Variation and genetics – Online MCQs Test – Biology MCAT

1. Each human being possesses ________ pairs of chromosomcs.

2. Mendelian recombination’s are due to:

Modifications

Linkage

Independent assortment of characters

Mutation

3. Genes A and B are necessary for normal hearing. A deaf man marries a deaf woman and all their children have normal hearing. The genotypes of the parents are:

Aabb and aaBb

AAbb and aaBB

AAbb and Aabb

aaBB and aaBB

4. Which of the following condition represents a case of co-dominant genes?

A gene expresses itself suppressing the phenotypic effect of its alleles, when present in Heterozygous condition.

Genes that are similar in phenotypic effect, when present separately, but when together interact to produce different unit

Alleles, each of which produces an independent effect in a heterozygous condition

Alleles both of which interact to produce a trait which mayor may not resemble either of the parental types

5. A plant heterozygous for tallness produces both tall and dwarf plants on self-pollination. This proves the

Principle of incomplete dominance

Law of independent assortment

Principle of dominance

Law of segregation

6. When red-eyed female (XRXR) is cross with white cyed male (X’Y) the F2 generation shows red-eyed & white-eyed, this is ratio of:

0.0423611111111111

3:1

0.04375

0.167361111111111

7. In pleiotropy:

One gene hides the effect of the other gene

One gene affects two or more traits

One gene dominates the other gene

One gene interferes the effect of the other gene

8. Mendels law of segregation is based on the fact that genes are located on chromosomes and that:

No crossing over takes place between homologues chromosomes

Analogous chromosomes pair and segregate

Homologous chromosomes pair and segregate

None of the above

9. What is the most common outcome in the F2 generation of a cross between a tall plant and a dwarf plant?

1 tall : 1 dwarf 1

1 tall : 2 medium : 1 dwarf

3tall : 1 dwarf

All tall

10. Variations are produced due to:

Mutation

Locus

Allele

Gene

11. Mutual exchange of segments of chromosomes is called:

Crossing over

Linkage

Pleiotropy

Synapsis

12. The ratio for law of independent assortment is:

0.377094907407407

0.0430671296296296

0.125694444444444

9:3:3:1

13. Mendel’s law of segregation states that.

Two different traits will be inherited independently of each other

Two factors for the same trait separate in the production of gametes

Gametes are produced by meiosis

All of the above

14. The tendency of genes in a chromosome to remain together is called:

Pleiotropy

Linkage

Synapsis

Crossing over

15. Which phenomenon reduces the chances of genetic recombination and variations among offspring?

crossing over

dominance

independent

Linkage

16. The multiple effects of a single gene or allele are termed:

Pleiotropy

Test Cross

Epistasis

Co dominance

17. Which of the following crosses is a test cross?

Unknown x Aa

Unknown x AA

Unknown x unknown

Unknown x aa

18. It is the chance of an event to occur

Epistasis

Pleiotropy

Dominance

Probability

19. When round and wrinkled were crossed, it gave all round. This round is:

P1, generation

F1 generation

F3 generation

F2 generation

20. The allele that masks the effects of the other and the masked allele are known as:

Dominant, recessive

Dominant, incomplete

Homozygous, heterozygous

Homozygous, recessive

Variation and genetics / inheritance-Medical College Admission Test Preparation Notes