TCATGAC

E) impossible to tell from the information provided.

 

 

 

16. One difference between eukaryotic and prokaryotic cells is that eukaryotic cells prokaryotic cells.

A) are found in animals, while plants are comprised of

B) have membrane-enclosed organelles, which are lacking in

C) have a plasma membrane, which is lacking in

D) have a nucleoid region, which is lacking in

 

 

17. A protist that contains contractile vacuoles in its cytoplasm most likely lives

.

A) in a marine environment

B) within the cells of another organism

C) in fresh water

D) where it can climb on vertical surfaces

 

18. Similar to the nucleus, chloroplasts and mitochondria are .

A) surrounded by two membranes

B) green

C) manufactured by the nucleolus

D) able to synthesize lipids

 

19. The endomembrane system includes .

A) ribosomes, lysosomes, vacuoles, and the endoplasmic reticulum

B) Golgi apparatus, ribosomes, vacuoles, and the endoplasmic reticulum

C) Golgi apparatus, lysosomes, ribosomes, and the endoplasmic reticulum

D) Golgi apparatus, lysosomes, vacuoles, and the endoplasmic reticulum

 

20. Which of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated within the cell than in the surroundings?

A) active transport

B) facilitated diffusion

C) diffusion

D) osmosis

 

21. If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?

A) expulsion of water by the plant cell’s central vacuole

B) the relative impermeability of the plant cell membrane to water

C) the relative impermeability of the plant’s nuclear membrane to water

D) the relative inelasticity and strength of the plant cell wall

 

 

 

22. Which of the following is not a common feature shared by all metabolic pathways?

A) Each pathway contains multiple intermediate products, and there are small molecular differences between the intermediates.

B) Each pathway is regulated to ensure the optimal use of resources and to maintain the health of the cell.

C) Many pathways are universal among living organisms.

D) Each step within the pathway, or the conversion from one intermediate to the next, is catalyzed by a nucleic acid with a reactive R group.

 

Use the following information to answer questions 23-24 below.

 

A group of medical researchers recently investigated the effects of Drug X on lowering blood pressure in a group of hypertensive middle-aged men. The researchers did the following experiment and obtained the indicated results: One group of 150 men took a tablet containing Drug X for 3 weeks – 95 of these men decreased their blood pressure by at least 10% (three men from this group dropped out of the study). Another group of 150 men was given a tablet with no added Drug X for 3 weeks – 10 of these men decreased their blood pressure by at least 10% (two men from this group dropped out of the study).

 

23. Which of the following was the control group in this experiment?

A) the group of participants that received tablets containing Drug X

B) the group of participants that received tablets that did not contain Drug X

C) the number of participants in each group at the beginning of the experiment

D) the number of participants in each group at the end of the experiment

E) the amount of Drug X contained in the tablet

 

24. Which of the following is the most reasonable and accurate conclusion based on the results obtained in this experiment?

A) Drug X is good for hypertensive men

B) Drug X is good for both men and women

C) Hypertensive men receiving Drug X for 3 weeks may show a decrease in blood pressure

D) Hypertensive men receiving Drug X for 3 weeks may show an increase in blood pressure

E) Drug X has no effect on blood pressure

 

 

 

 

25. Plant cells .

A) do not need chloroplasts because their mitochondria meet their energy needs

B) have chloroplasts and mitochondria

C) use carbon dioxide but do not use oxygen

D) do not need mitochondria because their chloroplasts meet their energy needs

E) are prokaryotic

 

 

 

26. The ultimate source of the energy in food is .

A) the sun

B) producers

C) ATP

D) consumers

E) lipids and nucleic acids

 

27. What compound directly provides energy for cellular work?

A) C6H12O6

B) glucose

C) ATP

D) fat

 

 

 

28. child is born with a rare disease in which mitochondria are missing from certain skeletal muscle cells. Physicians find that the muscle cells function. Not surprisingly, they also find that .

A) the muscles contain large amounts of lactic acid following even mild physical exercise

B) the muscles contain large amounts of carbon dioxide following even mild physical exercise

C) the muscles require extremely high levels of oxygen to function

D) the muscle cells cannot split glucose to pyruvic acid

 

 

 

29. The disease gonorrhea has become increasingly resistant to treatment with antibiotics. What is the most likely scientific explanation?

A) The gonorrhea bacteria learned to avoid antibiotics.

B) The gonorrhea bacteria changed their genes when they sensed antibiotics.

C) Antibiotic-sensitive gonorrhea bacteria died out, but antibiotic-resistant gonorrhea bacteria have flourished and persisted.

D) The antibiotic increased the mutation rate in the gonorrhea bacteria.

E) both b and d.

