CBSE 10 | Chapterwise 20 PYQS and Solutions
SUBJECT:
CLASS: X
CHAPTER: How do organisms reproduce ? No. of PYQs:20
Sl No QUESTIONS MARK
1 (i) Name and explain the two modes of asexual reproduction 2
observed in Hydra.
(ii) What is vegetative propagation ? List two advantages of
using this technique. (2023)
Ans. By budding and fragmentation, hydra can reproduce
asexually. A bud, or protrusion, is created during budding; this
bud matures into an adult and separates from the main body.
The body splits in two during fragmentation, with regeneration
occurring after.
Vegetative propagation is a process in which any vegetative
part of a plant root stem or leaf gives rise to a new plant under
appropriate conditions.
Two advantages:
i Large number of plants obtained in a short interval.
ii Propagation of seedless plants is made possible.
2 What happens when: 3
1. Leaves of Bryophyllum fall on the soil ?
2. Planaria is cut into many pieces?
3. Sporangia of Rhizopus on maturation liberates spores ?
Mention the modes of reproduction in each of the above
cases. (2023, 2020)
Ans.
1. When Bryophyllum leaf falls on the wet soil, the buds that are
produced in the notches along the leaf will develop into new
plants by the process known as vegetative propagation.
2. When Planaria accidentally gets cut into many pieces, each
piece grows the missing part and forms the complete organism.
This form of asexual reproduction is known as regeneration.
3. When the sporangia of Rhizopus burst upon maturation, the
spores spread out. So, with the help of different agents, the
spores are transferred to various places and when they land on
, a particular surface, a new organism (mycelium) starts growing.
3 Write the changes that occur in a flower once the fertilization 2
has taken place ? (2023)
Ans. After fertilization, the flower loses its shine. After
fertilization four major changes that take place are development
of endosperm and embryo, development or maturation of ovules
into seeds and formation of fruit from ovary.
4 (i) Where are testes located in human males and why ? State 5
two functions of the testes.
(ii) In the human female, one of the ovaries releases an egg
every month. State the changes that take place if
The egg is fertilized
The egg is no fertilized
(iii) What is done during the surgical method in males and
females to prevent pregnancy ? (2023)
Ans. I. A pair of the testis is placed in a structure called scrotum
which is located outside the abdominal cavity. The testis is
located outside the body because sperms develop best at a
temperature several degrees cooler than normal internal body
temperature.
II. The main function of the testes is producing and storing
sperm. They're also crucial for creating testosterone and other
male hormones called androgens.
1. The fertilized egg develops into an embryo, which eventually
grows into a fetus.
2. If the egg is not fertilized: - The unfertilized egg disintegrates
and is expelled along with the lining of the uterus during
menstruation
III. For male the surgical technique to prevent pregnancy is
Vasectomy. For females the surgical technique to prevent
pregnancy is Tubectomy.
5 (a) Why is it not possible to reconstruct the whole organisms 3
from a fragment in complex multicellular organisms ?
(b) Sexual maturation of reproductive tissues and organs are
necessary links for reproduction. Elucidate. (2013)
Ans. (a) The reason is that many multicellular organisms are not
simply a random collection of cells. Specialized cells are
organized as tissues, and tissues are organized into organs,
SUBJECT:
CLASS: X
CHAPTER: How do organisms reproduce ? No. of PYQs:20
Sl No QUESTIONS MARK
1 (i) Name and explain the two modes of asexual reproduction 2
observed in Hydra.
(ii) What is vegetative propagation ? List two advantages of
using this technique. (2023)
Ans. By budding and fragmentation, hydra can reproduce
asexually. A bud, or protrusion, is created during budding; this
bud matures into an adult and separates from the main body.
The body splits in two during fragmentation, with regeneration
occurring after.
Vegetative propagation is a process in which any vegetative
part of a plant root stem or leaf gives rise to a new plant under
appropriate conditions.
Two advantages:
i Large number of plants obtained in a short interval.
ii Propagation of seedless plants is made possible.
2 What happens when: 3
1. Leaves of Bryophyllum fall on the soil ?
2. Planaria is cut into many pieces?
3. Sporangia of Rhizopus on maturation liberates spores ?
Mention the modes of reproduction in each of the above
cases. (2023, 2020)
Ans.
1. When Bryophyllum leaf falls on the wet soil, the buds that are
produced in the notches along the leaf will develop into new
plants by the process known as vegetative propagation.
2. When Planaria accidentally gets cut into many pieces, each
piece grows the missing part and forms the complete organism.
This form of asexual reproduction is known as regeneration.
3. When the sporangia of Rhizopus burst upon maturation, the
spores spread out. So, with the help of different agents, the
spores are transferred to various places and when they land on
, a particular surface, a new organism (mycelium) starts growing.
3 Write the changes that occur in a flower once the fertilization 2
has taken place ? (2023)
Ans. After fertilization, the flower loses its shine. After
fertilization four major changes that take place are development
of endosperm and embryo, development or maturation of ovules
into seeds and formation of fruit from ovary.
4 (i) Where are testes located in human males and why ? State 5
two functions of the testes.
(ii) In the human female, one of the ovaries releases an egg
every month. State the changes that take place if
The egg is fertilized
The egg is no fertilized
(iii) What is done during the surgical method in males and
females to prevent pregnancy ? (2023)
Ans. I. A pair of the testis is placed in a structure called scrotum
which is located outside the abdominal cavity. The testis is
located outside the body because sperms develop best at a
temperature several degrees cooler than normal internal body
temperature.
II. The main function of the testes is producing and storing
sperm. They're also crucial for creating testosterone and other
male hormones called androgens.
1. The fertilized egg develops into an embryo, which eventually
grows into a fetus.
2. If the egg is not fertilized: - The unfertilized egg disintegrates
and is expelled along with the lining of the uterus during
menstruation
III. For male the surgical technique to prevent pregnancy is
Vasectomy. For females the surgical technique to prevent
pregnancy is Tubectomy.
5 (a) Why is it not possible to reconstruct the whole organisms 3
from a fragment in complex multicellular organisms ?
(b) Sexual maturation of reproductive tissues and organs are
necessary links for reproduction. Elucidate. (2013)
Ans. (a) The reason is that many multicellular organisms are not
simply a random collection of cells. Specialized cells are
organized as tissues, and tissues are organized into organs,
