Hey future toppers! 👋
Welcome to the very first post in our brand-new series designed to make you a champion in every chapter. We are kicking things off with one of the most important chapters in Biology: "How do Organisms Reproduce?".
In this post, we'll tackle the first and most crucial step in board exam preparation: cracking the objective questions. We have curated a list of the 20 most important Multiple Choice Questions (MCQs) and 10 crucial Assertion-Reason (A-R) Questions. Each question comes with its answer and a quick explanation right below it, so you can learn and revise on the go.
Let's dive right in!
Part 1: Top 20 Multiple Choice Questions (MCQs)
Q1. The ability of an organism to develop its lost body parts is called:
(a) Budding
(b) Fragmentation
(c) Regeneration
(d) Fission
Answer: (c) Regeneration
Explanation: Regeneration is the process where specialized cells help an organism regrow lost body parts, as seen in Planaria and lizards.
Q2. In Rhizopus, the tube-like structures bearing sporangia at their tips are called:
(a) Filaments
(b) Hyphae
(c) Rhizoids
(d) Roots
Answer: (b) Hyphae
Explanation: The thread-like structures in Rhizopus (bread mould) are hyphae. The ones with knob-like sporangia are involved in reproduction.
Q3. Which of the following is an example of a plant that reproduces using buds on its leaves?
(a) Rose
(b) Bryophyllum
(c) Jasmine
(d) Banana
Answer: (b) Bryophyllum
Explanation: Bryophyllum has notches on the margins of its leaves from which buds arise, which can grow into new plants.
Q4. The male reproductive part of a flower, the stamen, is collectively made of:
(a) Stigma and Style
(b) Anther and Ovary
(c) Anther and Filament
(d) Stigma and Ovary
Answer: (c) Anther and Filament
Explanation: The stamen consists of a stalk called the filament and a terminal structure called the anther, which produces pollen grains.
Q5. In humans, the site of fertilization is:
(a) Uterus
(b) Vagina
(c) Ovary
(d) Oviduct (Fallopian tube)
Answer: (d) Oviduct (Fallopian tube)
Explanation: The fusion of the male gamete (sperm) and the female gamete (egg) occurs in the fallopian tube.
Q6. The embryo in humans gets nutrition from the mother’s blood with the help of a special tissue called:
(a) Placenta
(b) Uterus wall
(c) Amnion
(d) Zygote
Answer: (a) Placenta
Explanation: The placenta is a disc-like tissue embedded in the uterine wall that facilitates the transfer of nutrients and oxygen from the mother to the embryo.
Q7. 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: The vas deferens is a tube that carries sperm from the testes, making it a part of the male reproductive system.
Q8. The process of binary fission in Leishmania is different from Amoeba because it occurs in:
(a) A random plane
(b) Multiple planes
(c) A definite orientation (longitudinally)
(d) A transverse plane
Answer: (c) A definite orientation (longitudinally)
Explanation: Leishmania has a whip-like structure, so binary fission occurs in a defined longitudinal plane, whereas Amoeba can divide in any plane.
Q9. After fertilization in a flower, the ovary develops into the ______ and the ovules develop into the ______.
(a) Seed, Fruit
(b) Fruit, Seed
(c) Petal, Seed
(d) Seed, Petal
Answer: (b) Fruit, Seed
Explanation: The ovary swells to become the fruit, and the ovules inside the ovary become the seeds.
Q10. What is the primary function of the testes in the male reproductive system?
(a) To produce testosterone only
(b) To produce sperm only
(c) To produce both sperm and testosterone
(d) To store urine
Answer: (c) To produce both sperm and testosterone
Explanation: Testes have a dual function: producing male gametes (sperm) and secreting the male sex hormone (testosterone).
Q11. A feature of reproduction that is common to Amoeba, Yeast, and Spirogyra is that:
(a) They all are multicellular
(b) They reproduce asexually
(c) They reproduce only sexually
(d) They all have a cell wall
Answer: (b) They reproduce asexually
Explanation: Amoeba (fission), Yeast (budding), and Spirogyra (fragmentation) are all examples of organisms that use asexual modes of reproduction.
Q12. The surgical method of contraception in human males, which prevents the flow of sperm, is called:
(a) Tubectomy
(b) Vasectomy
(c) IUCD
(d) Abstinence
Answer: (b) Vasectomy
Explanation: In vasectomy, the vas deferens is cut and tied to block the passage of sperm. Tubectomy is the equivalent procedure in females.
Q13. Which of the following is a sexually transmitted disease caused by a virus?
(a) Syphilis
(b) Gonorrhoea
(c) Chlamydia
(d) HIV-AIDS
Answer: (d) HIV-AIDS
Explanation: Syphilis and Gonorrhoea are caused by bacteria. HIV-AIDS is caused by the Human Immunodeficiency Virus (HIV).
Q14. An essential event during reproduction is the:
(a) Division of cytoplasm
(b) Creation of a DNA copy
(c) Synthesis of proteins
(d) Growth of the cell
Answer: (b) Creation of a DNA copy
Explanation: Creating a copy of the DNA (genetic material) is the fundamental event in reproduction, ensuring the transfer of traits to the offspring.
