DNA Double Helix

Q.

Why is replication called semiconservative?

Q. Go through the following statements
(i) A typical nucleosome contains 400 bp of DNA helix.
(ii) The positively charged DNA is wrapped around the negatively charged histone octamer to form a structure called nucleosome.
(iii) Histones are rich in the basic amino acid residues asparagine and valine
(iv) The packing of chromatin at higher level requires additional set of proteins that collectively are referred to as Non-histone chromosomal proteins.

Find the out the incorrect statements,

1. (i), (ii), & (iii)
2. (ii), (iii), & (iv)
3. (ii) & (iii)
4. (i), (iii), & (iv)

Q. If the frequency of dominant allele is 60%, find out the percentage of heterozygous individuals in the population.

1. 45 %
2. 47 %
3. 48 %
4. 50 %

Q.

What do you mean by Okazaki fragments?

Q. The iodine test can be used to detect starch but not cellulose because

1. cellulose has a linear structure
2. cellulose is the branched polymer of α - D Glucose
3. cellulose contains '1−4' glycosidic linkage
4. cellulose is a structural polysaccharide

Q.

Briefly mention the contribution of T.H. Morgan in genetics.

Q. Length of DNA segment having 200 nitrogen bases is _______.

1. 
2. 
3. 
4. 

Q. The distance between the two strands of a dsDNA is approximately uniform because of the following reason?

1. Presence of phosphodiester bonds
2. Purine always comes opposite to pyrimidine in a dsDNA
3. Presence of N-glycosidic linkage
4. Presence of hydrogen bonds

Q.

Which bond is present between adjacent glucose units in polysaccharides?

Q. A DNA segment of $340A^{\circ }$ will have _________ base pairs.

1. 10
2. 34
3. 100
4. 340

Q.

a) Expand DNA and RNA.

(b) In which part of the cell it is found? State its function.

(c) In which form is DNA present in (1) dividing cell and (2) non-dividing cell?

Q. In an experiment, DNA was found to have $31\%$ adenine and $19\%$ guanine. The quantity of cytosine would have been ___________.

1. 
2. 
3. 
4. 

Q.

The genetic material of a viroid is

1. DNA

2. Carbohydrate

3. RNA

4. Protein

Q.

Which amino acid has only a single genetic code?

Q. According to the chromosomal theory of inheritance, the behaviour of ____(A)____ was parallel to the behaviour of __(B)_____.

1. A-chromosomes, B-genes
2. A-genes, B-proteins
3. A-chromosomes, B-proteins
4. A-genes, B-cell organelles

Q.

How many bases make up a Codon?

Q. Which of the following is/are correct for Watson-Crick model of DNA structure?

1. DNA is a double stranded helical structure.
2. The two strands of DNA are anti-parallel.
3. The two strands of DNA are parallel.
4. The pitch is 34 A$°$ containing 10 base pairs.

Q. Read the assertion and reason carefully to mark the correct option in question


Assertion: Lipids present in the outer and inner side of the bilayer membrane are commonly different.

Reason: Oligosaccharides are attached to external surface as well as inner surface of a biomembrane.

1. If both assertion and reason are false.
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. If assertion is true but reason is false.
4. If both assertion and reason are true and the reason is the correct explanation of the assertion.

Q.

The genetic information is carried by long-chain molecules of

1. Enzymes

2. Proteins

3. Nucleotides

4. Peptides

Q.

Number of linkage groups in drosophila are

1. 2.

2. 4.

3. 6.

4. 8.

Q. Experimental verification of chromosomal theory of inheritance was done by

1. Sutton and Boveri
2. Morgan
3. Henking

4. Karl Correns

Q. Most number of genes are located on chromosome

1. $6$
2. Y
3. $1$
4. X

Q. Identify the correct combination with respect to DNA.

1. Adenine, thymine, cytosine, uracil
2. Adenine, guanine, cytosine, thymine
3. Adenine, cytosine, guanine, uracil
4. Cytosine, guanine, Uracil, thymine

Q. The following diagrams represent the nitrogenous bases of nucleic acid molecules. Identify the correct combination

1. A-uracil, B-adenine, C-thymine, D-guanine, E- cytosine
2. A - uracil, B-guanine, C-cytosine, D-adenine, E-thymine
3. A-uracil, B - guanine, C-thymine, D-adenine, E-cytosine
4. A-thymine, B-guanine, C-uracil, D-adenine, E-cytosine.

Q. Where exactly is DNA found in the body? What are the biggest difference between DNA and RNA?

Q. In 'B' model of DNA, the diameter is $20A^0$. It is …………… in Z DNA

1. $23A^0$
2. $21A^0$
3. $26A^0$
4. $18A^0$

Q.

Nuclear membrane is absent in

a)Nostoc . b)rhizobium

c) drosophila. d) both a) and d)

Q. The double helix structure of the DNA was proposed by

1. Watson and Crick
2. Gregor Mendel
3. Carolus Linnaeus
4. Robert Whittaker

Q. The sequence of nucleotides AUG CUU CUC indicates that it is a segment of

1. sense strand of DNA
2. antisense strand of DNA
3. RNA
4. Polypeptide chain

Q. Identify the correct combination with respect to DNA.

1. Adenine, thymine, cytosine, uracil
2. Adenine, guanine, cytosine, thymine
3. Adenine, cytosine, guanine, uracil
4. Cytosine, guanine, Uracil, thymine