reproduction in plants and animals

Question 1

what are the steps in tissue culture

Answer 1

● Explants: Small pieces of plant tissue (like stem, leaf, or root) are taken from a parent
plant.
● Sterilization: The explants are sterilized to remove any microorganisms that could
contaminate the culture.
● Nutrient Medium: The explants are placed in a nutrient-rich gel or liquid medium
containing essential nutrients for growth.
● Growth and Multiplication: The cells in the explants start dividing and forming new
tissues.
● Rooting and Acclimatization: Once sufficient growth occurs, the new plantlets are
transferred to soil and carefully acclimated to their new environment.

Question 2

what is pollination by insects called? What are the characteristics of insect-pollinated flowers?

Answer 2

-pollination by insects is called entomophily
-large and brightly coloured petals to attract insects
-pollen grains are rough and sticky
-flowers produce scent and nectar to attract insects

Question 3

what are the female reproductive organs

Answer 3

-Pair of ovaries present on either side of the uterus and they produce eggs (ova)
-oviducts or fallopian tubes through which the eggs travel from the ovary to the uterus. Here the ovum and the sperm fuse together and fertilisation takes place.
-uterus also known as the womb is the structure in which developement of the fertilised egg and embryo takes place
-lower part of the uterus is known as the cervix
-vagina: cervix is connected to the muscular tube like structure known as the vagina .the sperms enter the uterus through the vagina.it also servs as the birth canal throuh which the baby is delivered.

Question 4

what is grafting

Answer 4

-the desired plant is achieved from two different individuals.
-the root portion taken from one plant known as the stock
-the stem portion, the the plant which you want to propagate is know as the scion

Question 5

vegetative propagation by aerial stems

Answer 5

eg. strawberry
long stems that grow over soil surface known as runners that have axillary buds

Question 6

what bisexual flowers

Answer 6

flowers that have male and female parts in the one flower are known as bisexual or hermaphrodite flowers

Question 7

what are monoecious plants

Answer 7

the male and female parts are on different flowers but the same plant

Question 8

what is pollination by wind called and what are the characteristics of wind-pollinated flowers

Answer 8

-pollination by wind is called anemophily
-flowers are small with long filaments and large feathery stigmas
-pollen grains are produced in large numbers
-flowers are not showy and do not produce scent

Question 9

What is vegetative propagation

Answer 9

-asexual method of reproduction where the vegetative parts of plants give rise to new plants
-seeds are not produced
-the part of the plant used for vegetative propagation is the vegetative propagule

Question 10

what is pollination by water called and what are the characteristics of water pollinated flowers ?

Answer 10

-pollination by water is called hydrophily
-pollen grains are produced in large numbers
-plants are dioecious
small and inconspicuous flowers that can float on water easily

Question 11

disadvantages of vegetative propagation

Answer 11

-overcrowding near the plant
-plants produced are very genetically similar and prone to the same diseases. this can lead to the destruction of entire crop

Question 12

what are the advantages of vegetative propagation

Answer 12

-easier, rapid and less expensive
-seedless plants can be raised
-plats produced by this method do not show variations and are identical to the parents
-plants that do not produce viable seeds can be grown easily

Question 13

what is the importance of tissue culture

Answer 13

● Tissue culture is crucial for developing improved crop varieties that address challenges
like pests, diseases, and environmental conditions.
● It plays a role in preserving biodiversity and preventing extinction of rare plants.
● Scientists use tissue culture to study plant development, genetics, and responses to
various factors.

Question 14

what is pollination and its types

Answer 14

pollination is the transfer of pollen grains fro the mature anther to the stigma of the same flower or a different flower of the same species

Question 15

what is fertilization in humans?

Answer 15

Fertilisation takes place in the femal’s body, in the oviduct. The fertilized egg attaches itself to the womb’s inner lining, this is known as implantation. Here it develops into a new baby for the next none months or 180 days known as pregnancy or gestation.When an egg gets fertilized it goes under division and devlops into a embryo .

Question 16

what is tissue culture

Answer 16

● Tissue culture is a modern method of vegetative propagation used in plants.
● It involves growing plant cells or tissues in a controlled environment, allowing them to
develop into new plants.

