reproduction in organisms

Question 1

why is reproduction necessary

Answer 1

gives rise to new young ones and enables the continuity of the species

Question 2

what is asexual reproduction

Answer 2

when offspring is produced by a single parent without the involvement of gamete formation

Question 3

what is sexual reproduction

Answer 3

when 2 parents participate in reproductive process and also involve fusion of male and female gametes

Question 4

what are clones

Answer 4

morphologically and genetically similar individuals

Question 5

how does asexual rep take place in protists and monerans

Answer 5

cell division (the parent cell divides by mitosis into 2 to give rise to new individuals

Question 6

parthenogenesis

Answer 6

a form of reproduction in which an egg can develop into an embryo without being fertilized by a sperm

Question 7

how many types of asexual reproductions are there without gametes

Answer 7

binary fission
budding
sporulation
fragmentation
vegetative propagation

Question 8

what is binary fission

Answer 8

when a cell divides into 2 halves and each rapidly goes into an adult. eg- amoeba, paramecium

Question 9

what is budding

Answer 9

new organism develops from an outgrowth or bud due to cell division at one particular site. eg- yeast

Question 10

what is sporulation

Answer 10

organisms produce diploid spores that are released in the environment and grow into adults themselves.

Question 11

what is encystation

Answer 11

under unfavorable condition amoeba withdraws its pseudopodia and secretes a 3 layered hard covering or cyst around itself.

Question 12

what are zoospores

Answer 12

a motile asexual spore that uses a flagellum for locomotion.

Question 13

what are conidia (penicillium)

Answer 13

produced at the tip or side of hyphae or on special spore-producing structures called conidiophores. The spores detach when mature.

Question 14

what is fragmentation

Answer 14

if the body breaks into distinct fragments, each fragment grows into an adult capable of producing offspring

Question 15

what is vegetative propagation

Answer 15

asexual method of plant reproduction that occurs in its leaves, roots and stem.

Question 16

how is potato cultivated

Answer 16

when buds of the potato tuber called eyes come in contact with the damp soil/water they produce new plants

Question 17

what is juvenile phase

Answer 17

certain stage of growth and maturity in an organism’s lif before it can sexually reproduce

Question 18

what is oestrus cycle

Answer 18

the period from one ovulation to a subsequent ovulation

Question 19

what is gametogenesis

Answer 19

process of formation of 2 types of gametes i.e male and female. gametes are haploid n

Question 20

what are homogametes or isogametes

Answer 20

when the 2 gametes are so similar in appearance that it is impossible to categorise them into male and female gametes

Question 21

bisexual plants are also called

Answer 21

dioecious or heterothallic

eg: papaya, date palm

Question 22

unisexual plants are also called

Answer 22

monoecious or homothallic.

eg: cucurbit, coconut

Question 23

what are hermaphrodites

Answer 23

animals that possess both male and female reproductive organs
eg: earthworm, sponge, tapeworm, leech

Question 24

a haploid parent body produces gametes by _______ division

Answer 24

mitotic

Question 25

a diploid parent body produces gametes by _______ division

Answer 25

meiotic

Question 26

in diploid organisms, specialised cells called ____ undergo meiosis

Answer 26

meiocytes (gamete mother cells)

Question 27

why is the amount of male gametes produced so large in comparison to that of female gametes

Answer 27

to compensate the loss of male gametes during transport, the number of male gametes produced is several thousand times the number of female gametes produced.

Question 28

what is pollination

Answer 28

transferring pollen grains from the male anther of a flower to the female stigma

Question 29

fertilisation is also called ____ and results in the formation of _____

Answer 29

syngamy

diploid zygote

Question 30

disadvantage of external fertilisation

Answer 30

offspring are extremely vulnerable to the predators threatening their survival up to adulthood

Question 31

what is embryogenesis

Answer 31

process of development of embryo from zygote

Question 32

what is cell division

Answer 32

increases the number of cells in a developing embryo

Question 33

what is cell differentiation

Answer 33

helps groups of cells to undergo certain modifications to form specialised tissues and organs

Question 34

in oviparous animals, the fertilised eggs are covered by _______

Answer 34

hard calcareous shell