all exam questions that i dont know

Question 1

what is the maximum number of X chromosomes found in the nucleus of a sperm cell

Answer 1

1

Question 2

suggest the function of the acrosome

Answer 2

the acrosome’s function is to release enzymes that break down the membrane of the egg to allow for fertilisation.

Question 3

describe the route taken by a sperm cell from when it enters a women’s body to the site of fertilisation of the egg

Answer 3

It travels up the vagina, through the cervix into the oviducts.

Question 4

the fish they eat is initially crushed in part of their digestive system called the gizzard.

suggest why crushing the fish in the gizzard helps the birds to digest the fish.

Answer 4

1) increase surface area
2) enzymes

Question 5

the scientist concludes that training improves the athletic performance. (capillaries question)

Answer 5

1) more capillaries to transport oxygen
2) more aerobic repsiration
3) more energy
4) more muscle contraction
5) less lactic acid

Question 6

explain how natural selection could be responsible for the results shown in the graph between 0 and 100 metres.

Answer 6

1) more grass flourishes
2) less competition
3) mutation
4) reproduce
5) passes allele onto offspring

Question 7

describe a method the scientist could use to compare the population size of the grass species at 50 metres and 100 metres from the mine

Answer 7

1) use tape measure
2) quadrat
3) repeat
4) count plants

Question 8

give one reason why the student uses the same volume of water in each beaker

Answer 8

1) to prevent surface area affecting heat loss
2) fair test

Question 9

the scientist concludes that it is better for farmers to keep their animals indoors.

Discuss this conclusion

Answer 9

1) less heat loss indoors
2) depends upon outside temperature
3) animals move around less
4) more energy for growth
5) diseases are easier to spread

Question 10

describe how the student could modify his investigation to find out if an animal’s body size affects heat loss

Answer 10

1) use container of different sizes
2) keep beakers out of box

Question 11

explain the advantage of a withdrawal reflex when a finger touches a hot object

Answer 11

1) fast
2) automatic
3) less damage

Question 12

describe how the scientists could tell if a maize seed had germinated

Answer 12

if the shoot has grown

Question 13

explain the effect of increasing the concentration of salt solution on germination

Answer 13

1) increasing salt concentration decreases germination
2) as concentration of the solution increases , lower water potential
3) less water absorbed
4) by osmosis

Question 14

compare the responses of roots and stems to gravity

Answer 14

roots grow towards gravity meaning they are positively geotropic

Question 15

compare the responses of roots and stems to light

Answer 15

1) roots grow away from light
2) negatively phototropic

Question 16

suggest why spring and winter wheat have different percentages of insecticide applied to them

Answer 16

1) in winter there is a lower temp
2) fewer insects
3) less insecticide needed

Question 17

explain an alternative to insecticide that a farmer could use

Answer 17

1) use biological control
2) use a predator to target pests

Question 18

a person with sickle cell anaemia often suffers pain as some of their blood vessels become blocked by the sickle cells.

suggest why the person’s blood vessels may become blocked

Answer 18

sickle shaped red blood cells stick to eachother/caught trapped

Question 19

people with sickle cell anaemia have symptoms of tiredness and joint pain that get worse if they are exposed to cold temperatures and high altitudes.

suggest why these symptoms get worse

Answer 19

1) cold temp reduces blood flow
2) less oxygen at high altitudes
3) less repsiration
4) more lactic acid
5) less energy

Question 20

what is meant by the term recessive

Answer 20

no dominant allele present

Question 21

what type of organism causes malaria

Answer 21

protoctist

Question 22

give two differences in structure between red blood cells and white blood cells

Answer 22

1) red cells smaller
2) red cells have no nucleus
3) red cells are biconcave

Question 23

explain the factors that affect the rate if movement of substances into and out of cells

Answer 23

1) temp increases kinetic energy/more collisions
2) concentration gradient increases rate of movement
3) shorter distances increase diffusion
4) surface area to volume ratio increases diffusion
5) size of smaller particles move faster
6) charged particles cannot pass through membrane
7) increased energy for actibve transport

Question 24

describe the differences between
diffusion and active transport

Answer 24

1) diffusion is passive
2) diffusion from high to low concentration
3) active transport requires energy
4) active transport requires membrane
5) diffusion can take place in non-living systems

Question 25

design an investigation to find out if changing the starch content of the flour causes the bread to expand more.

