chapter 16: reproduction

Question 1

describe asexual reproduction

Answer 1

process resulting in the production of genetically identical offspring from one pareny

Question 2

describe the advantages and disadvantages of asexual reproduction in a wild species

Answer 2

advantages
- rapid population growth
- can exploit suitable environments quickly
- more time and energy efficient
- reproduction is completed faster
—
disadvantages
- less genetic variation
- vulnerabke to habitat changes
- disease likely to affect the whole population
- evolution is slow

Question 3

describe the advantages and disadvantages of asexual reproduction in crop plants

Answer 3

advantages
- crops can be produced with desired characteristics
- crops can be produced with uniform characteristics for commercial use
- faster production
- cost will be less
—
disadvantages
- crops will not adapt to changes in climate
- requires human input and management
- if parent is diseased, offspring will be diseased as well
- vulnerable to disease and pests possible, financial loss

Question 4

describe sexual reproduction

Answer 4

process involving the fusion of the nuclei of two gametes to form a zygote (fertilisation) and the production of offspring that are genetically different from each other

Question 5

describe the advantages and disadvantages of sexual reproduction

Answer 5

advantages
- increases genetic variation
- adapt to environment, more fit
- disease less likely to affect population
—
disadvantages
- takes time and energy to find mates
- difficult for isolated members of the species to reproduce
- offspring may be less successful than parents

Question 6

describe pollination

Answer 6

process by which pollen is transferred from the male part of a flower to the female part of the flower

Question 7

describe the function of the sepal

Answer 7

to protect the bud

Question 8

describe the function of the petals

Answer 8

attract pollinators

Question 9

state the parts of the stamen and their functions

Answer 9

• anther: produces and releases pollen
• filament: provides support to the anther

Question 10

state the parts of the carpel and their functions

Answer 10

• stigma: sticky top of the female part of the flower which collects pollen grains
• style: tube connecting the stigma and ovary
• ovary: contains the ovule

Question 11

describe the anther and stigma of a wind pollinated flower

Answer 11

• hanging outside of flower, feathery
• pollen can easily be blown away by the wind
• pollen can easily be caught by the stigmas of other flowers

Question 12

compare the pollen grains of insect pollinated flowers and wind pollinated flowers

Answer 12

• insect: larger, heavier, with spikes or hooks better stick to insects
• wind: small, lightweighted

Question 13

describe self pollination

Answer 13

• transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant
• reduces genetic variation

Question 14

describe cross pollination

Answer 14

• transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species
• improves genetic variation

Question 16

describe germination

Answer 16

• start of growth om a seed
• requires water, oxygen, and warmth

Question 17

describe the events that occur after pollination

Answer 17

• pollen tube grows down from the pollen grain all the way down the style to the ovary
• male nucleus of the pollen grain fuses with the female nucleus of the egg
• fertilisation occurs
• a zygote is formed

Question 18

describe the function of the prostate gland

Answer 18

produces semen to provide sperm cells with nutrients

Question 19

describe the function of the sperm duct

Answer 19

sperm passes through the sperm duct to be mixed with fouids produced by the glands before being passed into the urethra for ejaculation

Question 20

describe the function of the urethra

Answer 20

carries out urine or semen, has a ring of muscle to prevent them from mixing

Question 21

describe the function of the testis

Answer 21

produces sperm and testosterone hormone

Question 22

describe the function of the scrotum

Answer 22

sac supporting the testes outside the body to ensure the sperm are kept at a temperature slightly lower than the body temperature

Question 23

describe the function of the penis

Answer 23

passes urine out of the bidy and allows semen to pass into the vagina of a woman during sexual intercourse

Question 24

describe the function of the oviduct

Answer 24

connects the ovary to the uterus, lined with ciliated cells to help push the ovum down, site of fertilisation

Question 25

describe the function of the ovary

Answer 25

contains ova which will mature and develop when hormones are released

Question 26

describe the function of the uterus

Answer 26

muscular bag with a soft lining where the zygote will be implanted to develop into a fetus

Question 27

describe the function of the cervix

Answer 27

ring of muscle at the lower end of the uterus to keep tbe developing fetus in place during pregnancy

Question 28

describe the function of the vagina

Answer 28

muscular tube leading to the inside of the woman where the male penis enters during sexual intercourse and sperm are deposited

Question 29

describe the adaptive features of the sperm

Answer 29

- flagellum for locomotion - acrosome with digestive enzymes for penetrating the ova - many mitochondria to provide energy - haploid nucleus

Question 30

describe the adaptive features of egg cells

Answer 30

- cytoplasm containing a store of energy to provide energy for cell division in the developing zygote after fertilisation - jelly like coating to make an impenetrable barrier after fertilisation to prevent more sperm from entering the body

Question 31

compare the sperm and egg cells

Answer 31

- sperm is small, egg large - sperm like fish, egg round - sperm can move, egg no - sperm produced a lot every day, thousand of immature eggs but only one released each month

Question 32

describe the events that take place after fertilisation in a human

Answer 32

1. zygote travels towards the uterus and divides multiple times to form an embryo 2. embryo implants itself in the uterus, continues to grow and develop 3. development of organs in the first 12 weeks, embryo gets nutrients from mother by diffusion through uterus 4. placenta formed after all organs in place, embryo now a fetus

Question 33

describe the function of the umbilical cord

Answer 33

- has highly branched capillaries - increases surface area for diffusion of nutrients and excretory products - connects placenta to fetus

Question 34

describe the function of the amniotic sac

Answer 34

- allows the fetus to move, important for developing the skeleton - provides mechanical protection - regulates fetus temperature

Question 35

describe the function of the amniotic fluid

Answer 35

- prevents fetus from drying out - nutrient and oxygen exchange - medium for waste removal

Question 36

describe the function of the placenta in humans

Answer 36

- gas exchange - transfer of dissolved nutrients - transfer of excretory products - transfer of antibodies - barrier against pathogens and toxins

Question 37

describe the functions of the hormones in the menstrual cycle

Answer 37

- FSH: stimulates the development of eggs and the ovaries to produce oestrogen - oestrogen: inhibits release of FSH and stimulates the release of LH, stimulates the uterus lining to grow - LH: stimulates release of egg on 14th day - progesterone: levels increase and inhibits both FSH and LH; maintains the uterus lining thickness

Question 38

describe a STI

Answer 38

an infection transmitted through sexual contact

Question 39

what is AIDS (acquired immunodeficiency disease) caused by?

Answer 39

HIV pathogen (human immunodeficiency virus), spread by sharing unclean needles, blood transfusions, through placenta, and breastfeeding

Question 40

how can the spread of STIs be controlled?

Answer 40

- limiting body count - having protected sex - getting tested - education programmes - tracing