Olete.in – MCQs, Mock Tests & Government Job Prep | ICSE XII MCQ Questions for Class 12 Biology Set 3

Gunetical identification of male human is:

1. By Nucleus
2. By cells
3. By Autosome
4. By Sex-chromosome

✅ Correct Answer: 4

Rh+ individual gene may be:

1. rr
2. TT
3. Rr
4. Both (a) and (c)

✅ Correct Answer: 3

Cause of chromosomal mutation:

1. Euploidy
2. Polyploidy
3. Physical effect
4. All of these

✅ Correct Answer: 4

Mendal was born in:

1. 17th century
2. 18th century
3. 19th century
4. 8th century

✅ Correct Answer: 1

Two genes very close on a chromosome will show:

1. No crossing over
2. High crossing over
3. Hardly an crossing over
4. Only double crossing overy

✅ Correct Answer: 1

First geneticist/father of genetics was:

1. de Vries
2. Mendel
3. Darwin
4. Morgan

✅ Correct Answer: 2

An lndividual with into identical alleles is:

1. Hybrid
2. Dominant
3. Homozygous
4. Heterozygous

✅ Correct Answer: 3

Mendal’s law can be applicable only when:

1. Characters are linked
2. Parents are pore breed
3. F1 generation in monohybrid cross show 2 type of individuals
4. Onepair of contiasting characters depends on another pair

✅ Correct Answer: 1

A true hybrid condition is:

1. tt Rr
2. Tt rr
3. tt rr
4. Tt Rr

✅ Correct Answer: 3

The allele which is unable to express its effect in the presence of another is called :

1. Co-dominant
2. Supplementary
3. Complementary
4. Recessive

✅ Correct Answer: 4

Most of the mutations are:

1. Recessive
2. Harmful
3. Germinal
4. All of these

✅ Correct Answer: 1

Smallest segment of genetic material affected by mutation is :

1. Recon
2. Cistron
3. Muton
4. Exon

✅ Correct Answer: 3

Genes located on V-chroinosome are:

1. Mutant genes
2. Autosomal genes
3. Holandric genes
4. Sex-linked genes

✅ Correct Answer: 4

A strong mutagen is:

1. Cold
2. Heat
3. Water
4. X-rays

✅ Correct Answer: 4

A point mutation is:

1. Thalassemia
2. Sickel-cell anaemia
3. Down’s syndrome
4. Nightblindness

✅ Correct Answer: 2

Mendel’s second law is of the law of:

1. Segregation
2. Dominance
3. Polygenic inheritance
4. Independent assortment

✅ Correct Answer: 4

An organism with two unlike genes of a trait is called :

1. Homozygous
2. Hetrozygous
3. Both of these
4. None of these

✅ Correct Answer: 2

Mendel’s laws were discovered by:

1. Correns
2. Shermak
3. de meris
4. All of these

✅ Correct Answer: 4

Mendel’s formulated the law of purity of gametes on the basis of:

1. Test cross
2. Back cross
3. Monohybrid cross
4. Dihybrid cross

✅ Correct Answer: 3

tt mates with Tt. What will be characteristic of offspring:

1. 75% Ineffective
2. 50% Uneffective
3. 25% Uneffective
4. All Effective

✅ Correct Answer: 2

Failure of segregation of chromatids during cell division Cycle result in the gain or loss of a cromosome (s) is called :

1. Female heterogamety
2. Male heterogamety
3. Aneuploidy
4. None of these

✅ Correct Answer: 1

Exception of Mendel’s law is:

1. Dominance
2. Purity of gametes
3. Linkage
4. Independent assortment

✅ Correct Answer: 3

Haemophilia is a:

1. Mendelian disorder
2. Chromosomal disorder
3. Can be (a) or (b)
4. None of these

✅ Correct Answer: 1

Down’s syndrome is a:

1. Mendelian disorder
2. Chromosomal disorder
3. can be both
4. None of these

✅ Correct Answer: 2

Mendel worked on :

1. Edible pea
2. Wild pea
3. Garden Pea
4. None of these

✅ Correct Answer: 1

A gamete contains which of the following :

1. Both alleles of a gene
2. Only one allele of a gene
3. Al allele of a gene
4. No allele

✅ Correct Answer: 2

Name the scientist who discovered the law of Heredity :

1. Gregor Mendel
2. Newton
3. Piinnett
4. None of these

✅ Correct Answer: 1

Punnett square was developed by:

1. Mendel
2. Watson and Sutton
3. Raginald
4. Boveri

✅ Correct Answer: 3

Who introduced Chromosomal Theory of Inheritance?