Question 17

what is the procedure of artificial propagation

Answer 17

-plants with the desired features are selected
-pollen grains from the desired plant’s anther are carefully removed(emasculation) and dusted on the stigma
-these pollinated flowers are covered with a polythene bag(bagging) till the fruits and seeds are produced. Also, the flowers are also bagged to prevent them from being pollinated by other sources
-the seeds are sown in the next season, and the offspring with better features are produced
this repeated for a few generations

Question 18

what is reproduction

Answer 18

reproduction is the means of perpetuation or continuation of species.

Question 19

what are the parts of a flower?

Answer 19

A flower has four parts arranged in rings or whorls.
-sepals
-petals or corolla
-Stamens
-male parts of the flowers
-anther, the swollen structure present on the tip of the filament
-the anther produces a powdery substance called pollen grains that contain the male gamete
-carpel is the central part of the filament
-basal swollen portion called the ovary
-The ovary continues into a long style and ends in the knob-like part, the stigma.
-the ovary contains many ovules, and the female egg is the ovule.

Question 20

how does a fruit and seed form?

Answer 20

-pollen grains germinate on the stigma and form the pollen tube downwards towards the ovary through the style
-the ovule is contained in the ovary
-the male gamete reaches the female gamete present in the ovule
-the zygote divides, grows and gives rise to new embryo
-the ovary develops into a fruit that contains the ovule

Question 21

what are the applications of tissue culture

Answer 21

● Mass Production: Used to produce a large number of plants quickly and consistently for
commercial purposes.
● Conservation: Helps conserve rare or endangered plant species by propagating them in
controlled environments.
● Crop Improvement: Used to develop new plant varieties with improved traits, such as
disease resistance or higher yield.

Question 22

what are the aims of artificial propagation?

Answer 22

-produce varieties with high-yielding seeds
-produce plant varieties with better-quality flowers and seeds
-to produce plants with disease-resistant seeds
-produce plant varities of better quality, nutritional value, and palatability

Question 23

what are the disadvantages of tissue culture

Answer 23

● Requires specialised equipment and skills.
● Can be expensive due to the need for controlled environments and specific nutrients.
● Lack of genetic diversity in the propagated plants.

Question 24

what are the organs of the male reproductive system?

Answer 24

• a pair of testes present in the scrotal sac produces the male gametes. The testes are present outside the body in a sac called the scrotum
• epididymis is present on top of the testes and stores the sperm
  -vas deferens is also called the sperm duct through which the sperm leave the testes. Vas deferens opens into the urethra and reaches the penis
  -penis helps in inseminating the sperm inside the female body

Question 25

what is layering

Answer 25

-the stem bearing the axillary bud is bent at the node, so it is buried in eh soil while the growing tip of the plant is still above the soil.
- axillary bud grows into a separate plant and can now be cut from the parent plant
eg. jasmine,mint

Question 26

vegetative propagation by underground stems examples

Answer 26

the stems are known s corm
ginger (rhizome)
potato
gladiolus ( sword lily)
saffron
sugarcane

Question 27

what is cutting

Answer 27

-short lengths of the plant that under suitable conditions grow into individual plants
-stem cutting: stem-bearing axillary buds are cut and put into moist soil.it sometimes needs to be put in a rooting hormone. eg, Bougainville
-root cutting:lemon and tamarind, their root cuttings are put into soil and they grow into root and shoots.

Question 28

what is sexual reproduction

Answer 28

sexual reproduction is characterized by the fusion of two sex cells(gametes) derived from two parents of the opposite sex, male and female.

Question 29

vegetative propagation by roots examples

Answer 29

sweet potato, dahlia, asparagus

Question 30

what is binary fission

Answer 30

-most common method of reproduction of asexual reproduction in unicellular bacteria and ameoba
-the nucleus divides itself into two equal parts
-each of the nuclei grow into full size daughter cells
-when the nucleus divides itself into more than two parts, it is known as multiple fission, eg. chlorella

Question 31

what is fertilisation and its product?

Answer 31

fertilisation is the fusion of two gametes and its product is known as a zygote.

Question 32

what are the advantages of tissue culture?

Answer 32

● Rapid multiplication: Large numbers of plants can be produced from a small amount of
plant tissue.
● Disease-free plants: Tissue culture ensures the production of disease-free plants, as the
starting material is sterilised.
● Consistency: All offspring are genetically identical to the parent plant, maintaining
desirable traits.

Question 33

what are dioecious flowers

Answer 33

the male and female parts are on different flowers of different plants of the same species.