BIOLOGY

Question 1

KOCHS FIRST POSTULATE

Answer 1

The organism causing the disease must always be present when there are signs & symptoms of the disease

Question 2

KOCHS SECOND POSTULATE

Answer 2

Organism must be isolated from host & grown as a pure culture.

Question 3

KOCHS THIRD POSTULATE

Answer 3

Organisms from the pure culture are injected into health host – must produce same signs & symptoms.

Question 4

KOCH’S 4TH POSTULATE

Answer 4

Organism is re-isolated & grown as a pure culture – identified as same organism as original culture.

Question 5

secrete substances = destroy antigens directly, enhance the activity of macrophages and inhibit replication of viruses

Answer 5

KILLER T CELLS

Question 6

HELPER T CELLS

Answer 6

intimate immune response, enhance antibody production of B cells, activate b cells

Question 7

SUPPRESSOR T CELLS

Answer 7

help to turn off the immune response after an infection has been controlled (slow down immune response)

Question 8

retain the ability to recognise the original invading antigen so that a subsequent invasion can be dealt with quickly

Answer 8

MEMORY T CELLS

Question 9

WHAT IS THRUSH ?
CAUSE, SYMPTOMS, TREATMENT
PROBLEM = ANTIBIOTIC RESISTANCE

Answer 9

Fungus: candida.
Caused by imbalance of micro flora: acid/ alkaline imbalance.
Symptoms: itching, swelling, yeasty discharge, soreness.
Treatment: anti fungal drugs

Question 10

DEFENSE BARRIERS

Answer 10

Skin: prevents entry of pathogens
Mucus membranes: trap pathogens & flush them out.
Cilia: Push pathogens out.
Chemical barriers: stomach acid, swallow’s pathogens.
Bodily secretions: contain chemicals that kill pathogens.

Question 11

GENES

MAINTENANCE OF HEALTH

Answer 11

production of certain proteins essential for basic cell processes.

Question 12

MITOSIS

MAINTENANCE OF HEALTH

Answer 12

body’s ability to repair itself by producing cells, e.g. healing faster.

Question 13

CELL DIFFERENTIATION AND SPECIALISATION

Answer 13

different cells that function in different ways – e.g. immune respoce.

Question 14

MEIOSIS

Answer 14

sexually produces with sperm and egg cell = half chromosome number, new gamete combinations.

Question 15

MITOSIS

Answer 15

a sexually = identical genetic copies of parent cells. Separation and duplication of chromosomes.

Question 16

GAMETES

Answer 16

• Gamete formation = halving of chromosome number (diploid→ haploid)
• Sexual reproduction = combining gametes (haploid → diploid) results in variability of offspring.
• Formed during meiosis: processes of variation = random segregation & crossing over.

Question 17

DNA REPLICATION

Answer 17

1. DNA double helix is unwound by and enzyme.
2. The DNA unzips forming 2 single strands.
3. Nucleotides are added to the single strands resulting in 2 identical strands of DNA.

Question 18

PROTEIN/POLYPEPTIDE SYNTHESIS

: TRANSCRIPTION

Answer 18

1. Section of DNA unzips
2. Transcribed into messenger RNA→ (mRNA)
   * Ribosome = site of protein synthesis.
3. mRNA goes through nucleus wall into the cytoplasm & moves towards ribosome and through it, which causes protein to be ‘read’.

Question 19

PROTEIN/POLYPEPTIDE SYNTHESIS

: TRANSLATION

Answer 19

4. tRNA (transfer) = transport for AA to ribosome
5. AA becomes polypeptide.
6. AA→ polypeptide→ protein.

Question 20

• Evolution is seen as long periods of little change, followed by short periods of rapid change.
• Evolution is a sudden process rather than one of slow & gradual change.
• Evidence = fossil record, mass extinctions followed by appearance of new species.

Answer 20

punctuated equilibrium

Question 21

REPRODUCTIVE TECHNIQUES

Answer 21

Artificial insemination, artificial pollination & cloning.

Question 22

CO2 IN BLOOD

Answer 22

attached to haemoglobin &/ transported in plasma in a dissolved form.

