OCR Gateway GCSE Biology A organism level systems (B3) overview quiz quiz

The sensory and motor neurones

The receptors and effectors

The brain and the spinal cord

The synapses and neurotransmitters

The electrical impulse simply jumps straight across the synaptic gap on its own

The two neurones physically touch and merge together so the impulse flows on

The impulse turns around and travels back the way that it originally came from

A chemical neurotransmitter diffuses across the gap and triggers a new impulse

Because the impulse takes a short route through the spinal cord, bypassing conscious thought

Because the response is processed slowly and carefully by the conscious cerebral cortex of the brain

Because a reflex action uses fast-acting hormones in the blood rather than nerves

Because reflex actions only ever happen in plants and never in animals or in humans

The cerebral cortex

The medulla

The cerebellum

The retina

It is faster acting and much shorter-lasting than ordinary nervous control is

It uses electrical impulses sent along neurones to carry the message

It is slower and longer-lasting, using chemicals carried in the blood

It only ever affects one single precise area of the body at a time

Glucagon, by converting the stored glycogen back into glucose in the liver again

Oestrogen, by thickening the lining of the uterus during the cycle

Adrenaline, by speeding up the heart rate and breathing rate

Insulin, by making cells take up glucose and the liver store it as glycogen

The pancreas produces little or no insulin

The body cells gradually stop responding to insulin

The liver makes far too much glycogen from glucose

Far too much of the hormone glucagon is released

FSH

LH

Progesterone

Insulin

It kills all of the sperm cells once they have entered the body

It physically blocks the egg so that no sperm can ever reach it

Its hormones inhibit FSH, so no egg matures and ovulation does not happen

It only thins right down the lining of the uterus and does nothing else at all

On the lit side of the shoot, where it slows the growth of the cells right down

Evenly all the way around the shoot, so that the shoot simply grows straight up

Down in the roots of the plant, where it speeds right up the growth of all of the cells there

On the shaded side, where it makes cells elongate more so the shoot bends towards the light