Gene Mapping by Homologous Recombinatio

/in /by

Gene Mapping by Homologous Recombination (30 points) .*In  the  3rd  Edition  of  Snyder  and  Champness:  Pages,167-184  (Gene  mapping using  Hfr crosses, transduction), 243-263 (Conjugation background), 332-339 (Transduction/Phage background), 429-435  (Homologous  recombination  background). If  you  have  a  different edition, look in the table of contents of your book for titles similar to the ones listed.this for background info…you have to write full lab report of( exp2 ) including into,disscution,calculation,methods,conc,graph,references…etc,I will keep you updated with my new info which will be this Thursday,,You have to use my class data which will be on the excel sheet to do the calculation and explanation,last order was weak on the (last questions answering part)which is the last part of the report I got 21 points off because it was not complete and it need more explanation ,so try to avoid that weakness please

 

Experiment II: Gene Mapping by Homologous Recombination

September 13, 2016

 

 

Introduction •  Rifampin resistant mutants form spontaneously

when a culture of Escherichia coli HR171is growing.

 

 

Mapping

•  To map the mutation we are going to measure the frequency of recombination between your rifR sample and the wild type rifS .

•  We will be using two methods of measuring recombination: – Conjugation – Transduction

 

 

Conjugation

•  Transfer genetic information using a conjugative plasmid

•  If an Hfr strain is used, the plasmid will integrate into the chromosome and the entire chromosome will be transferred

•  The further a gene is on the chromosome from the origin of transfer (oriT) the less likely it will be transferred

 

 

Transduction

•  Transfer genetic information using a bacteriophage

•  DNA from one bacterium is packaged into a phage head which is inserted into another bacterium upon infection

•  The closer two genes are to each other on a chromosome, the more likely they are to be packaged and transferred together

 

 

Today •  Preparing for Conjugation and Transduction

•  Transduction: –  Add 5 µl of 0.1 M CaCl2 in a 1.5 ml Eppendorf

tube –  100 µl of culture of E. coli KL227 –  Add 50 µl of P1 (we will add for you) –  Incubate at 30°C for 10 min –  Plate 50 µl on LB plate with chloramphenicol –  Incubate plate at 30°C, overnight

 

 

Today •  Conjugation: •  Need to have single colonies!

– Innoculate 2 tubes •  Inoculate 2ml of LB + rif (the tube with the red top) with one colony from your rif plate (recipient).

i.e. Your rpoB mutant from last week

•  Inoculate 2ml of LB with one colony from of Hfr KL16 (donor)

•  Incubate in 37°C shaker at 200 rpm

 

 

Please  Cleanup

•  Place glass culture tubes in tray in the back of lab •  Empty biohazard cylinder into orange bin at end of

bench •  Wipe down bench with disinfectant •  Wash your hands

•  Thank you!

 

 

Suggested Reading: •  In the 3rd Edition of Snyder and Champness: •  167-184 (Gene mapping using Hfr crosses,

transduction) •  243-263 (Conjugation background) •  332-339 (Transduction/Phage background) •  429-435 (Homologous recombination

background) •  If you have a different edition, look in the

table of contents of your book for titles similar to the ones listed

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

Cell Cycle

/in /by

DATE___________________

Chapter 12- Cell Cycle

1. Phases of the cell cycle– An organism’s body cells have 4 chromosomes.

A. Identify the major characteristics of each phase.

B. OPTIONAL –Draw a picture to illustrate these characteristics.

Cell Cycle Phase A. Characteristics of phase B. OPTIONAL-Illustration of phase
Interphase G1-

S-

G2-

  
Prophase  

  
Metaphase  

  
Anaphase  

  
Telophase  

  
Cytokinesis  

  

-A researcher treats cells with a chemical that prevents DNA synthesis. This treatment traps the cells in which part of the cell cycle?

