How do Organisms Reproduce? — Class 10 Science PYQs

(D) / Assertion (A) is false and Reason (R) is true. (1 Mark)

(D) / they reproduce asexually (1 Mark)

(C) /Vegetative propagation (1 Mark)

(C) / Asexual reproduction by breaking up of Spirogyra filaments into smaller part. (1 Mark)

(C) / Assertion(A) is true, but Reason(R) is false. (1 Mark)

(D)/ Budding (1 Mark)

(A)/ Both A and R are true and R is the correct explanation of A. (1 Mark)

(C)/ Fragmentation (1 Mark)

(a) Because adrenal gland secretes adrenaline hormone that enables the animal body to face a scary situation. (1 Mark)
(b) To prevent female foeticide. (1 Mark)
(c) Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds / Such methods also make possible the propagation of plants such as banana, orange, rose and jasmine that have lost the capacity to produce seeds / All plants produced are genetically similar enough to the parent plant to have all its characteristics. (1 Mark)

(i) When spores land on a substance and get adequate moisture and temperature, it will develop into new Rhizopus. (1 Mark)
(ii) New plants grow from the buds located in the notches of the leaf. (1 Mark)
(iii) The pollen tube will not be formed. / No fertilisation will take place. (1 Mark)
(iv) Fertilization/Pregnancy will be prevented. (1 Mark)
(v) Each fragment or piece grows into a new individual organism. (1 Mark)

(i) Vegetative propagation. (1 Mark)
(ii) Advantages: -
• Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds.
• Plants produced by vegetative propagation are genetically similar to the parent plant.
• Plants that have lost the capacity to produce seed can reproduce by Vegetative propagation. (any two advantages) (1+1 Marks)
(iii) Roses, grapes, banana, orange, jasmine etc. (any other two examples) (½ + ½ Mark)
(iv) Regeneration is carried out by specialised cells. The organism which have those cells only can show regeneration. (1 Mark)

(D) / Pollination, Fertilisation, embryo, seed.

Pollination
Fertilization
i) It is the transfer of pollen
i) It is the fusion of male gamete
1
grains from anther to the
with the female gamete.
suitable stigma.
ii) It occurs in plants.
ii)It occurs in both plants and
1
animals.
(any other suitable difference)
2

(i) (a) Zygote: It divides several times to form an embryo within the ovule. (1 Mark)
(b) Ovule: It develops a tough coat and is gradually converted into a seed. (1 Mark)
(c) Ovary: Grows rapidly and ripens to form a fruit. (1 Mark)
(d) Sepals: They shrivel and fall off. (1 Mark)
(ii) Germination is the process when the mature seed develops into a seedling under appropriate conditions. (1 Mark)

(a) (i) Reproduction in which plant parts like root, stem and leaves develop into new plants under appropriate conditions is called as vegetative propagation. (1 Mark)
(ii) Advantages of vegetative propagation: -
• Plants raised by this method can bear flowers and fruits earlier than those produced from seeds.
• All the plants produced are genetically similar to the parent plant to have all its characteristics.
• Propagation of plants such as banana, orange, rose and jasmine that have lost the capacity to produce seeds.
(any two or any other suitable advantage) (1+1 Marks)
(iii) Unisexual flower
1 Contains either Stamens (male reproductive part) or Pistil (female reproductive part). (1 Mark)
2 Eg - Papaya or watermelon (1 Mark)
Bisexual flower
Contains both Stamens (male reproductive part) and Pistil (female reproductive part)
Eg - Hibiscus or mustard
(any other suitable difference or example)

(b) (i) Self-pollination
1 Transfer of pollens from stamens to stigma occur in the same flower. (1 Mark)
2 Polling agents may or may not be required. (1 Mark)
3 Genetic variation may or may not occur. (1 Mark)
Cross-pollination
Transfer of pollens from stamens to stigma occur from one flower to another.
Polling agents like wind, water or animals are always required.
Genetic variation always occur.
(any two, any other suitable difference)
(ii) After pollination, the pollen lands on a suitable stigma, a tube grows out of the pollen grains and travels through the style to reach the ovary. (1 Mark)
A female germ cell present inside ovary fuses with a male germ cell to form zygote and this process leads to fertilization. (1 Mark)
(iii) End products of sexual reproduction-
• Seed. (½ Mark)
• Fruit. (½ Mark)

(C)/ Uterus (1 Mark)

(i) Most of these bacteria would die, but the few variants resistant to heat would survive and grow further. (1 Mark)
(ii) Fertilization occurs to form a zygote. (1 Mark)
(iii) Cross pollination may occur leading to fruit formation. / No fertilization. / No fruit formation. (1 Mark)
(iv) If the egg is not fertilised, the thick and spongy lining of the uterus breaks and comes out through vagina as blood and mucus, known as menstruation. / Menstruation will take place. (1 Mark)
(v) The seed will develop into a seedling. / Germination will take place. (1 Mark)

(a) (i)
* Organ - Testes (1 Mark)
* Conditions - Requires a lower temperature than the normal body temperature/Secretion of testosterone. (1 Mark)
(ii) The sperms formed in the testes are carried by Vas deferens and delivered to urethra (Common passage for both sperms and urine). / Testes $\rightarrow$ Vas deferens $\rightarrow$ Urethra (2 Marks)
(iii) Long tail of sperms. (1 Mark)
OR
(b) (i)
* Mechanical barrier / Female condom (Diaphragm)/ similar covering worn in vagina. (2 Marks)
* Oral contraceptives/ Oral pills
* Copper - T/loops. (Any two methods, Any other method)
(ii) Surgical methods
* Vas deferens in the male is blocked / Vasectomy (2 Marks)
* Fallopian tube in the female is blocked /Tubectomy
(iii)
* Bacteria - Gonorrhoea / Syphilis (any other example) (½ Mark)
* Virus - Warts / AIDS (any other example) (½ Mark)

(C) / Gonorrhoea

(a) (i)
* Organ - Testes (1 Mark)
* Conditions - Requires a lower temperature than the normal body temperature/Secretion of testosterone. (1 Mark)
(ii) The sperms formed in the testes are carried by Vas deferens and delivered to urethra (Common passage for both sperms and urine). / Testes $\rightarrow$ Vas deferens $\rightarrow$ Urethra (2 Marks)
(iii) Long tail of sperms. (1 Mark)
OR
(b) (i)
* Mechanical barrier / Female condom (Diaphragm)/ similar covering worn in vagina. (2 Marks)
* Oral contraceptives/ Oral pills
* Copper - T/loops. (Any two methods, Any other method)
(ii) Surgical methods
* Vas deferens in the male is blocked / Vasectomy (2 Marks)
* Fallopian tube in the female is blocked /Tubectomy
(iii)
* Bacteria - Gonorrhoea / Syphilis (any other example) (½ Mark)
* Virus - Warts / AIDS (any other example) (½ Mark)

OR
(b)(i)
• Mechanical barrier / Female condom (Diaphragm)/ or similar covering worn in vagina
• Oral contraceptives/ Oral pills
• Copper - T / loops.
(Any two methods, Any other method)
(ii) Surgical methods
• Vas deferens in the male is blocked / Vasectomy
• Fallopian tube in the female is blocked /Tubectomy
(iii)
Bacteria - Gonorrhoea / Syphilis (any other example)
Virus - Warts / AIDS (any other example)