all exam questions that i dont know Flashcards
what is the maximum number of X chromosomes found in the nucleus of a sperm cell
1
suggest the function of the acrosome
the acrosome’s function is to release enzymes that break down the membrane of the egg to allow for fertilisation.
describe the route taken by a sperm cell from when it enters a women’s body to the site of fertilisation of the egg
It travels up the vagina, through the cervix into the oviducts.
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.
1) increase surface area
2) enzymes
the scientist concludes that training improves the athletic performance. (capillaries question)
1) more capillaries to transport oxygen
2) more aerobic repsiration
3) more energy
4) more muscle contraction
5) less lactic acid
explain how natural selection could be responsible for the results shown in the graph between 0 and 100 metres.
1) more grass flourishes
2) less competition
3) mutation
4) reproduce
5) passes allele onto offspring
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
1) use tape measure
2) quadrat
3) repeat
4) count plants
give one reason why the student uses the same volume of water in each beaker
1) to prevent surface area affecting heat loss
2) fair test
the scientist concludes that it is better for farmers to keep their animals indoors.
Discuss this conclusion
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
describe how the student could modify his investigation to find out if an animal’s body size affects heat loss
1) use container of different sizes
2) keep beakers out of box
explain the advantage of a withdrawal reflex when a finger touches a hot object
1) fast
2) automatic
3) less damage
describe how the scientists could tell if a maize seed had germinated
if the shoot has grown
explain the effect of increasing the concentration of salt solution on germination
1) increasing salt concentration decreases germination
2) as concentration of the solution increases , lower water potential
3) less water absorbed
4) by osmosis
compare the responses of roots and stems to gravity
roots grow towards gravity meaning they are positively geotropic
compare the responses of roots and stems to light
1) roots grow away from light
2) negatively phototropic
suggest why spring and winter wheat have different percentages of insecticide applied to them
1) in winter there is a lower temp
2) fewer insects
3) less insecticide needed
explain an alternative to insecticide that a farmer could use
1) use biological control
2) use a predator to target pests
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
sickle shaped red blood cells stick to eachother/caught trapped
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
1) cold temp reduces blood flow
2) less oxygen at high altitudes
3) less repsiration
4) more lactic acid
5) less energy
what is meant by the term recessive
no dominant allele present
what type of organism causes malaria
protoctist
give two differences in structure between red blood cells and white blood cells
1) red cells smaller
2) red cells have no nucleus
3) red cells are biconcave
explain the factors that affect the rate if movement of substances into and out of cells
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
describe the differences between
diffusion and active transport
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
design an investigation to find out if changing the starch content of the flour causes the bread to expand more.
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
explain the function of the paddles in the fermenter
1) to distribute food/nutrients
2) to distribute oxygen
explain why the ph in the fermenter needs to be controlled
1) it needs to be suitable for enzymes
2) would prevent denaturation of enzymes
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
1) stop air supply
2) open pressure release valve
describe the role of the air supply in the fermenter
to supply oxygen to the organism so they can repsire
suggest why the air filter is included in the fermenter
to prevent the entry of bacteria
explain what will happen to the growth of the microorganisms if temperature regulation fails
the temp will get too high and the enzymes will denature
what is meant by the term gentically modified transgenic organism?
An organism that contains genes from another species.
explain the benefits of cloning transgenic organisms
mroe genetically identical organisms produced
describe the process of making yoghurt from milk
1) pastureisation
2) kill bacteria
3) reduce temperature
4) add lactobacillicus
5) leave for a fixed amount of time
explain why people who are lactose intolerant are able to eat yoghurt without becoming ill
1) it contains no lactose
2) Therefore the lactose doesn’t need to be digested
suggest the benefits of adding fruit to sweeten yoghurt
1) it gives you fructose, natural sugar
2) provides vitamin c which prevents scurvy
name the carbohydrate stored in the cytoplasm of a yeast cell
glycogen
descirbe how the student makes sure that the yeast cells respire anaerobically
use oil
design an investiagtion to determine which variety of yeats is best for producing low alcohol beer.