#2 OPTIONAL PRACTICE

2. Phases of the cell cycle– An organism’s body cells have 2 chromosomes

A. Identify the major characteristics of each phase.

B. Draw a picture to illustrate these characteristics.

Cell Cycle Phase A. Characteristics of phase B. Illustration of phase
Interphase G1-

S-

G2-

  
Prophase  

  
Metaphase  

  
Anaphase  

  
Telophase  

  
Cytokinesis  

  

3. During anaphase, do kinetochore microtubules:

Hypothesis #1: shorten at their spindle pole ends?

Hypothesis #2: shorten at their kinetochore ends?

EXPERIMENTAL RESULT:

image1.png

-CONCLUSION:

-What observation would have to have been made to support the OTHER hypothesis?

4A. Cyclin combines with Cyclin Dependent Kinase (CdK) to form Maturation Promoting Factor (MPF). The Cyclin concentration and MPF activity during the cell cycle are shown in the figure below. Describe where a line on the graph would be drawn to represent the CdK concentration through the cell cycle.

image2.png

B. Using your understanding of the molecules that control the G2 checkpoint and the graph above, make at least one statement about when these molecules are present & absent during the cell cycle and how this results in cell cycle control.

5. Tumors

  Benign Malignant Metastatic
Describe basic structure of this tumor.      
Cancerous cells?      
Localized to single tissue/organ?      
Prognosis (good/fair/poor)      
Typical treatment?      

Chapter 13-Meiosis and Sexual Life Cycles

1. Important Terminology: Match the terms listed below with the appropriate letter in the figure below.

Sister chromatids

Nonsister chromatids

Homologous pair

Centromere

 

image3.emfCopyright Š 2005 Pearson Education, Inc. publishing as Benjamin Cummings

ABCD

 

2. Describe the differences between the somatic cell s and gametes in your body.

  Somatic cell Gamete
Number of chromosomes    
Ploidy (haploid or diploid)    
Example    

3. Phases of Meiosis– An organism’s body cells have 4 chromosomes (2 pairs)

A. Identify the major characteristics of each phase that differs from Mitosis.

B. OPTIONAL –Draw a picture to illustrate these characteristics.

Meiosis Phase A. Characteristics of phase that differs from Mitosis B. OPTIONAL-Illustration of phase
Interphase  

  
Prophase I  

  
Metaphase I  

  
Anaphase I  

  
Telophase I & cytokinesis  

  
Prophase II  

  
Metaphase II  

  
Anaphase II  

  
Telophase II & cytokinesis  

  

#4 OPTIONAL PRACTICE

4. Phases of Meiosis– An organism’s body cells have 2 chromosomes (1 pair)

A. Identify the major characteristics of each phase that differs from Mitosis.

B. Draw a picture to illustrate these characteristics.

Meiosis Phase A. Characteristics of phase that differs from Mitosis B. Illustration of phase
Interphase  

  
Prophase I  

  
Metaphase I  

  
Anaphase I  

  
Telophase I & cytokinesis  

  
Prophase II  

  
Metaphase II  

  
Anaphase II  

  
Telophase II & cytokinesis  

  

5. Fruit flies have a diploid number of 8, and honeybees have a diploid number of 32. Assuming no crossing over, is the genetic variation among offspring from the same two parents likely to be greater in fruit flies or honeybees? Explain.

Chapter 14-Mendel and the Gene Idea

1. Genetics Terminology

Match each commonly used genetics term with its appropriate definition or example.

TERMS: DEFINITIONS AND EXAMPLES:

​__ heterozygous a. Blue-eyed blonde mates with brown-eyed brunette

__ homozygous b. BB or bb

__ monohybrid cross c. not on sex chromosomes

__ autosomal d. blue or brown eyes

__ genotype e. Bb

___ phenotype f. locus on a chromosome that codes for a given polypeptide

__ gene g. Blonde mates with brunette.

__ allele h. BB, Bb, or bb

__ dihybrid cross i. Males have only one for each gene on the X chromosome

2. Make a punnett square using the following information.

Traits: Oval eyes = A, Round eyes = a

Parents: Mom Aa, Dad aa

-What eye shape does Mom have?

