Reproduction MCQ Quiz - Objective Question with Answer for Reproduction - Download Free PDF

The correct answer is Genesis of spermatozoan from spermatid.

Explanation:

• Spermiogenesis refers to the process during which spermatids (immature male gametes) mature into spermatozoa (functional and motile sperm cells).
• During spermiogenesis, spermatids undergo several morphological changes, such as condensation of the nucleus, formation of the acrosome, development of the flagellum, and shedding of excess cytoplasm, to become streamlined and motile spermatozoa.
• This is the final stage of spermatogenesis, which is the overall process of sperm production occurring in the seminiferous tubules of the testes.

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​ Additional Information

• Spermatogenesis is the process of sperm formation, which occurs in the seminiferous tubules of the testes.
• This process involves several stages, including the transformation of spermatogonia into spermatocytes, which then develop into spermatids, and finally mature into spermatozoa (sperms).

• Spermiation: Spermiation is the process where mature spermatozoa are released from the Sertoli cells into the lumen of the seminiferous tubules in the testes. This marks the final step in the maturation and eventual release of sperm cells.

The correct answer is 16

Explanation:

• The somatic chromosome number refers to the total number of chromosomes present in the somatic (body) cells of an organism. 
• Allium cepa, commonly known as onion, is a widely studied plant in genetics due to its relatively large chromosomes and ease of cultivation.
• Allium cepa has a diploid number of chromosomes equal to 16 (8 pairs). 
• Each cell of the onion contains 16 chromosomes in its somatic cells, while its gametes (reproductive cells) would have half this number, i.e., 8 chromosomes.

The correct answer is Triploid (3n)

Explanation:

• Endosperm is a tissue in seed plants, particularly angiosperms, that provides nourishment to the developing embryo. It plays a crucial role in seed development and germination.
• In angiosperms, the endosperm is formed as a result of double fertilization, a unique feature of flowering plants.
• Double fertilization involves the fusion of one sperm cell with the egg cell to form the zygote (2n) and another sperm cell with two polar nuclei (n+n) to form the endosperm (3n).
• The genetic composition of the endosperm is typically triploid (3n) in most angiosperms, meaning it contains three sets of chromosomes.

Additional Information:

• The formation of triploid endosperm is a defining characteristic of angiosperms and distinguishes them from gymnosperms, where the endosperm is haploid (n) because it develops directly from the female gametophyte.
• Endosperm development can be classified into three types: nuclear, cellular, and helobial, based on the pattern of cell division.
• The endosperm tissue can be either consumed during embryo development or persist in mature seeds to provide nutrients during seed germination.

The correct answer is Sertoli's cells

Explanation:

• Sertoli's cells are specialized cells found in the seminiferous tubules of the testes. They play a crucial role in the development, nourishment, and support of spermatozoa (sperm cells).
• Sertoli's cells are known as "nurse cells" because they provide structural and metabolic support to the developing sperm cells during spermatogenesis.
• They produce substances like androgen-binding protein (ABP) to maintain high testosterone levels, which are essential for sperm development. They also phagocytose (remove) defective sperm and residual cytoplasm during spermatogenesis.
• Spermatogenesis is the process through which sperm cells are produced in the seminiferous tubules.

The correct answer is P: Zygote, Q: Suspensor, R: Cotyledon, S: Plumule

Concept:

• Embryo formation takes place after the fertilization of egg cell by the male gamete.
• Flowering plants have the unique characteristic feature of double fertilization.
• Each pollen grain has 2 male gametes and both take part in fertilization.
• Double fertilization involves 2 processes:
  • Syngamy - It is the fusion of one male gamete with the egg cell to produce a zygote that later develops into embryo.
  • Triple fusion - It is the fusion of the 2nd male gamete with the 2 polar nuclei of the embryo sac to produce the endosperm.
• Therefore, double fertilization can be summed up as:

1st Male gamete (n) + Egg (n)  →  Zygote (2n)
2nd Male gamete (n) + 2 Polar nuclei (n)  →  Endosperm (3n)

Important Points

• The endosperm develops before the embryo to provide nutrition to the developing embryo.
• The embryo starts developing at the micropylar end of the embryo sac, where the egg cell was positioned.
• Most zygotes start dividing after partial development of endosperm, in order to assure nutrition to the embryo.
• The process of embryo development is known as embryogeny.
• The early stages of embryogeny are similar in dicots and monocots.
• In a dicot plant, the zygote first gives rise to the proembryo.
• The proembryo then subsequently forms the globular embryo, which is round in shape.
• Then the heart-shaped embryo is formed and the rest of the embryo sac starts degenerating.
• Lastly the mature embryo is formed.

Additional Information

• A typical dicot embryo consists of an embryonal axis and two cotyledons.
• The part of embryonal axis above the cotyledons is called epicotyl.
• The epicotyl terminates at the plumule, which later gives rise to the stem.
• Plumule is covered by the coleoptile.
• The portion below the cotyledons is the hypocotyl, which terminates at the radicle.
• Radicle gives rise to the root and is protected by coleorhiza.

The correct answer is Male gamete.

