Solution-Class 10-Science & Technology-2-Chapter-3-Life Processes In Living Organisms-2-Mah. Board

a. In humans, sperm production occurs in the organ testes.
b. In humans, Y chromosome is responsible for maleness.
c. In male and female reproductive system of human, bulbourethral gland is same.
d. Implantation of embryo occurs in uterus.
e. Asexual type of reproduction occurs without fusion of gametes.
f. Body breaks up into several fragments and each fragment starts to live as a new individual. This is fragmentation type of reproduction.
g. Pollen grains are formed by meiotic division in locules of anthers.

Growth of follicles present in the ovary occurs under the effect of follicle stimulating hormone. This follicle secretes estrogen. Endometrium of uterus grows/regenerates under the effect of estrogen. Under the effect of luteinizing hormone, fully grown up follicle bursts, ovulation occurs and corpus luteum is formed from remaining part of follicle. It secretes progesterone and estrogen. Under the effect of these hormones, glands of endometrium of uterus are activated and it becomes ready for implantation.

Asexual reproduction in unicellular organisms can be of three types:

1. Binary fission :

• The parent cell divides into two similar daughter cells.
• Occurs either by mitosis or amitosis.
• Performed usually during favorable conditions.
• Axis can be (1)Simple (2) Transverse (3) Longitudinal

2. Organisms : (1) Simple: Bacteria and Amoeba. (2) Transverse : Paramoecia. (3) Longitudinal : Euglena and eukaryotic cell-organelle like mitochondria and chloroplasts

3. Multiple Fission :

• Formation of pseudopodia stops, movements stop.
• Becomes round and covered over by protective cyst.
• In the cyst repeated nuclear divisions take place forming many nuclei.
• Cytoplasm divides forming many amoebulae.
• Cyst persists in adverse conditions.
• It breaks open after favourable conditions return by releasing many amoebulae.

   Organisms : Amoeba in unfavourable conditions.

Budding :

• Two daughter nuclei by mitotic division formed by parent cell.
• Appearance of a small bulge on the surface of parent cell.
• Bulge is bud.
• One daughter nucleus enters the bud.
• Bud separates from the parent cell after sufficient growth.
• Starts living independently.

Organisms : Yeast cells (Unicellular fungus)

Many couples all over the world who are unable to produce children due to various reasons. These couples can be assisted to have children through techniques called assisted reproductive technologies (ART). IVF is one such form of ART which includes different methods that can be a boon for childless couples:

In Vitro Fertilization : If Less sperm counts in Man or obstacles in oviduct of woman then fertilization is done in a test-tube .The embryo formed is implanted in uterus of woman.

Surrogacy- This is a technique which is used for women who face problem in implantation of embryo in uterus. In this technique the donor of the oocyte is the women itself who has problem in implanting the embryo in the uterus. The collected oocyte is fertilized with the sperm of her husband in a test tube. The embryo which is obtained after fertilization is implanted in the uterus of another female who is called the surrogate mother.

ZIFT − It stands for zygote intra fallopian transfer. In ZIFT, the sperm from a donor male and the ova from a donor female are fused in the laboratory. The zygote so formed is transferred into the fallopian tube at the 8 blastomeres stage.

IUT − It stands for intra uterine transfer. In this technique, embryos with more than 8 blastomeres are transferred into the uterus.
GIFT − It stands for gamete intra fallopian transfer. In GIFT, females who cannot produce ovum, but can provide suitable conditions for the fertilisation of ovum, are provided with ovum from a donor.
ICSI − It is a intra cytoplasmic sperm injection. In this method, sperm is directly injected into the cytoplasm of the ovum.
Artificial insemination − In this technique, the semen collected from the husband or a donor is injected into the vagina or uterus. This cures the infertility arising from the inability of the male partner to ejaculate, or due to low sperm count.

1. Reproductive health can be achieved by keeping genitals clean.
2. eat a balanced and nutritional diet
3. maintain personal hygiene
4. take adequate physical exercise
5. avoid taking any drugs

Menstrual cycle is the reproductive cycle in all primates and begins at puberty (menarche).

• In human females, menstruation occurs once in 28 to 29 days. The cycle of events starting from one menstruation till the next one is called the menstrual cycle.
•  Hormones from pituitary FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone) and hormones from ovary, estrogen and progesterone control the menstrual cycle
• Due to influence of FSH, the ovarian follicle grows along with the oocyte that is present in it.
• This growing follicle produces estrogen.
• Under the influence of estrogen, the uterine inner layer called endometrium grows or regenerates In the meantime the development of follicle is completed.
• LH from pituitary stimulates the bursting of ovarian follicle and releases the mature oocyte out of the follicle and the ovarian wall. This process is called ovulation.
• The empty ovarian follicle after the ovulation becomes corpus luteum. Corpus luteum produces hormone progesterone.
• Under the influence of progesterone, the glands from uterine endometrium start secreting The oocyte if fertilized implanted over this endometrium.
• If oocyte is not fertilized, the corpus luteum becomes a degenerate body called corpus albicans. The corpus albicans cannot secrete estrogen and progesterone.
• Due to lack of these hormones, the endometrial layer of the uterus collapses. The tissue debris, along with unfertilized egg is given out through the vagina as menstrual flow. This results in bleeding for about 5 days.
• If woman is not pregnant, then this menstrual cycle keeps on repeating with regularity.