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
describe the stages that are used to gentically modify a bacterium that is able to manafacture human growth hormone
1) human gene
2) restriction enzyme
3) plasmid
4) vector
5) same restriction enzyme
6) ligase
7) recombinant plasmid
what is meant by the term hormone
something that travels in the blood stream to target cells.
describe how selective breeding could be used to increase milk production
1) cow with high milk yield
2) are allowed to reproduce
3) repeat the process with high milk yield offspring
descibe how a name bacterium produced this yoghurt from milk
1) lactobacillicus
2) lactose
3) lactic acid
suggest the health benefits to a human of adding fruit to the yoghurt
1) fruit provides vitamin c prevents scurvy
2) fibre to help peristalsis
explain how stress affects the heart rate of a rhino
1) heart rate increases
2) because adrenaline is being released
explain why the aorta has a thicker wall than the capillary
1) wall contains muscle
2) blood is under high pressure from left ventricle
3) aorta needs to expand
4) need to transport more blood
name two structures in the bacterium that contain dna
1) chromosome
2) plasmid
explain why carbon monoxide is a harmful air pollutant
1) attaches to haemoglobin
2) therfore less oxygen transport
describe how food passes from the mouth to the stomach
- softened by saliva
- muscle contraction is oesophagus
- peristalsis
explain what happens to protein in the stomach
- churning
- digested
-protease - amino acids
- hydrochloric acid
suggest how coeliac disease could affect the growth of a child
- growth reduced
- lack of villi
- fewer capillaries
- less absorption of named food molecules
explain one difference between a dominant and recessive allele
- a dominant allele is always expressed
- dominant allele expressed in a heterozygote
- recessive allele only expressed in phenotype of homozygote
which factor is least likely to limit the rate of photosynthesis
oxygen concentration
which combination of factors is most likely to limit the rate of photosynthesis in the early morning
temperature and light intensity
describe the procedure to test this variegated leaf for starch
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.
describe how selective breeding could be used to improve the volume of milk produced by cows
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
suggest the advantages of using artificial insemination in selective breeding
1) cheaper
2) can use semen to mate with many cows
3) can store semen after bull has died
4) safer
describe how the use of a glasshouse improves the growth of crops
- control light intensity
- use heater to increase temperature
- provide additional carbon dioxide
- provide additional minerals
- control water supply
- reduce damage by pests
describe the stages by which a bacterium can be genetically modified to produce large amounts of a named human protein
1) restriction enzyme
2) gene
3) use same restriction enzyme
4) recombinant dna
5) name protein/insulin
Name the type of organism that makes antibiotics
bacteria
name the type of pathogen that is killed by antibiotics
bacteria
Some antibiotics are no longer effective in killing pathogens. Use your knowledge of natural selection to explain why (5)
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.
Describe the stages that are used to genetically modify a bacterium that is able to manufacture human growth hormone. (5)
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.
explain the function of the paddles in the fermenter
1) to distribute oxygen
2) to distribute nutrients
explain why the pH in the fermenter needs to be controlled
1) suitable for enzymes
2) prevents denaturation of enzymes
name one useful product that can be made in this fermenter
insulin
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
1) stop air supply
2) open pressure release valve
design an investiagtion to determine which variety of yeats is best for producing low alcohol beer.
