Download PDF
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.
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.
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.
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
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.
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.
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
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.
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.
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.
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
112
Eukaryotic RNA polymerase III catalyses the synthesis of
[A]
tRNA
[B]
hnRNA
[C]
mRNA
[D]
rRNA
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
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
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
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
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
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.
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.
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
Take Mock Tests