-What eye shape does Dad have?

-What fraction of the offspring will have oval eyes?

-What fraction of the offspring will have round eyes?

-What fraction of the offspring will have the Homozygous Dominant genotype AA?

-What fraction of the offspring will have the Heterozygous genotype Aa?

-What fraction of the offspring will have the Homozygous Recessive genotype aa?

3. Make a punnett square using the following information.

Traits: Brown eyes = B, Blue eyes = b

Parents: Mom Bb, Dad Bb

-What eye color does Mom have?

-What eye color does Dad have?

-What fraction of the offspring will have brown eyes?

-What fraction of the offspring will have blue eyes?

-What fraction of the offspring will have the Homozygous Dominant genotype BB?

-What fraction of the offspring will have the Heterozygous genotype Bb?

-What fraction of the offspring will have the Homozygous Recessive genotype bb?

4. Multi-hybrid cross #1:

3 characters = trihybrid cross

Parent 1: Purple flowers (Pp), Yellow (Yy), Round (Rr)

Parent 2: Purple flowers (Pp), green (yy), wrinkled (rr)

Parents: PpYyRr X Ppyyrr

Question: What percentage of the offspring from this cross would be predicted to have the following genotypes: Ppyyrr, PPyyrr

1. Consider each character separately (make a punnett square for each character)

Parents: PpYyRr X Ppyyrr:

Pp X Pp =

Yy X yy =

Rr X rr =

2. Calculate probability for each genotype using the Rule of Multiplication

Ppyyrr ½ x ½ x ½ = 2/16

PPyyrr

3. Use the Rule of Addition to determine the probability of offspring that have the following genotypes:

Ppyyrr =2/16

PPyyrr =

5. Multi-hybrid Cross #2

3 characters = trihybrid cross

Parent 1: White flowers (pp), Yellow (Yy), Wrinkled (rr)

Parent 2: Purple flowers (Pp), Green (yy), Round (Rr)

Parents : ppYyrr X PpyyRr

Question: What percentage of the offspring from this cross would be predicted to have the following genotypes: ppyyrr (phenotype: white flowers and green and wrinkled seeds)?

1. Consider each character separately (make a punnett square for each character)

Parents: ppYyrr X PpyyRr:

pp X Pp =

Yy X yy =

rr X Rr =

2. Calculate probability for the genotype using the Rule of Multiplication

ppyyrr=

3. Use the Rule of Addition to determine the probability of offspring that have the genotype ppyyrr (phenotype: white flowers and green and wrinkled seeds)?

6. Pedigree for a recessive trait . Determine the genotype and phenotype of each individual in the pedigree shown below. Use A for dominant, a for recessive.

image4.png

7. Joan was born with six toes on each foot, a dominant trait called polydactyly. Two of her five siblings and her mother, but not her father, also have extra digits. Draw a pedigree inclucing all family members mentioned in the question. Use D and d to symboloze the alleles for this character. What is Joan’s genotype for the “number-of-digits” character?

Chapter 15-The Chromosomal Basis of Inheritance

1. A heterozygous brown-eyed human female who is a carrier of color blindness marries a blue-eyed male who is not color-blind. Color blindness is a sex-linked trait. Assume that eye color is an autosomal trait and that brown is dominant over blue. What is the probability that any of the offspring produced have the traits listed? Construct two punnett squares, one for hair color and one for color blindness.

Eye color (autosomal trait):

  B b
b    
b    

Color blindness (sex-linked trait):

  XA Xa
XA    
Y    

a. Brown eyes

b. Blue eyes

c. Color blind OFFSPRING?

d. What fraction of the MALE OFFSPRING will be color-blind?

e. What fraction of the FEMALE OFFSPRING will be color-blind?

f. What fraction of the FEMALE OFFSPRING will be carriers for colorblindness?

g. What fraction of the MALE OFFSPRING will be carriers for colorblindness?

h. What fraction of the TOTAL OFFSPRING will have Brown-eyes and be color-blind?

i. Why do males show sex-linked traits more often than females?

