Question

only one answer per question

QUESTION 6

In a DNA molecule, what type of bond helds together the two antiparallel strands of nucleotide chains?

a		peptide bonds.
b		polar covalent bonds.
c		ionic bonds.
d		hydrogen bonds.
e		complementary base pairing bonds.

  

QUESTION 7

Who proposed the double helix model?

	a	Watson and Crick.
	b	Griffith.
c		Avery.
d		Franklin.
e		Beadle and Tatum.

QUESTION 8

Which of the following enzymes removes the primers used for DNA replication?

a		DNA pol I
b		DNA pol II
c		DNA pol III
d		DNA pol I, DNA pol II, and DNA pol III can all remove primers

QUESTION 9

The enzyme that attaches DNA sequences at the ends of eukaryotic chromosomes in order to prevent chromosome shortening is called _____.

a		Polymerase
b		Ligase
c		Telomerase
d		Topoisomerase
e		Primase

QUESTION 10

Which of the following statements about telomeres is INCORRECT?

a		Telomeres are produced by telomerase.
b		Telomeres are found at the ends of chromosomes.
c		Telomeres are short repeat sequences.
d		Telomeres would be longer in cells of older than younger individuals.
e		Telomeres are crucial to the viability of a cell that replicates often.

Answer 1

Answers :

Question number 6 : The right answer is D ( Hydrogen bonds)

Exaplanation : Hydrogen bonds (non covalent) found between the bases stabilises the structure of DNA. Adenine base pairs with thymine with two hydrogen bonds and guanine base pairs with cytosine with three hydrogen bonds.

Question number 7 : The right answer is A ( watson and crick)

Question number 8 : The right answer is A (DNA pol I)

Explanation : DNA polymerase I also known as Korenbergs enzyme is considered as DNA repair enzyme rather than a DNA replication enzyme. .Pol I possesses three enzymatic activities they include

1. 5' to 3' polymerase activity
2. 3' to 5' exonuclease activity for proofreading activity
3. 5' to 3' exonuclease activity mediating nick translation during DNA repair.

DNA polymerase is mainly involed in removing RNA Primers from okazaki fragments or precursor fragments generated in the lagging strand and filling the resultant gaps due to its 5’ to 3’ polymersing activity.

Question number 9 : The right answer is C ( Telomerase)

The enzyme that attaches DNA sequences at the ends of eukaryotic chromosomes in order to prevent chromosome shortening is called TELOMERASE.

Question number 10 : The incorrect statement among these is D (Telomeres would be longer in cells of older than younger individuals). Telomeres are longer in younger cells and telomerase shortening occurs as the cells keeps replicating.