Some photosynthetic Cyanobacteria can fix N2 to NH4 + (using the enzyme Nitrogenase) when they are otherwise starved for nitrogen. They sense nitrogen starvation by sensing an excess of the amino acid Glutamate (Glu) within the cell. If there is adequate nitrogen, much of the Glutamate is converted to Glutamine (Gln), so that the [Glutamate] remains low.

A. SKETCH the photosynthesis system in a typical aerobic Cyanobacterium. Be sure to show how O2 is involved, and how the three main forms of energy are generated.

B. When the [Glu] gets too high, the genes for Photosystem II are shut off, and the Nitrogenase genes are turned on. Assume that the Nitrogenase genes are under Negative control, and the PS-II genes are under Positive control. Make sketches showing how [Glu] affects both of these operons. Then explain each regulatory scheme in words. Be sure to label the regulatory proteins (‘A’ for activator and ‘R’ for repressor protein).

C. On your diagram from part (A), show and explain how turning off the genes for Photosystem II will affect the photosynthetic electron flow in this Cyanobacterium? Why is it important to turn off Photosystem II before the cells produce Nitrogenase?

D. Nitrogen fixation by Cyanobacteria (even with the normal regulation, as described above) is a lot more effective if the Cyanobacteria are grown in co-culture with nitrifying bacteria. Explain why the co-culture with nitrifiers helps with the process of nitrogen fixation.

Describe a purification scheme that starts with a mixture of cells, virions and proteins and ends with a tube containing pure virions. Or, how about obtaining a supernatant solution containing only pure virions?

What are 2 other cell types that the basophil cell interacts with, the results of that interaction and why they’re important. Please give detailed descriptions.

I was considering t cell, mast cell or b cells?

Question:

Is there a difference between oncogenes and tumor suppressor genes?

1. Yes, oncogenes are genes that can cause cancer when they become mutated to become proto-oncogenes, whereas tumor suppressor genes play no role in cancer.

2. Yes, oncogenes prevent cancer from forming unless they are mutated to become proto-oncogenes, whereas tumor suppressor genes stimulate the formation of cancer even in the absence of mutation.

3. No, oncogenes and tumor suppressor genes both stimulate the development of cancer, even in the absence of their becoming mutated.

4. Yes, oncogenes are mutated versions of genes that promote abnormal cell division (such as ras), whereas tumor suppressor genes are genes that normally hold cell division in check when it is not appropriate .

5. No, since both types of genes contribute to the development of cancer, there is no difference between them.

which is correct?

functions of glycolipids

9)List three modern challenges in public health microbiology and potential ways to mitigate them.

1. What other factors will promote oxygen release from hemoglobin? What factors promote binding of oxygen to hemoglobin?
2. High levels of CO2 will promote oxygen release/binding (Pick one). Explain in terms of metabolic pathways why high levels of CO2 would promote release/binding of oxygen
3. How does the protein sequence of hemoglobin differ from normal hemoglobin? How does this change affect the structure of the protein? Explain what happens on the protein level to cause the sickling of the Red blood cells.

How can examples of organisms and traits that exhibit different combinations of presence and absence of homology and/or analogy be used to indirectly test hypotheses of “descent with modification,” natural selection, the “law of succession,” vestigial traits, and convergent evolution. What explains repeated independent evolution of traits?

Give one reason why ascorbic acid is important to human health

Re: Lab #3, explain how you were able to determine the amount of ascorbic acid that was present in your unknown solution. (Please be sure to include the equipment used and the procedure followed.)

Why is it important for a person to know how much Vitamin C is contained in their food?

1- All of the following are types of modifications that can result in an active, functional protein EXCEPT:

a. Covalent disulfide bonds between cysteine amino acids

b. Cleavage of proteins

c. Glycosylation

d. Addition of lipids to the N- or C-terminus

e. Amyloidosis

2- All of the following are reversible protein modifications EXCEPT:

a. Proteolysis

b. Phosphorylation

c. Acetylation

d. Methylation

e. Ubiquitination

3- How can protein-protein interactions regulate enzymes?

a. These interactions change the pH of the local environment, causing enzymes to be less efficient

b. These interactions change the conformation of the enzyme, which may inactivate the enzyme

c. These interactions change the enzyme’s amino acid sequence, which may enhance enzyme activity

d. These interactions prevent translation of the enzyme’s mRNA, leading to lower levels of the enzyme

e. These interactions send enzymes out of the cell, so that they can no longer catalyze cellular processes

1) How would you increase the genetic diversity of the island populations with a low F coefficient?

2) If you can increase the genetic diversity on the island, what would you think would happen with the F value and would this change be fast or slow, and why?

Plasma hypocalcemia would stimulate the activity of  

This month, there was fanfare about the first case of using CRISPR invivo to treat Leber’s congenital amaurosis 10 (LCA10) which is a leading cause of blindness in childhood. This is due to mutations in a large gene, CEP290.

The article comments that:

“For the latest trial, the components of the gene-editing system – encoded in the genome of a virus — are injected directly into the eye, near photoreceptor cells.”

A. Specifically, what components are the authors referring to when they say “the components of the gene-editing system – encoded in the genome of a virus”?

B. How is the zinc finger technology similar to the CRISPR approach?

C. What is a potential risk of using the CRISPR technology invivo?

D. If there was a suitable safe harbor, or the possibility to use a AAV virus to replace the mutant CEP290 gene in the photoreceptor cells (Similar to replacing the CNG3B channel using AAV5). What would be the potential difficulties compared to fixing the gene with CRISPR?

E. If the mutation in the CEP290 gene was known to be a premature stop codon, would the gene therapy be the safest approach to treat this disease?

i) How does the ability of phyla Annelida to move compare with the phyla Platyhelminthes, which prominently use adhesive/releaser glands to facilitate movement? Describe their movement using two examples from specific groups of annelids (structures & how it's used) in one or two paragraphs. ii) Describe the circulatory & nervous systems of phyla Annelida and how they relate to their metamerism. Finally, iii) compare your answer from part iii with the myriapods found in the phyla Arthropoda.