2A. Describe the process of X inactivation in female mammal body cells.

2B. Why does this process not occur in male mammal body cells?

2C. Discuss at least one possible reason for this phenomenon.

3. Construct a linkage map using the following gene recombination frequencies.

The Recombination Frequency between characters:

A and B = 30%, A and C = 20%, and B and C = 10%.

4. Rip two long strips of paper from a piece of scrap paper. On the end of each strip of paper write “A B C D”. These letters represent gene alleles on non-sister chromosomes that are crossing over during prophase I of meiosis. Rip one strip between the B and C and Rip the other strip between the C and D. Transfer the pieces you ripped off to the other non-sister. Record the sequence of alleles on each non-sister below.

Sequence on non-sister 1:

Sequence on non-sister 2:

-What type of chromosome alterations have occurred?

PAGE

16

 

 

 

A

 

 

 

B

C

 

 

D

 

Copyright Š 2005 Pearson Education, Inc. publishing as Benjamin Cummings

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

Applied Human Genetics

/in /by

Lab 5: Follow the instructions and complete the assignment below. Submit your answers through the Lab 5 Assignment on Blackboard.

Lab 5 1

Lab 5: Solvents and cells

Part 1: Chemistry of Molecules Read/watch the provided resources and take notes, applying the information to what we learned this week. CO2 and Soda: https://www.youtube.com/watch?v=HFCeV5BVBh0 Dissolving M&Ms: https://www.youtube.com/watch?v=umJmRaG6v80 When you are finished, answer the following questions: 1. You are having a debate with a friend about the science behind the Diet Coke and Mentos phenomenon. Your friend thinks that since the volume of matter after the experiment (the big mess) seems to be more than what was originally present in the individual components (soda/Mentos) before they were combined, that the “explosion” is the result of carbon dioxide being produced (made) by the reaction. Is this true? Does the amount of carbon dioxide increase through this reaction? Use what you’ve learned this week to verify or debunk your friend’s argument.

2. During the M&Ms experiment, why did the scientist emphasize that each of the treatments in this experiment needed to be stirred the same say, for the same length of time?

3. For the M&M experiment, name and describe the chemical property that is demonstrated by both the sugar and the candy coloring in the shell of an M&M that permits dissolution in the water, but not in the oil.

4. In your own words discuss this quote. Was Jamf mistaken in his understanding of the relative strengths of ionic and covalent bonds? Explain why/why not (in your own words!).

 

5. The scientific field of organic chemistry is based entirely on studying the chemical structure and reactivity (bonds and chemical reactions) of carbon containing molecules. Based on what you learned in class this week, discuss why carbon is so important that entire fields of study are dedicated to understanding and applying it.

 

 

 

 

Lab 5: Follow the instructions and complete the assignment below. Submit your answers through the Lab 5 Assignment on Blackboard.

