MORE PAST QUESTIONS

1. Which of the following organelle is involved in photorespiration?

a) Peroxisomes

b) Ribosomes

c) Glyoxysomes

d) Dictyosomes

2. Which of the following is regarded as the “Living fossil”?

a) Cycas revoluta

b) Ginko biloba

c) Taxus brevifolia

d) Rhynia

3. What is the physiological pH of human beings?

a) 7

b) 6.8

c) 7.8

d) 7.4

4. Which of the following is a non ionizing radiation?

a) UV

b) X-ray

c) Beta

d) Gamma

5. BLOSUM stands for

a) Blocks amino acid substitution matrix

b) Basic local substitution matrix

c) Biological substitution matrix

d) Biological subtraction matrix

6. Brass is an alloy of

a) Cu and Zn

b) Cu and Ag

c) Zn and Ag

d) Zn and Fe

7. Which of the following is non-mutagenic?

a) Acridine

b) IR

c) UV

d) X-ray

8. Spontaneous theory of generation was disproved by

a) Louis Pasteur

b) Aristotle

c) Van Helmont

d) John Needham

9. Acid rain is due to

a) NO2

b) CO2

c) SO2

d) H2SO4

10. Which of the following is the best conductor of electricity

a) rain water

b) sea water

c) boiled water

d) distilled water

11. The unit of radioactive decay constant

a) Rontgen

b) Rad

c) Ram

d) Ampere

12. Spirulina is rich in

a) Carbohydrates

b) Fats

c) Proteins

d) Vitamins

13. The technology that involves silencing of transcriptional RNA

a) RNA interference

b) Antisense technology

d) Transcriptional inactivation

14. Non essential amino acids include

a) methionine, lysine, leucine

b alanine, aspartate glutamate

c) threonine, valine, Histidine

d)isoleucine, valine, histidine

15.DNA foot printing is a technique for identifying

a) DNA-DNA binding

b) DNA-RNA binding

c) Protein-DNA binding

d) Protein- RNA binding

Answers with Explanation

   1-a, 2-b, 3-d

   4-a

5-a

You can expect one or two questions from this topic. Let us discuss some major points.

This is a portion coming under sequence analysis. Sequence comparison is the basic step in sequence analysis. If two sequences are compared it is called as pair wise alignment, if more than two then called as multiple sequence alignment. Now I just want two tell you some important terms associated with sequence analysis that are common in many exams in one way or other.

• Homology: refers to sequence similarity due to common or shared ancestry. Sequences with similar structure and function are called homologs.

• Analogy: sequence similarity which is incidental.

• Orthologous genes: Genes in different species which are similar in structure and function due common ancestry.

• Paralogous genes: same genes occupying different positions in a genome as a result of duplication.

Alignment can be of two types global and local alignment.

Global alignment is when both the sequence compared are similar over their entire length. or 100% similarity. Think of the word meaning “global” entire whole is it like that?

Now local alignment here similarity between the two sequences compare is at certain localised areas.

The most basic sequence alignment method is the dot matrix method (dotplot method). Here two sequences are compared graphically in a 2 dimension matrix.

Then we need to reach a conclusion after comparing these sequences. Match or mismatch it must be scored. Suppose a match occurs we are giving ‘1’ or giving ‘0’ for a mismatch or gap. This type of scoring matrix where match or mismatch is assigned a number is referred as unitary matrix. This approach will work of comparing nucleic acid sequences but for aminoacids this won’t work.

I am just giving some important terms and points and not want to go deep.

For amino acids: PAM matrices or Dayhoff amino acid substitution matrix (Dayhoff PAM matrices). PAM (point or percent accepted mutation)

Programs best for detecting local alignment: BLOSUM (Blocks amino acid substitution matrix)

Programs best for Multiple sequence analysis: Clustal W and Clustal X and PRALINE progressive alignment program.

6-a, 7-b, 8-a, 9-c, 10-b

11-a , 12-c, 13-b, 14-b , 15-c

c) RNA blocking