Biology Key knowledge

Question 1

What 3 things do plant cells have that animal cells don’t?

Answer 1

Vacuole
Cell wall
Chloroplasts

Question 2

What are the key components of a reflex arc?

Answer 2

stimulus
↓
receptor
↓
neurones (sensory → relay → motor)
↓
effector
↓
response

Question 3

Dependent variable meaning

Answer 3

what you measure in an experiment

Question 4

Control variable meaning

Answer 4

what you keep the same in an experiment

Question 5

Independent variable

Answer 5

what you change in an experiment

Question 6

What is the stimulus in the reflex arc?

Answer 6

Any change in the environment that your body needs to respond to

Question 7

What do receptors do in the reflex arc?

Answer 7

They are found all over the body and they detect change, then initiate (start or cause an action/process to begin) a signalling process within the body

Question 8

What do neurones do in the reflex arc?

sensory, relay and motor

Answer 8

The sensory neuron sends electrical impulses to a relay neuron, which is located in the spinal cord of the CNS. Relay neurons connect sensory neurons to motor neurons, which then send electrical impulses to an effector.

CNS = central nervous system

Question 8

What do effectors do in the reflex arc?

Answer 8

This is a muscle or gland that brings about an action in response to a change ( detected by the receptor) in the internal or external environment.

Question 9

What is a response in the reflex arc?

Answer 9

Any action that is caused by the effector to help the organism to avoid the harmful situation