300 Words Essay- Scientific Method (D1)

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Thinking as a Scientist
After considering the scientific method explained in the textbook, write an essay about how it compares to the way nonscientists approach problems. Identify some problems that are solvable scientifically and some that are not. Using one or two small problems, describe the process you would go through in solving that problem using the scientific method. Discuss the significance of the scientific approach to the development and advancement of human knowledge. Your essay should be about 300 words.

The Scientific Method
Biology consists of a great deal of knowledge. Much of that knowledge takes the form of facts that we refer to as theories. Or perhaps this is better understood by saying that biologists treat theories as though they were facts. But, they are special kind of fact. They are not a fact the way your social security number is a fact. A theory is a fact that has been derived using the scientific method.

The scientific method always starts with an observation. And notice carefully that we use the singular word, observation, and not the plural ‘observations’, even if a thousand events were observed. The observation leads to a question. Questions come in many shapes and forms, but the scientific method needs to pose only very specific questions. This is because the question must be able to be worded as a hypothesis. What is a hypothesis? A hypothesis is a specific statement in which a cause and effect scenario is central. For an example, follow along with the scenarios presented in the assigned textbook readings. You will see that a hypothesis can never be an open ended question. It must be specific. For example, this is a hypothesis: If I put a cover over a flame, it will go out. This is not a hypothesis: Why does the flame go out when I put a cover over it? After you have created a hypothesis, you design experiments to see if you can support your hypothesis. Keep in mind that in the biological sciences, while you can support a hypothesis, you can never prove one. This is one of the most misunderstood concepts in science. You will never account for every possible condition for a given hypothesis; therefore, you can never prove it beyond any shadow of doubt.

 
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Microbiology Lab Questions

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Question 1

You are reading culture plates today and identifying pathogens that grow from patient samples.

Which two pieces of information are absolutely critical in determining which additional tests must be done to identify the pathogen?

a) Appearance on charcoal agar

b) Endospore Stain

c) Gram Stain

d) Oxygen sensitivity

Question 2

A 10 year old has a wound on the arm that the physician suspects is infected.

Upon culture, you see small white colonies growing on blood agar as well as chocolate agar.

You gram stain the colonies to find that they are gram positive cocci.

Which test will you perform first?

a) catalase

b) indole

c) lactose fermentation

d) coagulase

Question 3

You have isolated catalase positive gram positive cocci from a wound culture.

Which test will you perform next?

a) coagulase

b) P disc, containing optichin

c) A disc, containing bacitracin

Question 4

You are working on a sputum culture.

You see mucoid alpha hemolytic colonies that number many more than the normal flora present.

The gram stain of the colonies shows gram positive cocci that are in lancet shaped pairs.

Which test will you do?

a) P disc, containing optichin

b) A disc, containing bacitracin

c) motility

d) acid fast staining

Question 5

You are working up a throat culture.

Standard procedure in plating throat cultures in your lab includes dropping an A disc near the initial inoculum in the first quandrant when streaking the specimen.

You examine the blood agar plate and see moderate normal flora and many beta hemolytic colonies that do not grow up to the A disc.

The beta hemolytic colonies are catalase negative gram positive cocci.

Which pathogen is in this throat culture?

a)Streptococcus agalactiae

b) Staphylococcus aureus

c) Streptococcus pyogenes

d) Staphylococcus epidermidis

Question 6

You are working up a male genital culture.

You see no growth on the blood agar plate but small colonies growing on the chocolate agar plate. The gram stain shows gram negative cocci in pairs.

Which test will you do next?

a) oxidase

b) motility

c) catalase

d) indole

Question 7

You are working up a cerebrospinal fluid culture.

You find colonies growing on blood agar as well as chocolate agar.

The colonies are oxidase positive gram negative cocci.

The colonies ferment glucose and maltose but not sucrose or lactose.

You identify the pathogen as

a) Neisseria meningitidis

b) Haemophilus influenzae

c) Streptococcus pneumoniae

d) Neisseria gonorrhoeae

Question 8

You are working up a urine culture.

You see >100 colonies that are gray and flat on the blood agar plate and >100 colonies that are bright pink on the MacConkey agar.

The IMViC results are Indole positive, Methyl Red positive, Vogues-Proskauer negative, Citrate negative.