 

 

 

30. Which statement best describes the relationship between plants and animals on earth?

A) Plants produce O2 and sugars from CO2

B) Animals produce CO2 and H2O from sugars and O2

C) Plants produce O2 and sugars and animals produce CO2 and H2O

D) Animals produce O2 and sugars and plants produce CO2 and H2O

 

31. Think of the cell as a factory, in which the organelles are specialized sites of production. All cells have a power plant, the mitochondrion. Plant cells have an additional “reactor” for the production of usable energy. It is called the

.

 

A) Golgi body

B) rough endoplasmic reticulum

C) central vacuole

D) vesicle

E) chloroplast

 

 

32. A researcher planted seeds from four types of quinoa (Types A, B, C, and D) in a greenhouse to determine which type of quinoa grew the tallest. The plants were grown for 10 days and measured. The results are shown below. Choose the data set that demonstrates that Type C quinoa grew the tallest. A) A = 30 cm, B = 21 cm, C= 15 cm, D= 12 cm.

B) A = 22 cm, B = 11 cm, C= 25 cm, D= 4 cm

C) A = 2 cm, B = 5 cm, C= 1 cm, D= 2 cm

D) A = 30 cm, B = 12 cm, C= 28 cm, D= 1 cm

E) A = 21 cm, B = 12 cm, C= 20 cm, D= 15 cm

 

33. replicated chromosome consists of two joined at the .

A) diploid genes; locus

B) homologous chromosomes; crossing over point

C) genomes: centrosome

D) sister chromatids; centromere

 

34. Homologous chromosomes .

A) carry genes controlling the same inherited characteristics

B) include only the autosomes

C) are a set of chromosomes that the cell received from one parent

D) carry the same versions of all genes

 

35. In meiosis, how does prophase I differ from prophase II?

A) During prophase I there is one diploid cell; during prophase II there are two haploid cells.

B) During prophase I chromosomes line up single file in the middle of the cell; during

prophase II the chromosomes line up in double file in the middle of the cell.

C) During prophase I the chromosomes coil up; the chromosomes are not coiled up during prophase II.

D) In prophase I the sister chromatids are attached; in prophase II the sister chromatids are separated.

 

36. Genetic variation is accomplished by all but one of the following. Which is it?

A) the events of meiosis I

B) crossing over

C) independent assortment

D) the events of meiosis II

 

37. purebred plant that produces red seeds is crossed with a purebred plant that produces yellow seeds. The seeds of all of the offspring are red. Why?

A) The red allele is recessive to the yellow allele.

B) All of the offspring are homozygous red.

C) The red allele is dominant to the yellow allele.

D) The alleles are codominant.

 

38. This diagram of the human life cycle shows that .

 

 

 

A) meiosis produces a diploid zygote

B) meiosis produces haploid sperm and egg cells

C) fertilization produces a haploid zygote

D) a diploid zygote undergoes meiosis to produce an adult human

 

 

 

 

 

 

 

 

 

 

 

 

 

 

39. Attached earlobes are recessive to free earlobes. What genotypic and phenotypic ratios are expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

A) genotypic ratio = 2:1…phenotypic ratio = 50% attached earlobes: 25% free earlobes

B) genotypic ratio = 2:2 …phenotypic ratio = 2 attached earlobes: 2 free earlobes

C) genotypic ratio = 1:2:1…phenotypic ratio = 1 attached earlobes: 2: semi-detached earlobes: 1 free earlobes

D) genotypic ratio = 3:1…phenotypic ratio = 1 attached earlobes: 3 free earlobes

 

40. couple has two female children. What is the probability that their next child will be male?

A) 25%

B) 50%

C) 33%

D) 67%

 

41. What is the key to recognizing polygenic inheritance?

A) A mating between a homozygous and a heterozygous individual produces more than the expected number of offspring expressing the dominant trait.

B) All of the alleles of the gene for that trait are equally expressed.

C) Pleiotropy occurs.

D) The trait varies along a continuum in the population.

 

 

Please read the following scenario to answer the following question.

 

 Widow’s peak, a pointed hairline on the forehead, is a genetic trait caused by a somatic dominant allele. It can be traced back through a family’s history using pedigree analysis. The pedigree shown here shows three generations of a family. Notice that some individuals (shown in gray) have a widow’s peak (W = dominant allele and w = recessive allele).

 

 

 

 

42. Janice’s genotype is .

A) Ww

B) WW

C) ww

D) WW or Ww

 

 

 

 

 

 

43. After replication, .

A) each new DNA double helix consists of two old strands

B) each new DNA double helix consists of one old strand and one new strand

C) each new DNA double helix consists of two new strands

D) one new DNA double helix consists of two old strands and the other new DNA double helix consists of two new strands

 

44. Translation converts the information stored in to .

A) DNA… RNA

B) RNA… a polypeptide

C) DNA… a polypeptide

D) RNA… DNA

 

45. What is the smallest number of nucleotides that must be added or subtracted to change the triplet grouping of the genetic message?