Lab 5 2

Part 2: A Picture is Worth a Thousand Words This unit we learned about cells, their structure, and how they carry out the processes of life. We know that there are size restrictions that prevent living cells from being too small or too large. However, the rules that govern cell size may be more complex than scientists originally thought. The existence of ultra-small living cells has been debated for two decades. This debate was settled in February of 2015, when researchers from the U.S. Department of Energy’s National Laboratory at UC Berkeley obtained the first microscopy images of ultra-small bacteria- about as small as life can get. Follow this youtube link to view the research images/reconstructed videos of the cell structure: https://www.youtube.com/watch?v=ofNrtg-FpSc; primary article may be provided upon request. This part of the lab will focus on a popular media ScienceDaily article that summarizes the researchers’ findings. However, before we investigate these ultra-small nanobes, it is important that we fully comprehend the history and scientific impact behind this debate. For this, you’ll need to read the following extract: “In 1996, researchers published a description of a meteorite that fell from Mars, which sparked a long and complicated debate over the existence of what they called ‘nanobacteria’, later also described as nanobes. Various teams argued over whether life, theoretically, could live to be that size, but the debate didn’t really get anywhere because no one really had any evidence for either side. One side said all the things needed for life – DNA, RNA, proteins and solvents – couldn’t actually fit inside a cell that small, while others said life could be that small, but just in a starved, inactive state. Researchers argued over the theoretical limit for how small a cell could get in diameter and volume, and one team even reported finding some marine nanobes, but lacked direct microscopic evidence to prove they fit inside the size range to classify them as such. But now, such bacteria found in some Colorado groundwater have been imaged, and these things are undeniably tiny – several times tinier than several estimates for the lower size limit of life on Earth, in fact. And as difficult as it is to see them, the researchers think they could actually be quite common.” http://www.sciencealert.com/new-images-reveal-the-tiniest-known-life-forms-on-earth Next, click the link to read the article describing researchers’ findings and use this information, along with what you learned this week to answer the provided questions. https://www.sciencedaily.com/releases/2015/02/150227181339.htm When you are finished, answer the following questions: 6. The image at the beginning of the ScienceDaily article shows and describes the visible structure of the cell, and the authors state: “The cell has a very dense interior compartment and a complex cell wall.” As you remember from your readings, not all cell types contain a cell wall. What kinds of cells, other than bacteria, would you expect to possess a cell wall? List the

 

 

Lab 5: Follow the instructions and complete the assignment below. Submit your answers through the Lab 5 Assignment on Blackboard.

Lab 5 3

functions that this structure provides for these organisms. How do organisms that don’t have a cell wall execute these same functions? 7. The image at the beginning of the ScienceDaily article shows and describes the visible structure of the cell, and the authors state: “The darker spots at each end of the cell are most likely ribosomes.” Of all the different structures that could exist within a cell, why do you think that the authors think that these are ribosomes? (Hint: think about the types of cellular structures that are/aren’t found within bacteria, and what ribosomes do, and the importance of that job, within a cell.)

8. Interestingly, the ScienceDaily article states: “images also revealed dividing cells, indicating the bacteria were healthy and not starved to an abnormally small size.” This statement implies that in order for cells to divide they must be “healthy”. Discuss the requirements that a “healthy” eukaryotic cell must meet before it will under cell division. What are the consequences if a eukaryotic cell divides even if these requirements are not met? 9. The ScienceDaily authors state: “About 150 of these bacteria could fit inside an Escherichia coli cell and more than 150,000 cells could fit onto the tip of a human hair”. To provide you with some context so that you can really understand this statement: the spherical diameter of a

typical Escherichia coli cell is 1.3 m (micrometers), and the spherical diameter of these new

ultra-small bacteria is ~0.23 m. Compare the SVR of these new ultra-small bacteria to that of a typical E. coli cell (Hint: you need to calculate the SVR for each), which organism has a larger SVR, does this make sense in the context of the size of the cell? 10. Throughout the ScienceDaily article, the researchers studying these tiny bacteria acknowledge the challenges that such small cells face when it comes to performing the basic functions of life, and the additional challenges that limit our ability to study such small organisms. This makes sense, considering that previously calculated theoretical minimum diameter of a cell was established (and generally accepted by respected scientists and experts

in the field) to be 0.250-0.30 m. The authors say, “There isn’t a consensus over how small a free-living organism can be, and what the space optimization strategies may be for a cell at the lower size limit for life.” Why, before this, did scientists think that living cells couldn’t be much smaller than this lower limit (why is it that when a cell is too small, that it “can’t” survive)?

11. Choose another statement/quote from this article (or the other summary or the original research paper) and discuss how it relates to the material that we learned this week. Be sure to use specific examples (and your own words).