Key Points

• Sperm or spermatozoa is a gamete (sex cell) produced in the male reproductive system.
• It is a mobile cell with one goal - to fertilize a female egg.
• Each sperm contains the entire genome of the male that produced it.
• Combined with the female genome contained in the egg, a zygote is formed - a single pluripotent stem cell containing the fused male and female genomes.
• Sperm cells were first described in the late 17th century by Antonie van Leeuwenhoek.

Additional Information

• Isogamete:
  • Isogamete is a gamete that is similar in shape, size, and behavior to another gamete with which it can produce a zygote.
  • They are also known as homogametes.
• Female gamete:
  • Female gametes are produced in the ovary. It is called an egg or egg.
  • Each month, the female produces one egg during her menstrual cycle.
• Gamete:
  • A gamete is a haploid cell that fuses with another haploid cell during fertilization in sexually reproducing organisms.
  • Gametes are reproductive cells of an organism, also known as sex cells.

The correct answer is Vascular plants.Key Points

• The sporophyte stage is the dominant phase in vascular plants, which includes all plants except bryophytes (mosses, liverworts, and hornworts).
• In bryophytes, the gametophyte stage is the dominant phase, while the sporophyte is dependent on the gametophyte for survival. 
• Algae do not have a well-defined alternation of generations, and their life cycles can vary greatly depending on the type of algae.
• Pteridophytes, which include ferns and horsetails, have a dominant sporophyte stage that is independent of the gametophyte.
• The dominance of the sporophyte stage is characterized by the fact that it is the stage that produces the spores, which give rise to the next generation of plants.

Additional Information

• Bryophytes are small, non-vascular plants that grow in damp habitats.
  • They do not have true roots, stems, or leaves and rely on diffusion to transport water and nutrients.
• Algae are a diverse group of aquatic organisms that can range from single-celled organisms to large seaweeds.
  • They are not considered to be true plants because they lack specialized tissues and organs.
• Pteridophytes are vascular plants that reproduce by spores instead of seeds.
  • They have true roots, stems, and leaves, and can range from small herbaceous plants to large tree ferns.
• The alternation of generations is a life cycle that includes both a haploid (n) gametophyte and a diploid (2n) sporophyte stage.
  • In plants, the gametophyte produces gametes (eggs and sperm), which fuse to form a diploid zygote that develops into the sporophyte.
  • The sporophyte produces spores, which give rise to the next generation of gametophytes.

The correct answer is Testes.

Key Points

• Testosterone is the only male sex hormone present in the human body, which causes physical changes in puberty, increases bone density and muscle mass, growth of facial, pubic, and body hair, deepening of the voice, and also responsible for sexual and reproductive development.
• Testosterone is the main sex hormone in men, which is naturally produced in the testes and in small amounts by the adrenal glands.
• Testosterone belongs to a class of male hormones called androgens, which are also known as steroids.
• The production of male sex hormones is mainly controlled by the hypothalamus and pituitary gland.
• The testosterone levels gradually decrease with age, which results in impotence, shrinking of testes, low sperm count, depression, mood swings, irritability, etc.

Additional Information

• The pituitary gland is a small pea-sized gland that plays a major role in regulating vital body functions and general wellbeing.
  • It is referred to as the body's 'master gland' because it controls the activity of most other hormone-secreting glands. 
  • The pituitary gland is a small gland that sits in the sella turcica, a bony hollow in the base of the skull, underneath the brain and behind the bridge of the nose.
• Adrenal glands, also known as suprarenal glands, are small, triangular-shaped glands located on top of both kidneys.
  • Adrenal glands produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress and other essential functions.
• The ovary is an organ found in the female reproductive system that produces an ovum.
  • When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm.
  • There is an ovary found on each side of the body.

The correct answer is Option 4, i.e Carpel.

• Carpel is NOT a part of an anther.
• Pollen grains, Anther lobs, and Filament are the parts of the anther.
• Anther is the part of a stamen that contains the pollen.
• The stamen is the male reproductive organ of a flower.
• The stamen has two parts: Anther and stalk (filament).
• Collectively the stamens form the androecium.
• Carpel is the female reproductive organs in a flower, composed of an ovary, a style, and a stigma.

Key Points

• The placenta is an organ that develops in the uterus during pregnancy.
• It facilitates the supply of oxygen and nutrients to the embryo.
• It removes carbon dioxide and excretory/waste materials produced by the embryo.
• Placenta acts as an endocrine tissue and produces hormones:
  • Human chorionic gonadotropin (hCG)
  • Human placental lactogen (hPL)
  • Estrogens
  • Progestogens
• These hormones work together to control the growth and development of the placenta and the fetus.
• They act on the mother to support the pregnancy and prepare for childbirth.
• Placenta is connected to the embryo through an umbilical cord which helps in the transport of substances to and from the embryo.

Explanation:

• Androgen is the male sex hormone that is secreted by the Leydig cells of the testis in males.
• It plays an important role in spermatogenesis process.
• It also helps in developing male secondary sexual characters.

Hence, the correct answer is option 3.

