Monday, October 6, 2014

Chapter 8 How Do Organisms Reproduce [STUDY MATERIAL FOR 10th class SLOW LEARNERS]




One mark question
Q1. Name the type of fission carried out by amoeba.       

Ans.  Binary fission.
Q2.  What is vegetative propagation?

Ans. When new plants are grown by using vegetative parts like root, stem and leaves it is known as vegetative propagation.

Q3. Name an organism which reproduces by multiple fission.

Ans. Plasmodium {malarial parasite}

Q4. What is Puberty?

Ans. The age at which the human males and females becomes sexually mature is called puberty.

Q5. What is pollination?

Ans. The transfer of pollen grains from anther to the stigma of the same or another flower of the same kind is called pollination.

Q6. What is fertilization?

Ans. The fusion of male and female gametes is called fertilization.

Q7. What is placenta?

Ans. The tissue connecting developing embryo {foetus} and mother is called placenta.

Q8. What is asexual reproduction?

Ans. The process of reproduction in which only one parent is involved and no sex cells are involved 
is called asexual reproduction.

Q9. Write the expanded form of AIDS.

Ans. Acquired Immuno deficiency Syndrome is the full form of AIDS.

Q10. Name two sexually transmitted diseases.

Ans. 1.AIDS

2. Gonorrhea

3. Syphilis

Two mark question

Q1.Name those parts of the flower which serve the same function as the following do in the animals:

1. Testes

2.  Ovary

3.  Eggs

4.  Sperms

Ans.1.Stamen

2. Carpel

3. Ovule

4. Pollen grain

Q2. What methods will you use for growing jasmine and rose plant?

Ans. Layering method of artificial vegetative propagation can be used for growing jasmine plant. 
Stem cutting method can be used for growing rose plant.

Q3.Mention any two functions of human ovary.

Ans.1.It produces ovum the female gamete.

2. It secretes hormone estrogen.

Q4. Define menstruation.

Ans. The breakdown and removal of the inner thick and soft lining of the uterus along with its blood  vessels in the form of vaginal bleeding is called menstruation.

Q5. How the surgery methods are misused by people to prevent pregnancy?

Ans. Surgery methods are misused to prevent pregnancy. This method can be used for removal of unwanted pregnancies by people who do not want a particular child which happens in case of illegal sex selective abortion of female foetus.

Q6. What is the significance of human testes being located in the scrotum?

Ans. Scrotum protects the testes by regulating the temperature of the testes. Sperms need a 
temperature less than the body temperature for their production and development.

Q7. Questions: Name those parts of a flower which serve the same function as the following do in the animal        (i) Testis (ii) Ovary (iii) Eggs (iv) Sperms

Ans:

Testis as anther

Ovary ovules present inside ovary

Eggs as eggs

Sperms as pollen grains

Q.8 Pre - natal sex determination has been prohibited by law. State two reasons.

Ans: Prenatal sex determination has been prohibited by law because of indiscriminate female foeticide. As a result of this, child sex ratio is declining at an alarming rate in some sections of our society. For a healthy society, the female-male sex ratio must be maintained.

Q.9. What is placenta ? State its any two roles during pregnancy.

Ans: The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother’s blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and lizards with varying levels of development up to mammalian levels.the following are the roles :-
(a) For nine months the placenta feeds and nourishes the fetus while also disposing of toxic waste.
(b) Without it the baby could not survive. After your baby is born, the placenta no longer serves a function.


Q10. Small piece of root tissue was taken from the rose plant and placed in a nutrient medium. Each root tissue produced a new rose plant. Name the reproductive process involved. What type of genes will be possessed by new rose plant ?

Sol. (i) This process is called tissue culture.

(ii) Genes possessed by the new plant is same as that of the parent plant.

Three marks question

Q1. (a). What is fertilization? Distinguish between external fertilization and internal fertilization.

  (b). What is the site of fertilization in human beings?

Ans.(a)  Fertilization is defined as the fusion of male and female gametes to form a zygote during a 
sexual reproduction.

 Difference between external and Internal fertilization

External fertilization
Internal fertilization
1. The fusion of male and female gametes 
occurs outside the body.
1. The fusion of gametes occurs inside the body.

2. Both individual discharge their gametes 
outside the body and development occurs 
outside the body.
2. The gametes fuse inside the female body and 
development occurs inside the body.
Example: Frogs 
Example: Birds, cattle, humans

(b)  The site of fertilization in human beings is in the fallopian tube of female reproductive system.

Q2. Give two advantages of vegetative propagation.

Ans. 1(i). Vegetative propagation is a cheaper, easier and more rapid method of propagation in plants 
than growing plants from seeds.

(ii). The characteristics of the parent plant are preserved by vegetative propagation.

Q3. Describe the surgical methods of birth control. 

Ans. The surgical method can be done in males as well as in females.

In case of males the vas deference is blocked and sperm transfer is prevented. In case of females the 
fallopian tube is blocked the egg will not be able to reach the uterus. These are permanent methods of  birth control.

Q4. Why is DNA copying an essential part of the process of reproduction?

Ans. DNA copying is an essential part of the process of reproduction because-

  1. DNA provides cellular apparatus in the daughter cells.
  2. DNA in the daughter cells will control their functioning
  3. DNA copies will retain the characters.

Q5. What could be the reasons for the adopting of contraceptive methods?

Ans. Contraceptive methods are adopted for the following reasons:
1.      For preventing unwanted pregnancies and keeping the health of women.
2.      2. To prevent the transmission of fatal diseases mechanical barrier methods are used.

Q.6. Mention any three advantages of variation in individuals.

Ans:
(i) Variation helps in survival of species.
(ii) It is the basis of evolution.
(iii) It brings adaptation in individuals.

Q.7. Name the filamentous structure seen in pond. Explain how do they reproduce.

Ans:  Spirogyra have filamentous structure. They reproduce by the process of fragmentation in which they break up into smaller pieces upon maturation. These pieces grow into new individuals.

Q.8. A student noticed that an organism by mistake was cut in two parts.  After sometime both the parts developed into new individuals.
(a) Name the mode of reproduction used by the organism.
(b) State the type of cells which carry this process.
(c) Write examples of two organisms which multiply by this process.

Ans:
(a) Regeneration (asexual reproduction)
(b) Specialised cells.
(c) Hydra and Planaria

Q9. Ravi took three bread slices and kept the three pieces of the slices  in the following conditions.
(i) Slice 1 in a dried and dark place.
(ii) Slice 2 in a moist and dark place.
(iii) Slice 3 in moist and in refrigerator.

What would he observe in each of the above conditions ? Give reasons for your answer ?

Ans:
(i) In Slice 1, No spore will develop due to lack of  moisture.
(ii) A white cottony mass surrounded with a black mass is seen spreading on the surface of slice 2 due to formation of sporangia and spores as moisture and darkness provide favourable condition.
(iii) In slice 3, no spore will be formed as it is kept at a lower temperature in the refrigerator, which is not a favourable condition.

Q10. (i) State the function of (a) stigma (b) pollen tube.  (ii) What happens to the ovule after fertilization ?

Ans: .
(i) (a) Stigma receives pollens.
    (b) Pollen tube helps to carry the male germ cell to the female germ cell from the stigma to the ovary.

(ii) After fertilization, the ovule develops into seed.

Links For CBSE Class X Science Term-II
Carbon and Its Compounds                                  Periodic Classification of Elements of Elements

Light - Reflection and Refraction                       The Human Eye and the Colorful World

How Do Organisms Reproduce?                         Heredity and Evolution

Our Environment

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