TN 10th Science Guide

17. Reproduction in Plants and Animals

I. Choose the Correct Answer.

1. The plant which propagates with the help of its leaves is ______.

(a) Onion
(b) Neem
(c) Ginger
(d) Bryophyllum.

2. Asexual reproduction takes place through budding in:

(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Bacteria

3. Syngamy results in the formation of ______.

(a) Zoospores
(b) Conidia
(c) Zygote
(d) Chlamydospores.

4. The essential parts of a flower are:

(a) Calyx and Corolla
(b) Calyx and Androecium
(c) Corolla and Gynoecium
(d) Androecium and Gynoecium

5. Anemophilous flowers have ______.

(a) Sessile stigma
(b) Small smooth stigma
(c) Coloured flower
(d) Large feathery stigma.

6. Male gametes in angiosperms are formed by the division of:

(a) Generative cell
(b) Vegetative cell
(c) Microspore mother cell
(d) Microspore

7. What is true of gametes?

(a) They are diploid
(b) They give rise to gonads
(c) They produce hormones
(d) They are formed from gonads.

8. A single highly coiled tube where sperms are stored, get concentrated and mature is known as:

(a) Epididymis
(b) Vasa efferentia
(c) Vas deferens
(d) Seminiferous tubules

9. The large elongated cells that provide nutrition to developing sperms are ______.

(a) Primary germ cells
(b) Sertoli cells
(c) Leydig cells
(d) Spermatogonia.

10. Estrogen is secreted by:

(a) Anterior pituitary
(b) Primary follicle
(c) Graffian follicle
(d) Corpus luteum

11. Which one of the following is an IUCD?

(a) Copper – T
(b) Oral pills
(c) Diaphragm
(d) Tubectomy.

II. Fill in the Blanks.

1. The embryo sac in a typical dicot at the time of fertilization is double fertilization.

2. After fertilization the ovary develops into Fruit.

3. Planaria reproduces asexually by Regeneration.

4. Fertilization is Internal in humans.

5. The implantation of the embryo occurs at about 6 to 7 day of fertilization.

6. Colostrum is the first secretion from the mammary gland after childbirth.

7. Prolactin is a hormone produced by Anterior Pituitary.

III. Match the following.

Question 1.

Column I	Column II
1. Fission	(b) Amoeba
2. Budding	(c) Yeast
3. Fragmentation	(a) Spirogyra

Question 2.
Match the following terms with their respective meanings.

1. Parturition	(c) Delivery of baby from a uterus
2. Gestation	(a) The duration between pregnancy and birth
3. Ovulation	(d) Release of an egg from Graafian follicle
4. Implantation	(b) Attachment of zygote to the endometrium

IV. State whether the following statements are True or False. Correct the false statement.

1. The stalk of the ovule is called pedicle.
Answer: False.
Correct Statement: Stalk of the ovule is called funiculus.

2. Seeds are the product of asexual reproduction.
Answer: False.
Correct Statement: Seeds are the product of Sexual reproduction.

3. Yeast reproduces asexually by means of multiple fission.
Answer: False.
Correct Statement: Yeast reproduces asexually by means of budding.

4. The part of the pistil which serves as a receptive structure for the pollen is called as style.
Answer: False.
Correct Statement: The part of the pistil which serves as a receptive structure for the pollen is called as stigma.

5. Insect pollinated flowers are characterized by dry and smooth pollen.
Answer: False.
Correct Statement: Insect pollinated flowers are characterized by larger and spiny pollen.

6. Sex organs produce gametes, which are diploid.
Answer: False.
Correct Statement: Sex organs produce gametes, which are haploid.

7. LH is secreted by the posterior pituitary.
Answer: False.
Correct Statement: LH is secreted by the anterior pituitary.

8. Menstrual cycle ceases during pregnancy.
Answer: True.

9. Surgical methods of contraception prevent gamete formation.
Answer: True.

10. The increased level of estrogen and progesterone is responsible for menstruation.
Answer: False.
Correct Statement: The decreased level of estrogen and progesterone is responsible for menstruation.

V. Answer in a word or sentence.

1. If one pollen grain produces two male gametes, how many pollen grains are needed to fertilize 10 ovules?

One sperm fuses with the egg and forms a diploid zygote. So 10 pollen grains are needed to fertilize 10 ovules.

2. In which part of the flower germination of pollen grains takes place?

Germination of pollen grains takes place in the stigma of the female flower.