Question 23

attaches to haemoglobin & becomes oxyhaemoglobin.

Answer 23

O2 IN BLOOD

Question 24

makes up 90% of plasma.

Answer 24

WATER IN MAMMALIAN BLOOD

Question 25

carried as dissolved ions in plasma

Answer 25

SALTS IN MAMMALIAN BLOOD

Question 26

carried in a protein coated package

Answer 26

LIPIDS IN MAMMALIAN BLOOD

Question 27

Nitrogenous wastes IN MAMMALIAN BLOOD

Answer 27

dissolved in blood plasma

Question 28

OTHER DIGESTION PRODUCTS IN THE MAMMALIAN BLOOD

Answer 28

transported in plasma.

Question 29

ARTERIES: STRUCTURE

Answer 29

Thick elastic walls, made up of 3 tissue layers., SMALL LUMEN

Question 30

ARTERIES: FUNCTION

Answer 30

Carry blood away from heart, do not pump blood.

Question 31

VEINS: STRUCTURE

Answer 31

3 layers, not very thick, contain valves., LARGE LUMEN

Question 32

VEINS FUNTION:

Answer 32

Carry blood back to heart, valves prevent backflow of blood.

Question 33

CAPILLARIES STRUCTURE:

Answer 33

Thin walls, 1 cell thick

Question 34

CAPILLARIES FUNCTION:

Answer 34

Materials diffuse through their walls

Question 35

protects the cornea

Answer 35

CONJUNCTIVA

Question 36

efracts light to form help form an image on the retina.

Answer 36

CORNEA

Question 37

white of the eye, tough coat of fibres, protects & maintains shape of eyeball.

Answer 37

SCLERA

Question 38

Nourishes retina & prevents internal reflection.

Answer 38

CHOROID

Question 39

contains light sensitive receptor cells which detects light.

Answer 39

RETINA

Question 40

contacts & dilates to adjust amount of light entering eye.

Answer 40

IRIS

Question 41

transparent structure which allows light to enter the rear of the eye and refracts light to focus an image on the retina.

Answer 41

LENS

Question 42

water fluid, maintains shape of eye.

Answer 42

AQUEOUS HUMOUR

Question 43

jelly like fluid, maintains shape of eye.

Answer 43

VITREOUS HUMOUR

Question 44

supports lens & alters its shape.

Answer 44

CILIARY BODY

Question 45

transmits impulses generated in retina to the brain.

Answer 45

OPTIC NERVE

Question 46

450 - 850 nm ? animal

Answer 46

snake

Question 47

human eye can see ?

Answer 47

400-700 nm

Question 48

honey bee can see ?

Answer 48

300- 700 nm

Question 49

20 hz-20000hz hearing for

Answer 49

human

Question 50

150000 hz and echolocation ?

Answer 50

bats

Question 51

Flexible membrane which transfers vibrations to the cochlea fluid.

Answer 51

oval widnow

Question 52

Flexible membrane to allow displacement of fluid when vibrations are transferred to the cochlea.

Answer 52

round window

Question 53

Fluid filled spiral tube, detects frequencies of sound.

Answer 53

cochlea

Question 54

Hair cells which translate vibrations into electrochemical signals.

Answer 54

organ of corti

Question 55

leads from the cochlea to the brain & transfers the impulse.

Answer 55

auditory nerve

Question 56

- connects middle ear with the throat - usually closed, opens when we swallow or yawn. - air can pass through this opening, thus equalising the pressure between middle ear & atmosphere.

Answer 56

EUSTACHIAN TUBE

Question 57

nerve

Answer 57

A nerve is bunch of neuronal fibres which are bound together.

Question 58

A neurone is a nerve cell, consisting of a cell body, dendrites and an axon, covered by an insulating myelin sheath.

Answer 58

neurone

Question 59

- Interpretation of light (vision) & sound are controlled by the occipital lobes at the back of the cerebral cortex. - Sound is processed in 2 areas of the temporal lobe – Wernick’s & Brocha’s area.

Answer 59

CEREBRUM