533. You have added a drug that reduces the activity of the enzyme topoisomerase (gyrase). What will happen to the rate of activity of the helicase at the replication fork? Explain your reasoning.

534. You have added a drug that reduces the activity of the enzyme topoisomerase (gyrase). What will happen to the rate of activity of the DNA Polymerase activity on the leading strand? Explain your reasoning.

535. You have added a drug that reduces DNA Ligase activity. What will happen to the rate at which Okazaki fragments are joined on the lagging strand? Explain your reasoning.

536. You have added a drug that reduces DNA Ligase activity. What will happen to the rate at which Okazaki fragments are synthesized on the lagging strand? Explain your reasoning.

In one of the southern regions of the planet, several people were diagnosed with cholera. This is a particularly dangerous infectious disease that can spread rapidly if urgent measures are not taken. A patient with acute diarrhea, vomiting, muscle weakness, and spasms in the calf muscles was admitted to the admission department of the hospital. The skin of the hands is wrinkled, blood pressure is low. Examination of the patient confirmed the diagnosis of cholera. The causative agent of cholera, cholera vibrio, produces a toxin, one of the promoters of which is an enzyme - ADP-ribosyltransferase. Explain the mechanism of action of model toxin.
For an answer
1. Write the reactions catalyzed by this cholera toxin enzyme;
2. Explain the consequences of this reaction for the adenylate cyclase system in the cells of the intestinal mucosa;
3. Describe how cholera symptoms develop as a result of the toxin.

In some plants a red pigment is synthesized from a colorless precursor by a single enzyme coded for by gene A. The red pigment can be changed into a purple pigment by another enzyme coded for by gene B. A cross between pure-breeding purple plants and white plants with the resulting F₂:

94 purple

31 red

43 white

A. Give a concise genetic hypothesis for inheritance of flower color from these results (include number of genes, number of alleles, and the relations between genes and alleles).

B. Using symbols A and B to correspond to genes A and B as described above symbolize the genotypes and their ratios for each F₂ phenotypic class.

C. If the F₁ is used in a testcross, what phenotypic ratio would you expect in the progeny?

1. What are the official names of the genes that code for the C.bo two-component proteins that control toxin expression?

2. What does a protease do? A nuclease? A kinase? A DNA polymerase? An RNA polymerase?

3. What is the function of the wHTH effector protein? Of the BotR protein? Of the HA70 (hemagglutinin) protein (or any hemagglutinin protein)? Of the botA protein?

4. You have a 5kb linear fragment of DNA and you cut it with a Hind III restriction enzyme that has a recognition site at 500 bp from the left end and 1500 bp from the right end. Then you run the digested DNA on an agarose gel. Drae a picture placing the expected sizes of DNA on the gel.

5. You have the same DNA fragment as above but it is circular and not linear. You cut it with the same restriction enzyme (Hind III) and the restriction recognition sites are in the same places. What would this look like on an agarose gel?

6. You have a 4.5 kb linear fragment of DNA and you cut it with Pst I restriction enzyme that has a recognition site at 1500bp from the left end and 1500bp from the right end. What would this look like on an agarose gel?

7. You did a restriction digest on a linear DNA fragment 3000bp long. You ran it on the gel and discovered that the DNA was not cut. What reasons could yield this result?

8. If you want to cut a fragment of DNA with a restriction enzyme and you know that the DNA sequence has an EcoRI restriction site in it. (You use a computer to identify the EcoRI restriction site.) You look in your freezer for restriction enzymes and find that you only have Hind III and have no EcoRI. Could you substitute HInd III and have it cut the DNA at the same place as EcoRI?

How are glycolysis and gluconeogenesis are reciprocally regulated in the liver? Answer this question by providing explanations on all levels of pathway regulation. Discuss the reciprocal/opposite regulation in the categories shown in the following sections. However, this is not just a listing of the regulated enzymes and conditions or substances which are effectors of those reactions; you need to address types of regulation which are examples of reciprocal or opposite regulation of the two pathways.

Identify the most highly regulated steps of these pathways. Give the full reactions including reactants, produces and enzymes. For each identify the most highly regulated step AND other reactions which are regulated.  

What does “opposite” or “reciprocal” regulation of opposite pathways mean?

Discuss how reciprocal/opposite “allosteric” regulation of the most highly regulated steps of these two pathways.

Discuss the reciprocal/opposite “hormonal” regulation of the most highly regulated steps of these two pathways.

Discuss the reciprocal/opposite “reversible covalent modification” of these two pathways.

Discuss any other recipocal/opposite type of regulation that occurs in the regulation of these two pathways of glucose metabolism.

1a. You are researching a gene involved in the process of glycolysis. Which of the following would you expect to see in terms of regulation of this gene?  Select all that apply.

1b.

If you are genetically engineering a protein that you want to accumulate in the endoplasmic reticulum of a eukaryotic cell, what is the best answer for what you should do?

1c. Which of the following can be considered final products of a gene? Select all that apply.

1d. Indicate at least two possible reasons that eukaryotes have introns, and what benefits they may provide

Calculate the amount of energy released in the liver upon the complete oxidation of a triacylglycerol containing three 6-carbon saturated fatty acids. Compare that to 3 molecules of glucose. Which one is a better energy source? Show your calculations.

Find the pH of each of the following solutions of mixtures of acids.​

Part A

0.190 M in HCHO2 and 0.23 M in HC2H3O2​

Part B

6.0×10⁻² M in acetic acid and 6.0×10⁻² M in hydrocyanic acid

Excess production of ketone bodies can occur in a diabetic liver cell when the level of

a-NADH is very low

b- fatty acids are very low

c-oxaloacetate is very low

d-acetyl Co-A is very low