Here are practice Questions for SSC / Tenth Class Biology from the lesson Reproduction. One mark, two mark and four mark questions are given below.

One mark questions

Q. What is totipotency?
A. The ability of a plant cell to give rise to a whole plant when cultured under appropriate conditions is called totipotency.

Q. What is an explant?
A. The portion of the plant that is taken from the parent plant for culturing on media is called explant.

Q. What do you understand by sexual dimorphism?
A. The phenomenon of possession of only one sex by an organism is called sexual dimorphism.

Q. What prevents self fertilization in earthworm?
A. In earthworm, testes mature earlier than the ovaries and this prevents self fertilization.

Two marks questions

Q. What is corpus luteum? What is its function?
A. The ruptured graffian follicle which releases one ovum is called corpus luteum. It secretes female sex hormones such as oestrogen and progesterone.

Q. What is embryo rescue? When is this method followed?
A. There are certain embryos that do not develop inside the ovary. To get plants from these embryos, they must be grown in culture media. This is called embryo rescue. Plants tolerant to drought, pathogens etc., can be isolated by creating these conditions in the culture medium. New hybrid species can be evolved by tissue culture.

Q. Define milt and spawn.
A. Milt: Thousands of spermatozoa discharged in a group.
Spawn: Large number of eggs released in a mass is called spawn.

Q. What is menstrual cycle?
A. In females the production of ova takes place once in 28 to 30 days. During this period, the entire female reproductive system undergoes several changes in anticipation of pregnancy. If fertilization does not occur, the ovum degenerates in 24 hours after its release. Again, changes are repeated to produce the ovum. This cycle of changes in female reproductive system is called menstrual cycle.

Four marks questions

Q. What are the applications of plant cell and tissue culture?
A. The following are the advantages of tissue culture:
- Desirable plants can be rapidly multiplied.
- Multiplication can be done throughout the year in a small space under controlled conditions.
- Plants free from pathogens can be obtained.
- In embryo culture, embryos which do not develop inside the ovary can be grown in culture media.
- Plants tolerant to drought and pathogens can be isolated by creating these conditions in the culture medium.
- New hybrid species and mutants can be evolved by tissue culture.
- Useful chemicals, which are usually extracted from whole plant, can be produced in plant cell culture in liquid media.
- Synthetic or artificial seeds can be produced.

1. Draw a neat labelled diagram of longitudinal section of Datura flower.
2. Draw a neat labelled diagram of human sperm.

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