AQA A level Biology - Topic 6 - survival and response questions and answers already passed

What is a stimulus? A change in the environment of an organism What is a tactic response? Directional movement in response to a stimulus What is a kinetic response? Non directional random movement in response to a stimulus What is a positive and negative taxis? Positive taxis- organism moves towards stimulus Negative taxis - organism moves away from stimulus What Are receptors? Detect stimuli- can be cells or proteins on cell surface membrane , loads of different types What are effectors? Cells that bring about a response to a stimulus to provide an effect ( muscle cells, glands) Receptors communicate with effectors via the ....... Nervous or hormonal system or both What are the 3 types of neurones? Sensory neurones Motor neurones Relay neurones What do sensory neurons do? They carry impulses from receptors to the CNS.