2nd Year NotesBiology class 12th

2nd Year Biology Chapter 18 – Reproduction

2nd Year Biology Chapter 18 – Reproduction Question and Answer

Short And Simple Question And Answer

Q1: What happens to ovulation and menstruation during pregnancy?

Ans: Ovulation and menstruation do not occur during pregnancy.

Q2: What’s the difference between oogenesis and spermatogenesis in humans?

Ans: Oogenesis produces one egg through meiotic division, while spermatogenesis produces four sperm from a primary spermatocyte.

Q3: How is a seed formed?

Ans: A seed is formed after fertilization of an egg in an ovule.

Q4: Why are seeds important in a plant’s life cycle?

Ans: Seeds enable the embryo to survive adverse conditions like scarcity or low temperature.

Q5: Explain isomorphic and heteromorphic alternation of generations?

Ans: Isomorphic alternation involves similar sporophyte and gametophyte, often seen in green algae. Heteromorphic alternation involves different-looking sporophyte and gametophyte, found in all plants.

Q6: What’s the significance of the pollen tube’s evolution?

Ans: The pollen tube safely transports male gametes to the female gamete in the ovule, aiding seed plants’ success in harsh environments.

Q7: Why are neonates’ eyes affected by STDs?

Ans: If a woman with an STD gives birth, the infected birth canal can lead to eye infections in the newborn.

Q8: Define seed dormancy and its importance?Ans: Seed dormancy is a rest period for the embryo, crucial for surviving unfavorable conditions like water scarcity or low temperatures.

Q9: How do identical and fraternal twins differ?

Ans: Identical twins develop from one embryo splitting, while fraternal twins result from two separately fertilized eggs.

Q10: Explain the difference between viviparous and ovoviviparous?

Ans: Viviparous animals have internal embryo development and give live birth. Ovoviviparous animals internally develop embryos in shelled eggs that hatch upon completion.

Q11: What is lactation, and what hormones stimulate it?

Ans: Lactation is the production of milk from mammary glands. Hormones like prolactin and human placental lactogen stimulate it.

Q12: Which maternal hormones trigger birth?

Ans: A decrease in maternal progesterone and an increase in oxytocin trigger the birth process.

Q13: What is the placenta?

Ans: In placental mammals, the placenta is tissue that facilitates material exchange between the mother and fetus.

Q14: Define after birth?

Ans: After birth refers to the expulsion of the placenta and fetal remains from the uterus shortly after childbirth.

Q15: What is a test tube baby?

Ans: A test tube baby is born from an egg fertilized outside the body and then implanted in the mother’s uterus.

Q16: What are STDs, and can you name some?

Ans: STDs are infections transmitted through sexual contact. Examples include gonorrhea, syphilis, genital herpes, and AIDS.

Q17: Explain one bacterial and one viral STD?

Ans: Syphilis, caused by the bacterium Treponema pallidum, can damage reproductive organs and more. Genital herpes, caused by herpes simplex type 2 virus, affects the genital area with sores and ulcers.

Q18: What is AIDS?

Ans: AIDS (Acquired Immunodeficiency Syndrome) results from HIV infection and weakens the immune system, making individuals susceptible to fatal infections.

Q19: Define parthenocarpy and how it can be induced?

Ans: Parthenocarpy is fruit development without fertilization or seed formation. It can be induced artificially by applying auxins.

Q20: Name two Long Day Plants (LDPs) and two Short Day Plants (SDPs)?

Ans: LDPs include henbane and cabbage, while SDPs include cocklebur and soybean.

Q21: What is apomixis?

Ans: Apomixis is a form of parthenogenesis in flowering plants, where a diploid cell in the ovule develops into a functional embryo without the need for a male gamete.

Q22: What is an estrous cycle?

Ans: An estrous cycle is a reproductive cycle found in most female mammals, except for humans. It involves changes in estrogen production that prepare the uterus for conception.

Q23: Define Menopause?

Ans: Menopause is the complete cessation of the menstrual cycle in women.

Q24: What is ovulation, and where does fertilization occur in humans?

Ans: Ovulation is the release of an egg from a follicle. In humans, fertilization commonly occurs in the proximal part of the oviduct (fallopian tube).

Q25: Name fetal hormones involved in triggering birth?

Ans: ACTH (Adrenocorticotropic hormone) released from the fetal pituitary stimulates the fetal adrenal gland to produce corticosteroids, which enter the maternal bloodstream, leading to a decrease in progesterone production. This decrease triggers the release of oxytocin.

Q26: What is phytochrome, and what are its types?

Ans: Phytochromes are light-sensitive proteins involved in flowering. They exist in two forms: P660 (active in response to red light) and P730 (active in response to far-red light).

Q27: What is reproduction, and why is it important?

Ans: Reproduction is the process of producing new generations and maintaining a species. It is crucial for the survival and continuity of a species or population.

Q28: What is vernalization?

Ans: Vernalization is the treatment of plants with low temperatures to stimulate flowering.

Q29: Define cloning?

Ans: Cloning is a type of asexual reproduction in which genetically identical copies of an organism are produced through genetic engineering.

