Question 1

Which one of the following traits of garden pea studied by Mendel was a recessive feature?

Accepted Answer

Green seed colour was a recessive feature.

Question 2

The genes controlling the seven pea characters studied by Mendel are now known to be located on how many different chromosomes?

Accepted Answer

(d) : Mendel worked on seven characters. These characters showed complete independent assortment despite the seven characters chosen by him were present on four chromosomes −1,4,5 and 7 .

Question 3

According to Mendelism, which character shows dominance?

Accepted Answer

Green pod colour shows dominance.

Question 4

First geneticist/father of genetics was

Accepted Answer

An Austrian monk, Gregor Mendel, developed his theory of inheritance. He formulated the Law of Heredity. Therefore, he is called the 'father of genetics'.

Question 5

An organism with two identical alleles is

Accepted Answer

An organism with two identical alleles is homozygous. Homozygous have identical genes at the same locus on each member of a pair of homologous/ chromosomes.

Question 6

Multiple alleles control inheritance of

Accepted Answer

ABO blood group system is due to multiple allelism. A gene can have more than two alleles or allelomorphs, which can be expressed by mutation in wild form in more than one ways. These alleles or allelomorphs make a series of multiple alleles. The mode of inheritance in case of multiple alleles is called multiple allelism. A well known and simplest example of multiple allelism is the inheritance of ABO blood groups in human beings. In human population, 3 different alleles for this character are found −IAIB and IO. A person is having only two of these three alleles and blood type can be determined.

Question 7

Mendel's last law is

Accepted Answer

Mendel's last law is independent assortment. The principle of independent assortment states that when two individuals differ from each other in two or more pairs of factors, the inheritance of one pair is quite independent of the inheritance of other.

Question 8

ABO blood group system is due to

Accepted Answer

ABO blood group system is due to multiple allelism.

Question 9

Ratio of complementary genes is

Accepted Answer

If two genes present on different loci produce the same effect when present alone but interact to form a new trait when present together, they are called complementary genes. The F2​ ratio is modified to 9:7 instead of 9:3:3:1.

Question 10

A gene pair hides the effect of another gene. The phenomenon is called

Accepted Answer

A gene pair hides the effect of another gene. The phenomenon is called epistasis.

Question 11

When two dominant independently assorting genes react with each other, they are called

Accepted Answer

Complementary genes are those non-allelic genes which independently show a similar effect but produce a new trait when present together in the dominant form. Supplementary genes are a pair of non-allelic genes, one of which produces its effect independently in the dominant state while the dominant allele of the second gene is without any independent effect but is able to modify the effect of the former to produce a new trait. Duplicate genes are independent genes producing the same or similar effect.

Question 12

The phenomenon, in which an allele of one gene suppresses the activity of an allele of another gene, is known as

Accepted Answer

The phenomenon, in which an allele of one gene suppresses the activity of an allele of another gene, is known as epistasis.

Question 13

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

Accepted Answer

The allele which is unable to express its effect in the presence of another is called recessive. A member of a pair of alleles that does not show its effect in the phenotype in the presence of any other allele. It is denoted by small letter.

Question 14

Inheritance of skin colour in humans is an example of

Accepted Answer

Polygenic (or Quantitative) inheritance is that type of inheritance in which the complete expression of a trait is controlled by two or more genes in which a dominant allele of each gene contributes only a unit fraction of the trait and total phenotypic expression is the sum total of a additive or cumulative effect of all the dominant alleles of genes/polygenes. Human skin colour is an example of such polygenic inheritance which is controlled by three pairs of polygenes A, B and C. Negro/ black colour is due to presence of all the six dominant contributing alleles AABBCC. Very light colour or white colour is due to presence of all six recessive noncontributing alleles aabbcc.

Question 15

Which one of the following is an example of polygenic inheritance?

Accepted Answer

Skin colour in humans is an example of polygenic inheritance.

Question 16

In human beings, multiple genes are involved in the inheritance of

Accepted Answer

In human beings, multiple genes are involved in the inheritance of skin colour.

Question 17

A polygenic inheritance in human beings is

Accepted Answer

A polygenic inheritance in human beings is skin colour.

Question 18

When a single gene influences more than one trait it is called

Accepted Answer

The ability of a gene to have multiple phenotypic effect because it influences a number of characters simultaneously is known as pleiotropy.

Question 19

More than 70% of world's freshwater is contained in

Accepted Answer

Nearly about 97% of the earth's water is saline in the oceans and seas. 3\% of the earth's water is locked up on the polar ice caps. 85% of the frozen freshwater is in the Antarctic is ice cap, 15% of the frozen freshwater is in the northern polar ice cap and glaciers.

Question 20

Which was absent in the atmosphere at the time of origin of life?

Accepted Answer

(d) Am

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