Chapter 8 – How do Organisms Reproduce?

1) What is reproduction & why has it become necessary?

Ans – Reproduction is the biological process by which living organisms create offspring of their kind. It is vital to combine species, ensuring genetic diversity & survival.

2) Define Callus!

Ans – In vegetative distribution through artificial techniques, a callus refers to a mass of monotonous plant cells that forms at the site of a wounded or cut plant tissue. It is a cell source for developing new plant organs, such as roots or shoots & is used in tissue culture methods for plant propagation.

3) What are self & cross-pollination? Answer with examples.

Ans – Self-pollination occurs when pollen from the stamen of a flower is transferred to the stigma of the same flower or a different flower on the same plant like pea plants, rice & wheat.

Cross-pollination, on the other hand, occurs when pollen grains from one flower’s stamen are passed on to another flower’s stigma on a different plant of the same species like apples & plums.

4) What do you mean by a clone? Why does asexual reproduction produce identical offspring?

Ans – A clone is an exact genetic replica of a living being produced through asexual reproduction. Asexual reproduction or gamogenesis creates identical offspring due to its involvement in the replication of a single parent’s genetic element without genetic recombination. Hence, the offspring inherit identical genetic information from the parent, resulting in genetic similarity among individuals.

5) What is the operation behind the prostate & Cowper’s gland?

Ans – The prostate gland secretes a fluid that creates part of semen, nourishing & protecting sperm. It also helps in sperm motility. Cowper’s gland forms a pre-ejaculatory fluid that neutralizes acidity in the urethra, providing lubrication and enhancing sperm viability on ejaculation.

6) How is fission different from budding?

Ans – Fission is different from budding in the following ways:

Fission	Budding
In fission, the division of the parent organism occurs into two or multiple cells.	In budding, repeated cell division might form a bud as a cell outgrowth. The bud develops and detaches from the parent while growing.
Parental identity is not preserved in fission.	Parental identity is preserved in budding.

7) Mention the birth control surgical methods in males & females of human beings.

Ans – In males, the birth control surgical operation is vasectomy & castration, where the vas deferens (the tube that carries sperm from the testes to the urethra) are surgically cut or blocked & the testes are completely removed.

In females, the surgical method is tubal ligation or tubectomy, where the fallopian tubes are either cut, tied, or sealed (laparoscopy) to prevent eggs from reaching the uterus. Also, ovariectomy happens when ovaries are removed.

8) What do you mean by the term ‘micropropagation’? What are the benefits of it?

Ans – Micropropagation is a technique used to rapidly produce large amounts of genetically identical plants from a small piece of plant tissue, like a shoot tip or leaf, under sterile lab conditions.

Advantages include,

• Rapid propagation.
• Production of disease-free plants.
• Preservation of rare or endangered species.

9) Write 3 asexual reproduction methods.

Ans – Three major techniques of asexual reproduction include:

• Binary Fission: In this process, an organism divides into two equal parts, each developing into a new individual. In unicellular, organisms divide into 2 halves multicellular, the nucleus first divides followed by the cytoplasm. Example: Bacteria.
• Spore Formation: Spore formation is a method of asexual reproduction in which specialized reproductive cells called spores are produced by certain organisms, such as fungi, algae, and some plants. Spores are single-celled structures capable of germinating into new individuals under favorable conditions, allowing for the dispersal and propagation of the organism.
• Fragmentation: In this process, the parent organism breaks into fragments with each fragment capable of growing into a new individual. Example: Starfish.

10) How is asexual reproduction different from sexual reproduction?

Ans – Here are the differences between sexual & asexual reproduction.

Asexual reproduction	Sexual reproduction
Only one parent is involved.	Two parents are involved.
Offsprings are similar to parents.	Offsprings share features of both parents.
Cells divide in the form of mitosis.	Cells divide via mitosis and meiosis.
There is no fertilization.	Fertilization occurs by producing gametes.
There is no production of gametes.	Gametes are produced.
Offsprings produced with less adaptability.	Offsprings produced have more adaptability.
There are no genetic variations.	There are genetic variations in offspring.