1. Mendel
2. Sutton
3. Reginald
4. Boveri

✅ Correct Answer: 2

The plant Mendel used to study inheritance of two genes is:

1. Apple
2. Mango
3. Garden pea
4. Potato

✅ Correct Answer: 3

Mendel published his work on inheritance of character in?

1. 1870
2. 1900
3. 1865
4. 1845

✅ Correct Answer: 3

Female heterogamety is :

1. Two different types of gametes are produced by females
2. Four different types of gametes are produced by males
3. Can be both (a) and (b)
4. None of these

✅ Correct Answer: 1

Represser Lac-Operon protein attached to:

1. Operator
2. Inducer
3. Regulator
4. β-Glacto sidase

✅ Correct Answer: 2

Following is important in Ïranscription:

1. DNA Methylase
2. CAAT Box
3. Promotar
4. DNA Polymerase

✅ Correct Answer: 1

Anticodon found in:

1. On DNA
2. On t-RNA
3. On r-RNA
4. On m-RNA

✅ Correct Answer: 2

In DNA helix:

1. Quadrate structure
2. Polarity
3. Antiparallel Polarity
4. Disuiphide bond

✅ Correct Answer: 3

During splicing axon attached and inducer enzyme for reaction:

1. RNA Ligase
2. RNA Catalase
3. RNA permease
4. RNA poloymerase

✅ Correct Answer: 2

During DNA synthesis formed segment is:

1. Polymerase fragment
2. RNA fragment
3. Okazaki fragment
4. RNA Primer

✅ Correct Answer: 3

In a give DNA segment ATC ACC AGG ACC CCA ACA, the first base gets mutated. The effect of this on coding by the DNA segment will result in :

1. One amino acid less in protein
2. No change in the sequence
3. Complete change in the type and sequence of amino acid
4. Change in first amino acid only

✅ Correct Answer: 2

DNA fragments are joined in a correct sequence by :

1. DNA ligase
2. RNA polymerase
3. Helicase
4. DNA polymerase

✅ Correct Answer: 2

The ratio constant for a species is :

1. T+C/G + A
2. A+C/T + G
3. G + G/A + T
4. A + C/C + T

✅ Correct Answer: 2

DNA repairing is done by:

1. By DNA polymerase I
2. By DNA Polymerase II
3. Both (a) and (b)
4. By Ligase

✅ Correct Answer: 2

A ribotide is made up of:

1. Ribose + Phosphate + Uracil
2. Deoxribose + Uracil + Phosphate
3. Thymine + Ribose + Phosphate
4. Deoxyribpse + Phosphate + Adenine

✅ Correct Answer: 1

the enzyme involved in transcription is:

1. DNA Polymerase I
2. DNA Polymerase II
3. RNA Polymerase
4. DNA Polymerase

✅ Correct Answer: 4

Antiparallel strands of a DNA molecule means that:

1. One strand turns clockwise
2. One strand turns anticlockwise
3. The phosphate groups at the start of two DNA strands are in opposite position
4. The phosphate groups at the start of two DNA strands, at their ends, share the same position

✅ Correct Answer: 3

Which one is mainly transcribed:

1. Only RNA sequence
2. Middle repetitive DNA sequence
3. Highly repetitive DNA sequence
4. Single copy of DNA sequence

✅ Correct Answer: 3

Amino acid sequence, in protein synthesis is decided by the sequence of?

1. c-DNA
2. r-RNA
3. f-RNA
4. m-RNA

✅ Correct Answer: 2

DNA multiplication is also called:

1. Replication
2. Transduction
3. Translation
4. Transcription

✅ Correct Answer: 2

During Protein synthesis, atone point the process comes to a halt. Select the group of the three codons from the following, from which any one of the three could bring about this halt:

1. UUC, UUA, UAC
2. UAG, UGA, UAA
3. UUE, UCA, UCG
4. UUU, UCC, UAU

✅ Correct Answer: 2

One turn of the helix in p-from DNA is approximately:

1. 20 Å
2. 2 nm
3. 20 nm
4. 34 nm

✅ Correct Answer: 4