A) one

B) two

C) three

D) four

 

46. What is the ultimate source of all diversity?

A) natural selection

B) sexual recombination

C) meiosis

D) mutation

 

 

Please read the following scenario to answer the following two question(s).

 

While working with cultured mouse cells, a researcher unknowingly treated the cells with a mutagen that causes the deletion or insertion of individual nucleotides in DNA. Subsequently, she isolated and cultured a single cell from this group. She noticed that the progeny of this cell were not producing a certain protein and that this affected their survival.

 

47. The mutation that resulted from her accident was probably .

A) an amino acid substitution

B) one that changed the triplet grouping of the genetic message

C) an error in translation

D) a loss in regulation of gene expression

 

48. The mutation would be most harmful to the cells if it resulted in .

A) a single nucleotide insertion near the start of the coding sequence

B) a single nucleotide deletion near the end of the coding sequence

C) a single nucleotide in the middle of an intron

D) deletion of a triplet near the middle of the gene

 

 

 

 

 

 

49. How are cells in different body tissues able to perform different functions?

A) The cells exhibit different patterns of gene expression.

B) Different chromosomes have been inactivated in different cells.

C) The cells contain different genes in their nuclei.

D) The mutations that have accumulated in the cells of the different tissues control functions.

 

50. Genetically modifying human cells may directly affect future generations.

A) intestinal

B) immune

C) gamete

D) somatic

E) B and D only

 

51. Ethical dilemmas raised by DNA technology and knowledge of the human genome include .

A) the potential for interfering in evolution

B) the safety of GM foods

C) the potential discrimination against people predisposed to certain diseases

D) all of the above

 

52. Which of the following are homologous?

A) the forelimb of a dog and the hindlimb of a cat

B) the forelimb of a dog and the forelimb of a cat

C) wings of a butterfly and wings of a sparrow

D) the mouth of a mosquito and the beak of a hummingbird

 

53. The similarity of the embryos of fish, frogs, birds, and humans is evidence of

.

A) analogy

B) common ancestry

C) genetic drift

D) convergent evolution

 

54. Which one of the following statements is true?

A) Natural selection works on variation already present in a population.

B) Natural selection works on non-heritable traits.

C) Individuals evolve through natural selection.

D) Organisms evolve structures that they need.

 

55. What does evolutionary fitness measure?

A) physical health of individuals

B) longevity

C) relative reproductive success within a population

D) population size and dispersion

 

56. Which of the following is most likely to decrease genetic variation?

A) directional selection

B) mutation

C) stabilizing selection

D) diversifying selection

 

57. In the soil, some convert nitrogen to a form that can be used by plants.

A) protists

B) animals

C) protozoans

D) prokaryotes

 

58. The evolved from small prokaryotes that established residence within other, larger prokaryotes.

A) vacuoles and lysosomes

B) Golgi apparatus and endoplasmic reticulum

C) centrioles and ribosomes

D) mitochondria and chloroplasts

 

59. What type of interspecific interaction is described by a small fish that eats parasites from mouths of larger fish?

A) mutualism

B) herbivory

C) parasitism

D) pollination

 

60. Antibiotic resistance is an example of what type of evolution?

A) Allopatric.

B) Microevolution.

C) Gene pool magnification

D) Macroevolution.

 

61. Biomedical researchers study species as disparate as worms, fruit flies, mice, zebrafish, or rhesus monkeys to understand our genes, and even our diseases. Why?

 

A) Because these species have many inherited features that are very similar to our own.

B) Because these species are all prokaryotes, and therefore their genes are 99.9% identical to one another

C) Because they make up an interconnected food web when bacteria are added

D) Because rhesus monkeys gave us the Rh+ factor when they bit our ancestors

 

62. Unique features of all vertebrates include the presence of a(n) .

A) scales

B) mammary glands

C) skull and backbone

D) amnion

 

63. Consider the following food chain: A barn owl eats a shrew. This shrew has eaten a grasshopper. The grasshopper has eaten the leaves of a clover plant and a maple tree. What organisms are on the first trophic level?

A) the barn owl

B) the shrew

C) the grasshopper

D) the barn owl, the shrew and the grasshopper

E) the clover plant and maple tree

 

64. Water moves from land to the atmosphere through .

A) precipitation only

B) transpiration only

C) transpiration and evaporation

D) evaporation and precipitation

 

65. According to this evolutionary tree, approximately how many years ago did humans and orangutans share a common ancestor?

 

A) 1 million years ago

B) 7 million years ago

C) 12 million years ago

D) 20 million years ago

 

66. Which of the following is not a result of global warming?

A) changes in the breeding seasons of some species.

B) decreasing sea levels.

C) melting permafrost.

D) shifts in the ranges of some species.

 

 

 

67. Which of the following are not examples of renewable resources?

A) Biofuels produced from plants or plant-derived by-products such as crop wastes.

B) Power supplied by human labor or livestock.