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

BIOL123

/in /by

Lab 4 Selective Media & Agar BIO250L”

Student Name: Click here to enter text. Access Code (located on the underside of the lid of your lab kit):

“Pre-Lab Questions”

1. What is the difference between chemically defined and chemically complex media? Give either a

clinical or environmental research example for which each media type would be the most

appropriate choice for culturing microorganisms.

In chemically defined media, the ingredients that make up the chemical media are know

and can be identified and quantity known such a medium is use to determine the least

amount of nutrients that a microbe needs to survive In chemically complex media the

chemical composition is unknown.the ingredients in this media have an organic origin for

instance, blood, and animal or human tissue can be added to a culture to enable a

pathogen to grow. The reason these organic ingredients are added is because the

pathogen is already know to grow in an animal or a human being

2. Why is differential media typically inoculated with isolated colonies that have been previously

cultured on general growth media?

Differential media is used in previously isolated colonies to identify specific microbes on

basis of the characteristics of that mircorogranism. One example is how agar can

differentiate between hemolytic and non hemolytic bacteria-

3. Use a textbook or a reputable internet source (such as www.cdc.gov) to research and describe a

scenario in a lab or clinical setting in which a selective and/or differential test would be

necessary.

In the case where a microbe is resistant to an antibiotic, selective test can and have

been used on a culture that is already resistant to anti-biotic.this allows for the cells that

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L” have already grown a resistance to the antibiotic to be identified and marked. This was

done to cells that were resistant to neomycin. In a differential test, pin points the

presenceof a certain organism this makes it possible to eliminate this organism as soon

as it has been spoted https://bio.libretexts.org/Bookshelves/Microbiology/Book

%3A_Microbiology_(Boundless)/6%3A_Culturing_Microorganisms/6.3%3A_Culturing_B

acteria/6.3C%3A_Selective_and_Differential_Media

“EXPERIMENT 1: Bioprospecting for Starch Degrading Bacteria

Data Tables Table 3: Starch Agar and Gram Iodine Results

Sample Growth on Starch Agar? (Yes or No)

Clear area around colonies?

Do these bacteria contain amylase?

A Yes no y

B Yes yes- yes-

C Yes y- -yes

D No no no

Post-Lab Questions 1. Why is cow manure used as a potential source of starch-degrading bacteria? (If you are not

familiar with the process of digestion in cows, use a reputable internet source to inform your

answer.)

Because of the presence of Amylase which is needed to digest starch in the mouth

2. What are some other potential sources of starch-degrading bacteria?

potential sources of starch degrading bacteria can be found in fermenting food like hops

in the process of beer making, kombucha, and milk kefir

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L” 3. What component makes starch agar selective for starch-degrading bacteria?

Because starch agar usually has in it the bacteria that degrades starch, it makes a good

selective media because it is will act as a selective nutrient to promote the growth of this

degrading bacteria

4. Why were each of the following steps performed in this experiment?

a. Serial dilution:

To act as a dilutant of microbes so that they it is possible to count them The

stock solution has too many microbes to be effective in the other process of

microbe identification thought isolation.-

b. Growth on the nutrient agar plates:

this was for purpose of bacteria isolation then transfer a single type of bacteria

hence being able to identify them

c. Streak on the starch agar plates:

to introduce a different media that would identify the presence of starch

degrading bacteria

Insert a photo of your plates. Include your name and access code handwritten in the background of

your photo.

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L”

“EXPERIMENT 2: Selection and Differentiation of Body Inhabiting Gram-Positive Bacteria

Data Tables Table 4: Experiment 2 MSA Growth Observations

Surface Tested

Growth (Yes or No) –

Nutrient Agar

Growth (Yes or No) – MSA Agar

MSA color around colonies (Red or

Yellow)

Other Observations

Face Yes Yes Yellow Cfogged up –

nose Yes Yes Yellow Thick and droppy-

Controller Yes Yes Yellow Many organisms

–

Control No No Select one: clear –

Post-Lab Questions 1. What chemical in MSA confers selectivity? How?