Q30: Differentiate between oviparous and viviparous animals?

Ans: Oviparous animals lay externally developed eggs with protective shells, while viviparous animals internally develop embryos and give birth to live offspring.

Q31: What is tissue culturing?

Ans: Tissue culturing is the cultivation of tissues for reproducing new, genetically identical varieties.

Q32: Explain the disease gonorrhea?

Ans: Gonorrhea is a sexually transmitted disease caused by the bacterium Neisseria gonorrhoeae. It affects the mucous membranes of the urinogenital tract, and newborns can acquire eye infections if they pass through an infected birth canal.

Q33: What are spermatophytes?

Ans: Spermatophytes are seed-producing plants.

Q34: What is the function of germinating pollen grain?

Ans: A germinating pollen grain facilitates safe gamete transfer, contributes to fertilization, and is a source of auxins, which stimulate tissues in the style and ovary for fruit development.

Q35: What is diploid parthenogenesis?

Ans: Diploid parthenogenesis occurs when egg-producing cells undergo a modified form of meiosis, retaining a diploid number of chromosomes, leading to the development of female offspring.

Q36: What are fraternal twins or triplets?

Ans: Fraternal twins or triplets result from the simultaneous fertilization of two or more separately released eggs, leading to offspring with different genetic combinations.

Q37: What do you mean by Hermaphrodite?

Ans: Hermaphrodite refers to organisms that possess both male and female reproductive organs within the same individual.

Q38: What is fertilization?

Ans: Fertilization is the process that involves the union of gametes, typically leading to the formation of a zygote.

Q39: What is ovoviviparous condition?

Ans: Ovoviviparous condition occurs in certain mammals, like the duckbill platypus, where internal fertilization leads to the development of offspring inside shelled eggs. The eggs are laid, and the offspring hatch from them.

Q40: Which method of reproduction is considered more primitive: asexual or sexual?

Ans: Asexual reproduction is generally considered more primitive than sexual reproduction.

Q41: What is asexual reproduction?

Ans: Asexual reproduction involves a single parental organism producing offspring through mitotic cell division, resulting in genetically identical offspring.

Q42: What are different methods of asexual reproduction?

Ans: Various methods of asexual reproduction include fission, sporulation, budding, vegetative propagation, artificial propagation, parthenogenesis, and apomixis.

Q43: What is sexual reproduction?

Ans: Sexual reproduction involves two parents, with specialized sex cells uniting to produce a fertilized egg, leading to genetic diversity in offspring.

Q44: What is fruit set?

Ans: Fruit set refers to the retention of the ovary, which becomes a fruit after fertilization. The continued production of auxins after fertilization is essential for fruit development.

Q45: Define climacteric?

Ans: Climacteric is a burst of respiratory activity associated with the ripening of fruits. It often involves ethylene production, which aids in fruit ripening.

Q46: What is photoperiodism?

Ans: Photoperiodism refers to the ability of organisms to sense and respond to variations in day length (photoperiod).

Q47: What is florigen?

Ans: Florigen is a hormone found in leaves that travels through the phloem to floral buds, initiating the flowering process.

Q48: Name some advantages of cloning?

Ans: Advantages of cloning include the production of desirable animals, the ability to conduct quantitative studies of hormone and drug effects, and the generation of identical offspring.

Q49: Name some disadvantages of cloning?

Ans: Disadvantages of cloning include potential environmental hazards associated with cloned organisms and incomplete knowledge of clone development.

Q50: What are external genitalia in human males?

Ans: The external genitalia in human males include the testes, which are located outside the body within the scrotum.

Q51: What are spermatocytes and spermatids?

Ans: Spermatocytes are the cells that result from the differentiation of spermatogonia in seminiferous tubules. They undergo meiotic division to form secondary spermatocytes and spermatids, which ultimately develop into sperm.

Q52: What are Sertoli cells?

Ans: Sertoli cells are present in the testes and secrete fluid that provides a liquid medium, protection, and nourishment for sperm while they are in the seminiferous tubules.

Q53: What is testosterone?

Ans: Testosterone is a hormone produced by the interstitial cells of the testes. It is essential for successful sperm production and the development of male secondary sexual characteristics during puberty.

Q54: What are the various parts of the female reproductive system?

Ans: The female reproductive system includes the ovaries, oviducts (fallopian tubes), uterus, and external genitalia.

Q55: What is FSH?

Ans: FSH (Follicle-Stimulating Hormone) is a hormone released by the pituitary gland at the onset of puberty. It stimulates the development of primary follicles in the ovaries.

Q56: What is a fetus?

Ans: A fetus is the term used to describe the developing human organism from the third month of pregnancy onward. It is during this stage that most major organs begin to form.

Q57: What is the average blood loss during delivery?

Ans: The average blood loss during delivery is approximately 350 cm^3.

Q58: What is syphilis?

Ans: Syphilis is a sexually transmitted disease caused by the spirochete bacterium Treponema pallidum. It can damage the reproductive organs, eyes, bones, joints, central nervous system, heart, and skin, and is primarily transmitted through sexual contact.

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