C) Fertilizers made from animal manure and composted plants.

D) Metal, cement, and glass, made using mined materials.

 

Please read the following scenario to answer the following two question(s).

 

Salmon eggs hatch in freshwater streams and, during the first year of their life, the young salmon migrate up to 1,000 km to the ocean. They spend varying amounts of time in the ocean (ranging up to five years), where they feed and grow, rapidly acquiring more than 95% of their biomass during this period. During the summer of their maturing year, they begin the long journey back to their home streams where they spawn. Although it is still uncertain how salmon navigate back to their spawning grounds, current hypotheses suggest that they have a highly developed sense of smell. At the spawning grounds, females use their tails to form a hollow cavity where they lay up to 8,000 eggs. The male fertilizes the eggs, and both adults typically die soon thereafter.

 

68. The physiological response that allows salmon to survive in fresh water, then in salt water, and then fresh water again is an example of .

A) a behavioral response

B) evolution

C) acclimation

D) an anatomical response

 

69. At different times in their lives, salmon can be found in all of the following

except .

A) a freshwater biome

B) a chaparral

C) the pelagic realm

D) an estuary

 

 

 

 

70. In an ideal, unlimited environment, what shape does a population’s growth curve most closely resemble?

A) S

B) J

C) ∧

D) ∪

 

 

 

71. According to the logistic growth model, what happens to a population when the size of the population reaches carrying capacity?

A) The growth rate remains unchanged.

B) The growth rate begins to decrease in size.

C) The population crashes.

D) The growth rate is zero.

 

72. Non-native species can have influence biological communities by .

A) preying upon native species

B) competing with native species for resources

C) reducing biodiversity

D) doing all of the above

 

73. species exerts a particularly strong influence on an ecosystem out of proportion to its size or abundance; its decline or extinction can cause a cascade of future extinctions within an ecosystem.

A) commensal

B) trophic

C) keystone

D) groundwater

 

 

 

74. An example of a mutualism, or +/+ relationship, is .

A) the relationship between corals and unicellular algae

B) cryptic coloration in frogs

C) herbivory

D) the relationship between Virginia’s warblers and orange-crowned warblers, which use some of the same resources

 

75. Populations of two coexisting species are both tertiary consumers in a community. What relationship may exist between these two organisms?

A) predation

B) mutualism

C) competition

D) commensalism

 

76. On average, only about of the available energy in one trophic level is incorporated and stored as calories in the bodies of the next level up.

A) 10%

B) one-third C) 50%

D) 75%

 

77. The primary goal of conservation biology is to by .

A) catalog species; protecting federally listed endangered species

B) maximize the land set aside for wildlife; countering pollution

C) integrate human culture back into nature; maintaining genetic diversity within species

D) counter the loss of biodiversity; sustaining entire ecosystems and habitats

 

Use the following information to answer the following three questions.

 

Malaria is an infectious disease caused by a unicellular eukaryotic organism belonging to the genus Plasmodium. These eukaryotic organisms are transmitted from one person to another by the female Anopheles mosquito when it feeds on human blood. Within humans, the Plasmodium spp. destroy red blood cells and, without effective treatment, serious infections can lead to death. Currently, more than 400 million people are afflicted with malaria and between 1 to 3 million people die from it each year. Historically, a chemical compound called quinine has been used in developing effective drugs against malaria. In its natural environment, quinine is produced by certain trees native to South America. This chemical is synthesized in the outer layer of tree trunks and acts as an herbivore deterrent.

 

78. Based on the relationship between Plasmodium spp. and humans, these organisms would be considered .

A) parasites

B) hosts

C) producers

D) carnivores

 

 

 

79. Humans, mosquitoes, and Plasmodium together would be considered a(n)

.

A) population

B) community

C) ecosystem

D) population and community

 

 

 

80. Despite being used for many years, quinine-based drugs have not led to the eradication of malaria and currently there are mosquitoes that are resistant to the compound. Which of the following were likely important in the development of this resistance to quinine?

A) natural selection

B) mutualism

C) interspecific competition

D) biological magnification

 

****************************************************************************************************

 

 

TERM or CONCEPT Answer Definition/Association
1. genetic drift   A. DNA molecule with attached proteins
2. chromosome   B. a haploid cell that combines with another haploid cell during fertilization
3. crossing over   C. a specific portion of a chromosome that contains information for a particular inherited trait
4. gamete   D. New species form in geographically isolated populations
5. gene   E. an interaction during meiosis in which chromatids exchange segments; results in genetic recombination
6. germ cell   F. a change in the gene pool of a population due to chance
7. sympatric speciation   G. the process in which ribosomes synthesize proteins using the mRNA transcript
8. mitosis   H. the synthesis of mRNA from a DNA template
9. translation   I. the type of cell division which is used in asexual reproduction and tissue growth and repair
10. transcription   J. the type of cell division responsible for gamete formation and sexual reproduction
11. allopatric speciation   L. a type of cell whose primary function is the formation of gametes for sexual reproduction
12. meiosis   M. New species form within populations in the same geographic area

 

 

MATCHING SECTION #1 (6 points)

MATCHING SECTION INSTRUCTIONS: Read all instructions carefully. Please answer all questions. Each question is worth 0.5 points. Type in the letter you select from the right column as the best answer on the Answer Sheet provided by your instructor.