You have identified the pathogen as

a) Citrobacter freundii

b) Escherichia coli

c) Enterobacter aerogenes

d) Proteus vulgaris

Question 9

You are working up a stool culture.

On MacConkey agar you see many bright pink colonies and many clear colonies.

Which colonies are potential pathogens that require further testing?

a) Clear colonies, non lactose fermenters

b) Bright pink colonies, non lactose fermenters

c) Bright pink colonies, lactose fermenters

d) Clear colonies, lactose fermenters

Question 10

DNA technology is useful in the identification of :

a) pathogens that are unable to be grown readily on artificial lab media.

b) pathogens that are no longer alive in the patient sample,

c) species that cannot be differentiated by conventional testing.

d) All of the above.

Question 11

You are preparing a sample of DNA from an unknown colony of bacteria.

After adding digestion buffer and incubating for the time suggested by the manufacturer, you centrifuge the sample.

The DNA is found:

a) stuck to the gel in the tube.

b) stuck to the sides of the tube.

c) in the pellet in the bottom of the tube.

d) in the supernatant in the tube.

Question 12

Which of the following is not true of the Polymerase Chain Reaction?

a) PCR is facilitated by a heat labile DNA polymerase.

b) PCR is a method of replicating DNA in a test tube.

c) PCR can facilitate the detection of DNA that is too low to detect by other methods.

Question 13

Why are dATP, dCTP, dTTP and dGTP added to a PCR reaction tube?

a) They catalyze the polymerase.

b) They buffer the mixture.

c) They allow the DNA in the sample to anneal.

d) They provide the building blocks of DNA.

Question 14

Why are universal 16S rDNA primers used in your experiment?

a) They will anneal to highly conserved areas of the gene that encodes bacterial 16S rRNA.

b) They will anneal to unique sequences of genes encoding 16S rRNA in specific bacteria.

Question 15

If universal primers are used to amplify DNA in a PCR reaction, then the PCR product must be sequenced to determine the bacteria that the DNA belongs to.

True

False

Question 16

How is the PCR product separated from the PCR mixture at the completion of the reaction?

a) Perform electrophoresis in an agarose gel, stain the gel and cut the band corresponding to the PCR product from the gel.

b) Pour the PCR mixture into a commercially prepared DNA microconcentrator column and follow the manufacturer’s directions to adhere and elute the PCR product from the column.

c) Both of the above procedures may be used.

d) Neither of the above procedures may be used.

Question 17

Your PCR product was sequenced by a method known as Cycle Sequencing.

Which of the following statements is false?

a) An automatic sequencer performs electrophoresis and reads the tagged DNA pieces, providing a read out of the nucleotide bases comprising the DNA sequence of the fragment being tested

b) Cycle sequencing is done in a PCR machine.

c)Tagged terminator nucleotides facilitate the creation of a series of nested DNA sequences of different length.

d) Cycle sequencing can be completed in just one test tube.

Question 18

The National Library of Medicine has a databank called GenBank that has deposited in it the DNA sequences of numerous genes isolated from known bacterial species.

True

False

Question 19

You obtained the following BLAST data from your sample:

99.9% Enterobacter sakazakii

95.2% Enterobacter aerogenes

93.7% Enterobacter cloacae

The pathogen in your sample is:

a)Enterobacter sakazakii

b)Enterobacter aerogenes

c)Enterobacter cloacae

d)Enterobacter species

 
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SCIN 130 Lab 6: The Origin of Corn

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SCIN130 Lab 6: The Origin of Corn

SCIN 130 Lab 6: The Origin of Corn

 

General Instructions

 

Be sure to read the general instructions from the Lessons portion of the class prior to completing this packet.

 

Remember, you are to upload this packet with your quiz for the week!

 

Background

Ten thousand years ago, corn didn’t exist anywhere in the world, and until recently scientists argued vehemently about its origins. Today the crop is consumed voraciously by us, by our livestock, and as a major part of processed foods. So where did it come from? Popped Secret: The Mysterious Origin of Corn tells the story of the genetic changes involved in the transformation of a wild grass called teosinte into corn.

 

 

 

Specific Lab Instructions

 

Name:

Date:

 

Go to: The Mysterious Origin of Corn from HHMI Biointeractive

 

Watch the short film, and answer these questions as you progress.

 

1. What was the purpose of domestication in ancient civilizations?

 

2. What TWO features made Dr. Beadle believe that teosinte was an ancestor of modern maize?

1.

