The number of seeds in the fruit of a plant species, H₀ : μ=30. A random sample of 9 fruits gives the mean number of seeds as 24 with a standard deviation of 6.12. (a) What are the confidence limits for the sample mean? (b) Would you reject or accept the null-hypothesis at 95% confidence level?

• (a) 18 and 30; (b) reject the hypothesis

• (a) 20 and 28; (b) reject the hypothesis

• (a) 20 and 28; (b) accept the hypothesis

• (a) 18 and 30; (b) accept the hypothesis

A chromatin immunoprecipitation (ChIP) assay was performed to determine specific transcription factor binding sites on the promoter of a gene. Pull down was done using either IgG or anti-bodies against c-myc. A DNA containing c-myc binding regions was used as a control for PCR amplification (input). Which one of the following PCR representations of DNA is correct?

In an attempt to detect protein expression profile in a cell, Western blot technique is employed. Expression of two new proteins is to be followed by probing with respective high affinity antibodies (raised in rabbit). Unfortunately, the two proteins were found to co-migrate in SDS-PAGE profile. Under this situation, using one-dimensional SDS-PAGE and by Western blot, which one of the following is the best way to demonstrate the presence of both the proteins?

• Develop Western blots with their antibodies in the same gel.

• Prior to doing SDS-PAGE/ Western blot, one protein could be removed by immune precipitating in the cell extracts.

• Silencing the expression of one protein at a time by siRNA and performing Western blotting.

• Subjecting the technique of stripping/ reprobing of the gel after transferring to nitrocellulose membrane while doing Western blotting.

4.

Nichrome coated stainless steel electrodes were implanted in a rat brain for chronically recording the electrical activity of deep brain structures. During a study of 3 months, the intensity of electrical signals gradually decreased. The following statements may explain the cause of this observation.

A. The deposition of metallic iron from the electrode tips caused degeneration of some neurons.

B. The gradual accumulation of microglia at the electrode tips increased the resistance of electrodes.

C. The neurons at the electrode tips were hyperpolarized gradually.

D. The threshold for firing action potential in the neurons at the electrode tips was increased sue to prolonged presence of electrodes.

Which one of the following is correct?

• A only

• A and B

• C only

• C and D

A researcher was repeating a FACS experiment but somehow got confused with the labeling of the tubes. There are four tubes, one control, C (with no fluorescent label), one standard 1, S1 (with FITC label), one standard 2, S2 (with PE label) and the last one test, T (which should be FITC) positive. Given below is the result of the FACS experiment.

What should be the correct labeling?

• a,S2; b,S1; c,T; d,C

• a,S1; b,T; c,C; d, S2

• a,S2; b,S1/T; c,C; d,S1/T

• a,S1/T; b,S2; c,S1/T; d,C

Small molecular weight compounds affect the activity of luciferase differently. The oil/ water solubility of various compounds is one property important for its effect on luciferase. The straight line in the graph was obtained by plotting the activity data with 50 different compounds. The luciferase activity, of two new derivatives of Benzene (A and B) are shown below:

Which of the following statements is correct?

• A is phosphate and B is amine.

• A is methyl and B is amine.

• A is methyl and B is propyl.

• A is amine and B is phosphate.

Following are certain statements regarding somatic hybridization, a technique used for plant improvement.

A. Protoplasts of only sexually compatible plant species can be fused.

B, Hybrids are produced with variable and asymmetric amounts of genetic material of parental species.C. Protoplast fusion permits transfer of gene block or chromosomes.

D. Genes to be transferred need to be identified and isolated.

Which one of the following combinations of the above statements is correct?

• A and C

• B and C

• A and D

• B and D

A student was asked to design a knockout cassette for specifically deleting the p53 gene from the prostate gland of mice. Which one of the following pairs of cassettes will ensure the deletion of the gene?

During the production of alcohol by fermentation using budding yeast, oxygen supply is kept limited. Why?

• Budding yeasts are obligate anaerobes and cannot tolerate oxygen.

• Budding yeasts lose mitochondria in the absence of oxygen.

• Budding yeasts are facultative anaerobes.

• Alcohol is oxidized further in the presence of oxygen.

Which of the following statements is NOT correct regarding effect of genetic drift?

• It alters allele frequency substantially only in small populations.

• It can cause allele frequencies to change at random.

• It can lead to a loss of genetic variation within populations.

• It can cause harmful alleles to become eliminated.