3. Name two organisms which reproduce through budding.

Yeast, Hydra.

4. Mention the function of endosperm.

Endosperm provides food to the developing embryo.

5. Name the hormone responsible for the vigorous contractions of the uterine muscles.

Oxytocin, from the posterior pituitary, is responsible for the vigorous contractions of the uterine muscles.

6. What is the enzyme present in acrosome of sperm?

Acrosome contain hyaluronidase an enzyme that help the sperm to enter the ovum during fertilization.

7. When is World Menstrual Hygiene Day observed?

Every year May 28 is observed as World Menstrual Hygiene Day.

8. What is the need for contraception?

Contraception is one of the best birth control measures to check population growth.

9. Name the part of the human female reproductive system where the following occurs.

Fertilization
Implantation

Answer:

Oviduct of the female genital tract.
Uterus

VI. Short Answer Questions.

1. What will happen if you cut Planaria into small fragments?

Breaking of fragments of Planaria results into many fragments. Each fragment having one cell will give rise to a new Planaria, by cell division.

2. Why is vegetative propagation practiced for growing some type of plants?

No gametic fusion is required in vegetative reproduction. In this type, new plantlets are formed from vegetative cells, buds or organ of plant. The vegetative part of plant get detached from the parent body and grows into an Independent daughter plant.

3. How does binary fission differ from multiple fission?

Binary fission	Multiple fission
1. The nucleus divides into two parts.	1. The nucleus divides into many parts.
2. It gives rise to new individuals.	2. It gives rise to many individuals
3. Cytoplasm divides after each nuclear division.	3. Cytoplasm does not divide after every nuclear division.
4. eg. Amoeba.	4. eg. Plasmodium.

4. Define Triple fusion.

The fusion of one male gamete (n) fuses with the secondary nucleus (2n) to produce primary endosperm nucleus (3n) is called Triple fusion.

5. Write the characteristics of insect-pollinated flowers.

Pollination with the help of insects like flies and honey bees are called Entomophily. To attract those insects, these flowers are brightly coloured, have smell and nectar.

6. Name the secondary sex organs in male.

Secondary sex organs in male are seminiferous tubules, epididymis, sperm duct, seminal vesicles, prostrate gland, cowper’s gland and penis.

7. What is colostrum? How is milk production hormonally regulated?

The first fluid which is released from the mammary gland after childbirth is called colostrum. Milk production from alveoli of the mammary gland is stimulated by prolactin secreted from the anterior pituitary. The ejection of milk is stimulated by the posterior pituitary hormone oxytocin.

8. How can menstrual hygiene be maintained during menstrual days?

Menstrual hygiene to be maintained during menstrual days are:

Sanitary pads should be changed regularly to avoid infections due to microbes from vagina and sweat from genitals.
Use of warm water to clean genitals helps to get rid of menstrual cramps.
Wearing loose clothing rather than tight-fitting clothes will ensure the airflow around the genitals and prevent sweating.

9. How does developing embryo gets its nourishment inside the mother’s body?

The placenta allows the exchange of food materials, diffusion of oxygen, excretion of nitrogenous wastes and elimination of carbon-di-oxide. A cord, containing blood vessels that connect the placenta with the foetus is called the umbilical cord.

10. Identify the parts A, B, C and D.

Answer:
The parts A, B, C and D are:

A : Exine.

B : Intine.

C : Generative cell.

D : Vegetative nucleus.

11. Write the events involved in the sexual reproduction of a flowering plant.
(a) Discuss the first event and write the types.
(b) Mention the advantages and the disadvantages of that event.

(a) The first event is pollination. Pollination is the process of transfer of pollen grains from anther to stigma of a flower. The two types of pollination are self-pollination and cross pollination.

(b) Advantages of self-pollination:

Self-pollination is possible in certain bisexual flowers.
Flowers do not depend on agents for pollination.
There is no wastage of pollen grains.

Disadvantages of self-pollination:

The seeds are less in numbers.
The endosperm is minute. Therefore, the seeds produce weak plants.
New varieties of plants cannot be produced.

Advantages of cross pollination:

The seeds produced as a result of cross pollination, develop and germinate properly and grow into better plants, i.e., cross pollination leads to the production of new varieties.
More viable seeds are produced.

Disadvantages of cross-pollination:

Pollination may fail due to distance barrier.
More wastage of pollen grains.
It may introduce some unwanted characters.
Flowers depend on the external agencies for pollination.

12. Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present?

