AQA A-LEVEL BIOLOGY PAPER 3 QUESTIONS AND ANSWERS 2024 2025
When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the
presynaptic knob. Describe how - ANSWER nerve impulse causes calcium ion channels to open
calcium ions enter by facilitated diffusion
causes synaptic vesicles to fuse with presynaptic membrane
Use your knowledge of how myosin and actin interact to suggest how the myosin molecule moves the
mitochondrion towards the presynaptic membrane - ANSWER myosin head attaches to actin and
performs powerstroke
this pulls mitochondria along the actin
next myosin head attaches to actin and performs powerstroke
This movement of mitochondria happens when nerve impulses arrive at the synapse. Suggest and
explain one advantage of the movement of mitochondria towards the presynaptic membrane when
nerve impulses arrive at the synapse - ANSWER mitochondria supply ATP
for active transport of ions
Give two examples of biological molecules containing nitrogen that would be removed when a crop is
harvested - ANSWER DNA
proteins
Outline a method ecologists could use to determine plant species richness at one site - ANSWER grid
with coordinates selected using random number generator
use of quadrat
identify plant species in each quadrat
Name 2 enzymes involved in the semi-conservative replication of DNA - ANSWER DNA polymerase
DNA helicase
The arte of water movement through a shot in a potometer may not be the same as the rate of water
movement through the shoot of a whole plant. Why - ANSWER plants have roots
When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the
presynaptic knob. Describe how - ANSWER nerve impulse causes calcium ion channels to open
calcium ions enter by facilitated diffusion
causes synaptic vesicles to fuse with presynaptic membrane
Use your knowledge of how myosin and actin interact to suggest how the myosin molecule moves the
mitochondrion towards the presynaptic membrane - ANSWER myosin head attaches to actin and
performs powerstroke
this pulls mitochondria along the actin
next myosin head attaches to actin and performs powerstroke
This movement of mitochondria happens when nerve impulses arrive at the synapse. Suggest and
explain one advantage of the movement of mitochondria towards the presynaptic membrane when
nerve impulses arrive at the synapse - ANSWER mitochondria supply ATP
for active transport of ions
Give two examples of biological molecules containing nitrogen that would be removed when a crop is
harvested - ANSWER DNA
proteins
Outline a method ecologists could use to determine plant species richness at one site - ANSWER grid
with coordinates selected using random number generator
use of quadrat
identify plant species in each quadrat
Name 2 enzymes involved in the semi-conservative replication of DNA - ANSWER DNA polymerase
DNA helicase
The arte of water movement through a shot in a potometer may not be the same as the rate of water
movement through the shoot of a whole plant. Why - ANSWER plants have roots