a. Hormones related with male reproductive system- Testosterone, Follicle stimulating hormone, ICSH or Luteinizing hormone
b. Hormones secreted by ovary of female reproductive system- Estrogen and Progesterone
c. Types of twins- Monozygotic, Siamese and Dizygotic twins
d. Any two sexual diseases- AIDS, Syphilis and Gonorrhea
e. Methods of family planning- Oral pills, condoms, IUD's, Copper T

The statement Gender of child is determined by the male partner of couple is true

Human females have two X chromosomes (XX) and human males have one X and one Y chromosome (XY). Therefore, the eggs produced by females have only X chromosomes while the sperms produced by males can have either X or Y chromosome. If an unfertilised egg fuses with a sperm containing X chromosome, then it gives rise to a girl child having two X chromosomes. If an unfertilised egg fuses with a sperm containing Y chromosome, then it gives rise to a male child having one X and one Y chromosome.

1) Vegetative propagation is the method of asexual reproduction in plants.

This form of asexual reproduction occurs in plants only. In vegetative propagation, parts of old plant like stems, roots and leaves are used to grow a new plant. The buds which are present in dormant state in old plant are provided with suitable conditions like moisture and warmth so that they grow and develop to form a new plant.

Plants that undergo vegetative propagation are green grass, Bryophyllum, money plant, potato plant, onion, banana, etc.

(1) It takes place with the help of vegetative parts like root, stem, leaf and bud.
(2) Carrot, beet root and radish are the modified roots that perform vegetative propagation.
(3) Potato, suran (Amorphophallus) and other tubes propagate with the help of 'eyes' which are buds. These eyes are present on the stem tubers.
(4) In case of plants like sugarcane & grasses, buds present on nodes perform vegetative propagation.
(5) Plants like Bryophyllum performs vegetative propagation with the help of buds present on leaf margin.

The various methods of vegetative propagation are:

From underground stem: A potato plant has an underground stem known as the tuber. It has many buds called eyes. A vegetative bud consists of a short stem, around which immature overlapping leaves are present in a folded state. A bud can give rise to a new plant through asexual reproduction.

Rhizome: The underground stem of ginger is known as the rhizome which is capable of giving rise to a new plant. Corm is the underground stem as found in Gladiolus. It can also be used for vegetative propagation.

Through leaves: Leaves perform the function of photosynthesis. However, they can take part in asexual reproduction as well. In some plants, leaves can give rise to a new plant asexually. For example, the leaves of the plant Bryophyllum contain buds on its margins. These buds give rise to a new plant through asexual reproduction.

From aerial stem: In certain plants, a slender stem arises from the base of the plant and touches the soil, it develops roots and buds at the point of contact with the soil and gives rise to new plants. When the new plant is old enough the stem connecting it to the parent plant withers away.

(1) Some couples want a child but they are not able to bear one due to various problems either in mother or in father In such cases modern techniques such as IVE, surrogacy and sperm bank are useful in conceiving a child.

(2) In woman if there are problems like irregularity in menstrual cycle, difficulties in oocyte production or implantation in uterus, obstacles in the oviduct, etc. then she can resort to any one technique of the above.

(3) In man if there are ho sperms in the semen. slow movement of sperms, or anomalies in the sperms then he becomes sterile

(4) But now with the help of advanced medical techniques these problems can be overcome and a childless couple can be parents

(5) These methods are as follows :

• Surrogacy - In woman if there is problem regarding the implantation of embryo in uterus then help of another women is taken. This women is called surrogate mother Oocyte from real mother is taken out and fertilized with sperms collected from her husband. These gametes are fertilized outside in a test tube and then the fertilized zygote is implanted tn the surrogate mother.
• Sperm bank - It is a new concept which is similar to blood banks. Sperms are collected from the male donors after a thorough medical checkup and stored for future use. These sperms are used to fertilize the ovum of the women and then this fertilised ovum is implanted in the uterus of the same women.

• ZIFT− It stands for zygote intra fallopian transfer. In ZIFT, the sperm from a donor male and the ova from a donor female are fused in the laboratory. The zygote so formed is transferred into the fallopian tube at the 8 blastomeres stage.

• IUT − It stands for intra uterine transfer. In this technique, embryos with more than 8 blastomeres are transferred into the uterus.
• GIFT − It stands for gamete intra fallopian transfer. In GIFT, females who cannot produce ovum, but can provide suitable conditions for the fertilisation of ovum, are provided with ovum from a donor.
• ICSI − It stands for intra cytoplasmic sperm injection. In this method, sperm is directly injected into the cytoplasm of the ovum.
• Artificial insemination − In this technique, the semen collected from the husband or a donor is injected into the vagina or uterus. This cures the infertility arising from the inability of the male partner to ejaculate, or due to low sperm count.

• • In sexually reproducing plants, flowers function as the reproductive organs.
  • In flowers, male organ is the stamen and female organ is the carpel.
  • Flowers which have both the male and female organs i.e. stamens and carpels are called bisexual flowers whereas flowers which have either male or female organs are called unisexual.
  • Male gametes called pollen grains are produced by stamen, and carpels produce female gametes called ovules or egg cells inside ovaries.
  • Fertilization takes place in the ovule where the egg cell and pollen grain fuse.
  • This fertilized egg cell later develops into an embryo and the entire ovule gets converted into a seed.
  • Under favourable conditions, the seed germinates to give rise to a new plant.