Chapter 4 : Principles of Inheritance and Variation

Question 1

Whatson met Crick and discovered their common interest in solving the _____________ structure.

Answer 1

DNA

Question 2

____________ completed Ph.D. in 1954 on a thesis entitled “X-ray Diffraction: Polypeptides and Proteins”

Answer 2

Francis Harry Compton Crick

Question 3

The Honours to Watson with Crick include:

1. The john Collins warren prize of the Massachusetts general hospital,1959
2. The Lasker Award, in 1960
3. The Research Corporation prize, in 1962
4. _______________________

Answer 3

The Noble Prize in 1962

Question 4

____________ subject deals with the inheritance, as well as the variation of characters from parents to offspring.

Answer 4

Genetics

Question 5

___________ is the process by which characters are passed on from parent to progeny

Answer 5

Inheritance

Question 6

____________ is the degree by which progeny differ from their parents.

Answer 6

Variation

Question 7

Through artificial selection and domestication from ancestral wild cows, we have well-known Indian breeds, _____________ cows in Punjab.

Answer 7

Sahiwal

Question 8

Gregor Mendel, conducted hybridisation experiments on garden peas for seven years (1856-1863) and proposed the _________________ in living organisms.

Answer 8

laws of inheritance

Question 9

A ____________ line is one that, having undergone continuous self-pollination, shows the stable trait inheritance and expression for several generations.

Answer 9

true-breeding

Question 10

Mendel selected _____ true-breeding pea plant varieties, as pairs which were similar except for one character with contrasting traits.

Answer 10

14

Question 11

Contrasting traits Studied by Mendel in pea are:-

1. Stem height :- Tall/dwarf
2. Flower colour :- Violet/white
3. Flower position :- Axial/terminal
4. Pod shape:- Inflated/constricted
5. Pod colour:- _________________
6. Seed colour:- _________________
7. Seed shape:- Round/wrinkled

Answer 11

Pod colour:- Green/yellow
Seed colour:- Yellow/green

Note:- 7 contrasting traits studied by Mendel in pea

Question 12

Hybridisation experiment carried out by Mendel where he crossed tall and dwarf pea plants to study the _________________

Answer 12

inheritance of one gene

Question 13

Mendel collected the seeds produced by tall and dwarf pea cross and grew them to generate plants of the first hybrid generation.This generation is also called the __________ or the ____

Answer 13

Filial₁ progeny
F₁

Question 14

Mendel observed that all the ___________ progeny plants were tall, like one of its parents, none were dwarf.

Answer 14

F₁

Question 15

Mendel found that the _____ always resembled either one of the parents, and that the trait of the other parent was not seen in them.

Answer 15

F₁

Question 16

Mendel then self-pollinated the tall F₁ plants and to his surprise found that in the ___________ generation some of the offspring were ‘dwarf’

Answer 16

F₂

Question 17

Mendel proposed that something was being stably passed down, unchanged, from parent to offspring through the __________, over successive generation. He called these things as ___________ . Now we call them as ___________

Answer 17

gametes
‘factors’
genes

Question 18

_________ are the units of inheritance

Answer 18

genes

Question 19

Genes which code for a pair of contrasting traits are known as ____________

Answer 19

alleles

Note:- they are slightly different forms of the same gene

Question 20

In case of the character of height, T is used for the Tall trait and t for the dwarf, and T and t are __________ of each other

Answer 20

alleles

Question 21

Mendel also proposed that in a true breeding, tall or dwarf pea variety the allelic pair of genes for height are identical or ______________ , TT and tt

Answer 21

Homozygous

Question 22

TT and tt are called the ____________ of the plant while the descriptive term tall and dwarf are the _____________

Answer 22

genotype
phenotype

Question 23

Mendel found the phenotype of the F₁ heterozygote Tt to be exactly like the TT parent in appearance, he proposed that in a pair of dissimilar factors, one dominates the other(as in F₁,Tt) and hence is called the _____________ factor while the other factor is _______________

Answer 23

dominant
recessive

Question 24

Alleles can be similar as in the case of ___________ TT and tt or can be dissimilar as in the case of the __________ Tt

Answer 24

homozygotes
*heterozygote

Question 25

The **Tt** plant is ***heterozygous*** for genes controlling **one character(height)**, it is a _____________ and the cross between **TT** and **tt** is a _____________ cross

Answer 25

**monohybrid** **monohybrid cross**