B1 T2

Question 1

What does homeostasis mean

Why does it need to be done?

Answer 1

Maintaining a stable internal environment as conditions in your body need to be kept steady so that cells can function properly

Question 2

What is osmoregulation

Answer 2

Regulating water content in the body, need to keep a balance between water gained and water lost through wee sweat and resperation

Question 3

What is thermoregulation

Answer 3

Regulating body temp

Question 4

Osmoregulation controls the amount of water

What happens if there is too much or too little water

Answer 4

If there's is too much water 
Sweat glands produce more sweat 
Kidneys produce more urine 
If there is too little 
Kidneys produce less urine 
Brain makes you feel thirsty

Question 5

What is the hypothalamus?
What does it do?
What is the dermis?

Answer 5

Something in the brain that controls body temperature, contains receptors sensitive to blood temp in brain
Receive impulses from receptors in skin- skin temp
When the hypothalamus detects a change it causes a response in the dermis
The dermis is a deep layer of the skin

Question 6

Why is it important to maintain body temp

Answer 6

Enzymes work best. At 37°

Question 7

What happens when the hypothalamus detects the skin temperature is too hot

Answer 7

Sweat glands produce sweat which evaporates on the skin cooling you down
Vasodilation causes blood vessels to widen so the blood can travel closer to the surface of the skin to transfer more heat to the surrounding
Erecter hair muscles relax so that hair lie flat so they don’t trap any heat

Question 8

What happens when the hypothalamus detect the skin temperature is too cold

Answer 8

Vasoconstriction causes blood vessels to constrict so the blood can’t flow close to the service of the skin so it doesn’t transfer and heat to surroundings
Hair erector muscles contract making hairs stand up to trap air
No sweat is secreted from sweat glands

Question 9

Explain how negative be back helps homoeostasis

When does it not work ?

Answer 9

When the body detect a change in the environment it causes a response to counteract the change
It only works if the change isn’t too drastic if it’s too drastic then it can’t counteract it

Question 10

What is the definition of hormones

Answer 10

Chemical messengers which travel in the blood to activate target cells

Question 11

What are target cells

What is an organ that contains a target cell called

Answer 11

Target cells have the right receptors to respond to specific hormones
A target organ

Question 12

Where are hormones produced?

Answer 12

Hormones are chemicals produced in various glands called Endocrine glands

Question 13

What do neurones do?

Answer 13

Neurons transmit information about the body as electrical impulses

Question 14

How is the electrical impulse passed along the neurone?

How does the Mylin Sheth help do this

Answer 14

The electrical impulses are passed along the axon of the cell
The Myleen sheath arts as an electrical insulator to make sure the electrical impulses don’t get lost and helps to speed it up

Question 15

Why does neurons being long help speed up the electrical impulses

Answer 15

Connecting with another neuron slows the impulse down so one neurone is much quicker than lots of short ones joined together

Question 16

What are dendrons?

Answer 16

Branched endings on a neurone that can connect with other neurones

Question 17

What is a synapse in a neurone?

How are the nerve impulses transmitted across the synapse

Answer 17

The connection between two neurons, it’s basically just a very tiny gap

Impulses are transmitted by chemicals called neurotransmitters which diffuse across the gap.
the neurotransmitters set off a new electrical impulse

Question 18

What are the differences between Hormones and nerves

Answer 18

Nerves send a fast message. Hormones send a slow message
Nerves act for a short time. Hormones act for a long time
Nerves act on a very precise area. Holmans act in a more general area
Nerves are electrical messages. Hormones are chemical messages

Question 19

What is a stimulas

Answer 19

A change in your environment that you may need to respond to

Question 20

What are receptors and what do they do

Answer 20

Groups of cells that are sensitive to a stimulating they change stimulas energy into electrical impulses

Question 21

How does the central nervous system co ordinate a response

Answer 21

When is a stimulus is detected by receptors In sensory organs information is sent along sensory neurone to the CNS
CNS co ordinates response, sends information to an effector like a muscle along a motor neurone. Effector responds accordingly

Question 22

What is a reflex

Answer 22

An automatic response to a specific stimulus

Question 23

What happens Ina reflex arc

Answer 23

Receptor detects environmental stimulus, information travels along sensory neurons to central nervous system and then sends information to effector through motor neurone which triggers a response in a muscles or gland

Question 24

What happens if blood glucose levels are too high

Answer 24

Insulin is secreted by pancreas, insulin mixes with glucose in blood, blood goes into liver, insulin makes the lives turn glucose into glycogen

Question 25

What happens if the blood glucose level is too low

Answer 25

Glucagon is secreted by pancreas, blood with glucagon in goes into lives, glucagon makes liver turn glycogen into glucose

Question 26

How is type one diabetes controlled
How does the amount of insulin injected depend on Te
persons diet
Where is the insulin injected

Answer 26

Limiting intake in foods rich in carbohydrates
Insulilin injected at meal times so the lives removes the glucose quickly once food has been digested this stops blood sugar getting too high
Very effective treatment
Healthy diet n regular exercise reduces amount of insulin that needs to be Injected
Subcutaneous tissue

Question 27

How do you work out body mass index

Answer 27

Body mass divided by( height)2

Question 28

How can type 2 diabetes be controlled

Answer 28

Healthy died, regular exesize, medication, insulin injection

Question 29

What is gibberellin

Answer 29

Plant hormone
Stimulates seed germination, stem growth and flowering
Stems elongate so plants can grown tall

Question 30

Explain a practical to investigate plant growth responses

Answer 30

Put 10 cress seeds into 3 Petri dishes each lines with moist filter paper
Shine a light at each from different direction s
Leave them alone until you an observe a response
Seeds grow toward light

Question 31

What variables do u need to control in the plant growth practical

Answer 31

Number of seeds 
Type of seeds 
Temperature 
Intensity of light 
Same amount of water

Question 32

Selective weed killers

Answer 32

Weeds have broad leaves
Grasses n other crops have narrow leaves
Selective weed killers adapted from plant growth hormones to only affect broad leaves plants
Disrupt normal growth patterns

Question 33

How does rooting powder help growers produce clones of good plants

Answer 33

Stick cutting in soil with rooting powder (plant growth hormone) produce roots rapidly and start growing as new plants

Question 34

Controlling ripening of food

Answer 34

Fruit picked whilst still not ripe so doesn’t get damaged in transport as firmer
Ripening hormone added in transport so ripe for shelves at supermarket

Question 35

Producing seedless fruit

Answer 35

Fruit with seeds in normally only grow on plants that have been pollinated by insects
If growth hormones are applied to unpollinated plants the fruit will grow without seeds in it