Zoology
During cytokinesis, a constriction on cleavage furrow appears in the:
A.
Equatorial region
B.
North polar region
C.
South polar region
D.
None of these
Mutations occur during
A.
Cell division
B.
DNA replication
C.
DNA repairing
D.
Transcription
Inversion occurring in both the members of a homologous pair is called:
A.
Chromosomal
B.
Allelosomal
C.
Allelobrachial
D.
Heterosomal
If the recombination frequency of a pair of genes in a test cross is lower than the expected value of 50 percent, they may be said to be:
A.
Linked gene
B.
Epistatic gene
C.
Complementary gene
D.
Supplementary gene
The somatic chromosome number in honey bee male is:
A.
16 (2n)
B.
32 (2n)
C.
32 (n)
D.
16 (n)
The inheritance of skin colour and its frequency distribution can also be termed as:
A.
Quantitative inheritance
B.
Qualitative inheritance
C.
Incomplete inheritance
D.
None of these
The disease caused by the absence of the enzyme which catalyzes the first step in the metabolism of phenylalanine is known as:
A.
Alkaptonuria
B.
Phenylketonuria
C.
Sickle-cell anaemia
D.
None of these
Mutant genes that give slightly modified phenotypes are called:
A.
Forward mutations
B.
Isoalleles
C.
Dominant mutations
D.
None of these
The ultra violet light is an:
A.
Ionising mutagen
B.
Non-ionising mutagen
C.
Chemical mutagen
D.
None of these
Persons having supernumerary chromosome 21 are known to suffer from:
A.
Patau's syndrome
B.
Edward's syndrome
C.
Down's syndrome
D.
Turner's syndrome
Polymorphic nucleus of leukocytes in human ___________ possesses a small drumstick like pedunculate lobule:
A.
Female
B.
Male
C.
Both female and male
D.
None of these
Identical twins in human being arise from a single zygote formed by the fertilization of:
A.
A single egg with a single sperm
B.
A single egg with two sperms
C.
Two eggs with a single sperm
D.
Two eggs with two sperms
The spontaneous inheritable change which occurs suddenly in nature is termed as:
A.
Variation
B.
Mutation
C.
Speciation
D.
Aberration
Excess development of hairs on pinna of ear in human male is an inheritance of:
A.
X-linked genes
B.
Y-linked genes
C.
Both X and Y linked genes
D.
Sex limited genes
Which of the following diseases is associated with dominant sex-linked genes?
A.
Colour blindness
B.
Haemophilia
C.
Night blindness
D.
Defective tooth enamel
The chronic granulocytic leukaemia is due to:
A.
Deletion of the 22nd chromosome
B.
Deletion of the 22nd chromosome and its addition to the 9th chromosome
C.
Deletion of 5th chromosome
D.
Deletion of the 18th chromosome
Two dominant non allelic genes are exactly 50 map units apart. It means that the linkage is:
A.
CIS' type
B.
Trans' type
C.
Complete
D.
Absent
A gene when present in the homozygous form causes the death of bearer and disturbs phenotypic ratio from 3 : 1 to 02 : 1 (or simply 2 : 1) is:
A.
Lethal gene
B.
Supplementary gene
C.
Complementary gene
D.
Epistatic gene
1 : 2 : 3 : 1 ratio is due to which type of gene interaction:
A.
Recessive epistasis
B.
Dominant epistasis
C.
Codominance
D.
Incomplete dominance
To a curly haired mother and straight haired father, 8 children are born. The ratio of curly straight haired will be:
A.
6:1
B.
5:1
C.
4:1
D.
2:1
A couple has all normal sighted daughters and all colour-blind sons. What is the genotype of the couple?
A.
XcX and XY
B.
XX and XcY
C.
XcXc and XcY
D.
XcXc and XY
A normal female whose brother is haemophilic marries a normal man, what is the chance of her first child being a haemophilic boy?
A.
50%
B.
25%
C.
75%
D.
100%
A couple has five children, three sons and two daughters. The eldest son shows the symptoms of muscular dyhtrophy, what are the chances of their other children in developing the disease?
A.
50% of the sons will be normal
B.
50% of the daughters will be normal
C.
25% of the sons will be normal
D.
25% daughters will be carriers
Premature onset of baldness is most often observed in young men, and vary rarely so in women. This is so because the gene for such baldness is located on:
A.
Y-chromosome
B.
X-chromosome, and its function is controlled by male sex-hormones
C.
Autosomes and its function is controlled by male sex-hormones
D.
Mitochondrial DNA, contributed by the father through his sperm
The wobble hypothesis is based on the fact that the:
A.
Number of t-RNA molecules is much less than 64, which happens to be the number of codons coding for various amino acids
B.
Three codes are responsible for initiating and terminating polypeptide
C.
Codon AUG codes for amino acid methionine, while it also initiates polypeptide chain
D.
Amino acid leucine is coded by as many as 6 codons