Answer 25

1) change amount of starch 2) use same species of yeast 3) repeat each flour type more than once 4) measure height using ruler 5) after stated time 6) use same measure of flour 7) same temperature

Question 26

explain the function of the paddles in the fermenter

Answer 26

1) to distribute food/nutrients 2) to distribute oxygen

Question 27

explain why the ph in the fermenter needs to be controlled

Answer 27

1) it needs to be suitable for enzymes 2) would prevent denaturation of enzymes

Question 28

explain two changes that need to be made to the design of the fermenter so it can be used to produce biogas by anaerobic fermentation

Answer 28

1) stop air supply 2) open pressure release valve

Question 29

describe the role of the air supply in the fermenter

Answer 29

to supply oxygen to the organism so they can repsire

Question 30

suggest why the air filter is included in the fermenter

Answer 30

to prevent the entry of bacteria

Question 31

explain what will happen to the growth of the microorganisms if temperature regulation fails

Answer 31

the temp will get too high and the enzymes will denature

Question 32

what is meant by the term gentically modified transgenic organism?

Answer 32

An organism that contains genes from another species.

Question 33

explain the benefits of cloning transgenic organisms

Answer 33

mroe genetically identical organisms produced

Question 34

describe the process of making yoghurt from milk

Answer 34

1) pastureisation 2) kill bacteria 3) reduce temperature 4) add lactobacillicus 5) leave for a fixed amount of time

Question 35

explain why people who are lactose intolerant are able to eat yoghurt without becoming ill

Answer 35

1) it contains no lactose 2) Therefore the lactose doesn't need to be digested

Question 36

suggest the benefits of adding fruit to sweeten yoghurt

Answer 36

1) it gives you fructose, natural sugar 2) provides vitamin c which prevents scurvy

Question 37

name the carbohydrate stored in the cytoplasm of a yeast cell

Answer 37

glycogen

Question 38

descirbe how the student makes sure that the yeast cells respire anaerobically

Answer 38

use oil

Question 39

design an investiagtion to determine which variety of yeats is best for producing low alcohol beer.

Answer 39

1) use yeast A and B 2) same concentration of yeast 3) repeat 4) measure concentration of alcohol in beer 5) add same concentration of starch 6) control temperature

Question 40

describe the stages that are used to gentically modify a bacterium that is able to manafacture human growth hormone

Answer 40

1) human gene 2) restriction enzyme 3) plasmid 4) vector 5) same restriction enzyme 6) ligase 7) recombinant plasmid

Question 41

what is meant by the term hormone

Answer 41

something that travels in the blood stream to target cells.

Question 42

describe how selective breeding could be used to increase milk production

Answer 42

1) cow with high milk yield 2) are allowed to reproduce 3) repeat the process with high milk yield offspring

Question 43

descibe how a name bacterium produced this yoghurt from milk

Answer 43

1) lactobacillicus 2) lactose 3) lactic acid

Question 44

suggest the health benefits to a human of adding fruit to the yoghurt

Answer 44

1) fruit provides vitamin c prevents scurvy 2) fibre to help peristalsis

Question 45

explain how stress affects the heart rate of a rhino

Answer 45

1) heart rate increases 2) because adrenaline is being released

Question 46

explain why the aorta has a thicker wall than the capillary

Answer 46

1) wall contains muscle 2) blood is under high pressure from left ventricle 3) aorta needs to expand 4) need to transport more blood

Question 47

name two structures in the bacterium that contain dna

Answer 47

1) chromosome 2) plasmid

Question 48

explain why carbon monoxide is a harmful air pollutant

Answer 48

1) attaches to haemoglobin 2) therfore less oxygen transport

Question 49

describe how food passes from the mouth to the stomach

Answer 49

- softened by saliva - muscle contraction is oesophagus - peristalsis

Question 50

explain what happens to protein in the stomach

Answer 50

- churning - digested -protease - amino acids - hydrochloric acid

Question 51

suggest how coeliac disease could affect the growth of a child

Answer 51

- growth reduced - lack of villi - fewer capillaries - less absorption of named food molecules

Question 52

explain one difference between a dominant and recessive allele

Answer 52

- a dominant allele is always expressed - dominant allele expressed in a heterozygote - recessive allele only expressed in phenotype of homozygote

Question 53

which factor is least likely to limit the rate of photosynthesis

Answer 53

oxygen concentration

Question 54

which combination of factors is most likely to limit the rate of photosynthesis in the early morning

Answer 54

temperature and light intensity

Question 55

describe the procedure to test this variegated leaf for starch

Answer 55

1) place leaf in boiling water 2) place leaf in boiling ethanol 3) use water bath 4) place leaf in water 5) place leaf in iodine solution 6) blue black indicates starch; orange yellow indicates no starch.