2.

3. Stop the film at the 6:55 and answer the following:

a. Answer the Let’s Review Questions. Embed a screenshot of your answer to question 1 in this packet:

Question 1:

 

b. Why did botanists expect the wild relative of maize to look similar to modern maize?

 

c. Why did Dr. Beadle use so many plants in his experiments? Would his data have been as meaningful if he had grown only 1,000 plants? Why or why not?

d. How many genes did Dr. Beadle deduce were involved in the changes between maize and teosinte?

4. Resume the film. Near what river did Dr. Doebley discover that all modern maize varieties originate?

5. What type of evidence left behind on the plant grinding tools was Dr. Piperno looking for to show the presence of maize?

6. Stop again at 12:10 and answer the following

a. How did archaeological evidence support the molecular evidence for the timing and geographic location of maize domestication?

b. Based on the quiz in the video, Dr. Doebley and his team compared the DNA sequence of maize to that of a number of teosinte varieties from throughout Mexico. What did their analysis reveal? Select all that apply.

|_|That teosinte and maize have the same number of chromosomes.

|_|That maize originated from a variety of teosinte that existed about 9,000 years ago.

|_|That maize and teosinte could interbreed to produce viable hybrid plants.

|_|That maize is most closely related to a teosinte variety in the Balsas region of Mexico.

 

7. Watch the film to the end.

a. Fill in the table below to compare teosinte and maize.

  Extent of branching Number of rows of kernels per cob Kernel type (naked or enclosed in a hard fruitcase)
Teosinte

Maize

b. Pick one of the characteristics of maize from the table above and explain how it makes the crop more useful to humans than teosinte?

 

c. What does the fact that teosinte can be “popped” help to explain?

 

 

 

 

8. Explain how changes in a small number of genes can result in very different looking plants.

 

 

 

Adapted from:

Rice, E. (2016). Keep, S., Bonetta, L., Beardsley, P. & York, A. (Eds). Click and Learn “The Mysterious Origin of Corn.” HHMI Biointeractive Teaching Materials.

Additional References:

Beadle, G.W. (1977). “The origin of Zea mays.” In Origins of Agriculture, edited by C. E. Reed, 615–535. The Hague: Mouton.

 

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UMUC Biology 102/103 Lab 7: Ecological Interactions

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This contains 100% correct material for UMUC Biology 103 LAB07: Ecological Interactions. However, this is an Answer Key, which means, you should put it in your own words. Here are the questions that will be answered. Attached is the lab that is fully completed. Enjoy!

 

 

 

Pre-Lab Questions

1.    Would you expect endangered species to be more frequently generalists or specialists? Explain your answer.

 

2.    How does temperature affect water availability in an ecosystem?

 

3.    Choose a species and describe some adaptations that species developed that allow them to survive in their native habitat.

 

Experiment 1: Effects of pH on Radish Seed Germination

Data Tables and Post-Lab Assessment

Table 1: pH and Radish Seed Germination

Stage/Day Observations      
Initial pH      
1 (0400hrs)      
2 (0400hrs)      
3 (0400hrs)      
4 (0400hrs)      
5 (0400hrs)      
6 (0400hrs)      
7 (0400hrs)      

 

 

 

 

Post-Lab Questions

1.    Compare and construct a line graph based on the data from Table 1 in the space below. Place the day on the x axis, and the number of seeds germinated on the y axis. Be sure to include a title, label the x and y axes, and provide a legend describing which line corresponds to each plate (e.g., blue = acetic acid, green = sodium bicarbonate, etc…).

 

 

2.    Was there any noticeable effect on the germination rate of the radish seeds as a result of the pH? Compare and contrast the growth rate for the control with the alkaline and acidic solutions.

 

3.    According to your results would you say that the radish has a broad pH tolerance? Why or why not? Use your data to support your answer.

 

 

4.    Knowing that acid rain has a pH of 2 – 3 would you conclude that crop species with a narrow soil pH range are in trouble? Explain why, or why not, using scientific reasoning. Is acid rain a problem for plant species and crops?

 

 

 

 

 

 

 

5.    Research and briefly describe a real world example about how acid rain affect plants. Be sure to demonstrate how pH contributes to the outcome, and proposed solutions (if any). Descriptions should be approximately 2 – 3 paragraphs. Include at least three citations (use APA formatting).

 
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