Reproduction in Humans
The testes are located within the:
- Penis
- Scrotum
- Ureter
- Urinary bladder
Answer
Scrotum
Reason — Sperms are produced in the testes. A pair of testes lie outside the abdominal cavity in a sac called the scrotum.
Amoeba most commonly reproduces by:
- Budding
- Regeneration
- Binary fission
- Multiple fission
Answer
Binary Fission
Reason — Binary fission is the most common method of reproduction in single-celled organisms. In Amoeba, it results in the division of the parent amoeba into two daughter amoeba.
Which of the following is a stage formed after the fertilisation of the egg by the sperm?
- Ovule
- Foetus
- Embryo
- Zygote
Answer
Zygote
Reason — A zygote is a fertilised egg. The zygote is formed when the male gamete (sperm) and female gamete (egg) fuse. It's created when sperm meets an egg in one of the fallopian tubes. The zygote grows by cell division and produces an embryo.
Internally, the uterus opens into:
- Urethra
- Vagina
- Oviduct
- Vulva
Answer
Vagina
Reason — The uterus is a hollow, inverted pear shaped muscular organ which opens to the outside through a long, muscular tube called the vagina, situated between the rectum and the urethra.
Arrange the following terms in a logical sequence
(a) Gestation, Birth, Fertilization, Implantation
(b) Urethra, Epididymis, Sperm duct, Testis
Answer
(a) Fertilization → Implantation → Gestation → Birth
(b) Testis → Epididymis → Sperm duct → Urethra
Choose the odd one out and mention the category to which the remaining terms belong.
(a) Testis, Uterus, Vas deferens, Epididymis
(b) Ovary, Uterus, Seminal vesicle, Oviduct
(c) Vagina, Seminal vesicle, Cowper's gland, Prostate gland
(d) Amoeba, Hydra, Paramecium, Bacteria
Answer
(a) Odd term: Uterus
Category: Male reproductive parts
(b) Odd term: Seminal vesicle
Category: Female reproductive parts
(c) Odd term: Vagina
Category: Male accessory glands
(d) Odd term: Bacteria
Category: Eukaryotic organisms
List the structures, in their correct sequence, through which the sperms must pass from the time they are produced in the testes to the time they leave the urethra.
Answer
Testes → Sperm duct → Urethra
Define Fertilization.
Answer
The fusion of the male gamete (sperm) and the female gamete (ovum) to form a zygote is called fertilisation.
Define Implantation.
Answer
The process of fixing of the fertilized egg (embryo) to the wall of the uterus is termed implantation.
Distinguish between Egg and sperm
Answer
Difference between Egg and Sperms:
| Egg | Sperms |
|---|---|
| Egg is stationary. | Sperm is capable of performing locomotion. |
| Egg has no locomotory organ. | Sperm has a special locomotory organ, the tail. |
| Released one at a time. | Released in millions. |
| The female gamete. | The male gamete. |
Distinguish between Sexual Reproduction and asexual reproduction
Answer
Difference between Sexual Reproduction and Asexual reproduction
| Sexual Reproduction | Asexual Reproduction |
|---|---|
| In Sexual Reproduction male and female gametes are involved and fertilised. | In Asexual Reproduction male and female gametes are not involved. |
| Two organisms or parents are involved to produce an organism. | A single parent divides itself to two or more number of daughter cells. |
| This type of reproduction can be seen in higher level organisms. | This type of reproduction can be seen in lower level organisms. |
| E.g: Humans | E.g: Amoeba |
Distinguish between Budding and regeneration
Answer
Difference between Budding and Regeneration
| Budding | Regeneration |
|---|---|
| Budding is a process in which buds grow on the outside of the parents body. The buds detach themselves once they are capable of independent existence. | Regeneration is the process of generating lost parts of the body. It is also happens for reproductive purposes. Some organisms, when cut into multiple pieces then each piece develops into a young organism itself. |
| Budding is exclusively for reproduction. | Regeneration is for regrowth of lost body and in some cases also for reproduction. |
State the reason why testes lie outside the abdomen in a scrotum?
Answer
Testes lie outside the body because the normal body temperature does not allow the maturation of the sperms. In such an arrangement, the testes are at a temperature which is 2-3°C lower than that of the body. This is the most suitable temperature for sperm production and development.
Why is it important that a very large number of sperms should be present in the semen?
Answer
Semen contains a very large number of sperms because out of the millions of sperms released into the vagina, only a few of them are able to reach up to the upper parts of the oviducts. Some die on the way and are absorbed. Only a few of them reach the ovum. Thus, to increase the chances of fertilisation, a very large number of sperms should be present in the semen.
