Chapter 16: Reproduction

Question 1

Describe asexual reproduction

Answer 1

a process resulting in the production of genetically identical offspring from one parent

Question 2

Advantage of Asexual Reproduction in plants and population

Answer 2

Population
-Population can increase rapidly.
-Can exploit a suitable habitat quickly.
Crop
-Only one parent needed.
-Rapid colonization of favorable environments

Question 3

Disadvantage of Asexual Reproduction in plants and population

Answer 3

Population
-Does not lead to variation in a population.
-The species may only suited to one habitat.
-Disease may affect all individuals in a population.

Crop
-No variation, so any change in environmental conditions will affect all individuals (ex. disease)

Question 4

Describe sexual reproduction

Answer 4

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

Question 5

Describe fertilisation

Answer 5

the fusion of the nuclei of gametes

Question 6

Are gametes and zygote haploid or diploid

Answer 6

nuclei of gametes are haploid and that the nucleus of a zygote is diploid

Question 7

Advantage of sexual reproduction

Answer 7

• produces combination of greater survival value
• new varieties can be created = may have resistance to disease
• in plants, seeds are produced, which allow dispersal away from parent plant, reducing competition

Question 8

Disadvantage of sexual reproduction

Answer 8

• usually two parents are needed
• growth of a new plant to maturity from a seed is slow

Question 9

Structure of flower

Answer 9

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Question 10

Function of sepal

Answer 10

to protect the flower bud as it develops

Question 11

Function of petals

Answer 11

attract insects for pollination

Question 12

Function of stamen

Answer 12

Stamens are the male reproductive organs which are responsible for producing and dispersing pollen

Question 13

Function of filament

Answer 13

carry nutrients to the anther for the development of the anther and pollen grains.

Question 14

Function of anther

Answer 14

to produce and provide the pollen

Question 15

Function of carpel

Answer 15

The carpel is the female reproductive part of the plant. It facilitate reproduction in flowering plants.

Question 16

Function of style

Answer 16

generates the pollen tube but also prevents incompatible pollen from entering the ovary.

Question 17

Function of stigma

Answer 17

The stigma is a sticky surface that catches the pollen during pollination.

Question 18

Function of ovary

Answer 18

prepare the ovules for fertilization, protect developing zygotes, and develop into a seed-bearing fruit.

Question 19

Function of ovule

Answer 19

The ovules are the structures that eventually develop into seeds; Each ovule contains an ovum

Question 20

describe the anthers and stigmas of a wind-pollinated flower

Answer 20

anthers: external position and long filaments
The stigmas are comparatively large and protruding ( sticking out), sometimes branched and often feathery.

Question 21

Distinguish between the pollen grains of insect-pollinated and wind-pollinated flowers

Answer 21

In wind-pollinated flowers pollen: spiky,
heavier,
larger,
small amounts
In insect-pollinated flowers pollen: smooth,
lightweight,
small,
large amounts

Question 22

Describe pollination

Answer 22

the transfer of pollen grains from an anther to a stigma

Question 23

Describe self-pollination

Answer 23

the 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

Question 24

Describe cross-pollination

Answer 24

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

Question 25

Effects of self pollination on its population

Answer 25

- reduced diversity - increased competition between plants; - little ability to evolve - no pollinators required

Question 26

Effect of cross pollination in its population

Answer 26

- allows, genetic diversity; - resistance to disease; - evolve; - relies on pollinators

Question 27

When does fertilization occur

Answer 27

when a pollen nucleus fuses with a nucleus in an ovule

Question 28

The pathway of pollen to fertilization

Answer 28

After pollen has landed on the stigma, it grows a pollen tube down through the style to the ovary. The nucleus of the pollen grain travels down the pollen tube and fertilises the nucleus in the ovule.

Question 29

Describe the structural adaptations of insect-pollinated flowers

Answer 29

- nectar; - spiky,pollen; - sticky stigma; - colourful petals

Question 30

Describe the structural adaptations of wind-pollinated flowers

Answer 30

- petals dull; - large amounts of pollen, released; - small, pollen; - smooth pollen

Question 31

describe the environmental conditions that affect germination of seeds

Answer 31

water: for softening testa / seed coat + activation of enzymes + solvent; oxygen: for respiration suitable temperature: for optimum temperature for enzymes; break down food stores

Question 32

Describe the growth of the pollen tube and its entry into the ovule followed by fertilisation

Answer 32

After pollen has landed on the stigma, it grows a pollen tube down through the style to the ovary. The nucleus of the pollen grain travels down the pollen tube and fertilises the nucleus in the ovule.