 

 

 

TERM or CONCEPT Answer Definition/Association
1. microtubules   A. contain enzymes for intracellular digestion
2. chloroplasts   B. are primary cellular structures (or components) where proteins are assembled
3. Golgi bodies   C. package cellular secretions for export
4. DNA molecules   D. extract energy stored in carbohydrates; synthesize ATP; produce water and carbon dioxide
5. RNA molecules   E. synthesize subunits that will be assembled into two part ribosomes in the cytoplasm
6. central vacuoles   F. translate hereditary instructions into specific proteins
7. lysosomes   G. increase cell surface area; store substances
8. mitochondria   H. encode hereditary information
9. nucleoli   I. help distribute chromosomes to the new cells during cell division
10. ribosomes   J. convert light energy to chemical energy stored in the chemical bonds of glucose or starch

 

 

 

FILL IN THE BLANK SECTION (12 points)

 

INSTRUCTIONS: Provide the best answer for the items below. Each item is worth three (3) points. Please answer all questions in this section. Type in your best answer on the Answer Sheet provided by your instructor.

 

1. You take a sample from a mysterious “blob” that has washed up on the shore of a nearby lake, and view the cells and their contents under a very high-resolution microscope. You can see that the cells are polygonal and you can identify the cell membrane, mitochondria, chloroplasts, the nucleus, and some Golgi bodies. You conclude that it must be a cell.

 

2. A resists changes in pH by accepting hydrogen ions from or donating hydrogen ions to solutions.

 

MATCHING SECTION #2 (5 points)

MATCHING SECTION INSTRUCTIONS: Read all instructions carefully. Please answer all questions. Each question is worth 0.5 points. Type in the letter you select from the right column as the best answer on the Answer Sheet provided by your instructor.

 

 

 

3. A dog gets many nutrients from its food including amino acids. What macromolecule can be built directly from amino acids?

 

4. selection can lead to a balance of two or more contrasting phenotypes in a population.

 

SHORT ANSWER SECTION

INSTRUCTIONS: Each question is worth two (2) points. Total points for this section is 12 points. Complete 6 questions in this Short Answer Section.

 

**Do not enter your answers here.** Type your answers into the Answer Sheet provided by your instructor.

 

1. Lithops, also called Stoneplants, are a type of plant that resembles little stones. These plants have the ability to blend in with their surrounding, which affords them protection from predators. If you were in an area containing Lithops, describe four characteristics you could identify to distinguish these plants from the stones they mimic.

 

2. A population of grasshoppers in the Kansas prairie has two color phenotypes, green and brown. Typically, the prairie receives adequate water to maintain healthy, green grass. Assume a bird that eats grasshoppers moves into the prairie. How will this affect natural selection of the grasshoppers? How might this change in a drought year?

 

3. DNA and RNA are similar yet distinct components of the cell. Describe three differences between RNA and DNA with respect to their chemical composition and structure. Describe in detail each characteristic you chose in your response.

 

4. When does a logistic population growth curve show the highest rate of growth? Why?

 

5. Soil pH determine what types of plants will grow the best. If soil is too acidic, lime can be added, and if it is too basic, peat moss can be added. You test your soil and find that its pH is 3.5, and you want to grow cucumbers, which prefer to grow in soils in the 7.5-

8.5 range. Would you add lime or peat moss to adjust your soil’s pH? Why?

 

6. The total solute concentration in a red blood cell is about 1-2%. Sucrose cannot pass through a red blood cell’s plasma membrane, but water and urea can. Osmosis will cause a red blood cell to expand the most when placed in which of the following solutions? Explain your answer.

A. a hypertonic sucrose solution

B. a hypotonic sucrose solution

C. a hypertonic urea solution

D. a hypotonic urea solution

 

 

 

 

ESSAY SECTION

ESSAY. Eight Essays @ 10 points each. Total points for this section is 80 points. INSTRUCTIONS: Choose and answer eight (8) essay questions from the list below. The full number of points will be awarded for accurate and complete answers. Partial credit will be given for less than thorough answers, so answer eight essay questions from the list. If you answer more than eight, I will grade the first eight that you answer. Remember to address all parts of a question.

 

**Do not enter your answers here.** Type your answers into the Answer Sheet provided by your instructor. Indicate the number of the question you selected on the answer sheet.