Q15. In vegetative propagation by grafting, the part of the plant that is grafted onto the other plant is called:
(a) Stock
(b) Scion
(c) Stem
(d) Bud
Answer: (b) Scion
Explanation: The scion is the desired stem cutting or bud that is grafted onto the rooted plant, known as the stock.
Q16. Which of the following is a unisexual flower?
(a) Hibiscus
(b) Mustard
(c) Papaya
(d) Rose
Answer: (c) Papaya
Explanation: A unisexual flower contains either male parts (stamens) or female parts (pistil). Papaya plants bear separate male and female flowers. Hibiscus, mustard, and rose are bisexual.
Q17. The onset of the reproductive phase in human females is known as:
(a) Menopause
(b) Menstruation
(c) Menarche
(d) Ovulation
Answer: (c) Menarche
Explanation: Menarche marks the beginning of puberty and the first occurrence of menstruation in females. Menopause is the end of the menstrual cycle.
Q18. The number of chromosomes in human sperm and egg cells is:
(a) 46
(b) 22
(c) 23
(d) 44
Answer: (c) 23
Explanation: Human gametes (sperm and egg) are haploid, meaning they contain half the number of chromosomes (23) as a normal body cell (46).
Q19. The breakdown and discharge of the inner, thick, and soft lining of the uterus along with blood is called:
(a) Fertilization
(b) Menstruation
(c) Implantation
(d) Ovulation
Answer: (b) Menstruation
Explanation: If the egg is not fertilized, the uterine lining, which had prepared for a pregnancy, breaks down and is shed during menstruation.
Q20. An advantage of vegetative propagation is that plants produced this way:
(a) Show more genetic variation
(b) Are more resistant to diseases
(c) Bear fruits and flowers earlier
(d) Can grow in any soil type
Answer: (c) Bear fruits and flowers earlier
Explanation: Plants grown from vegetative propagation bypass the immature seedling phase, allowing them to mature and produce fruits much faster than those grown from seeds.
Part 2: Top 10 Assertion-Reason (A-R) Questions
Directions: For the following questions, two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the codes (a), (b), (c), and (d).
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q21.
Assertion (A): The testes in human males are located in the scrotum outside the abdominal cavity.
Reason (R): Sperm formation requires a temperature lower than the normal body temperature.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: The scrotum maintains a temperature 2-2.5°C lower than the body temperature, which is optimal for spermatogenesis (sperm production).
Q22.
Assertion (A): Vegetative propagation produces plants that are genetically identical to the parent plant.
Reason (R): This method of reproduction involves only a single parent.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: Since there is no mixing of genes from two different parents, the offspring produced asexually are genetically identical clones of the single parent.
Q23.
Assertion (A): A wind-pollinated flower is typically small and does not produce nectar or scent.
Reason (R): Wind-pollinated flowers do not need to attract insects.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: Features like nectar, scent, and bright petals are adaptations to attract pollinators like insects. Wind pollination doesn't require these, so the flowers are inconspicuous.
Q24.
Assertion (A): The use of condoms can help prevent the spread of sexually transmitted diseases.
Reason (R): Condoms act as a barrier, preventing direct contact of body fluids.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: By preventing the exchange of infected body fluids, barrier methods like condoms are effective in preventing both pregnancy and STDs.
Q25.
Assertion (A): Planaria, if cut into pieces, can regenerate into new individuals.
Reason (R): Planaria possesses specialized cells that can proliferate and differentiate.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: The remarkable regenerative ability of Planaria is due to the presence of a large number of stem cells (specialized cells) that can form all the different body parts.
Q26.
Assertion (A): Variation is crucial for the survival of a species.
Reason (R): DNA copying mechanisms are absolutely accurate and produce no errors.
Answer: (c) A is true but R is false.
Explanation: Variation allows species to adapt to changing environments. This variation arises precisely because DNA copying is not perfect and small errors (mutations) occur.
Q27.
Assertion (A): In humans, the mother's body is designed to undertake the development of the child.
Reason (R): The uterus prepares itself every month to receive and nurture the growing embryo.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: The monthly preparation of the uterine lining (endometrium) is a key aspect of the female body being adapted for pregnancy.
Q28.
Assertion (A): Amoeba reproduces by multiple fission under unfavourable conditions.
Reason (R): A protective cyst is formed around the cell, inside which the nucleus divides repeatedly.
Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: Forming a cyst is a survival mechanism. Inside it, multiple fission allows Amoeba to produce many daughter cells that are released when conditions become favourable again.
Q29.
Assertion (A): Post-fertilization, the petals and sepals of a flower usually fall off.
Reason (R): The ovary of the flower develops into a fruit.
Answer: (b) Both A and R are true but R is not the correct explanation of A.
Explanation: Both statements are correct events that happen after fertilization. However, the ovary developing into a fruit is not the reason why petals fall off. The primary role of petals (attraction) is over, so they are shed.
Q30.
Assertion (A): Tubectomy is a method of contraception in females.
Reason (R): In tubectomy, the vas deferens is cut and tied to prevent sperm from being released.
Answer: (c) A is true but R is false.
Explanation: The reason describes vasectomy (male sterilization). In tubectomy, the fallopian tubes are blocked to prevent the egg from reaching the uterus.
How did you find this format? Learning and checking your answers instantly is a great way to build confidence.
Stay tuned for our next post in this series: "Top 30 Very Short Answer Questions (2 Marks) on Reproduction!"
Happy learning! 🚀
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