Describe the role of V(D)J recombination in anti- body diversification. Explain why nonhomologous end joining is an advantageous mechanism to repair the double-stranded DNA breaks (fusion of the coding segments after the hairpins are hydrolyzed) in the V(D)J recombination pathway.

Explain how the major and minor grooves in DNA are involved in binding of enzymes and other proteins.

You are studying the source of a new virus that has recently infected humans. You suspect that the virus was transferred from oter primates (they exhibit a similar infection), specifically chimpanzees, gorillas, or orangutans. You sample blood from several infected humans and sequence some viral genes. You then build a phylogenetic tree with the human sequences and all the known strains from each primate. Draw a hypothetical phylogenetic tree that would suggest that the virus came from gorillas, and this transfer occured twice independently. Label chimp sequences (c), gorilla (g), orangutans (o), and humans (h).

Mapping traits to a chromosome

Fruit flies have four chromosomes. Fruit flies also have a number of body markers that are useful for mapping genes to given chromosomes. Chromosome I is the X chromosome, which has eye color alleles w+ (red eyes, dominant) and w- (white eyes, recessive). Curly O (Cyo), located on chromosome II, is a dominant marker mutation which causes the wings to curl on the ends instead of beings straight (WT). Stubble (Sb), a dominant marker mutation located on chromosome III, causes the fly’s normally (WT) long and slender bristles to be short and stubbly. (Chromosome IV is very tiny, and has very few genes on it, so we'll ignore it for this problem.)

You have a new mutation that causes the fly to have four antennae instead of two, which you've named double. This mutation is dominant to the wild type allele (two antennae). You want to know which chromosome it is on, so you perform tests for linkage of double to the three markers on the three major chromosomes. Assume all parents are pure-breeding.

Cross I: Test for linkage with white You cross a white-eyed female with two antennae to a red-eyed male with four antennae. Offspring: 405 females with red eyes and four antennae 399 males with white eyes and four antennae

Cross 2: Testing for linkage with CyO and Sb You cross a fly with four antennae to a fly with curly wings and stubbly bristles. The offspring all have four antennae, curly wings, and stubbly bristles. You cross one of these F1 hybrid offspring to a WT fly (all recessive), and get the following outcomes: 226 curly wings, stubbly bristles, two antennae 224 straight wings, stubbly bristles, two antennae 223 curly wings, long bristles, four antennae 227 straight wings, long bristles, four antennae 23 curly wings, stubbly bristles, four antennae 24 straight wings, stubbly bristles, four antennae 26 curly wings, long bristles, two antennae 27 straight wings, long bristles, two antennae

To which of the three markers is double linked?

Which chromosome is it on?

Calculate the distance between double and that marker, showing your calculations below.


This is for a Stem Cell Class

Suppose you are tasked with developing a cell therapy for the treatment of COVID-19. Briefly describe:

a) what cells you would use and why?

b) how you would make the cells?

c) what pre-clinical experiments you would do?

d) how you would carry out the clinical trial?

Give an example to discuss the X-linked human phenotypes.

Please discuss the structure and function of telomeres and their involvement in cellular aging.

Explain how PCR amplifies a particular sequence of DNA.

A 17-year-old boy came to the emergency room after a road traffic accident with multiple
injuries. Upon initial check-up, he has multiple lacerations on his chest, head and right
forearm. On examination, he is unable to extend his right arm as well as forearm. The X-ray of
right arm shows fracture of mid shaft of humerus.
A. Which nerve is mostly likely damaged due to fracture of humerus? (2)
B. Enumerate the muscles in forearm supplied by the involved nerve. (4)
C. Write down the origin, course and termination along with branches of the involved nerve. (4)

Competition can function as a mechanism if density dependent population regulation. How might scamble and contest competition differ in their effect on population growth (regulation)?

What condition must hold true for territoriality to function as a density dependent mechanism regulating population growth (and density)?

You have a bacterial infection for which your doctor prescribes you a ten-day treatment of antibiotics. You take the antibiotic for three days and stop because you feel better. Briefly describe what you have inadvertently done to the bacterial population within your body.

1) Self-pollination would be avoided by all except which of these mechanisms?

a)Pollen is released before the stigma in the same flower is ready

b)Plants recognize and reject their own self-pollination (S-gene) alleles.

c)Plants are dioecious

d)Pollinator only visits flowers of the same species when they are in bloom

you are purifying enzyme Z. You think that the preparation is not pure, based on the following data (choose all correct answers):

Group of answer choices

there are three bands on an SDS-PAGE gel

there is only one band on a native PAGE gel

there are two bands on an IEF gel

in 2 paragraphs, please expkain ...how do both forensic pathologist and forensic anthropologist use skeletal remains?

1a. There are no fossils of ancient prokaryotes, nor of the early eukaryotes. No one was present to observe events first-hand, yet we know that eukaryotes arose from an endosymbiotic event between two prokaryotic organisms... Describe TWO lines of evidence that strongly supports the endosymbiotic origin of eukaryotic life; and, state what is compelling (convincing) about this evidence