Question 1

Question 1Write about different parts of the male reproductive system of human beings.

Accepted Answer

The male reproductive system of human beings consists of a pair of testes, sperm ducts, urethra, penis and accessory glands. Each of them is briefly described below:Testes — Testes are located outside the abdomen in a sac-like structure called scrotum. They are the primary reproductive organs of the male reproductive system. They produce the male gametes called sperms.Sperm Ducts — The sperms produced in the testes, travel through the sperm duct or vas deferens to reach the urethra.Accessory Glands — As the sperms pass through the sperm duct, secretions from the accessory glands are mixed with them. This mixture is called semen.Urethra — It is a tube through which urine and semen passes.Penis — Through penis, sperms are discharged and deposited into the vagina of the female body. In males, the penis is the organ used both for the discharge of the urine and the sperms.

Question 2

Question 3Explain the process of development of a zygote into a foetus.

Accepted Answer

The formation of an individual from the zygote is called development. In human beings, the zygote undergoes continuous cell division to form a ball of cells. The ball gets implanted in the uterine wall for further development. The implanted ball of cells undergoes many cell divisions. The cells change their size, shape and function to become different types of cells such as nerve cells and blood cells. From these, tissues and organs develop and get organized into various organ systems of the baby. From the third week of development till the end of the second month, the developing organism is referred to as the embryo. From the third month until birth, it is called foetus.

Question 3

Question 2Draw 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 ?

Accepted Answer

Labelled diagrams of a sperm and ovum are shown below:SpermOvum(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.

Question 4

Question 4Draw 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.

Accepted 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.

Question 5

Question 6Answer 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.

Accepted 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.

Question 6

Question 2(c)Distinguish between Budding and regeneration

Accepted Answer

Difference between Budding and RegenerationBuddingRegenerationBudding 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.

Question 7

Question 4Why is it important that a very large number of sperms should be present in the semen?

Accepted 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.

Question 8

Question 5State the functions of the following:(a) Ovary(b) Testes(c) Fallopian Tubes(d) Seminal Vesicles(e) Uterus

Accepted 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.

Reproduction in Humans

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