Find the heredity exercise sample for science and technology. You can find complete notes of heredity, based on CDC syllabus. You can read the notes portion and try to do the exercise by yourself. You can take this as a refrence and comment down your problems.

A. Multiple Choice Question

1.Karyokinesis is the division of.

a. nucleus (✓)

b. mitochondria

c. cytoplasm

d. nucleolus

2. The shortest phase of mitosis is.

a. prophase

b. anaphase

c. metaphase (✓)

d. telophase

3. Synapsis occurs in.

a. leptotene

b. pachytene (✓)

c. zygotene

d. diplotene

4. Crossing Over occurs during.

a. leptotene

b. pachytene

c. zygotene (✓)

d. diplotene

5. The total pairs of chromosomes present in a cell of human beings is.

a. 46

b. 10

c. 25

d. 23 (✓)

6. The basic genetic material of chromosomes is.

a. DNA (✓)

b. proteins

c. RNA

d. telomere

7. Which of the following is not the nitrogenous base of RNA?

a. Adenine

b. Thymine

c. Guanine (✓)

d. Uracil

8. Mendel experimented on.

a. pea plant (✓)

b. mouse

c. mango plant

d. human being

9. The ratio of tall pea plant to dwarf pea plant observed by Mendel in his experiment after cross-pollination was found.

a. 1:3

b. 1:2:1 (✓)

c. 3:1

d. 4:1

10. On the course of seed selection, … seeds are not avoided.

a. wrinkled

b. crushed

c. broken

d. infection free (✓)

B. Very Short Answer Questions

1. What is a gene?

Ans. A segment of DNA that codes for a particular character in an organism is known as a gene.

2. Why is mitosis cell division also called equational cell division?

Ans. In the mitosis cell division, the cells of the same types having the same numbers of chromosomes similar to that of the mother cell are formed, hence it is called homotypic or equational cell division.

3. Define Cytokinesis.

Ans. Cytokinesis is known as the division of cytoplasm present in the cell.

4. Why is meiosis cell division also called reductional cell division?

Ans. In meiosis cell division, germinal cells divide to form four daughter cells having half the number of chromosomes in each of them, hence it is called reductional cell division.

5. Define Chromosome.

Ans. Chromosomes are thread-like structures that are visible only at the time of cell division and are responsible for the transfer of genetic information to the daughter cells.

6. Write a function of the chromosome.

Ans. Sex determination is one of the functions of the sex chromosome.

7. How many chromosomes are present in a cell of the human body?

Ans. There are 23 pairs (46) numbers of chromosomes in a cell of the human body.

8. What is the number of chromosomes in a cell of a pea plant?

Ans. There are 14 numbers (7 pairs) of chromosomes in a pea plant.

9. Write the position of the centromere in the metacentric chromosome.

Ans. The position of the centromere in the metacentric chromosome is in the middle of the chromosome.

10. Write the function of DNA.

Ans. The function of DNA is to transfer hereditary characteristics from parents to offspring.

11. Name the nitrogenous bases found in RNA.

Ans. The nitrogenous bases present in RNA are Adenine, Guanine, Cytosine, and Uracil.

12. What is a sex chromosome?

Ans. The sex chromosome is one of the types of chromosome, which is responsible for the sex determination of an organism.

13. What sex chromosomes are found in males and females?

Ans. Paired X chromosome is found in females and a single X or Y chromosome is found in males. Y-chromosome is found in only male individuals.

14. What chromosome of the human male is responsible for the formation of a male child?

Ans. The Y chromosome of the human male is responsible for the formation of a male child.

15. What is phenotype?

Ans. The physical traits that can be observed in an individual are known as phenotypes. Examples – the color of the eye, hair, tallness, etc.

16. Define Genotype.

Ans. Genotype refers to the genetic constitution of the individual which cannot be studied by direct observation but can be known through the study of the ancestors, offspring, etc.

17. Define monohybrid cross.

Ans. The genetic cross between the gametes of two parents considering a single pair of characters is known as a monohybrid cross. Only the inheritance of a single trait is studied.

