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Free download in PDF CBSE Class 12 Biology MCQs with Answers. Here Gkseries provide Biology Solve Questions and Answers for CBSE Class 12 Students.
101
ZIFT is transfer of
A
zygote into fallopian tube.
B
a mixture of sperms and ova into the fallopian tube.
C
a mixture of sperms and ova into the uterus.
D
embryo into the uterus.
View Answer
Answer: zygote into fallopian tube.
102
Diaphragms are the contraceptive devices used by females. Choose the correct option about them.
A
They are placed to cover the cervix.
B
They block the entry of sperms.
C
They are reusable.
D
All of these.
View Answer
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103
When ‘Aa’ is crossed with ‘aa’, (A is dominant over a)
A
all the offspring will have dominant phenotype.
B
all the offspring will have recessive phenotype.
C
50% of offspring will have dominant phenotype and 50% will have recessive phenotype.
D
75% of offspring will have dominant phenotype and 50% will have recessive phenotype.
View Answer
Answer: 50% of offspring will have dominant phenotype and 50% will have recessive phenotype.
104
The possibility of all genotypes of offspring in a genetic cross is calculated by a graphical representation which was developed by
A
Gregor Mendel
B
Reginald Punnett
C
Komberg
D
T.H. Morgan
View Answer
105
Study the pedigree chart given
Select the correct option about the conclusion.
A
It is a sex-linked recessive trait.
B
It is an autosomal recessive trait.
C
It is an autosomal dominant trait.
D
It is a sex-linked dominant trait.
View Answer
Answer: It is an autosomal recessive trait.
106
Mother and father of a person with ‘O’ blood group have ‘A’ and ‘B’ blood group respectively. What would be the genotype of both mother and father? [NCERT Exemplar]
A
Mother is homozygous for ‘A’ blood group and father is heterozygous for ‘B’.
B
Mother is heterozygous for ‘A’ blood group and father is homozygous for ‘B’.
C
Both mother and father are heterozygous for ‘A’ and ‘B’ blood group, respectively.
D
Both mother and father are homozygous for ‘A’ and ‘B’ blood group, respectively.
View Answer
Answer: Both mother and father are heterozygous for ‘A’ and ‘B’ blood group, respectively.
107
If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is: [NCERT Exemplar]
A
Sex-linked recessive.
B
Sex-linked dominant
C
Autosomal dominant
D
Autosomal recessive
View Answer
Answer: Sex-linked recessive.
108
In a dihybrid cross, if you get 9:3:3:1 ratio it denotes that: [NCERT Exemplar]
A
It is a case of multiple allelism.
B
The alleles of two genes are segregating independently.
C
The alleles of two genes are interacting with each other.
D
It is a multigenic inheritance.
View Answer
Answer: The alleles of two genes are segregating independently.
109
Which of the following traits studied by Mendel in garden pea is a dominant trait?
A
Inflated pod.
B
Yellow colour of pod.
C
Green colour of seed.
D
Terminal flowers.
View Answer
110
If a haemophilic woman marries a normal man,
A
all their children will be normal.
B
all their sons will be haemophilic.
C
all their daughters will be haemophilic.
D
50% sons and 50% daughters will be haemophilic.
View Answer
Answer: all their sons will be haemophilic.
111
Operon model for regulation of transcription was proposed by
A
Meselson and Stahl
B
Jacob and Monod
C
Watson and Crick
D
Hershey and Chase
View Answer
112
Eukaryotic RNA polymerase III catalyses the synthesis of
A
tRNA
B
hnRNA
C
mRNA
D
rRNA
View Answer
113
The sequence of nitrogen bases in a # segment of a coding strand of DNA is ’ AATGCTTAGGCA. What will be the sequence of nitrogen bases in the wRNA transcribed by it?
A
UUA CGA AUC CGU
B
AAU GCU UAG GCA
C
AAU GCU AAC CGA
D
AAU GCA AUC CGU
View Answer
114
Which of the following sets of codons contains only termination codons?
A
UAA, UGA, UAG
B
UUU, UCC, UGG
C
UAA, UUU, UGG
D
UAA, UAG, UAC
View Answer
115
The central dogma of molecular biology (genetic information flow) was modified by the discovery of
A
RNA polymerase
B
DNA ligase
C
Reverse transcriptase
D
DNA polymerase
View Answer
Answer: Reverse transcriptase
116
The human chromosome with the highest and least number of genes in them are respectively
A
Chromosome 21 and Y
B
Chromosome 1 and Y
C
Chromosome X and Y
D
Chromosome 1 and X
View Answer
Answer: Chromosome 1 and Y
117
The net electric charge on DNA and histone, is
A
positive, negative
B
negative, positive
C
positive, positive.
D
negative, negative
View Answer
Answer: negative, positive
118
In E.coli, the lac operon gets switched on when [NCERT Exemplar]
A
lactose is present and it binds to the », repressor.
B
repressor binds to operator.
C
RNA polymerase binds to the operator.
D
lactose is present and it binds to RNA polymerase.
View Answer
Answer: lactose is present and it binds to the », repressor.
119
Which of the following are the functions of RNA?
A
It is a constituent component of ribosomes
B
It carries amino acids to ribosomes
C
It is a carrier of genetic information from DNA to ribosomes synthesising polypeptides.
D
All of the above.
View Answer
Answer: All of the above.
120
In the lac operon of E.coli, the i gene codes for
A
inducer
B
repressor
C
lactase
D
β-galactosidase
View Answer
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