Key Points

• The occurrence of more than one embryo in a seed is referred to as polyembryony.
• It is commonly found in citrus fruits like lemon and orange.
• Ways of forming polyembryonic seeds:
  • Developing of cells like synergids, cells of the nucellus, cells of integument into the embryo.
  • Formation of more than one embryo sac in an ovule.
  • Formation of more than one egg in an embryo sac.

Additional Information

According to Webber, polyembryony is classified into three different types :

1. Cleavage Polyembryony: In the case of this type, a single fertilized egg gives rise to a number of embryos.
2. Simple polyembryony: In this type, a number of embryos develop as a result of the fertilization of several archegonia.
3. Rosette polyembryony: Additional embryos develop from the rosette cells in certain gymnosperms, this type of polyembryony is termed rosette polyembryony.

The correct answer is asexual reproduction.Key Points

• Asexual reproduction is a type of reproduction in which offspring are produced by a single parent without the involvement of gametes or fertilization.
• In asexual reproduction, the offspring are genetically identical to the parent, as there is no genetic recombination or mixing of genetic material from two parents.
• Examples of asexual reproduction include binary fission in bacteria, budding in yeast, and fragmentation in starfish.
• Asexual reproduction is advantageous in stable environments, as it allows for rapid reproduction and the ability to colonize new habitats quickly.

Additional Information

• In vitro fertilization (IVF) is a type of assisted reproductive technology that involves fertilizing an egg with sperm outside of the body and then transferring the resulting embryo into the uterus.
  • IVF is used in cases of infertility or genetic disorders. 
• External fertilization is a type of sexual reproduction that occurs outside of the body, such as in aquatic animals like fish and amphibians.
  • The eggs and sperm are released into the water, where fertilization occurs.
• Sexual reproduction involves the fusion of gametes from two parents to produce offspring with genetic diversity.
  • This type of reproduction is common in animals, plants, and some fungi.
  • It allows for genetic variation, which can be advantageous in changing environments.

The correct answer is Frog
Key Points 

• External fertilization occurs when eggs are shed by the female and fertilized by the male outside of the body. This type of fertilization is common in aquatic organisms, such as fish and amphibians.
• Among options (hen, cat, frog, and snake), the frog is an example of a species where external fertilization takes place. The other listed animals - hen (a species of bird), cat (a mammalian species), and snake (a species of reptiles) - practice internal fertilization.

Concept:

• Vigorous contraction of the uterus at the end of pregnancy causes expulsion/delivery of the foetus. This process of delivery of the foetus (childbirth) is called parturition.

Explanation:

• Foetal Ejection reflex - 
• The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex.
• This triggers the release of oxytocin from the maternal pituitary.
• Oxytocin then acts on the uterine muscle and causes stronger uterine contractions, which in turn stimulates the further secretion of oxytocin.
• The stimulatory reflex between the uterine contraction and oxytocin secretion continues resulting in stronger and stronger contractions.
• This leads to the expulsion of the baby out of the uterus through the birth canal – parturition.

Additional Information

• Prolactin: It is also called lactotrophic hormone. It regulates the growth and milk formation of mammary glands.
• Estrogen, or oestrogen: It is a sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics.
• Relaxin as the name suggests is used to keep the smooth muscles of the uterus relaxed. It is secreted in large amounts during parturition.

Key Points

• There are three main modes of reproduction observed in animals:

1. Viviparity - 
   • It involves giving birth to young ones directly.
   • Fertilization in viviparous animals takes place internally.
   • Embryonic development takes place inside the mother's body.
   • The embryo is connected to the mother by the placenta.
   • E.g.: Mammals like a horse. Fishes like shark (some species) are viviparous as well.
2. Oviparity - 
   • It involves the laying of eggs by the animal.
   • Embryonic development takes place within the egg.
   • Fertilization can take place internally or externally.
   • E.g.: Birds, some fish, amphibians, etc.
3. Ovoviviparity - 
   • This method involves laying of eggs and then keeping them inside the mother's body till the young are nearly ready to hatch.
   • Fertilization takes place internally.
   • The embryonic development takes place within a thin membranous eggshell in the oviduct.
   • E.g.: Some lizards and snakes.

Explanation:

• House lizard - 
  • ​House lizard belongs to Class Reptilia.
  • House lizards are oviparous.
  • They lay eggs and the development of the young takes place inside the egg.
• Ostrich - 
  • Ostrich belongs to Class Aves.
  • On fertilization, the ostrich lays a fertilized egg within which the young one develops.
  • Ostrich eggs are considered to be the largest egg of all.
  • Thus ostrich is an oviparous.
• Pigeon - 
  • Pigeon belongs to Class Aves.
  • Pigeon is an oviparous.
  • The development of a young one takes place inside the egg.
  • Once the development of the young one is complete at the end of 18 days, eggs are hatched.
• Kangaroo - 
  • ​Kangaroo belongs to Class Mammalia.
  • Kangaroo is a viviparous animal.
  • It gives birth to the immature young one.
  • The young one (joey) born is immature, naked and one inch long.
  • Immediately after birth, it is transferred into the large marsupium (pouch) of the mother.
  • It comes out when it turns four months old.

Hence, the correct answer is option 4.