 

1. Before bringing a new drug to the marketplace, extensive testing is done on the drug by administering the drug to large numbers of individuals. Explain the importance of the scientific method, sample size, controls and variable in the drug evaluation process.

 

 

2. List the four “large molecules of life.” Identify their composition (building blocks) and structure, and describe one function they each perform in the cell.

 

 

3. How can you explain the occurrence of birth defects (caused by altered genes) in children and grandchildren of WWII atomic bomb victims, when the victims themselves were only mildly affected?

 

 

4. During the past 50 years, more than 200 species of insects that attack crop plants have become highly resistant to DDT and other pesticides. Based on what you have learned in this class regarding evolution, explain the rapid and widespread evolution of resistance. Now that DDT has been banned in the US, what do you expect to happen to levels of resistance to DDT among insect populations in the US? Why?

 

 

5. Water is crucial for life as we know it. One of the most important characteristics of water is its ability to act as a solvent. Explain why water is such a good solvent for polar and charged molecules.

 

 

6. Tobacco is the leading cause of preventable cancers today. In fact, there are very few known cancers for which smoking is not considered a risk factor. The relationship between cigarette smoking and disease has been studied for years. How can this problem be studied at many different levels of biological organization? Give some examples.

 

 

 

7. Predict what will happen in the following experiment based on what you know about photosynthesis and cellular respiration.

a. You place a plant alone in a covered airtight container in the presence of sunlight.

Assume a watering system is provided. What will happen to the plant (will it live or die), and why?

b. You place a butterfly alone in a covered airtight container with nectar and a source of water. What will happen to the butterfly, and why?

c. You place a plant and a butterfly together in a covered airtight container with food, water, and sunlight. What will happen to the plant and the butterfly, and why?

 

8. a. You are comparing two cells. One cell is very small, and the other cell is huge.

Under which conditions would you expect the larger cell to be more successful, or the small cell to be more successful? Give a specific explanation for your answer.

b. Explain why animal cells would be unable to exist without the presence of plant cells. Is this relationship reciprocal?

 

9. Two examples of chemotherapeutic drugs (used to treat cancer) and their cellular actions are given below. Explain why each drug could be fatal to a cancer cell.

a. Vincristine: damages the mitotic spindle

b. Adriamycin: binds to DNA and blocks messenger RNA synthesis

c. Compare and contrast tumor suppressor genes and proto-oncogenes. Which of these must mutate to produce cancer?

 

10. a. Cystic fibrosis is a recessive genetic disease. Two parents do not have cystic fibrosis; however, their child does. Fully explain how this could have happened using a Punnett square.

b. Hypophosphatemia (vitamin D-resistant rickets) is inherited as an sex-linked dominant trait. The relevant gene is found on the X chromosome. What is the expected genotypic ratio and phenotypic ratio of a cross between a homozygous recessive woman and a man with hypophosphatemia? Explain your answer using a Punnett square.

 

10. With the ability to clone animals, such as endangered species, their population numbers can be increased in a short time. How would cloning a population of animals from a one or a few individuals impact these populations from the perspective of the gene pool and genetic variability?

 

11. a. Explain why it takes about the same amount of photosynthetic productivity to produce 10 kilograms of corn as 1 kilogram of bacon.

 

b. Why do food chains and food webs typically have only three to five levels?

 

 

 

 

 

 

BONUS QUESTIONS (6 points)

Instructions: Type in the letter that represents your best answer to the questions below. Each question is worth 2 points. Total points for this section is 6 points; no penalty for incorrect answers.

 

1. Which of the following demonstrates the correct use of a parenthetical in-text citation formatted in APA style?

 

A) According to Simon, Dickey and Reece, roughly half the corn crop in the U.S. is genetically modified. (2013).

B) Glycolysis produces O2 even in the absence of oxygen. Simon, Dickey and Reece, (Essential Biology)

C) According to Simon, Dickey and Reece (2013), vacuoles bud from the ER, Golgi apparatus, or plasma membrane.

D) Gel electrophoresis has many uses besides STR analysis. (Simon, Dickey & Reece, 2013)

E) An endospore is a thick-coated protective cell produced within a prokaryotic cell under harsh conditions (Essential Biology, Simon, Dickey & Reece).

F. None of the above.

 

 

2. Which of the following journal articles is documented correctly in APA style?

 

A) Madison, Portia Lee. “How exams affect heart rate.” Journal of Cardiac Stress. 26.2 (2005): 168-180.

B) Madison, P. L. (2005). How exams affect heart rate. Journal of Cardiac Stress, 26(2), 168-180.

C) Portia Lee Madison, 2005, How exams affect heart rate, Journal of Cardiac Stress, Volume 26, (2), 168-180.

D) Journal of Cardiac Stress. (2005). How exams affect heart rate. P. L. Madison. P.

 

168.

 

E) Madison, Portia L. (2005). “How exams affect heart rate.” Journal of Cardiac Stress.

 

26.2 (2005): 168-180.

