AQA A-Level Biology 7402-2 Paper 2: June
2024 Exam Questions with Marking Scheme
and Answers
air spaces between them = rapid diffusion, long and narrow and are packed
with chloroplast the thin tissue of the leaf allows light to reach mesophyll -
Name three advantages of mesophyll in the leaf
stroma in the fluid filled matrix - where does the LIR occur?
the dry weight of the total mass of living material in a specific area at a given
time - what is biomass?
phosphates from rocks are eroded into oceans and running water that is
absorbed by plants and excreted into the soil via death that then taken up by
water to form new rocks - describe the phosphorus cycle
algae build up on surface of water due to nitrogen from water that limits light
to lower level plants that can no longer photosynthesise and die that are fed
on by saprobiants that multiply and take up oxygen in the water so that O2
,becomes the limiting factor and larger organsims die as a result that are also
fed on by saprobiants that release toxins into the water - what is
eutrophication?
natural = dead decomposing plants and artificial = mined from rocks t provides
nutrients to plant - what is an example of a natural and artificial fertiliser?
the change of speed of direction in response to a stimulus - what is kinesis?
response to a stimulus where the direction is determined by the stimulus itself
that is moving the entire organism away or towards - what is taxis?
Calcium ions from sarcoplasmic reticulum causes by AP diffuse into muscle via
concentration gradient that then causes tropomyosin to move that exposes
the binding site of the actin filament, an ADP molecule then attaches to the
myosin head that causes it to form a cross bridge with actin filament binding
site, the actin filament is then pulled by the myosin head changing shape/angle
that releases ADP, ATP then allows the myosin head to detach from the actin
filament that is then broken by ATPase which provides the energy for myosin
head to change back to its original shape and the process is repeated -
Describe how the contraction of skeletal muscles work?
Sliding filament theory - What is the theory behind skeletal muscle contraction
called?
, The distance between two Z lines - What is the sarcomere?
Stay the same - What happens to the a-bands during muscle contraction?
Decreases in size - What happens to the H-zone and I band during the skeletal
muscle contraction?
Calcium reabsorbed by the sarcoplamsic reticulum that causes the tropmysoin
to be blocked again - How does the muscle relax?
Pair of muscles where one relaxes and the other contracts - What are
antagonistic muscles?
Numerous mitochondria, large store of myoglobin, rich supply of blood vessels
and contract slowly - What are the features of a slow twitch muscle fibre?
Thicker, more myosin filaments, high concentration of glucose, higher
concentration of enzymes and store of phosphocreatine to rapidly gain ATP
from ADP - What are the features of a fast twitch muscle fibre?
gross primary production - respiratory losses = the chemical energy left - what
is the calculation for net primary production? and what is it?
total chemical plant biomass - what is gross primary production?
2024 Exam Questions with Marking Scheme
and Answers
air spaces between them = rapid diffusion, long and narrow and are packed
with chloroplast the thin tissue of the leaf allows light to reach mesophyll -
Name three advantages of mesophyll in the leaf
stroma in the fluid filled matrix - where does the LIR occur?
the dry weight of the total mass of living material in a specific area at a given
time - what is biomass?
phosphates from rocks are eroded into oceans and running water that is
absorbed by plants and excreted into the soil via death that then taken up by
water to form new rocks - describe the phosphorus cycle
algae build up on surface of water due to nitrogen from water that limits light
to lower level plants that can no longer photosynthesise and die that are fed
on by saprobiants that multiply and take up oxygen in the water so that O2
,becomes the limiting factor and larger organsims die as a result that are also
fed on by saprobiants that release toxins into the water - what is
eutrophication?
natural = dead decomposing plants and artificial = mined from rocks t provides
nutrients to plant - what is an example of a natural and artificial fertiliser?
the change of speed of direction in response to a stimulus - what is kinesis?
response to a stimulus where the direction is determined by the stimulus itself
that is moving the entire organism away or towards - what is taxis?
Calcium ions from sarcoplasmic reticulum causes by AP diffuse into muscle via
concentration gradient that then causes tropomyosin to move that exposes
the binding site of the actin filament, an ADP molecule then attaches to the
myosin head that causes it to form a cross bridge with actin filament binding
site, the actin filament is then pulled by the myosin head changing shape/angle
that releases ADP, ATP then allows the myosin head to detach from the actin
filament that is then broken by ATPase which provides the energy for myosin
head to change back to its original shape and the process is repeated -
Describe how the contraction of skeletal muscles work?
Sliding filament theory - What is the theory behind skeletal muscle contraction
called?
, The distance between two Z lines - What is the sarcomere?
Stay the same - What happens to the a-bands during muscle contraction?
Decreases in size - What happens to the H-zone and I band during the skeletal
muscle contraction?
Calcium reabsorbed by the sarcoplamsic reticulum that causes the tropmysoin
to be blocked again - How does the muscle relax?
Pair of muscles where one relaxes and the other contracts - What are
antagonistic muscles?
Numerous mitochondria, large store of myoglobin, rich supply of blood vessels
and contract slowly - What are the features of a slow twitch muscle fibre?
Thicker, more myosin filaments, high concentration of glucose, higher
concentration of enzymes and store of phosphocreatine to rapidly gain ATP
from ADP - What are the features of a fast twitch muscle fibre?
gross primary production - respiratory losses = the chemical energy left - what
is the calculation for net primary production? and what is it?
total chemical plant biomass - what is gross primary production?