18. Define dihybrid cross.

Ans. The genetic cross between the gametes of two parents considering two pairs of contrasting traits is known as a dihybrid cross. Inheritance of two independent traits is studied.

19. Who is known as the father of genetics?

Ans. Greoger Johann Mendel, an Austrian scientist, is known as the father of genetics.

20. State Mendel’s law of dominance.

Ans. Mendel’s law of dominance states that when two parents having contrasting pair of characters are crossed, only one form of character appears in the next generation.

21. State Mendel’s law of purity of gametes.

Ans. Mendel’s law of purity of gametes states that though the two contrasting pair of characters, either dominant or recessive, remain together for a long time, they do not mix up and only segregate at the time of gamete formation so that each gamete carry only one character. This is also called the law of segregation.

C. Short Answer Questions

1. Write any two functions of genes.

Ans. The two functions of genes are:

i. Genes carry hereditary information from one generation to another.

ii. Genes control the structure and mechanism of the body.

2. What are the significances of mitosis cell division? Write any two points.

Ans. The significances of mitosis cell division are as follows.

i. This division maintains genetic stability in successive generations.

ii. It plays a significant role in organisms that follow an asexual mode of reproduction.

3. How does meiosis help in maintaining the stability of chromosome numbers in organisms?

Ans. Meiosis is a process that forms special cells called gametes. These gametes have half the number of chromosomes compared to other cells, making them haploid. When a male and female gamete combine, they create a zygote. This helps maintain the same number of chromosomes in a species.

4. How does a zygote have a diploid chromosome? Show with a chart.

A zygote has a diploid chromosome number because it is formed by the fusion of two haploid gametes, one from each parent.

5. Write any two differences between the sex chromosome pairs found in humans?

Ans. The differences between the sex chromosome pairs found in humans are:

i. It occurs paired in females and single in males.
ii. It contains genes for female sex determination.
i. It is found only in the cells of male individuals.
ii. It contains genes for male sex determination.

6. A woman has got only four daughters but not a son. Does it mean that the husband did not produce the ‘Y’ chromosome-bearing sperm? Explain it.

Ans. It does not mean that the husband did not produce the ‘Y’ chromosome-bearing sperm. The sex of a child is determined by the type of sperm that fertilizes the egg, with X-bearing sperm resulting in female offspring and Y-bearing sperm resulting in males. The combination of sperm and egg during fertilization is a matter of chance, and in this case, it happened that each time an egg was fertilized, an X-bearing sperm fused with it, leading to the birth of daughters. It does not indicate a deficiency in the husband’s ability to produce Y-bearing sperm, but rather a random outcome of fertilization.

7. A woman has given birth to three daughters only. Her family members are blaming her for giving birth to daughters only. With the help of a sex determination chart, justify that the woman is not responsible for the birth of the daughters.

Ans. A sex determination chart clearly shows that the woman’s genetic contribution is always an X chromosome, while the father determines the sex of the child by providing either an X or Y chromosome. It is the father’s genetic contribution that determines the sex of the child, not the mother’s. Therefore, the woman is not responsible for the birth of daughters only, as it is solely determined by chance and the father’s contribution.

8. Which process is represented by the given chart? According to that process, write down the differences between (44, XX) and (44, XY).

Ans. In the genetic notation of human sex chromosomes, (44, XX) represents a female individual with 44 autosomes and two X chromosomes, while (44, XY) represents a male individual with 44 autosomes, one X chromosome, and one Y chromosome.

9. Why did Mendel select the pea plant to perform his experiment? Write any two reasons.

Ans. Mendel selected the pea plant for his experiment to perform his experiment due to the following methods.

  • Pea plants have easily distinguishable traits.
  • Pea plants have both self-pollinating and cross-pollinating capabilities.

10. How is a hybrid produced? Explain with an example.

Ans. Hybrid is produced by the cross-pollination of dominant and recessive characters. i.e. hybrid tall pea plants are produced when pure tall and pure dwarf pea plants are cross-pollinated.

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