Topic G - Coordination & Response

Question 1

how do organisms respond to changes in their surroundings

Answer 1

Tropisms

Question 2

what tropism detects light

Answer 2

phototropism

Question 3

what tropism detects moisture ( water)

Answer 3

hydrotropism

Question 4

what tropism detects gravity

Answer 4

geotropism

Question 5

in what direction of growth do shoots grow ( 2 things )

Answer 5

1. towards light = +ve phototropism

2. away from gravity = -ve geotropism

Question 6

in what direction of growth do roots grow ( 2 things )

Answer 6

1. towards moisture = +ve hydrotropism

2. towards gravity = +ve geotropism

Question 7

what are the 5 steps to co-ordinated/ reflex arc response

Answer 7

1. stimulus =change in enviroment
2. Receptor= sensor organs (nerve ending)
3. Co-ordinating centre = brain + spinal chord
4. Effector = muscle
5. Response = movement

Question 8

what is homeostasis

Answer 8

maintenance of constant internal enviroment

Question 9

what are examples of homeostasis

Answer 9

body water content

body temperature

Question 10

what do plants respond to

Answer 10

stimuli = light, heat, moisture

Question 11

what is auxin

Answer 11

plant hormone that controls growth

Question 12

where is auxin produced

Answer 12

in the shoot tips

Question 13

what does auxin increase and decrease

Answer 13

increases growth in shoots

decreases growth in roots

Question 14

how does auxin work in response to light

Answer 14

auxin accumulates on the dark side= growth on that side= bend towards light

Question 15

what are 2 parts of the central nervous system and what are they linked to and how

Answer 15

brain + spinal chord

link to sense organs by nerves

Question 16

what does stimulation of receptors in sense organs do

Answer 16

sends electrical impulse along nerves into and out of central nervous system= rapid responses ( reflex)

Question 17

1. what do synapses do

2. what do neurotransmitters (chemicals ) do at the synapse

Answer 17

1.connect neurons (connection between 2 neurons =synapse)

2. transfers nerve signals by diffusing across the gap
   + set of new a new electrical signal in the next neurone

Question 18

describe process of reflex arc - removal of finger from a hot object

(CNS= central nervous system)

Answer 18

1. stimulus = hot object
2. receptors (skin) detect stimulus
3. impulse sent along sensory neurone to the CNS
4. in CNS impulses are passed along relay neurone (via a synapse)
5. relay neurones relay impulse to a motor neurone
6. impulse travels along motor neurone to the effector (muscle)
7. muscle contracts + moves finger away from hot object

Question 19

what is the eye and what does it do

Answer 19

receptor = major sense organ = detects light

Question 20

how does the eye focus on distant objects

Answer 20

cilary muscles relax= suspensory ligament pulled tight= lens = less convex (flat) = refracts light by smaller amount

Question 21

how does the eye focus on nearer objects

Answer 21

cilary muscles contract = smaller amount of space = suspensory ligament relax = lens = more convex (rounded) = refracts light by larger amount

Question 22

function of iris

Answer 22

muscle which contracts or relax to change pupil size

Question 23

how does eye react to bright light

Answer 23

circular muscles contract= radial muscles relax= pupil constricts( smaller )= lets less light in

Question 24

how does eye react to dim/ no light

Answer 24

circular muscles relax = radial muscles contract = pupil dilates = lets more light in

Question 25

What process can help us cool down when we are to hot

Answer 25

Vasodilation | sweating- when it evaporates it transfers energy from skin to the environment= cooler

Question 26

How does vasodilation work

Answer 26

1. Muscles relax widening entrance to capillaries. 2. More blood flows through capillaries towards surface of skin 3. Increased heat loss by radiation and reduction

Question 27

What process helps to warm us up when to cold

Answer 27

Vasoconstriction | shiver + exercise = increase rate of respiration= transfers more energy to warm body

Question 28

How does vasoconstriction work

Answer 28

1. Muscles contract constricting entrance to capillaries. 2. Very little blood flows through capillaries 3. Reduced heat loss

Question 29

How does hair on our body react when cold

Answer 29

1. Hair muscles pull hairs on end. 2. Erect hairs trap air. 3. Blood flow in capillaries decreases.

Question 30

How does sweating occur when hot

Answer 30

1. Hair muscles relax. Hairs lie flat so heat can escape. 2. Sweat secreted by sweat glands. Cools skin by evaporation. 3. Blood flow in capillaries increases.

Question 31

Describe differences in type of signal of nervous system ( N ) and hormonal system ( H )

Answer 31

1. N = electrical | H = chemical

Question 32

Describe differences in transmitting of signal ( how message sent ) of nervous system ( N ) and hormonal system ( H )

Answer 32

``` N = nerve cells. ( exocrine ) H= nerve cells in blood stream ( endocrine ) ```

Question 33

Describe differences in effectors of nervous system ( N ) and hormonal system ( H )

Answer 33

``` N = muscle or glands H = target cells in particular tissues ```

Question 34

Describe differences in type of response of nervous system ( N ) and hormonal system ( H )

Answer 34

N= muscle contraction or secretion H = chemical change

Question 35

Describe differences in speed of response of nervous system ( N ) and hormonal system ( H )

Answer 35

N= very rapid H= slower

Question 36

Describe differences in duration of response of nervous system ( N ) and hormonal system ( H )

Answer 36

N= short ( until nerve impulses stops H = long ( until hormone is broken down

Question 37

Where is adrenaline found and what does it do

Answer 37

1. Found in Adrenal gland | 2. Prepares body for physical activity

Question 38

Where is insulin found and what does it do

Answer 38

1. Found in Pancreas gland | 2. Lowers blood glucose

Question 39

Where is testosterone found and what does it do

Answer 39

1. In Testes gland | 2. Controls development of male secondary characteristics

Question 40

Where is progesterone found and what does it do

Answer 40

1. In Ovaries | 2. Regulates menstrual cycle

Question 41

Where is oestrogen found and what does it do

Answer 41

1. In Ovaries | 2. Controls the development of female secondary sexual characteristics

Question 42

PAPER 2 What 4 hormones are found in the Pituitary

Answer 42

1. Follicle stimulating hormone ( FSH ) 2. Luteinising hormone ( LH ) 3. Anti - diuretic hormone ( ADH ) 4. Growth hormone ( GH )

Question 43

PAPER 2 What is the role of the follicle stimulating hormone ( FSH )

Answer 43

Stimulates egg development and oestrogen secretion in females and sperm production in males

Question 44

PAPER 2 What is the role of the luteinising hormone ( LH )

Answer 44

Stimulates egg release ( ovulation ) in females and testosterone in males

Question 45

PAPER 2 What is the role of the anti - diuretic hormone ( ADH )

Answer 45

Controls water content of the blood

Question 46

PAPER 2 What is the role of the growth hormone ( GH )

Answer 46

Speeds up rate of growth and development in children

Question 47

what 3 things does a co-ordinated response require

Answer 47

stimulus receptor effector