Sensitivity and Coordination

Question 0

What are responses in plants called?

Answer 0

Tropisms

Question 1

What is a stimuli?

Answer 1

Changes in the external or internal environment e.g. Light waves, pressure or internal stimuli.

Question 2

What is a kinesis?

Answer 2

A type of simple behavioural response, a random movement not in any particular direction.

Question 3

What are the types of kinesis?

Answer 3

Orthokinesis - a change in speed e.g. Getting faster in response to a stimulus.

Klinokinesis - change in rate of turning in response to a stimulus.

Question 4

What is a taxis?

Answer 4

A movement in response to the direction of a stimulus.

Question 5

How does a reflex arc work?

Answer 5

Sensory neurones carry info from sensory receptors to CNS.
Interneurones (or relay neurones) in the CNS carry info between sensory neurones and motor neurones.
Motor neurones carry info to effector organs.

Question 6

What are fixed action patterns (FAP’s) ?

Answer 6

They are brought about by specific stimuli called sign stimuli e.g. nest building, courtship dances etc…

Question 7

What are the two main divisions of the autonomic nervous system, what do they do?

Answer 7

The sympathetic nervous system – Speeds up activities and thus allows us to cope with stressful situations (fight or flight response).

The parasympathetic nervous system – Inhibits effects and slows down activities. This allows energy to be conserved. Controls under normal resting conditions

Question 8

What light intensity do rod cells work at best, why?

Answer 8

Low light intensity as many rods are connected to one neurone so they can combine to reach a threshold.

Question 9

What is the visual acuity of rod cells like, why?

Answer 9

Bad because many rods connect to one neurone so the brain cannot tell the difference between two points close together.

Question 10

What pigment do rod cells break down?

What pigment do cone cells break down?

Answer 10

Rod cells - rhodopsin

Cone cells - iodopsin

Question 11

What is IAA, what does it do?

Answer 11

Indoleacetic acid, causes plant cells to elongate.

Question 12

What does the somatic nervous system do?

Answer 12

Controls conscious activities.

Question 13

What makes up the CNS?

Answer 13

The brain and spinal cord.

Question 14

What makes up the peripheral nervous system?

Answer 14

The neurones that connect the CNS to the rest of the body.

Question 15

What is a chemical mediator?

Answer 15

A chemical messenger that acts locally (i.e on nearby cells).

Question 16

What is the role of auxins in the control of phototropism?

Answer 16

Auxin is redistributed to the shaded side of the plant. In shoots auxin stimulates cell elongation. So the shoots bend and grow towards the light. In roots high concentrations of auxin inhibit cell elongation. So roots bend to grow away from the light.

Question 17

What is an effector?

Answer 17

Cells that effect a response. In humans they are muscles and glands.

Question 18

What do receptor cells do?

Answer 18

Detect stimuli. Receptor cells are often part of sense organs.

Question 19

What type of receptor is a pacinian corpuscle?

Answer 19

A mechanoreceptor (responds to pressure/ movement).

Question 20

What is the black pigmented layer that lies behind the retina of the human eye? What does it do?

Answer 20

The choroid layer. Provides retinal cells with nutrients and oxygen.

Question 21

Where is the SAN located in the heart?

Answer 21

In the wall of the right atrium.

Question 22

What are plant growth factors?

Answer 22

Are chemicals that regulate various aspects of plant growth and development. The equivalent of hormones in animals.

Question 23

What is the process by which IAA moves from the growing regions of a plat shoot to other tissues.

Answer 23

Diffusion.

Question 24

What is a…

Answer 24

Photoreceptor - detects light and other electromagnetic radiation.
Mechanoreceptor - detects movements, pressure, tension gravity and sound waves.
Chemoreceptors - detects specific chemicals such as glucose, H+ or pheromones.
Thermoreceptors - detecting hot and cold temperatures.