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
the yield is often measured in dry mass rather than fresh mass
suggest why dry mass is used
dry mass excludes water
suggest how the dry mass of 10kg of fresh potato tubers could be determined
1) weigh sample
2) heat up oven
3) until mass stays the same
explain why a percentage is used rather than changes in kg per meter squared
1) allows for comparison
2) different sized plants/different masses
describe how selective breeding could be used to increase milk production
1) cow with high milk yield
2) are allowed to reproduce
3) repeat the process with high milk yield offspring
state 3 advantages of using biological control rather than pesticides
1) no need to reapply
2) specific, only kills the pests
3) no risk of resistance
describe a test to show that the meal contains glucose
1) benedicts solution
2) boil for 3 minutes
3) red means glucose, blue means no glucose
give three chemical elements found in lipids and also found in protein
- carbon, hydrogen and oxygen
explain why a leaf becomes destarched when it is placed in the dark
because there is no respirationn and prevents photosynthesis
descibe a safe method of testing this leaf for starch
1) use hot water
2) boil ethanol
3) no naked flame
4) soak in water
5) add iodine
6) use goggles
anaaerobic word equation for yeast
glucose —> ethanol + carbon dioxide
explain the role of the liquid paraffin in this investigation
1) to stop oxygen from entering the yeast solution
2) prevent aerobic respiration
explain the role of the diaphragm when a person breathes out
1) diaphragm relaxes
2) diaphragm moves up
3) volume of chest cavity decreases
4) pressur eof chest cavity increases
explain how two abiotic factors could cause differences in plant populations
1) more sunlight, more photosynthesis
2) high temperatures, more photosynthesis
explain how the structure of the small intestine is adpated for efficient absorbption of substances
1) villi have a large surface area
2) thin wall for efficient and quick diffusion
3) capillaries absorb glucose
4) capillaries maintain concentration gradient
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
1) glucose
2) respiration
The deer releases a hormone when it sees the wolf
Explain how this hormone helps the deer to run away
1) adrenaline
2) increased heart rate
3) increase blood flow to muscles
describe the function of the retina
detects light
describe the function of the optic nerve
sends impulses to the brain
chickens in factory farms are kept in cages inside buildings rathe rthan being kept outdoors
suggest how factory farming can affect egg production
1) less movement
2) less respiration
3) less heat loss
explain what happens to a plant cell if it is put into a concentrated salt solution
1) osmosis
2) dilute -> concentrated solution
3) all membrane shrinks away from the cell wall
4) flacid
explain how the spongy mesophyll layer is adapted for photosynthesis
1) air spaces
2) diffusion of gases co2 and o2 take place
reflexes in animals and phototropism in plants are both responses to stimuli
give two similarities between the mechanisms involved in each response
1) chemicals involved
2) receptors involved
give two differences between mechanisms involved in each response
1) animals electricaL impulses, plant has chemical impulses
2) animals fast/plants slow
name the molecule that a fungus uses to stroe carbohydrates
glycogen
explain how enzymes can be used to genetically modify plants
1) restriction enzyme cuts the plants DNA
2) ligase seals dna strands
describe the events that lead to seed formation
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
why arent viruses classified as living
1) dont move
2) dont respire
explain why breathing rate is higher after exercise
1) muscles
2) respiration
3) oxygen required
4) remove lactic acid
5) oxygen debt
6) remove co2
why dont cells store glucose
1) glucose is soluble
2) osmotic effect
suggest 3 ways which fish gills are adpated for efficient ghas exchange
1) permeable
2) blood supply/capillaries
describe how food is moved through the gut
1) peristalsis
2) contraction
3) muscles
4) squeezed
explain how egestion differs to excretion
1) faeces vs excretory product
2) undigested food vs metabolic waste product
3) anus vs kidney/lung
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.
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.
give 3 ways in which viruses differ from other living organisms
1) they only reproduce in living cells
2) they do not respire
3) no cytoplasm
explain how being large helps the penguin to survive at very low temperatures
1) small surface area: volume ratio
2) less heat loss
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
The layer of fat gives them an energy store and the soft downy feathers are a good insulator and retain heat well
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
1) muscles left warm
2) respiration
3) enzymes
penguins huddle together to maintain their body temperature
explain how this behaviour is an advantage to penguins
1) less heat loss
2) not exposed to cold
use your knowledge of osmosis to explain why the mass of each cube increased
water entyers a dilute to concentrated solution through a partially permeable membrane
explain the effect of different SA:VOL ratios on the rate of osmosis into the potato
There is more osmosis when you have a larger SA:VOL ratio
explain how the structure of the leaf is adapted for its role as the organ of photosynthesis
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
