Spaced rep - 5A

Question 1

What are the eukaryotic kingdoms?

Answer 1

animal
plant
Protoctista
Fungi

Question 2

Which kingdom is multicellular and has cell walls made from chitin?

Answer 2

Fungi

Question 3

Which kingdom is only unicellular and all the cells have a membrane bound nucleus?

Answer 3

Protoctista

Question 4

Describe 3 differences between eukaryote and prokaryote cell structures

Answer 4

• only eukaryotes have a membrane-bound nucleus;
• only eukaryotes have mitochondria;
• only eukaryotes have chloroplasts;
• only prokaryotes have plasmids;

Question 5

Name 3 things transported by the plasma

Answer 5

Any 3 from:
carbon dioxide
heat
glucose
amino acids
vitamins
minerals
urea
proteins
antibodies

Question 6

Explain two ways arteries are specialised to their role of carrying blood under high pressure

Answer 6

Thick muscular layer – contracts to maintain blood pressure;
Thick elastic layer – expands to prevent bursting / recoils to maintain blood pressure;
Narrow lumen – maintains blood pressure;

Question 7

Describe two differences between arteries and veins

Answer 7

Arteries have a thicker muscular layer;
Arteries have a thicker elastic layer;
Veins have a wider lumen;
Only veins have valves;

Question 8

Explain two ways red blood cells are specialised to transport oxygen

Answer 8

Contain haemoglobin – which binds oxygen;
Biconcave shape – increases surface area for diffusion of oxygen;
Small – increases surface area to volume ratio for diffusion of oxygen;
No nucleus – more space for haemoglobin

Question 9

Explain why, on average, only 10% of energy is transferred from one trophic level to the next

Answer 9

Not all eaten;
Excretion;
Death / decomposition;
Egestion of undigested material;
Respiration of biomass and energy used for movement / maintaining body temperature

Question 10

What is pollination?

Answer 10

Transfer of pollen from anther to stigma

Question 11

Describe the process of seed formation (assume pollination has just occurred)

Answer 11

Pollen tube grows from pollen grain;
Formed by digestive enzymes;
Down style to ovary, to ovule;
Pollen nucleus passes down the pollen tube to the ovule;
In ovule, pollen tube nucleus fuses with the ovum (egg) – fertilisation;
Fertilised ovum becomes the embryo (divides by mitosis);
Ovule becomes the seed;
Ovary becomes the fruit

Question 12

Explain the appearance of the cells in the salt solution

Answer 12

Water has diffused out of the cytoplasm;
By osmosis;
As the water potential (concentration) is higher in the cytoplasm;
Cytoplasm has shrunk;
Cell membrane has pulled away from the cell wall;
Plasmolysed

Question 13

Explain why you would not see any red blood cells if they were put into distilled water

Answer 13

Cells have burst (lysed);
Due to water moving in by osmosis;
Because there is a higher water potential (concentration) outside of the cell

Question 14

Describe fully the reflex arc which occurs in the eye when you enter a dark room

Answer 14

Low light is detected by (receptor) cells in the retina;
Electrical impulse sent along sensory neurone (optic nerve) to the spinal cord;
Neurotransmitter released at synapse;
Starting an electrical impulse in a relay neurone in the spinal cord;
Electrical impulse travels along a motor neurone to the iris;
Radial muscles contract and circular muscles relax;
Pupil dilates, so more light enters the eye

Question 15

Explain one precaution that should be taken when making yoghurt so that it is safe for humans
to eat

Answer 15

Heat the milk to 90°C then cool before adding bacteria - kills any unwanted bacteria / fungi
which could cause disease;
Sterilise the containers prior to adding yoghurt - kills any unwanted bacteria / fungi which could cause disease

Question 16

Describe how you would selectively breed salmon to produce rapidly growing fish for farming.

Answer 16

Select the fastest growing male and female salmon
breed them together
select the fastest breeding male and female offspring and breed them together again
repeat for many generations

Question 17

Explain why fish farmers remove waste products such as faeces

Answer 17

prevent decomposition by bacteria; which would respire and use oxygen; decreasing the oxygen content of the water

Question 18

Explain why fish farmers keep the fish of different sizes in different nets

Answer 18

prevent intraspecific predation (the fish eating each other)