Question 56

describe how selective breeding could be used to improve the volume of milk produced by cows

Answer 56

1) use info about milk yield of daughters/mothers 2) to select bulls as male parents 3) mate with cows with high milk yield 4) repeat over generations

Question 57

suggest the advantages of using artificial insemination in selective breeding

Answer 57

1) cheaper 2) can use semen to mate with many cows 3) can store semen after bull has died 4) safer

Question 58

describe how the use of a glasshouse improves the growth of crops

Answer 58

- control light intensity - use heater to increase temperature - provide additional carbon dioxide - provide additional minerals - control water supply - reduce damage by pests

Question 59

describe the stages by which a bacterium can be genetically modified to produce large amounts of a named human protein

Answer 59

1) restriction enzyme 2) gene 3) use same restriction enzyme 4) recombinant dna 5) name protein/insulin

Question 60

Name the type of organism that makes antibiotics

Answer 60

bacteria

Question 61

name the type of pathogen that is killed by antibiotics

Answer 61

bacteria

Question 62

Some antibiotics are no longer effective in killing pathogens. Use your knowledge of natural selection to explain why (5)

Answer 62

Due to mutation, variation occurs within a population. If a pathogen develops a mutation that makes it resistant to antibiotics, it can survive treatment. Resistant pathogens then reproduce, passing on the resistant gene. Over time, the population becomes dominated by resistant pathogens, rendering the antibiotics ineffective in killing them. This demonstrates the process of natural selection favoring traits that enhance survival and reproduction.

Question 63

Describe the stages that are used to genetically modify a bacterium that is able to manufacture human growth hormone. (5)

Answer 63

First, the human gene for growth hormone is isolated and cut using a restriction enzyme. A plasmid from a bacterium is also cut using the same enzyme. The cut human gene is then inserted into the cut plasmid, creating a recombinant plasmid. This plasmid acts as a vector, carrying the human gene into the bacterium. Ligase is used to seal the DNA strands, completing the genetic modification process.

Question 64

explain the function of the paddles in the fermenter

Answer 64

1) to distribute oxygen 2) to distribute nutrients

Question 65

explain why the pH in the fermenter needs to be controlled

Answer 65

1) suitable for enzymes 2) prevents denaturation of enzymes

Question 66

name one useful product that can be made in this fermenter

Answer 66

insulin

Question 67

explain two changes that need to be made to the design of this fermenter so it can be used to produce biogas by anaerobic fermentation

Answer 67

1) stop air supply 2) open pressure release valve

Question 68

design an investiagtion to determine which variety of yeats is best for producing low alcohol beer.

Answer 68

1) use yeast A and B 2) same concentration of yeast 3) repeat 4) measure concentration of alcohol in beer 5) add same concentration of starch 6) control temperature

Question 69

the yield is often measured in dry mass rather than fresh mass suggest why dry mass is used

Answer 69

dry mass excludes water

Question 70

suggest how the dry mass of 10kg of fresh potato tubers could be determined

Answer 70

1) weigh sample 2) heat up oven 3) until mass stays the same

Question 71

explain why a percentage is used rather than changes in kg per meter squared

Answer 71

1) allows for comparison 2) different sized plants/different masses

Question 72

describe how selective breeding could be used to increase milk production

Answer 72

1) cow with high milk yield 2) are allowed to reproduce 3) repeat the process with high milk yield offspring

Question 73

state 3 advantages of using biological control rather than pesticides

Answer 73

1) no need to reapply 2) specific, only kills the pests 3) no risk of resistance

Question 74

describe a test to show that the meal contains glucose

Answer 74

1) benedicts solution 2) boil for 3 minutes 3) red means glucose, blue means no glucose

Question 75

give three chemical elements found in lipids and also found in protein

Answer 75

- carbon, hydrogen and oxygen

Question 76

explain why a leaf becomes destarched when it is placed in the dark

Answer 76

because there is no respirationn and prevents photosynthesis

Question 77

descibe a safe method of testing this leaf for starch

Answer 77

1) use hot water 2) boil ethanol 3) no naked flame 4) soak in water 5) add iodine 6) use goggles

Question 78

anaaerobic word equation for yeast

Answer 78

glucose ---> ethanol + carbon dioxide

Question 79

explain the role of the liquid paraffin in this investigation

Answer 79

1) to stop oxygen from entering the yeast solution 2) prevent aerobic respiration

Question 80

explain the role of the diaphragm when a person breathes out

Answer 80

1) diaphragm relaxes 2) diaphragm moves up 3) volume of chest cavity decreases 4) pressur eof chest cavity increases

Question 81

explain how two abiotic factors could cause differences in plant populations

Answer 81

1) more sunlight, more photosynthesis 2) high temperatures, more photosynthesis

Question 82

explain how the structure of the small intestine is adpated for efficient absorbption of substances

Answer 82

1) villi have a large surface area 2) thin wall for efficient and quick diffusion 3) capillaries absorb glucose 4) capillaries maintain concentration gradient

Question 83

cellulose is an insoluble molecule made from the same simple sugar molecule as starch. The rabits intestine contains bacteria that can digest cellulose suggest why this is an advantage for the rabit

