Zoology
Mutation that arises from the insertion or the deletion of a single base causing the rest of the message downstream to be read out phase is called:
A.
Frame shift mutation
B.
Chemical mutation
C.
Suppressor mutation
D.
Nonsense mutation
Some females have XY chromosome composition with streak ovaries and lack of secondary sexual characteristic due to:
A.
Defective genes which suppress the male determining function of Y-chromosome
B.
Defective genes that alter the male determining role of Y-chromosome
C.
Non-disjunction of Y-chromosome
D.
None of these
The chromosome analysis of a newly born male revealed that non-disjunction of sex chromosomes at mitosis has occurred once. The most likely sex chromosome composition of the individual is:
A.
XY
B.
XO
C.
XXY
D.
XYY
If a male and female, Heterozygous for a recessive trait marry each other, then:
A.
25% of the male and female children express the recessive trait
B.
50% of the male and female children express the recessive trait
C.
75% of the male and female children express the recessive trait
D.
All the children are normal
Which among the following is not an autosomal recessive character in man?
A.
Pattern baldness
B.
Phenylketonuric
C.
Diabetes mellitus
D.
Microcephali
The correct sequence of enzymes acting in the dark, reactivation mechanism is:
A.
Endonuclease => Exonuclease => Polymerase => Ligase
B.
Exonuclease => Endonuclease => Polymerase => Ligase
C.
Exonuclease => Polymerase => Endonuclease => Ligase
D.
Polymerase => Exonuclease => Endonuclease => Ligase
The reason why some mutations which are harmful do not get eliminated from the gene pool is that:
A.
They have future survival value
B.
They are dominant
C.
They are recessive
D.
Genetic drift occurs because of a small population area
A family has five girls and no sons. Probability of son as the 6th child will be:
A.
50%
B.
75%
C.
Full
D.
No change
Albinism in man is caused due to the non-synthesis of melanin in the absence of:
A.
Luciferin
B.
Lysine
C.
Melanase
D.
Tyrosinase
If an albino marries a normal woman and 50% offsprings are albino and 50% normal, the woman is:
A.
Heterozygous normal
B.
Homozygous normal
C.
Both (a) and (b)
D.
None of these
Webbed neck is a characteristics of:
A.
XXY male
B.
XO female
C.
YY male
D.
XXX female
In the buccal cavity slide, cell of an individual, a dark stained body near nuclear membrane is seen. The genotype of the individual may be:
A.
XX
B.
XXX
C.
XXY
D.
XY
In human being the sex of a foetus is differentiated and can be determined with 95% confidence by studying:
A.
Size of the child
B.
Expansion of the uterus
C.
Hormone concentration in the blood of the women concerned
D.
Barr bodies
Conjoint twins are known as:
A.
Fraternal twins
B.
Siamese twins
C.
Dizygotic twins
D.
None of these
The character of organisms is said to be sex-linked when its gene is carried on:
A.
Y-chromosome
B.
X-chromosome of male or female
C.
X and Y chromosome
D.
A particular autosomes
Which one of the following is genetically dominant in man?
A.
Rh positive
B.
Haemophilia
C.
Albinism
D.
Colour blindness
The gene responsible for colour blindness is located on:
A.
X chromosome and is recessive
B.
Y chromosome and is recessive
C.
Y chromosome and is dominant
D.
Y chromosome and is recessive
Mutation in which one base is replaced by another base is termed as:
A.
Deletion
B.
Translocation
C.
Addition
D.
Substitution
How many barr bodies can be seen in XXX condition?
A.
1 only
B.
2 only
C.
2 or 3
D.
3 only
Monogenetic condition is one in which the:
A.
Alleles are present on the same chromosome
B.
Alleles are present on the same loci in homologous chromosomes
C.
Characters are controlled by more than one gene
D.
All of these
Polymorphic variations are due to:
A.
Dominant genes
B.
Recessive genes
C.
One or two genes
D.
More than one gene
Which of the following supports the idea that the mutational changes have been more frequent at the time when living cell first evolved?
A.
Early cells did not have DNA which is a stable compound and hence changes were frequent
B.
More ozone was present in the primitive earth's atmosphere, thus permitting more radiation to penetrate the earth's atmosphere
C.
Less ozone was present, thus permitting more radiation to penetrate up to the earth
D.
Early cells reproduced asexually, hence mutational changes occurred
A mutant which has lost its ability to synthesize one or more essential compounds is:
A.
Auxotroph
B.
Axoneme
C.
Autotroph
D.
Heterotroph
Omission of barr body results in:
A.
Down's syndrome
B.
Turner's syndrome
C.
Klinafelter's syndrome
D.
Triple female
Episomes may be factor in:
A.
Cytoplasmic inheritance
B.
Chromosomal inheritance
C.
Incomplete dominance
D.
Codominance