The HIGH concentration of sodium chloride allows for the growth of microgranisms like

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L” staphylococcus which while other types of this organism cannot ferment MSA, The

staphylococcus does

2. What chemical makes MSA differential? How?

Sugar mannitol is the differential chemical presence of organisms that can use sugar

mannitol as a source of nutrition will ferment it causing to become acidic which in turn

change the ph .This change in ph accounts for color change when this kind of bacteria is

present.-

3. Why are the nutrient agar plates used in this experiment?

The agar plates are serve to help compare the growth rates in MSA and Agar

4. Was there any growth on you MSA plates? Did any of the colonies change the color of the MSA?

What does this tell you about the bacteria taken from each area of your body?

yes there was a change in color which serves as confirmation that there were bacteria

that allowed for MSA to ferment hence making the set up acidic. The acidity is what

made the co

Insert a photo of your plates. Include your name and access code handwritten in the background of

your photo.

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L”

EXPERIMENT 3: Selection and Differentiation of Body Inhabiting Gram-Negative Bacteria from

Liquid Samples

Data Tables Table 5: MacConkey Agar Results

Sample Growth?

(Yes or No) Colony Color (Clear or Red)

Analysis

CTap water- Yes Select one: Cpretty clean-

Spring water – Yes Select one: C pure and seems extremely safe –

Pond water – Yes Select one: extremely dirty-

Experiment 3 Post-Lab Questions 1. What types of bacteria are inhibited on MacConkey agar? What ingredient(s) in MacConkey agar

selects against those bacteria?

MacConkey agar are inhibited by Gram positive bacteria the ingredients

that allow for for selection are crystal violet and salts .

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L” 2. What ingredient(s) makes MacConkey agar differential?

MacCoknkey agar is a differential Because it contains lactose. When bacteria works on

lactose to break it down, there is a release of acidic waste which changes the ph and

gives it the red-pink look

3. Using a textbook and a reputable online source (such as the CDC), research and describe some

potentially pathogenic members of the intestinal bacteria family Enterobacteriaceae. Which

pathogenic species are lactose fermenters that will grow on MacConkey agar?

Salmonella typhimurium- i will ferment lactose that is on the MacConkey agar.E-coli is

also a lactose fermenting bacteria.

4. Use a reputable internet source to research and describe some potentially pathogenic intestinal

bacteria that do not ferment lactose that will grow on MacConkey agar.

C-Legionella, Bordetella, Helicobacter are non lactose fermenting bacteria

5. Use a reputable internet source to research and describe what variations of MacConkey agar can

be used to detect other species of bacteria.

there is a variation of MacConkey Agar without Crystal Violet it detects Gram-Positive

cocci.- There there is MacConkey Agar that has Violet it is used to control t bacteria

like Proteus which interfere with other results.:

6. How would you verify that the colonies that grew on a MacConkey agar plate were Gram-

negative?

Crystal violet and bile salts usage helps identify gram negative colonies because they

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L” stop the growth of gram-positive bacteria thus all that is left in the sample are gram

negative bacteria

7. Look up the formula for MacConkey agar either in a microbiology textbook or online. Is this a

chemically defined or a chemically complex media? Why is that important?

MacConkey agar is a complex chemically defined media because within it there

ingredients that propagate the growth of some bacteria while other ingredients inhibit the

growth of othes.

Insert a photo of your plates. Include your name and access code handwritten in the background of

your photo.

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

 

 

Lab 4 Selective Media & Agar BIO250L”

This study source was downloaded by 100000792411801 from CourseHero.com on 11-13-2021 20:22:52 GMT -06:00

https://www.coursehero.com/file/115934914/BIO250LV2Lab4-completed-docx/

Th is

stu dy

re so

ur ce

w as

sh ar

ed v

ia C

ou rs

eH er

o. co

m

Powered by TCPDF (www.tcpdf.org)

 

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