ln genetics, what are the biological effects of radiation in humans ?

What would happen if we use Polymerase I instead of Polymerase III for DNA replication in a PCR? If we used an enzyme with low fidelity, how would the DNA product compare to the original template?

Epidemiology: Draw a DAG of the relationship between exposure and outcome, accounting for other variables discussed. Then, write either “Yes” if it appears that confounding of the relationship between the exposure and the outcome is supported (based on the general rule for confounding) and “No” if it appears that confounding is not supported. If “No”, please indicate why it is not a confounder.

• Researchers are investigating a potential association between high-density lipoprotein (HDL) cholesterol and lung cancer where there appears to be a relationship between low HDL and lung cancer. Smoking is known to cause a decrease in HDL levels and is known to cause lung cancer.

The enzymes involved in glycolysis are.....

• A.

  constitutive proteins

• B.

  inducible proteins

• C.

  repressed proteins

• D.

  regulated proteins

Problem 1. Molecular Genetics

A sea urchin mutation results in an unusual positioning of the mitotic spindle during the very first cleavage division:instead of the zygote dividing along the animal-vegetal axis, the cell is now dividing perpendicular to the A-V axis (as if a globe were divided in halves at the equator plane). You decide to repeat Hans Driesch’s 19th century experiments, carefully separate the resulting blastomeres and let them develop further.

True or false?

Since sea urchins are known to have highly regulative earlydevelopment, you expect to see normally developing embryos. Explain youranswer.

1. What is the concentration of bleach that is used to disinfect your work area? Why is it      used to disinfect rather than to sterilize? When do you disinfect your work area? (3             points)
2. Can a pure culture be prepared directly from a mixed-broth or a mixed-slant culture?             Explain. (3 points)
3. As demonstrated in the video, why do you pass the mouth of the tube through the flame? What is the correct angle? (3 points)

5. How do you know that you have used aseptic technique correctly and have achieved a pure culture? (3 points)
6. What are some advantages and disadvantages of the serial dilution agar plate        technique? (3 points)

7. Describe the different cultural characteristics identified when you use agar plates,         agar slants, and nutrient broth. (3 points)

8. Distinguish between the following: (2 points)

1. Disinfectant (1 point)
2. Antiseptic (1 point)

9. What are some advantages of an agar plate over a slant tube? (3 points)
10. Describe how discrete colonies can appear from a mixed culture using the streak- plate subculture process. (4 points)

mtr: tryptophan-specific transport protein – transports tryptophan into the cell

trpA: tryptophan synthase, a protein – synthesizes tryptophan from its basic components

cusF: Periplasmic copper binding protein – binds copper ions

tnaA: Tryptophanase – enzyme for tryptophan catabolism

trpB: Tryptophan synthase, b protein – synthesizes tryptophan

Q. If tryptophan caused the expression level to change, explain why these changes occur for each gene (that is, how does the presence of tryptophan in the media influence expression of the gene...you should be able to infer this based on each gene’s known function).

QUESTION 21

1. Critical results from the microbiology department must be communicated to the clinician immediately. All of the following results are considered critical except:

   	a.	positive spinal fluid gram stain on culture
   	b.	blood smear for malaria
   	c.	negative acid fast stain
   	d.	Streptococcus pyogenes from a surgical wound

QUESTION 22

1. The tech working on an aerobic wound culture is identifying a colony that is large, gray, and non-hemolytic on blood agar. The tech prepares a gram stain of the colony and notices a consistency similar whisked egg whites. The gram stain reveals a large gram-positive Bacillus. What is the most likely identification of this colony?

   	a.	Bacillus anthracis
   	b.	Burkholderia mallei
   	c.	Bacillus cereus
   	d.	Fransicella tularensis

QUESTION 23

1. Which of these describes the mode of action of the antibiotic beta-lactam class of antibiotics?

   	a.	inhibits DNA synthesis
   	b.	inhibits RNA synthesis
   	c.	inhibits protein synthesis
   	d.	inhibits cell wall synthesis

Consider an ion for which there are only passive leakage channels. If the membrane potential is farther from the ion’s Nernst potential, the magnitude of the current associated with that ion will be:

a. greater

b. smaller

c. the same

d. none of the above

And why?

What does it mean to say all organisms are identical in the assumptions for the exponential growth model? Does that mean both males and females can reproduce?

1. Describe the path followed by water from the soil, through the plant and into the atmosphere. Where in the path are the important resistances to water movement?

2. What is meant by the term "active transport"? What is the difference between "primary" and "secondary" active transport?

3. Both membrane channels and carriers show changes in protein conformation. What is the role of such conformation changes (a) in channels, and (b) in carriers?

5. (3 pts) What is the minimum number of base substitutions that must be made to change the codons from:

1. glutamic acid to lysine?

2. leucine to alanine?

3. phenylalanine to glycine?

Explain the condition and consequences of directional selection and balancing selection.

*This is a Population Genetics topic.

a. How does regulated secretion differ from constitutive secretion?

b. What would be the effect of mutating the KDEL sequence of a resident ER protein (like BiP)? Would this effect be similar or different from that of mutating the KDEL receptor protein?

c.The pH of a compartment can be critical for association of a receptor and its cargo. How does the acidic pH of a late endosome result in different fates for the receptor and its cargo?

d. Why are carbohydrate groups of glycoproteins always exposed on the surface of the cell?

e.Compare and contrast the sorting of proteins to lysosomes to the packaging of proteins into regulated secretory granules such as those containing insulin.

f. How is a lysosomal protein targeted to a lysosome? What effect would be the addition of a lysosomal signal sequence have of subcellular localization of a protein that is normally cytosolic?  How would it affect localization of a protein that is normally secreted?