Practice Questions for Science Class 10th "How do Organisms Reproduce"

Multiple Choice Questions (MCQs):

1. C) Fertilization - Fertilization is a process of sexual reproduction, not asexual.
2. B) Asexual reproduction - Asexual reproduction results in genetically identical offspring from one parent.
3. C) Fallopian tube - Fertilization in humans typically occurs in the fallopian tube.
4. B) Ovary - After fertilization, the ovary of the flower develops into the fruit.
5. C) Stamen - The stamen is the male reproductive part of a flower, consisting of anther and filament.
6. B) Tuberculosis - Tuberculosis is not an STD; it's a bacterial infection affecting the lungs.
7. C) Both A and B - DNA replication occurs before both mitosis and meiosis.
8. D) All of the above - The placenta performs all these functions during pregnancy.
9. C) Testosterone - Testosterone is the primary hormone responsible for male puberty changes.
10. A) Pollination - The transfer of pollen grains to the stigma is pollination.
11. B) Germination - Germination is the process where an organism grows from a spore or seed.
12. B) Testes - Sperm are produced in the testes.
13. A) To connect the fetus to the mother's blood supply - The umbilical cord provides this connection.
14. C) Sporulation - Sporulation is not a method of vegetative propagation; it's more related to spore formation.
15. A) Ovum and sperm - The zygote is formed by the fusion of an ovum and a sperm cell.
16. D) All of the above - Menopause involves all these changes.
17. A) Hydra by budding - Hydra reproduces asexually through budding.
18. D) Both B and C - Estrogen and progesterone are primary female sex hormones.
19. B) Ovary - Eggs mature in the ovaries.
20. B) Meiosis - Meiosis is the cell division process involved in gamete formation.

Short Answer Questions:

21. Reproduction Definition:

• Reproduction is the biological process by which new individual organisms are produced from their parents. It's essential for species survival as it ensures the continuity of species, genetic diversity, and adaptation to environmental changes.

22. Asexual vs. Sexual Reproduction:

• Asexual: One parent, no gamete fusion, offspring are genetically identical, quicker and simpler.
• Sexual: Two parents, involves gamete fusion, leads to genetic diversity, slower but promotes evolution.

23. Binary Fission in Amoeba:

• Amoeba divides into two identical daughter cells by duplicating its nucleus followed by the division of the cell body.

24. Advantages of Vegetative Propagation:

• Quick multiplication, maintains desirable traits, no need for seeds, and can be done in controlled conditions.

25. Pollination Process:

• Pollen from anthers is transferred to the stigma, either by wind, water, or pollinators like insects, birds, or bats.

26. Role of Uterus:

• The uterus provides a nurturing environment for the developing fetus, supports implantation, and contracts during childbirth.

27. Male Reproductive System Function:

• Testes produce sperm, which travel through the epididymis, vas deferens, and are mixed with fluids from accessory glands (like the prostate) before ejaculation.

28. Menstrual Cycle Significance:

• Prepares the female body for potential pregnancy by thickening the uterine lining and releasing an ovum. If no pregnancy occurs, the lining sheds, leading to menstruation.

29. Regeneration Example:

• In planarians (flatworms), a piece of the body can regenerate into a complete organism.

30. Sexual Reproduction Advantage:

• It introduces genetic variation, which is key for evolution, adaptation, and survival in changing environments.

31. Pollen Tube Function:

• It grows from the pollen grain on the stigma to deliver sperm nuclei to the ovule for fertilization.

32. Flower Structure Supporting Reproduction:

• Stamen and carpel are specialized for producing and receiving gametes. Bright colors and scents attract pollinators.

33. Germination Process:

• A seed absorbs water, leading to embryo growth, root emerges first, followed by the shoot, using stored nutrients in the cotyledons or endosperm.

34. Preventing STDs:

• Use of condoms, maintaining sexual hygiene, avoiding multiple partners, regular health checks, and vaccinations where available.

35. Testosterone in Puberty:

• Causes growth of body hair, deepening of voice, muscle development, and initiation of sperm production.

36. Prostate Gland Role:

• Produces a fluid that nourishes and protects sperm, aiding in their motility.

37. Parthenogenesis:

• Development of an embryo from an unfertilized egg. Example: Some species of lizards where females can produce offspring without mating.

38. Placenta's Role:

• Facilitates gas exchange, nutrient supply, waste removal, and hormone production for pregnancy maintenance.

