Explanation: – Yeast: Reproduces by budding (small outgrowth).
– Amoeba/Leishmania: Reproduce by Binary Fission.
– Plasmodium: Reproduces by Multiple Fission.
[Image of budding in yeast diagram]
Q2
Which of the following is not a part of the female reproductive system in human beings?
(a) Ovary (b) Uterus
(c) Vas deferens (d) Fallopian tube
Answer: (c) Vas deferens
Explanation: Vas deferens is a tube that carries sperm in the Male reproductive system. Ovary, Uterus, and Fallopian tube are parts of the Female system.
Explanation: Anther is the part of the Stamen (male reproductive part of a flower) which produces and stores Pollen grains.
Q4
What are the advantages of sexual reproduction over asexual reproduction?
1. Genetic Variation: Sexual reproduction involves DNA from two parents, leading to variations in offspring.
2. Evolution: Variations accumulate over generations, helping in the evolution of new species.
3. Adaptation: Organisms with variations are better adapted to survive changes in the environment compared to identical clones from asexual reproduction.
Q5
What are the functions performed by the testis in human beings?
The testes perform two main functions:
1. Production of Sperms: Testes produce the male gametes called sperms (spermatogenesis).
2. Secretion of Hormone: Testes produce the male sex hormone Testosterone. This hormone regulates the production of sperms and brings about changes during puberty (like voice deepening, beard growth).
[Image of human male reproductive system]
Q6
Why does menstruation occur?
1. Every month, the uterus prepares itself to receive a fertilized egg by thickening its lining (endometrium) with blood vessels.
2. If the egg released by the ovary is not fertilized, this thick lining is not needed.
3. The lining breaks down and comes out through the vagina as blood and mucus. This process is called menstruation.
Q7
Draw a labelled diagram of the longitudinal section of a flower.
(Since I cannot draw, here is a description of parts you must label in your diagram)
2. Chemical Methods: Oral pills change hormonal balance to prevent egg release.
3. Intra-Uterine Devices (IUD): Devices like Copper-T placed in the uterus to prevent implantation.
4. Surgical Methods: – Vasectomy: Vas deferens blocked in males.
– Tubectomy: Fallopian tubes blocked in females.
Q9
How are the modes for reproduction different in unicellular and multicellular organisms?
Unicellular Organisms: – Reproduce mostly by Asexual methods (Fission, Budding).
– Simple cell division leads to new individuals.
– No specialized reproductive organs.
Multicellular Organisms: – Reproduce mostly by Sexual methods (though simple ones use fragmentation/regeneration).
– Have specialized reproductive organs and germ cells (gametes).
– Involves complex processes like fertilization and embryo development.
Q10
How does reproduction help in providing stability to populations of species?
1. Continuity: Reproduction ensures new individuals replace the dying ones, preventing extinction.
2. DNA Copying: The transfer of DNA ensures that body design features are maintained across generations (a human gives birth to a human).
3. Variation: Sexual reproduction introduces variations, which allows the species to adapt to changing environments, ensuring long-term stability and survival.
Q11
What could be the reasons for adopting contraceptive methods?
1. Population Control: To limit family size and control population growth.
2. Health: To maintain the health of the mother by spacing pregnancies.
3. STI Protection: Barrier methods (condoms) protect against Sexually Transmitted Infections (STIs) like HIV/AIDS.