Explain how the cell reproduction rate and differentiation are kept within the normal range to avoid the formation of neoplasms. (in regards to leukemia cancer)
In: Biology
I am trying to purify DNA polymerase from cells DNA polymerase is a large soluble posivitely charged protein for each purification step below select which fractions you will keep in order to end up with pure DNA polymersase :
1. Cell fractioniation by centrifiguation:
a) Keep Nuclear Pellet
b) Keep mitochondrial Pellet
c) Keep microsomal supernatant
d) Keep microsomal Pellet
2) Salt fractionation with low salt concentration (low salt):
a) Keep precipitate
b) Keep supernatant
3) Gel Filtration
a) Keep later fractions
b) Keep middle fractions
c) Keep earlier fractions
4) Cation exchanger:
a) Keep middle fractions
b) Keep later fractions
c) Keep earlier fractions
5) DNA containing affinity column:
a) Later fractions
b) Earlier fractions
In: Biology
You are a judge in a civil trial where a young man is attempting to prove that he is the illegitimate child of a very wealthy man who has recently died. He wishes to be included in the distribution of the wealth. After considering all the testimony about how this person was conceived, the key evidence seems to come down to two main facts. The wealthy man and the mother of the young man are both deaf but the young man is not. Therefore the lawyer of the family suggests that the wealthy man is not the father. The mother, wealthy man, and young man all have O, MM, Rh blood type at the phenotypic level but a genotyping screen indicates that the wealthy man is actually IAIA hh blood type. How do you interpret the evidence presented and how does it influence your decision in this case?
In: Biology
Some scientists believe that fructose is particularly bad for human health because it promote fat synthesis, contributing to development of type II diabetes and fatty liver disease. You are a scientist working for a lab attempting to develop a drug to help with such diseases called fructono. The idea is that fructono could be added to the diet to reduce fructose absorption; even though fructono would be absorbed, it would not be metabolized, and would be excreted by the kidney. The hypothesis is that fructono binds to the fructose transporter, competitively displacing fructose. This cannot be easily studied in humans, so you are investigating this hypothesis with a mouse small intestine, which is known to transport fructose using a transporter that is quite similar in amino acid sequence and structure to the human protein. For your research, you set up a perfused intestine prep. You cut out about 1 cm of small intestine, and put it in a dish containing saline. You insert a tube into the intestinal section, and use a pump to push any fluid you want through the lumen of the intestine. You have radio-labeled fructono, so you can measure its appearance in the saline outside the intestine. How can you measure the rate of transport of fructono? 1 pt Describe experiments that would test whether the absorption of fructono is protein-mediated vs. passive (just leaking through cracks, or diffusing through membranes). What results will you get if the transport is protein-mediated vs. passive? 2 pts. Describe experiments that would test whether the absorption of fructono is active, and the predicted results if transport is active or not. 2 pts. Describe experiments that will test whether the active transport of fructono requires luminal Na+, and the predicted result if transport is Na+-dependent or not. 1 pt. Describe experiments that will test whether fructono can reduce the transport of fructose in a dose-dependent manner. 2 pts What side-effects might fructono have? 2 pts
In: Biology
i) Discuss the importin-alpha nuclear import cycle, mechanistically accounting for the key steps of nuclear transport. (Essay style include appropriate diagrams)
ii) Quantitative reasoning, 10 marks: During DNA replication, the genome is duplicated as chromatin. How fast does nuclear transport of histones have to take place in terms of molecules/pore/second in order to support S-phase in human cells? Assume the genome is 6 x 109 bp, a nucleosome spans 200 bp and that 75% of the genome is replicated in the first 3 hr of S-phase. Nuclei contain 2000 nuclear pore complexes. (show work)
In: Biology
In: Biology
Which of the following are exocrine functions of the pancreas?
1) synthesis of hormone sensitive lipase
2) Secretion of insulin from beta islet cells
3) Synthesis of alkaline lipase
4) Synthesis of phospholipase A2
5) Synthesis of phospholipase D
6) Synthesis of trypsinogen
7) Synthesis and Release of salivary amylase
8) Synthesis and release of lingual acid lipase
In: Biology
Discuss the different levels of protein folding, giving example of particular folds. Discuss the difference between motifs and domains in folded proteins. Briefly discuss the difference between globular and fibrous protein structures.
In: Biology
Nondisjunction at meiosis II produces higher frequency of aneuploid gametes compared to meiosis I nondisjunction.
True or False?
Explain
In: Biology
In: Biology
How many different explanations can you think of for the observation that the rate of mutation varies across the genome? How would you weigh up evidence for these different ideas to decide which ones have the most explanatory power?
In: Biology
What four components are added to a transmitted light microscope to make it a DIC (differential interference contrast (DIC) microscopy ) microscope?
How do you adjust the bias on a DIC (differential interference contrast (DIC) microscopy ) microscope?
Although the images produced by a DIC (differential interference contrast (DIC) microscopy )microscope appear to be three-dimensional, they do not actually give real 3D information. Explain why.
Why is it important that all glass and plastic-ware used on or with the DIC (differential interference contrast (DIC) microscopy )microscope is strain-free?
What are the advantages of DIC (differential interference contrast (DIC) microscopy ) microscopy over phase contrast microscopy?
What are the advantages of phase contrast microscopy over DIC (differential interference contrast (DIC) microscopy ) microscopy?
In: Biology
1) Some bacterial pathogens are highly infectious via the respiratory route. Determining whether the pathogen can make an enzyme that breaks down hydrogen peroxide by the catalase method could be hazardous. How? Also include in your answer how the test is performed. (2 pts)
2) Kovac's reagent was used in the indole test. If isoamyl alcohol were not present in the Kovac's reagent, then describe what would be observed following testing of an indole-positive bacterium, and why? Also include in your answer the function of isoamyl alcohol in the test? (2 pts)
In: Biology
Distinguish between sex, recombination and mutation for generating variation for natural selection and evolution.
In: Biology
A fish with a 6 cm long tail and a fish with a 30 cm long tail are bred. All of the F1s have tails that are 18 cm. The F1s were interbred and out of 256 F2 offspring, 1 had a 6 cm tail and 1 had a 30 cm tail. All other F2s had tails that ranged in length from 6 to 30 cm in 3 cm intervals. Given these numbers, you suspect that in these fish, tail length is inherited via polygenic quantitative alleles.
A) How many gene pairs are involved in inheritance of tail length?
B) How many F2 individuals would you predict to have a 9 cm long tail?
In: Biology