Answer 83

1) glucose 2) respiration

Question 84

The deer releases a hormone when it sees the wolf Explain how this hormone helps the deer to run away

Answer 84

1) adrenaline 2) increased heart rate 3) increase blood flow to muscles

Question 85

describe the function of the retina

Answer 85

detects light

Question 86

describe the function of the optic nerve

Answer 86

sends impulses to the brain

Question 87

chickens in factory farms are kept in cages inside buildings rathe rthan being kept outdoors suggest how factory farming can affect egg production

Answer 87

1) less movement 2) less respiration 3) less heat loss

Question 88

explain what happens to a plant cell if it is put into a concentrated salt solution

Answer 88

1) osmosis 2) dilute -> concentrated solution 3) all membrane shrinks away from the cell wall 4) flacid

Question 89

explain how the spongy mesophyll layer is adapted for photosynthesis

Answer 89

1) air spaces 2) diffusion of gases co2 and o2 take place

Question 90

reflexes in animals and phototropism in plants are both responses to stimuli give two similarities between the mechanisms involved in each response

Answer 90

1) chemicals involved 2) receptors involved

Question 91

give two differences between mechanisms involved in each response

Answer 91

1) animals electricaL impulses, plant has chemical impulses 2) animals fast/plants slow

Question 92

name the molecule that a fungus uses to stroe carbohydrates

Answer 92

glycogen

Question 93

explain how enzymes can be used to genetically modify plants

Answer 93

1) restriction enzyme cuts the plants DNA 2) ligase seals dna strands

Question 94

describe the events that lead to seed formation

Answer 94

1) pollen grain lands on stigma 2) pollen tube grows out of the pollen grain down the style into the ovary and out of the ovule 3) the male nucleus travels down the pollen tube to form with the female egg nucleus in the ovule, to form a zygote 4) tyhe zygote undergos mitosis 5) the ovule will become the seed and the ovule wall becomes the seed coat (testa) 6) the ovary will be the fruit of the plant

Question 95

why arent viruses classified as living

Answer 95

1) dont move 2) dont respire

Question 96

explain why breathing rate is higher after exercise

Answer 96

1) muscles 2) respiration 3) oxygen required 4) remove lactic acid 5) oxygen debt 6) remove co2

Question 97

why dont cells store glucose

Answer 97

1) glucose is soluble 2) osmotic effect

Question 98

suggest 3 ways which fish gills are adpated for efficient ghas exchange

Answer 98

1) permeable 2) blood supply/capillaries

Question 99

describe how food is moved through the gut

Answer 99

1) peristalsis 2) contraction 3) muscles 4) squeezed

Question 100

explain how egestion differs to excretion

Answer 100

1) faeces vs excretory product 2) undigested food vs metabolic waste product 3) anus vs kidney/lung

Question 101

another chracteristic shown by animals is the abilility to respond to tehir surroundings. For example, a person may withdraw their hand from a hot object. Describe the sequence of events that causes this response.

Answer 101

A receptor detects the heat, triggering an impulse in a sensory neurone. This impulse travels to the CNS, crossing synapses via relay neurones. The CNS processes the information and sends an impulse through a motor neurone to the muscle, which then contracts, causing the hand to withdraw.

Question 102

give 3 ways in which viruses differ from other living organisms

Answer 102

1) they only reproduce in living cells 2) they do not respire 3) no cytoplasm

Question 103

explain how being large helps the penguin to survive at very low temperatures

Answer 103

1) small surface area: volume ratio 2) less heat loss

Question 104

penguins also have soft downy feathers and a thick layer of fat just below the skin. suggest how having these features helps the penguins to survive

Answer 104

The layer of fat gives them an energy store and the soft downy feathers are a good insulator and retain heat well

Question 105

one part of the penguin that is especially exposedd to the cold is their feet. The muscles that operate the feet are located in the penguin's body than in the feet themselves suggest how this benefits the penguin

Answer 105

1) muscles left warm 2) respiration 3) enzymes

Question 106

penguins huddle together to maintain their body temperature explain how this behaviour is an advantage to penguins

Answer 106

1) less heat loss 2) not exposed to cold

Question 107

use your knowledge of osmosis to explain why the mass of each cube increased

Answer 107

water entyers a dilute to concentrated solution through a partially permeable membrane

Question 108

explain the effect of different SA:VOL ratios on the rate of osmosis into the potato

Answer 108

There is more osmosis when you have a larger SA:VOL ratio

Question 109

explain how the structure of the leaf is adapted for its role as the organ of photosynthesis

Answer 109

1) large surface area 2) thin leaf 3) upper eppidermis is transparent 4) lots of chloroplasts close to the surface 5) xylem controls the movement of gases in a plant