Paper 2 Flashcards
Gametes are formed in sexual reproduction.
Name the male gamete formed in flowering plants
pollen (grain)
Earthworms: box
* live in soil
* feed on dead and decaying plant matter
* have soft, moist skin
* exchange gases through their skin.
Give two abiotic factors and two biotic factors that could affect the size of an earthworm population.
Abiotic
any two from:
* water
* oxygen / air (in soil)
* pH (of soil)
* minerals / ions
* temperature
* size of soil particles or texture
/ type of soil
biotic
any two from:
* food
* predators / consumers /
carnivores
* disease / pathogens / bacteria
/ fungi
Students investigated the populations of earthworms in the soil in two different areas:
* Area A: a grass lawn
* Area B: a farmer’s field.
Chemical X can be mixed with water and poured onto the soil.
The mixture brings earthworms to the surface of the soil but does not harm
the earthworms.
Plan an investigation using chemical X to compare the number of earthworms per m2
in areas A and B.
same concentration of chemical / X applied to the soil
* same volume / amount of chemical / X applied to the soil
* same size of area sampled – eg 1 m2 or 0.25 m2
* use of a quadrat
* same time between application and collecting worms
* same time allowed for collecting worms after application
* each sample area selected randomly
* method of achieving randomness – eg random coordinates
* (collect and) count worms in each of areas A and B
* at least 5 repeats in each of areas A and B
* calculate mean (per unit area) or total for each of areas A and B
* compare means / totals for areas A and B
Explain the effect a high concentration of insulin has on blood glucose concentration.
[3 marks]
effect : lowered
explanation:
glucose taken in
or
glucose converted to glycogen
or
glucose used in respiration by cells / liver / muscles
Give two ways that a person can reduce the chance of developing
Type 2 diabetes.
[2 marks]
(more) exercise
eat less carbohydrate / sugar or eat a low carbohydrate diet
Name one harmful substance that could cause air pollution.
[1 mark]
carbon dioxide or acidic gas(es)
Name three harmful substances that could cause water pollution.
Do not refer to plastic or to litter in your answer.
[3 marks]
any three from:
* fertiliser
* sewage
* toxic chemicals
* herbicide
* fungicide
Describe how substances that pollute air and water could be harmful to humans and other living organisms. (air pollution)
[6 marks]
air pollution:
(carbon dioxide or methane or greenhouse gases)
* global warming / climate change / traps heat
o floods / fire / drought or ice caps melt or rise in sea level or extreme weather
o loss of habitat / food
o migration
(acidic gas / named – eg SO2 / NOx)
* damage to leaves so less photosynthesis
* damage to roots or alters ions in soil (/ e.g. phosphates / iron)
o (so) less protein manufacture
* damage to lungs
o breathing difficulties / bronchitis / asthma
(carbon monoxide)
* combines with haemoglobin
o less oxygen carried (by haemoglobin / blood) (particulates / ‘soot’)
* cover leaves or block light
o less photosynthesis so less glucose made
* damage to lungs
o breathing difficulties / bronchitis / asthma
Describe how substances that pollute air and water could be harmful to humans and other living organisms. (water pollution)
[6 marks]
water pollution:
(sewage)
* bacteria multiply
o use oxygen in respiration
o water animals cannot respire
o pathogens in water
(fertiliser)
* algae multiply
o (algae) block light so plants cannot photosynthesise
o lack of oxygen for respiration – fish die
Explain why a person with MSUD must have a low-protein diet.
proteins contain amino acids
or
proteins are made of amino acids
must keep (certain) amino acids in low amount
(so) toxic substance or P does not build up in the body and cause damage to cells / tissues / organs
Give two uses of water in plants.
[2 marks]
any two from:
* photosynthesis
* support
* (solvent for) transport
or
translocation
or
for the transpiration stream
It is more energy-efficient to rear cows indoors than to rear cows outdoors.
Give two reasons why.
[2 marks]
less energy lost as heat
less energy lost in movement
Suggest two possible disadvantages of rearing cows indoors.
[2 marks]
any two from:
* increased spread of disease
or
increased use of drugs
/ antibiotics (to reduce disease)
* more antibiotics in meat / milk
* (extra) cost of heating / lighting / food / drugs
* aggressive behaviour
(causing harm)
or
‘emotional’ stress reduces
productivity
What is a mutation?
[1 mark]
any one from:
a change in
* DNA
* base code or nucleotide
sequence
* a base (in DNA)
* a gene / allele
* part of a chromosome
* number of chromosomes
* genetic code / material