39. Hormonal Changes in Female Puberty:

• Increased levels of estrogen and progesterone lead to breast development, menstrual cycle initiation, and body fat redistribution.

40. Asexual Reproduction Conditions:

• Often in stable environments or when rapid population growth is advantageous, like in bacteria or some plants under stress.

Long Answer Questions:

41. Asexual Reproduction in Plants:

• Vegetative Propagation: Includes cuttings (e.g., sugarcane), layering (e.g., jasmine), grafting (e.g., fruit trees), and runners (e.g., strawberries).
• Spore Formation: Seen in ferns and mosses where spores develop into new plants under suitable conditions.
• Fragmentation: Algae or fungi where parts of the organism break off and grow into new individuals.

42. Fertilization in Humans:

• Sperm travel through the female reproductive tract, one sperm penetrates the egg's zona pellucida, leading to the fusion of sperm and egg nuclei forming a zygote.

43. Puberty Changes in Females:

• Physical: Breast development, growth spurt, body hair, and onset of menstruation.
• Hormonal: Increased estrogen and progesterone, triggering secondary sexual characteristics and menstrual cycle regulation.

44. Contraceptive Methods:

• Natural: Fertility awareness methods, withdrawal, or abstinence.
• Artificial: Barrier methods (condoms), hormonal methods (pills, implants), IUDs, sterilization. They work by preventing sperm-egg meeting, altering hormone levels, or blocking fertilization.

45. Human Embryonic Development:

• Zygote: After fertilization.
• Cleavage: Rapid cell division.
• Morula: Solid ball of cells.
• Blastocyst: Hollow ball implanting in the uterus.
• Embryo: From implantation to 8 weeks, with organ formation.
• Fetus: From 9 weeks until birth, growth and maturation.

46. Hormones in Menstrual Cycle:

• FSH: Stimulates egg maturation.
• LH: Triggers ovulation.
• Estrogen: Thickens uterine lining, prepares for pregnancy.
• Progesterone: Maintains pregnancy if fertilization occurs, otherwise its drop leads to menstruation.

47. Reproductive Strategies Comparison:

• Yeast: Can reproduce asexually by budding or sexually when conditions are harsh.
• Hydra: Primarily asexual via budding, but can reproduce sexually with environmental cues.
• Humans: Sexual reproduction for genetic diversity, involving complex behavioral and physiological changes.

48. Flower Adaptations for Reproduction:

• Pollination: Bright petals, nectar, and scent attract pollinators; stamen position facilitates pollen transfer.
• Fertilization: Stigma and style design allow pollen tube growth for sperm delivery.

49. Types of Pollination:

• Self-pollination: Within the same flower or plant (e.g., peas).
• Cross-pollination: Between different plants, often aided by external agents like insects (e.g., apple trees).

50. Genetic Variation and Evolution:

• Sexual reproduction shuffles genetic material, leading to variations which natural selection acts upon, driving evolution.

51. Seed Dispersal:

• Methods include wind, water, animals, and self-propulsion. Significance lies in spreading species, reducing competition, and colonizing new habitats.

52. Environmental Factors on Reproduction:

• Temperature, light, water availability, and predation can influence reproductive timing, method, and success rate, leading to adaptations like seasonal breeding.

53. Population Growth Implications:

• Can lead to resource depletion, habitat alteration, or increased competition, potentially driving evolutionary changes or species extinction.

54. Cloning as Asexual Reproduction:

• Cloning produces genetically identical organisms, similar to asexual reproduction, but through artificial means like nuclear transfer.

55. Ethical Considerations of IVF:

• Issues include embryo selection, disposal, multiple pregnancies, genetic screening for non-medical traits, and access to technology.

56. Plant Reproduction and Biodiversity:

• Plants contribute to biodiversity through genetic diversity from cross-pollination, co-evolution with pollinators, and habitat creation.

57. Impacts of STDs:

• Biological: Health issues, fertility problems, increased disease transmission.
• Societal: Stigma, economic burden, impact on public health systems.

58. Seeds and Vegetative Propagules:

• Allows for both genetic diversity (seeds) and rapid, reliable reproduction (vegetative parts) under different environmental conditions or for different survival strategies.

59. Reproductive System and Homeostasis:

• Hormones regulate not only reproduction but also aspects like bone density, metabolism, and mood, maintaining the body's internal balance.