The testicles, produce sperm and testosterone. The testicles are located outside the body because the sperms develop best at a temperature, several degrees lower than normal body temperature. The pouch, is scrotum, a sac – like structure, in which the testes are present.

13. Luteal phase of the menstrual cycle is also called the secretory phase. Give reason.

In leutal phase LH and FSH decreases, corpus luteum produces progesterone and its level increases followed by a decline progesterone also stimulates the glands in the uterus to secrete substances that maintain the endometrium and keep it from breaking down. For this reason, this phase of menstrual cycle is called secretory phase.

14. Why are family planning methods not adopted by all the people of our country?

· Illiteracy

· Emphasis is in rural areas and not in villages.

· Door to door campaign to encourage families could not be done because of overpopulation.

· Poor economic status and poverty of most of the people in India.

· Age-Old cultural norms continue to cause, poor family planning practices, all across the country.

VII. Long Answer Questions.

1. With a neat labelled diagram describe the parts of a typical angiosperms ovule.

The main part of the ovule is the nucellus which is enclosed by two integuments, leaving an opening called micropyle. The ovule is attached to the ovary wall by a stalk, called funiculus. The basal part is Chalaza.

The embryo sac contains seven cells and the eighth nuclei located within the nucellus. Three cells at the micropylar end form the egg apparatus and the three cells at the chalazalnte9uments end are the antipodal cells. The remaining two nuclei are called polar nuclei found in the centre. In the egg apparatus, one is the egg cell (female gamete) and the remaining two cells are the synergids.

2. What are the phases of the menstrual cycle? Indicate the changes in the ovary and uterus.

The four phases of the menstrual cycle are:

Menstrual or Destructive phase
Follicular or Proliferative phase
Ovulatory phase
Luteal or secretory phase.

Events of the menstrual cycle and changes in ovary and changes in the uterus.

Phase	Days	Changes in Ovary	Changes in Uterus	Hormonal changes
Menstrual phase	4 – 5 days	Development of primary follicles.	Breakdown of uterine endometrial lining leads to bleeding.	The decrease in progesterone and oestrogen.
Follicular phase	6th – 13th day	Primary follicles grow to become a fully mature Graafian follicle.	Endometrium regenerates through proliferation.	FSH and Oestrogen increase.
Ovulatory phase	14th day	The Graafian follicle ruptures, and releases the ovum (egg).	Increase in endometrial thickness.	LH peak.
Luteal phase	15th – 28th day	Emptied Graafian follicle develops into corpus luteum.	The endometrium is prepared for implantation if fertilization of the egg takes place if fertilization does not occur corpus luteum degenerates, uterine wall ruptures, bleeding starts and unfertilized egg is expelled.	LH and FSH decrease, Corpus luteum produces progesterone and its level increases followed by a decline, if menstrual bleeding occurs.

VIII. Higher Order Thinking Skills (HOTS) Questions

1. In angiosperms the pollen germinates to produce pollen tube that carries two gametes. What is the purpose of carrying two gametes when single gamete can fertilize the egg?

In angiosperms, one sperm cell fuses with the egg cell to form the zygote, while the other fuses with the two polar nuclei that form the endosperm which nourishes the developing embryo.

2. Why the menstrual cycle does not take place before puberty and during pregnancy?

The reproducing period of a women’s life starts and becomes functional and an increase in sex hormone production starts only in puberty. So the menstrual cycle does not take place before puberty. The release of a mature egg, maintains the lining of the uterus, during pregnancy. During pregnancy, the placenta produces progesterone. This maintains the lining of the uterus during pregnancy and it means that menstruation does not happen.

3. Read the following passage and answer the questions that follow.
Rahini and her parents were watching a television programme. An advertisement flashed on the screen which was promoting use of sanitary napkins. Rahini’s parents suddenly changed the channel, but she objected to her parents and explained the need and importance of Such advertisement.

(a) What is first menstruation called? When does it occur?

The first menstruation is called Menarche. In human females, the menstrual cycle starts at the age of 11 – 13 years which marks the onset of puberty.

(b) List out the napkin hygiene measures taken during menstruation?

1. The sanitary pad and tampons should be wrapped properly and discarded because they can spread infections.

2. Sanitary pad or tampon should not be flushed down the toilet.

3. Napkin incinerators are to be used properly for disposal of used napkins.

(c) Do you think that Rahini’s objection towards her parents was correct? If so, Why?

Yes. Awareness to be created in maintaining menstrual hygeine and importance of menstrual hygeine for good health.