Mendel's Work

Q. Mendel selected pea plant for his experiments because of the following reasons, except

1. Garden pea has distinct, easily detectable contrasting characters
2. The pea plant is self-pollinating in nature because pea flower is bisexual
3. The plant reproduces well and grows to maturity in a single season
4. Cross pollination could not be done artificially

Q.

Why did mendel choose pea plants for his experiments?

Q.

Choose the correct option-

A molecule that can act as a genetic material must fulfill the traits given below, except-

1. It should be able to generate its replica

2. It should be able to express itself in the form of ‘Mendelian characters’

3. It should provide the scope for slow changes that are required for evolution

4. It should be unstable structurally and chemically

Q.

What is a two-point test cross?

Q.

After self-pollination in pea plants with round, yellow seeds. Following types of seeds were obtained by Mendel: Round-Yellow- 630, Round-Green - 216, Wrinkled- Yellow -202, Wrinkled- Green - 64. Analyze the result and describe the mechanism of inheritance which explains these results.

Q.

Mendel first crossed pure-bred pea plants having round -yellow seeds with pure-bred pea plants having wrinkled -green seeds and found that only round- yellow seeds were produced in the $F_1$ generation. When $F_1$ generation pea plants having round-yellow seeds were cross-bred by self-pollination, then peas having round-yellow seeds, round green seeds, wrinkled-yellow seeds and wrinkled -green seeds were produced. Mendel collected a total of 2160 seeds.

(a) What will be the number of (i) round green seeds (ii) wrinkled green seeds (iii) round yellow seeds, and (iv) wrinkled-yellow seeds?

(b) Which 'ratio' as established by Mendel have you made use of in answering the part (a) above?

Q. The ratio obtained in the ${\text{F}}_2$ generation for a dihybrid cross between round yellow seeds and green wrinkled seeds is ____.

1. 9:5:5:3
2. 9:3:4:3
3. 9:3:3:3
4. 9:3:3:1

Q.

In peas, a pure tall plants (TT) is crossed with a pure short plant (tt). The ratio of pure tall plants to pure short plants in $F_2$ generation will be :

(a) 1 : 3 (b) 3 : 1 (c) 1 : 1 (d) 2 : 1

Q.

Law of independent assortment is ___.

1. Applicable to all dominant genes only

2. Applicable to all genes on all chromosomes

3. Applicable to those genes present on the same chromosome

4. Not applicable to genes present on the same chromosome

Q.

Different versions of the same gene are called _______.

1. alleles

2. chromosomes

3. centromeres

4. gametes

Q.

Which of the following statements about alleles is not true?

1. There may be several at a locus

2. One may be dominant over another

3. They may show incomplete dominance

4. They occupy different loci on the same chromosome

Q.

What is it called when two homologous chromosomes code for different alleles?

Q.

How does Hardy-Weinberg show evolution?

Q.

Study the following cross and show self-pollination in F1, fill in the blank and answer the question that follows.

Q.

The genetic constitution of an organism is called alleles.

1. True

2. False

Q.

Is blood a polygenic trait?

Q.

The physical appearance of an individual is known as

1. genotype

2. morphotype

3. Phenotype

4. heterotype

Q. Assertion (A) : The sex of a child in human beings will be determined by the type of chromosome he/she inherits from the father.
Reason (R) : A child who inherits ‘X’ chromosome from his father would be a girl (XX), while a child who inherits a ‘Y’ chromosome from the father would be a boy (XY).

1. Both (A) and (R) are true, but (R) is not the correct explanation of the assertion (A).
2. (A) is false, but (R) is true.
3. Both (A) and (R) are true and (R) is the correct explanation of the assertion (A).
4. (A) is true, but (R) is, false.

Q.

Some individuals with blood group A may inherit the genes for blond hair, while other individual with blood group A may inherit the gene for brown hair. This can be best explained by the principle of:

1. Dominance

2. Multiple alleles

3. Independent assortment

4. Incomplete dominance

Q.

Plant height and its growth is regulated by hormones. Hormone production is controlled by ___________.

1. genes which control enzyme activity for hormone production

2. proteins which control growth

3. essential nutrients supplied from soil

4. nucleus and certain minerals in the cytoplasm of plant cells

Q. In a family, a girl and her brother are said to be more closely related as compared to girl and her first cousin on evolutionary basis. Identify the correct statement based on this information.

Statement 1: They have a common ancestor in the second generation.

Statement 1: They have a common ancestor in the first generation.

1. Both the statements are correct
2. Only statement 1 is correct
3. Only statement 2 is correct
4. Both the statements are incorrect

Q.

(a) Name the scientist who gave the laws of inheritance.

(b) Name an animal in which individuals can change sex. What does this indicate ?

Q.

Mendel conducted his experiments on which plant to study the mechanism of inheritance?

Q.

How Mendel interpreted his result to show that the traits may be dominant or recessive?

Q. a) Among lion, tiger and domestic cat, all the three have the same number of 38 chromosomes, yet they have different appearances. How do you account for such differences? [5 MARKS]
b) List any three features of garden pea with their dominant and recessive traits.

Q.

Which of the following may be used to obtain an $F_2$ generation ?

(a) allowing flowers on a parent plant to be self -pollinated

(b) allowing flowers on an $F_1$ plant to be self -pollinated

(c) cross-pollinating an $F_1$ plant with a parent plant

(d) cross-pollinating two parent plants

Q.

In order to ensure that he had pure-breeding plants for his experiments, Mendel :

(a) cross-fertilised each variety with each other

(b) let each variety self fertilise for several generations

(c) removed the female parts of the plants

(d) removed the male parts of the plants.

Q.

Consider that curly hair were dominant over straight hair. If a person was heterozygous for the characteristic of hair, what would it mean?

1. The person would have curly hair

2. The person would have straight hair

3. The person could have either straight or curly hair

4. The person would have neither straight nor curly hair

Q. Which of the following is not an appropriate reason for Mendel's choice of pea plant?

1. They are easy to grow in the garden.
2. Pea flowers are hermaphrodite.
3. Self-fertilization makes it simple to obtain pure breed plants.
4. Pea plants have a longer generation time.

Q.

Is blonde hair a genotype or phenotype?