State the functions of the following:
(a) Ovary
(b) Testes
(c) Fallopian Tubes
(d) Seminal Vesicles
(e) Uterus
Answer
(a) Ovary — The ovaries have two main reproductive functions in the body. They produce eggs and secrete the reproductive hormones, Oestrogen and Progesterone.
(b) Testes — The two main functions of Testes are to produce and store sperms and to secrete the male reproductive hormone Testosterone.
(c) Fallopian Tubes — Fallopian Tubes transfer the egg from the ovaries to the uterus.
(d) Seminal vesicles — They produce a secretion which serves as a medium for the transportation of the sperms.
(e) Uterus — The embryo grows and develops in the Uterus.
Given here is a section of the female reproductive system of humans.
(a) Name the parts labelled 1 to 4.
(b) Name the part where fertilisation occurs in the female reproductive system.
Answer
(a) The parts are:
- 1 → Ovary
- 2 → Fallopian tube
- 3 → Uterus
- 4 → Vagina
(b) Fallopian tubes (also called Oviduct)
Draw neat and labelled diagrams of a sperm and ovum. Answer the following questions:
(a) Is a sperm and an ovum unicellular or multicellular ?
(b) Name the organ of the human body where these gametes are produced.
(c) Name the process of the fusion of these gametes.
(d) Name the organ where the fusion of these gametes take place.
(e) What is formed by the fusion of the sperm and ovum ?
Answer
Labelled diagrams of a sperm and ovum are shown below:
Sperm
Ovum
(a) A sperm and an ovum are unicellular.
(b) In males, the testes produce male gametes (sperms), and in females, the ovaries produce female gametes (eggs).
(c) Fertilisation.
(d) The fusion of male and female gametes in humans takes place in the fallopian tube.
(e) Zygote is formed by the fusion of the sperm and ovum.
Given alongside is a diagram of male reproductive system in humans. Label the parts indicated by numbers 1 to 5, and state their functions.
Answer
- 1 → Seminal vesicle — Produce a secretion which serves as a medium for the transportation of the sperms.
- 2 → Prostate gland — Pours an alkaline secretion into the semen as it passes through the urethra.
- 3 → Testes — To produce and store sperms and to secrete the male reproductive hormone Testosterone.
- 4 → Urethra — Carries either Urine or Semen.
- 5 → Sperm duct — Carries the sperms from the Epididymis to the Urethra.
Draw a neat and labelled diagram showing the reproduction in amoeba. Answer the following questions :
(a) Is reproduction in amoeba of the sexual or asexual kind ?
(b) Name the specific kind of reproduction which occurs in amoeba.
(c) How many offsprings are produced from one division?
(d) What kind of cell division occurs during the reproduction in amoeba?
(e) Give one more example of an organism which reproduces by the same mode of reproduction as that of amoeba.
Answer
Labelled diagram showing the reproduction in amoeba is shown below:
(a) Reproduction in amoeba is asexual.
(b) Amoeba reproduces by binary fission.
(c) Two offsprings are produced from one division.
(d) During the reproduction in amoeba, the type of cell division that occurs is mitosis.
(e) E. coli also reproduces by binary fission.
Draw a neat and labelled diagram of the human female reproductive system. From the diagram, name the following :
(a) The organ where ovum is produced.
(b) The muscular tube situated between the rectum and the urethra.
(c) A hollow, inverted pear-shaped muscular organ found in the pelvic cavity.
(d) A pair of narrow, muscular long ducts extending from each ovary to the upper part of the uterus.
(e) A small lower constricted part of the uterus.
Answer
Labelled diagram of the human female reproductive system is shown below:
(a) Ovary
(b) Vagina
(c) Uterus
(d) Fallopian tube
(e) Cervix
Answer the following questions:
(a) What is budding? Define it.
(b) Is it asexual or sexual mode of reproduction?
(c) Mention one example of a plant and one of an animal that reproduce by budding.
(d) Draw and label the diagram of an animal showing the process of budding.
(e) Write the specific locomotory structures of the animal drawn by you in part (d) above.
Answer
(a) Budding is a form of asexual reproduction in which a protuberance of cell grows from the parent body to form an independent individual.
(b) Budding is an asexual mode of reproduction.
(c) Budding is seen in Hydra and yeast.
(d) Below labelled diagram shown the process of budding in Hydra:
(e) The specific locomotory structures of Hydra, which reproduces by budding, are its tentacles.