 

F. None of the above.

 

 

 

3. For APA format, the reference sources at the end of your paper should be

 

A) numbered in the order in which they are cited in the text of the paper.

 

B) listed under separate subheadings according to the type of source (book, film journal article, website, etc.).

 

C) listed first by sources with authors, then by those without authors, then by those without publication years.

 

D) in alphabetical order by authors’ surname or by organization (if there is no author), regardless of the type of reference (book, film journal article, website, etc.).

 

E) in order of publication year (oldest references first, then the most recent last).

 

You have completed the exam.

 

Congratulations on completing BIO 103

[Type text]

 
"Looking for a Similar Assignment? Get Expert Help at an Amazing Discount!"

Perfect Solution: UMUC Biology 102 103 Lab 5: Meiosis

/in /by

Your Full Name:

 

UMUC Biology 102/103

Lab 5: Meiosis

INSTRUCTIONS:

 

·         On your own and without assistance, complete this Lab 5Answer Sheet electronically and submit it via the Assignments Folder by the date listed intheCourse Schedule (underSyllabus).

·         To conduct your laboratory exercises, use the Laboratory Manual located under Course Content. Read the introduction and the directions for each exercise/experiment carefully before completing the exercises/experiments and answering the questions.

·         Save your Lab 5Answer Sheet in the following format:  LastName_Lab5 (e.g., Smith_Lab5).

·         You should submit your document as a Word (.doc or .docx) or Rich Text Format (.rtf) file for best compatibility.

 

Pre-Lab Questions

 

  1. Compare and contrast mitosis and meiosis.

 

 

  1.  What major event occurs during interphase?

 

 

Experiment 1: Following Chromosomal DNA Movement through Meiosis

In this experiment, you will model the movement of the chromosomes through meiosis I and II to create gametes.

concept_tab_l

Materials

2 Sets of Different Colored Pop-it® Beads (32 of each – these may be any color)

8 5-Holed Pop-it® Beads (used as centromeres)

    
   

 

Procedure:

Part 1: Modeling Meiosis without Crossing Over

As prophase I begins, the replicated chromosomes coil and condense…

  1. Build a pair of replicated, homologous chromosomes. 10 beads should be used to create each individual sister chromatid (20 beads per chromosome pair). Two five-holed beads represent each centromere. To do this…
Figure 3: Bead set-up. The blue beads represent one pair of sister chromatids and the black beads represent a second pair of sister chromatids. The black and blue pair are homologous.
Figure 3: Bead set-up. The blue beads represent one pair of sister chromatids and the black beads represent a second pair of sister chromatids. The black and blue pair are homologous.
    1. Start with 20 beads of the same color to create your first sister chromatid pair. Five beads must be snapped together for each of the four different strands. Two strands create the first chromatid, and two strands create the second chromatid with a 5-holed bead at the center of each chromatid.  This creates an “I” shape.
    2. Connect the “I” shaped sister chromatids by the 5-holed beads to create  an “X” shape.
    3. Repeat this process using 20 new beads (of a different color) to create the second sister chromatid pair.
  2. Assemble a second pair of replicated sister chromatids; this time using 12 beads, instead of 20, per pair (six beads per each complete sister chromatid strand).
  3. Pair up the homologous chromosome pairs created in Step 1 and 2. DO NOT SIMULATE CROSSING OVER IN THIS TRIAL. You will simulate crossing over in Part 2.
  4. Configure the chromosomes as they would appear in each of the stages of meiotic division (prophase I and II, metaphase I and II, anaphase I and II, telophase I and II, and cytokinesis).
  5. Diagram the corresponding images for each stage in the sections titled “Trial 1 – Meiotic Division Beads Diagram”. Be sure to indicate the number of chromosomes present in each phase.
Figure 4: Second set of replicated chromosomes.
Figure 4: Second set of replicated chromosomes.
  1. Disassemble the beads used in Part 1. You will need to recycle these beads for a second meiosis trial in Steps 8 – 13.

Part 1 – Meiotic Division Beads Diagram

Prophase I

 

Metaphase I

 

Anaphase I

 

Telophase I

 

Prophase II

 

Metaphase II

Anaphase II

 

Telophase II

 

