Section 6 - Coordination and Response

Question 1

Answer 1

Question 2

What is the job of the conjunctiva and what number is it (2)

Answer 2

• Lubricates and protects the surface of the eye
• 1

Question 3

What is the job of the cornea and what number is it (3)

Answer 3

• Cornea refracts light into the eye
• Cornea is transparent and has no blood vessels to supply it with oxygen, so oxygen diffuses in from the outer surface
• 3

Question 4

Explain why a cloudly cornea can cause blindness (2)

Answer 4

• Less light into the eye
• Less light hits retina

Question 5

What is the job of the iris and what number is it (3)

Answer 5

• Controls the diameter of the pupil
• Therefore how much light enters the eye
• 2

Question 6

What is the job of the lens and what number is it (2)

Answer 6

• Focuses the light onto the retina
• 5

Question 7

What is the retina and what number is it (2)

Answer 7

• Light sensitive part covered in light receptors called rods and cones
• 10

Question 8

What is the difference between rods and cones (3)

Answer 8

• Rods are more sensitive in dim light but can’t sense colour
• Cones are sensitive to colours but aren’t so good in dim light
• Cones are found all over the retina, but there are loads of them at the fovea

Question 9

What is the optic nerve and what number is it (2)

Answer 9

• Carries impulses from the receptors to the brain
• 8

Question 10

What are hormones (2)

Answer 10

• Hormones control things in organs and cells that need constant adjustment
• They are chemicals released directly into the blood

Question 11

What are hormones carried in (1)

Answer 11

• Blood plasma

Question 12

Properties of hormones (3)

Answer 12

• Produced in various glands
• Travel quite slowly
• Tend to have relatively long lasting effects

Question 13

What are the six most important hormones in the body (6)

Answer 13

• ADH
• Adrenaline
• Insulin
• Testosterone
• Progesterone
• Oestrogen

Question 14

Where is ADH produced, what is its role and what are the effects of it (3)

Answer 14

• Pituitary gland
• Controls water content
• Increases permeabilty of the kidney tubules to water

Question 15

Where is adrenaline produced, what is its role and what are the effects of it (3)

Answer 15

• Adrenal glands on top of the kidneys
• Readies the body for a fight or flight response
• Increases heart rate, blood flow to muscles, and blood sugar level

Question 16

Where is insulin produced, what is its role and what are the effects of it (3)

Answer 16

• Pancreas
• Helps control the blood sugar level
• Stimulates the liver to turn glucose into glycogen for storage

Question 17

Where is testosterone produced, what is its role and what are the effects of it (3)

Answer 17

• Testes
• Main male sex hormone
• Promotes male secondary sexual characteristics, e.g facial hair

Question 18

Where is progesterone produced, what is its role and what are the effects of it (3)

Answer 18

• Ovaries
• Supports pregnancy
• Maintains the lining of the uterus

Question 19

Where is oestrogen produced, what is its role and what are the effects of it (3)

Answer 19

• Ovaries
• Main female sex hormone
• Controls the menstrual cycle, promotes secondary sexual characteristics, e.g widening of the hips

Question 20

What are the differences between nerves and hormones (3)

Answer 20

• Nerves : very fast message, hormones : slower message
• Nerves : act for a very short time, hormones : act for a long time
• Nerves : act on a very precise area, hormones : act in a more general way

Question 21

For these circumstances, is it nerves or hormones that carry out the response (5)

1. If the response is really quick
2. If some information needs to be passed to effectors really quickly
3. If the response lasts for a long time
4. When you get a shock

Answer 21

1, 2 - nerves

3,4 - hormones

Question 22

What is homeostasis (1)

Answer 22

• Homeostasis is the maintenance of a constant internal enviornment

Question 23

Two examples of homeostasis (4)

Answer 23

• Water content (balance between water you gain and water you lose)
• Body temperature (rid of excess body heat when hot, retain heat when the environment is cold)

Question 24

Give three ways water is lost from the body (6)

Answer 24

• through the Skin (as sweat)
• via the Lungs (as breath)
• via the Kidneys (as urine)

Question 25

What temperature do enzymes work best at (1)

Answer 25

• 37 degrees

Question 26

What body part maintains homeostasis of body temperature (3)

Answer 26

• CNS
• Signals from receptors in the skin
• Activates necessary effectors to maintain homeostasis

Question 27

What has a larger surface area to volume ratio : small or large organsims (1)

Answer 27

• small

Question 28

Why is it an advantage/disadvantage for smaller organisms to have a high surface area to volume ratio (3)

Answer 28

• Can gain/lose heat faster because there is more area for the heat to transfer across
• Lose body heat more easily in hot climates (don’t overheat)
• Very vunreable in cold enviornments

Question 29

How are animals living in cold conditions adapted (3)

Answer 29

• Compact (rounded) shape
• Keeps surface area to a minimum
• Reduces heat loss

Question 30

What are auxins (3)

Answer 30

• Plant hormones
• Control growth at the tips of roots/shoots
• Move through the plant dissolved in water

Question 31

What 2 growth responses of plants are auxins involved in (2)

Answer 31

• Geotropism
• Phototropism

Question 32

Where is auxin produced and where does it move to and why (3)

Answer 32

• Produced in the tips
• Diffuses backwards to stimulate cell elongation process
• Which occurs just behind the tips

Question 33

Auxin promotes growth in the ……. , but actually inhibits growth in the ……

Answer 33

• shoot
• root

Question 34

Are shoots positvely or negatively phototropic? How does this affect growth and why (4)

Answer 34

• Positively (grow towards light)
• Shoot tip exposed to light : accumulates more auxin on the side that’s in the shade than the side that’s in the light
• Makes cells elongate faster on the shaded side
• Shoot bends towards light

Question 35

Are shoots positively or negatively geotropic, how does this affect plant growth and why (4)

Answer 35

• Negatively geotropic (grow away from gravity)
• When a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip
• More auxin on the lower side
• Causes lower side to grow faster
• Bending the shoot upwards

Question 36

Are roots positively or negatively geotropic, how does this affect the plant and why (5)

Answer 36

• Positively (grow towards gravity)
• A root growing sideways has more auxin on lower side
• In a root, extra auxin inhibits growth
• Cells on top elongate faster
• root bends downwards

Question 37

What effects are these diagrams showing (3)

Answer 37

• Shoots are negatively geotropic
• Shoots are positvely phototropic
• Roots are positively geotropic

Question 38

How are hormones released (1)

Answer 38

• Directly into the blood