60. Reproduction and Population Control:

• Understanding reproduction informs policies on contraception, family planning, and education, aiming to manage population growth sustainably.

Application-Based Questions:

61. Runners in Plants:

• Runners or stolons are a form of vegetative propagation where new plants grow from horizontal stems, e.g., strawberry plants.

62. Unisexual vs. Bisexual Flowers:

• Unisexual: Have either stamens or carpels (e.g., papaya).
• Bisexual: Contain both stamens and carpels (e.g., rose).

63. Potato Growth:

• Each piece with an "eye" (bud) can grow into a new plant because potatoes reproduce vegetatively through tubers.

64. Fertility Factors:

• Age, health (including STDs), lifestyle, genetics, environmental toxins, and psychological stress can all affect fertility.

65. Grafting in Agriculture:

• Grafting combines desirable traits from different plants (e.g., disease resistance and fruit quality). Benefits include quicker fruiting, uniform growth, and propagation of non-seed producing varieties.

66. Observing Mitosis in Onion Root Tips:

• Stain the root tips, squash them on a slide, and observe under a microscope. Look for stages like prophase, metaphase, anaphase, and telophase.

67. Seed Germination Issues:

• Reasons might include insufficient water, temperature, light, oxygen, seed dormancy, or poor seed quality.

68. Bees and Plant Reproduction for Kids:

• Bees collect nectar, moving pollen from one flower to another, helping plants make seeds and fruits.

69. Signs of Puberty in Girls:

• Breast development, growth spurt, menstruation. Management includes education, hygiene, nutrition, and emotional support.

70. Experiment on Light and Germination:

• Plant seeds in two sets, one in light and one in dark, keeping other conditions constant. Observe germination rates to see light's effect.

Critical Thinking Questions:

71. Climate Change and Reproduction:

• Altered seasons can mismatch reproductive cycles with resource availability, affect sex ratios in temperature-dependent species, or shift pollinator-plant interactions.

72. Evolutionary Advantages of Sexual Reproduction:

• Genetic diversity increases adaptability, reduces genetic diseases, and allows for rapid evolution in response to environmental changes.

73. Switching Between Reproduction Types:

• Organisms might use asexual reproduction for rapid population increase in stable conditions and switch to sexual when environmental pressures favor genetic diversity.

74. Reproductive Strategies and Ecosystem Distribution:

• Strategies like seed dispersal or the number of offspring can determine how far and effectively a species can colonize new areas

75. Human Population Growth Implications:

• Rapid growth can lead to overuse of natural resources, habitat destruction, increased pollution, and challenges in providing food, water, and healthcare. It can also influence reproductive decisions due to economic and social pressures.

76. Invasive Species and Reproduction:

• Invasive species often reproduce rapidly (e.g., through prolific seed production, asexual reproduction), allowing them to outcompete natives by quickly establishing large populations and adapting to new environments without natural predators or diseases.

77. Plant Reproduction in Agriculture and Conservation:

• Understanding plant reproduction helps:
  • In Agriculture: Breeding programs for disease resistance, yield improvement, and desired traits through selective pollination or genetic modification.
  • In Conservation: Restoring plant populations, protecting pollinators, and ensuring genetic diversity through managed breeding or reintroduction programs.

78. Ethical Considerations of Genetic Engineering in Reproduction:

• Concerns include:
  • Altering human gene pools, potentially leading to eugenics.
  • Privacy and consent issues related to genetic information.
  • The moral status of genetically modified organisms or human embryos.
  • Access to technology and the potential for creating social disparities.

79. Reproductive Biology for Pest Control:

• Knowledge can be applied in:
  • Sterile Insect Technique (SIT): Releasing sterile males to decrease pest population through infertile matings.
  • Biological Control: Introducing natural enemies that specifically target pest reproduction.
  • Gene Drive Systems: Modifying genes to spread traits that reduce pest fertility or survival.

80. Importance of Comprehensive Sex Education:

• It's crucial for:
  • Reducing unintended pregnancies and STDs by providing accurate information on contraception and safe sex practices.
  • Promoting healthy relationships and consent.
  • Educating on reproductive health, including recognizing and addressing issues like menstruation, puberty changes, and fertility.
  • Encouraging responsible decision-making regarding sexual activity.
  • Breaking down cultural taboos and reducing stigma associated with sexual health.