c16 reproduction

Question 1

define mitosis

Answer 1

cell division
gives rise, genetically identical cells, in which chromosome no. maintained

Question 2

define meiosis

Answer 2

reduction cell division
gives rise, genetically dissimilar cells, chromosomal number halved (separation, homologous chromosomes)

Question 3

mitosis products

Answer 3

• 2 daughter cells/parent cell
• genetically identical daughter cells
• diploid (2n), same no. of chromosomes, parent cell

Question 4

meiosis products

Answer 4

• 4 daughter cells/parent cell
• genetically dissimilar daughter cells
• haploid (n), half the no. of chromosomes, parent cell

Question 5

mitosis purpose

Answer 5

growth of multicellular organism
repair, worn out tissues
asexual reproduction

Question 6

meiosis purpose

Answer 6

formation, gametes
gametes must contain only half no. of chromosomes compared 2 somatic cell
fusion of nuclei, female, male gamete, fertilisation
restore diploid no. of chromosomes in zygote
maintain same no. chromosomes between somatic cells, parent, offspring

Question 7

asexual reproduction
def
advantages
disadvantages

Answer 7

process, result reproduction, genetically identical offspring, one parent w/o fusion, gametes

advantages
reproductive process most likely take place bcoz
- fusion gametes not req
- does not depend, external agents i.e. wind, pollination/seed dispersal

development, mature plant from vegetative tissue, faster than seeds

all beneficial qualities, passed from parent -> genetically identical offspring

disadvantages
offspring genetically identical, less variation, less able adapt, changes, env

Question 8

sexual reproduction
def
advantages
disadvantages

Answer 8

process involve fusion, nuclei, male, female, gametes -> zygote, produce genetically dissimilar offspring

advantages
offspring, genetically dissimilar, result more variation, more able adapt changes, env

disadvantages
more complicated process
- fusion, nuclei, gametes
- depend, external agents, processes, pollination, seed dispersal, plants
- courting ritual, animals

development, mature plant from seeds, slower than from vegetative tissue

Question 9

sexual, asexual reproduction differences

Answer 9

sexual
one or 2 parents
fusion gametes, fertilisations
genetically dissimilar offspring
slow process involving pollination, mating, zygote develop, adult

asexual
always only one parent
genetically identical offspring
faster development, diploid ovum/vegetative tissue -> adult organism

Question 10

sepal struct, funct

Answer 10

modified leaf, encloses, protects flower, initial development

Question 11

petal struct, funct

Answer 11

absent, reduced, wind-pollinated flowers
modified leaf,
- large, brightly coloured, attract insects
- provide landing platform, insects, pollination

Question 12

stamen, carpel contains…

Answer 12

stamen
- anther
- filament

carpel
- stigma
- style
- ovary
- ovule

Question 13

anther struct, funct

Answer 13

produces, stores pollen grains
grains carry male gametes

Question 14

filament struct, funct

Answer 14

• holds anther, suitable position, disperse pollen grains
• contain vascular bundle, made of xylem, phloem vessels, supply water, mineral salts, nutrients -> anther

Question 15

stigma struct, funct

Answer 15

struct, recieve pollen grains

Question 16

style struct, funct

Answer 16

holds stigma in suitable position, trap pollen grains

Question 17

ovary struct, funct

Answer 17

contains one or more ovules
develop -> fruit, after fertilise female gamete (ovule)
aids in seed dispersal

Question 18

ovule struct, funct

Answer 18

contains an ovum
develop -> seed after fertilisation of ovum

Question 19

when is asexual reproduction preferred, plants

Answer 19

plants
1. colonise area
2. no nearby mates

Question 20

external factors that plant need to depend on for sexual reproduction

Answer 20

1. pollinators
2. seed dispersers (wind, animal, explosive action, water)

Question 21

self pollination

Answer 21

transfer, pollen grains
from anther -> stigma of same flower
or different flower, same plant

Question 22

cross pollination

Answer 22

transfer pollen grains
from anther, stigma of flower, different plant, same species,
by external factors like wind currents, insects

Question 23

self pollination
adv
disadv

Answer 23

advantages
1. stigma closer, anther, high probability, successful pollination, less pollen grains wasted
2. only 1 parent req, low population density, can occur
3. not dependant, external factors i.e. regardless of wind condition

disadv
1. offspring less genetic variation, less likely adapt, changes, env
2. higher probability offspring homozygous, more likely, harmful reccessive alleles expressed

for cross pollination jst reverse adv and disadv.

Question 24

prevent self-pollination ways

Answer 24

spatial: anther, stigma situated far, each other (i.e. one plant only all anther/stigma)
temporal: anther, stigma mature diff times
chemical: stigma secrete chemicals, prevent germination, pollen grains, similar genetic make-up

Question 25

insect pollination

Answer 25

1. insect land, standard petal, follow nectar guide -> nectary 2. insect force way, base of flower, collect nectar, force open wing, keel petals, expose anther, stigma 3. insect back brush against stigma, transfer pollen grains from back -> stigma 4. insect leaves, pollen grains from anthers, adheres onto its back, transfer -> another flower

Question 26

**insect pollinated vs wind pollinated flower**

Answer 26

1. petals 2. nectar, nectar guides 3. scent 4. stigma 5. stamen 6. pollen grains