Survival And Response

Question 1

What is kinesis

Answer 1

Response to stimulus that results in the movement of an organism in no particular direction

Question 2

What things the plants and animals respond to

Answer 2

Light intensity
Temperature
Humidity
Pressure
Sound

Question 3

What is a positive phototropic response

Answer 3

The tips of the plant is towards the area with the highest light intensity
For photosynthesis

Question 4

What is a negative phototropic response

Answer 4

Roots move away from the highlight intensity

For water and nutrients

Question 5

How does phototropism work

Answer 5

Indoleatic acid (IIA) diffusers from the tip at a constant rate
IIA diffuses along one side of the tip at a higher concentration in order to elongate the cells therefore making the root bent
DIFFUSES FROM ROOT TO TIP

Question 6

How does geotropism work

Answer 6

IIA diffuses from the root to the tip

High concentrations of IIA along one side of the root inhibits cell growth

Question 7

What is Taxis

Answer 7

Response to stimulus the results movement of an organism towards or away from the stimulus

Question 8

What are the two photoreceptors in the eye?

Answer 8

Rod Cells and Cone Cells

Question 9

The Fovea is mainly comprised of ____ Cells

Answer 9

Cone

Question 10

Your peripheral vision is mainly using ____ cells

Answer 10

Rod

Question 11

Apart from Shape, what are the differences between Cone and Rod Cells? (6 Points)

Answer 11

• Rods are Monochrome, Cones are Colour Vision
• Rods are for Night Vision, Cones are for Day Vision
• Rods have high sensitivity to light, cones have low
• There is one type of rod but 3 types of cone
• Rods have low visual acuity Cones have high
• Many rods synapse onto one bipolar cell, where a single cone synapses onto a single bipolar cell

Question 12

What do bipolar neurones synapse with?

Answer 12

Rod/Cone Cells and Ganglion Cells

Question 13

Why do you have a blind spot in your eye?

Answer 13

The blind spot is where no photoreceptors are because that is where all Ganglion Cells converge to form the optic nerve.

Question 14

What kind of photo pigment do Rod Cells have inside them?

Answer 14

Rhodopsin

Question 15

What kind of photo pigment do Cone Cells have inside them?

Answer 15

Iodopsin

Question 16

Why do cones have high visual acuity, where rods have low?

Answer 16

Many rod cells synapse onto a single bipolar cell. Therefore, photons of light falling onto different rod cells within a group is perceived by the brain as a single stimulus
A single cone cell synapses onto a single bipolar cell. Therefore, photons of light falling onto different cone cells are perceived as separate stimuli.

Question 17

Why are rods good for night vision?

Answer 17

They have relatively high light sensitivity compared to cones so less light is necessary to cause an action potential, and also spatial summation from many rods synapsing onto the same bipolar neurone means even less light is needed to cause an action potential in the bipolar neuron

Question 18

What is an after image and how is it formed?

Answer 18

When photoreceptors become fatigued from overstimulation and no longer effectively respond to stimulus, the area where the cone cell of whatever variety/s have been fatigued will show whatever colour you are looking at, sans whatever cones have been fatigued. (e.g. red cone fatigued, look at white paper, get cyan because blue + green = cyan = white - red)