Biology Times (^19)
March
(b) one strand of DNA will be radioactive
(c) none of the strands will be radioactive
(d) half of one strand of DNA will be radioactive
- The length of one complete turn of a DNA
double helix is [2011]
(a) 34 Å (b) 34 nm (c) 3.4 Å (d) 3.4 μm - Ribonucleic Acids (RNA) that catalyze enzymatic
reactions are called ribozymes. Which one of the
following acts as a ribozyme? [2010]
(a) Ribosome (b) Amylase
(c) tRNA (d) Riboflavin - The distance between two consecutive DNA base
pairs is 0.34 nm. If the length of a chromosome is 1
mm, the number of base pairs in the chromosome
is [2010]
(a) 3 million (b)30 million
(c) 1.5 million (d) 6 million - Two students are given two different double
stranded DNA molecules of equal length. They
are asked to de nature the DNA molecules
by heating. The DNA given to student A
has the following composition of bases
(A:G:T:C:35:15:35:15) while that given to
student B is (A:G:T:C::12:38:12:38). Which of
the following statements is true?
[2010]
(a) Both the DNA molecules would denature at
the same rate
(b) The information given is insufficient to draw
any conclusion
(c) DNA molecule given to student B would
faster than that of student A
(d) DNA molecule given to student A would
denature faster than that given to student B - The amino acid sequences of a bacterial protein
and a human protein carrying out similar function
are found to be 60% identical. However the DNA
sequences of the genes coding for these proteins
are only 45% identical. This is possible because
[2010]
(a) Protein sequence does not depend on DNA
sequence
(b) DNA codons having different nucleotides
in the third position can code for the same
aminoacids
(c) DNA codons having different nucleotides
in the second position can code for the same
aminoacids
(d) Same DNA codons can code for multiple
amino acids
34. The following DNA sequence (5’ → 3’) specifies
part of a protein coding sequence, starting from
position I.Which of the following mutations will
give rise to a protein that is shorter than the full-
length protein? [2010]
(a) Deletion of nucleotide 13
(b) Deletion of nucleotide 8
(c) Insertion of a single nucleotide between 3
and 4
(d) Insertion of a single nucleotide between 10
and 11Excretory product and their elimination- By which of the following mechanisms is glucose
reabsorbed from the glomerular filtrate by the
kidney tubule? [2012]
(a) osmosis (b) diffusion
(c) active transport (d) passive transport - Some animals excrete uric acid in urine (uricotelic)
as it requires very little water. This is an adaptation
to conserve water loss. Which animals among the
following are most likely to be uricotelic?
[2012]
(a) fishes (b) amphibians
(c) birds (d) mammals
Microbes in human welfare- bacteria were spread on an agar plate containing
penicillin. After incubation overnight at 37º C ,
10 bacterial colonies were observed on the plate.
That the colonies are likely to be resistant to
penicillin can be tested by [2013]
(a) measuring their growth rate
(b) observinghe colour of the colonies
(c) checking their ability to grow on another plate
containing penicillin.
(d) checking their ability to cause disease
Plant growth and development- In an experiment represented in the schematic
below, a plant species was grown in different day
and night cycles and its photoperiodic flowering
behaviour was noted. This species is a [2016]