Question 33

Male reproduction system

Answer 33

testes, scrotum, sperm ducts, prostate gland, urethra and penis

Question 34

Female reproductive system

Answer 34

ovaries, oviducts, uterus, cervix and vagina

Question 35

What is fertilization

Answer 35

the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell)

Question 36

Explain the adaptive features of sperm

Answer 36

flagellum: for movement and swimming; mitochondria: to provide energy from respiration for movement; enzymes in the acrosome: to dig through the jelly coat and membrane of an egg cell

Question 37

Explain the adaptive features of egg cells

Answer 37

energy stores: provides energy to divide the zygote; the jelly coat that changes at fertilisation: to form a barrier after fertilisation to prevent other sperm from entering the cell

Question 38

Compare male and female gametes

Answer 38

egg cell much larger than sperm; sperm is capable of locomotion while egg cannot; sperm produced everyday in huge numbers, while egg released once a month

Question 39

State what happens to the zygote in early development

Answer 39

in early development, the zygote forms an embryo which is a ball of cells that implants into the lining of the uterus

Question 40

Function of umbilical cord in development of fetus

Answer 40

Transfer substances ( oxygen and nutrients) between placenta and fetus

Question 41

Function of placenta in development of fetus

Answer 41

supplies, nutrients removes waste acts as a barrier against toxins or pathogens

Question 42

Function of amniotic sac and amniotic fluid

Answer 42

maintains temperature; (mechanical) protection; provides support (of the fetus); prevents infections; allows movement (of the fetus); (movement) allows for development of bones and muscles; fetal drinking; lubrication

Question 43

Describe the function of the placenta and umbilical cord

Answer 43

exchange of dissolved nutrients, gases and excretory products between the blood of the mother and the blood of the fetus

Question 44

Can everything be blocked by placenta

Answer 44

Some pathogens and toxins can pass across the placenta and affect the fetus

Question 45

roles of testosterone in the development and regulation of secondary sexual characteristics during puberty

Answer 45

voice deepens; growth spurt; sperm, production; facial hair grows;

Question 46

Describe the roles of oestrogen in the development and regulation of secondary sexual characteristics during puberty

Answer 46

breasts grow; pubic hair growth growth spurt; menstrual cycle begins

Question 47

Describe the menstrual cycle in terms of changes in the ovaries and in the lining of the uterus

Answer 47

days 1-5: uterus lining lost; days 8-14: uterus lining,increases; day 14: egg cell is released;

Question 48

Describe the sites of production of oestrogen and progesterone in the menstrual cycle and in pregnancy

Answer 48

ovary

Question 49

Explain the role of oestrogen in controlling the menstrual cycle and pregnancy

Answer 49

repair of the lining of uterus; womb thickening; development; prepares for, implantation; release of LH; inhibits release of FSH; stops, release, of more eggs; causes change in cervical mucus

Question 50

Explain the role of LH in controlling the menstrual cycle and pregnancy

Answer 50

maintains the thickness of the lining of the uterus during pregnancy; ovulation gland

Question 51

Explain the role of FSH in controlling the menstrual cycle and pregnancy

Answer 51

FSH stimulates follicle; to grow; to secrete oestrogen; maturation of egg; subsequent effect on LH at ovulation; low FSH after ovulation, prevents further follicle stimulation;

Question 52

Explain the role of progesterone in controlling the menstrual cycle and pregnancy

Answer 52

maintains, uterine lining; inhibits, FSH / LH (release)

Question 53

Describe a sexually transmitted infection (STI)

Answer 53

an infection that is transmitted through sexual contact

Question 54

what Is the human immunodeficiency virus (HIV)

Answer 54

is a pathogen that causes an STI

Question 55

What might HIV infection lead to

Answer 55

AIDS

Question 56

Describe the methods of transmission of HIV

Answer 56

blood to blood contact ; sharing needles; breastfeeding; transfusions;

Question 57

Explain how the spread of STIs is controlled

Answer 57

use of, condoms; tracing of sexual contacts; testing for STIs; treating infections;