Cytokinesis

Part 2: Modeling Meiosis with Crossing Over

  1. Build a pair of replicated, homologous chromosomes. 10 beads should be used to create each individual sister chromatid (20 beads per chromosome pair). Two five-holed beads represent each centromere. To do this…
    1. a. Start with 20 beads of the same color to create your first sister chromatid pair. Five beads must be snapped together for each of the four different strands. Two strands create the first chromatid, and two strands create the second chromatid with a 5-holed bead at the center of each chromatid.  This creates an “I” shape.
    2. Connect the “I” shaped sister chromatids by the 5-holed beads to create  an “X” shape.
    3. Repeat this process using 20 new beads (of a different color) to create the second sister chromatid pair.
  2. Assemble a second pair of replicated sister chromatids; this time using 12 beads, instead of 20, per pair (six beads per each complete sister chromatid strand). Snap each of the four pieces into a new five-holed bead to complete the set up.
  3. Pair up the homologous chromosomes created in Step 8 and 9.
  4. SIMULATE CROSSING OVER. To do this, bring the two homologous pairs of sister chromatids together (creating the chiasma) and exchange an equal number of beads between the two. This will result in chromatids of the same original length, there will now be new combinations of chromatid colors.
  5. Configure the chromosomes as they would appear in each of the stages of meiotic division (prophase I and II, metaphase I and II, anaphase I and II, telophase I and II, and cytokinesis).
  6. Diagram the corresponding images for each stage in the section titled “Trial 2 – Meiotic Division Beads Diagram”. Be sure to indicate the number of chromosomes present in each cell for each phase. Also, indicate how the crossing over affected the genetic content in the gametes from Part1 versus Part 2.

Part 2 –  Meiotic Division Beads Diagram:

Prophase I

 

Metaphase I

 

Anaphase I

 

Telophase I

 

Prophase II

 

Metaphase II

 

Anaphase II

 

Telophase II

 

Cytokinesis

 

 

Post-Lab Questions

1.      What is the ploidy of the DNA at the end of meiosis I? What about at the end of meiosis II?

 

2.      How are meiosis I and meiosis II different?

 

3.      Why do you use non-sister chromatids to demonstrate crossing over?

 

4.      What combinations of alleles could result from a crossover between BD and bd chromosomes?

 

 

 

5.      How many chromosomes were present when meiosis I started?

 

6.      How many nuclei are present at the end of meiosis II? How many chromosomes are in each?

 

7.      Identify two ways that meiosis contributes to genetic recombination.

 

8.      Why is it necessary to reduce the number of chromosomes in gametes, but not in other cells?

 

9.      Blue whales have 44 chromosomes in every cell. Determine how many chromosomes you would expect to find in the following:

 

Sperm Cell:

Egg Cell:

Daughter Cell from Mitosis:

Daughter Cell from Meiosis II:

 

10.  Research and find a disease that is caused by chromosomal mutations. When does the mutation occur? What chromosomes are affected? What are the consequences?

 

11.  Diagram what would happen if sexual reproduction took place for four generations using diploid (2n) cells.

 

 

Experiment 2: The Importance of Cell Cycle Control

Some environmental factors can cause genetic mutations which result in a lack of proper cell cycle control (mitosis). When this happens, the possibility for uncontrolled cell growth occurs. In some instances, uncontrolled growth can lead to tumors, which are often associated with cancer, or other biological diseases.

In this experiment, you will review some of the karyotypic differences which can be observed when comparing normal, controlled cell growth and abnormal, uncontrolled cell growth. A karyotype is an image of the complete set of diploid chromosomes in a single cell.

 

 

 

 

concept_tab_lProcedure

Materials

*Computer Access

*Internet Access

  

*You Must Provide

 

 

 

  1. Begin by constructing a hypothesis to explain what differences you might observe when comparing the karyotypes of human cells which experience normal cell cycle control versus cancerous cells (which experience abnormal, or a lack of, cell cycle control). Record your hypothesis in Post-Lab Question 1.

    Note: Be sure to include what you expect to observe, and why you think you will observe these features. Think about what you know about cancerous cell growth to help construct this information

  2. Go online to find some images of abnormal karyotypes, and normal karyotypes. The best results will come from search terms such as “abnormal karyotype”, “HeLa cells”, “normal karyotype”, “abnormal chromosomes”, etc. Be sure to use dependable resources which have been peer-reviewed
  3. Identify at least five abnormalities in the abnormal images. Then, list and draw each image in the Data section at the end of this experiment. Do these abnormalities agree with your original hypothesis?

Hint: It may be helpful to count the number of chromosomes, count the number of pairs, compare the sizes of homologous chromosomes, look for any missing or additional genetic markers/flags, etc.

Data

 

 

 

 

 

Post-Lab Questions

1.      Record your hypothesis from Step 1 in the Procedure section here.

 

 

2.      What do your results indicate about cell cycle control?

 

 

3.      Suppose a person developed a mutation in a somatic cell which diminishes the performance of the body’s natural cell cycle control proteins. This mutation resulted in cancer, but was effectively treated with a cocktail of cancer-fighting techniques. Is it possible for this person’s future children to inherit this cancer-causing mutation? Be specific when you explain why or why not.

 

 

4.      Why do cells which lack cell cycle control exhibit karyotypes which look physically different than cells with normal cell cycle.

 

 

5.      What are HeLa cells? Why are HeLa cells appropriate for this experiment?

 

 
"Looking for a Similar Assignment? Get Expert Help at an Amazing Discount!"