Paper 1 Cards

Question 1

How do animals increase chance of survival

Answer 1

By adapting and responding to internal and external environments to make sure all metabolic reactions are happening at the correct rate

Question 2

What is a change in an environment called

Answer 2

A stimulus

Question 3

Role of receptors and effectors and how do they communicate

Answer 3

Receptors detect the stimuli whilst the effectors bring about a response. They do this through the Nervous system or the hormonal system

Question 4

Structure of nervous system

Answer 4

• The two main parts are the CNS ( made from brain and spine) and the peripheral nervous system(made of neurones that connect rest of body to CNS)
• The peripheral splits into 2 parts the somatic (which controls conscious thought) and the autonomic( which controls unconscious thought)
• The autonomic splits again into the parasympathetic ( rest and digest) and sympathetic (fight or flight)

Question 5

Parts of brain and their functions

Answer 5

• Cerebrum largest part of brain split into 2 and controls vision, learning and thinking.
• hypothalamus controls body temperature, water levels and it produces hormones that control pituitary gland
• medulla oblongata controls breathing and heart rate
• cerebellum controls muscle coordination and balance
• pituitary gland controlled by hypothalamus and it releases hormones and stimulates other glands

Question 6

Reflex pathway

Answer 6

Stimulus- receptor-sensory neurone-relay neurone- motor nuerone- effector- response

Question 7

Blinking reflex

Answer 7

• Stimulus is something touching your eye
• receptor is the sensory nerve endings in your cornea and a nerves impulse is sent along sensory neurone to relay neurone
• goes to the motor nuerone and the effector ( orbicularis oculi muscle muscles) will move your eyelids and makes them close

Question 8

Knee jerk reflex

Answer 8

• stimulus is that quad is stretched
• stretch receptors detect change and send message down sensory neurone
• sensory neurone communicates directly with motor neurone
• motor carries impulse the quad muscles
• response is the lower leg moves forward quickly

Question 9

Control of heart rate

Answer 9

• The SAN controls the heart rate as it depends entirely on how often it fires
• adapting your heart to conditions such as low BP and different O2 and CO2 amounts is key to survival

Question 10

High blood pressure response

Answer 10

Baroreceptors detect high blood pressure and send impulse along sensory nuerone to cardio vascular centre which send impulse to parasympathetic pathway which will then secrete acetylcholine which binds to receptors on SAN which slows heart down to reduce BP

Question 11

Low blood pressure response

Answer 11

Baroreceptors detect change in BP and send nervous impulse down sensory nuerone to cardio vascular centre. This the. secretes Nora adrenaline which will bind to receptors on SAN allowing it to increase the speed at which it contracts increasing the heart rate

Question 12

High blood oxygen and low CO2

Answer 12

Chemoreceptors detect change and send message via sensory nuerone to cardiovascular centre. These secrete acetylcholine which binds to SAN receptors and puts all oxygen and CO2 levels back to normal

Question 13

Low blood O2 levels

Answer 13

Chemoreptors detect change and send message down sensory nuerone to cardiovascular centre which secretes noradrenaline which binds to receptor on SAN which increases heart rate to return things to usual levels

Question 14

Skeletal muscle structure

Answer 14

• Cell membrane called sarcolemma
• Transverse T tubules are flooded sarcolemma and help spread electrical impulse across the whole muscle fibre
• Sarcoplasmic reticulum stores and release calcium ions for muscle contraction

Question 15

Myofibril structure

Answer 15

Contain thick( made of protein myosin) and thin filaments( made of protein actin)

Question 16

Structure of sarcomere

Answer 16

Sarcomere is a section of a myofibril

• has Z line at both ends
• dark part À band light part I band
• M line is middle of it
• H zone contains only myosin

Question 17

What happens as a muscles contracts

Answer 17

As a muscle contracts the H zone gets smaller due to the actin overlapping the myosin and Z line get close together

Question 18

Myosin filament

Answer 18

-Myosin filament has a globular head which has a binding sight for actin and ATP

Question 19

Muscle contraction mechanism

Answer 19

• action potential from motor nuerone stimulates a muscle cell
• it will depolarise the sarcolemma and will eventually depolarise the sarcoplasmic reticulum which will the release Calum ions into sarcoplasm
  -calcium ion attach to troponin and makes it change shape which the pulls down the attached tropomyosin and unblocks the binding site
  -this allows myosin head to form actin myosin cross bridge with actin filament
• the calcium ion also activate ATPase, the energy from the ATP moves myosin head to the side which pulls along the actin filament whilst also providing enemrgy to break the actin myosin cross bridge
  -cycle repeats
  -

Question 20

How do muscle return to resting state

Answer 20

Calcium ions leave their binding site on tropinin so then the tropomyosin returns to its original place blocking the binding site calcium leaves sartoplasmic reticulum via active transport

Question 21

How is atp produced

Answer 21

Aerobic respiration, aneroobic respiratio, ATP creatine phosphate system

Question 22

Types of muscle

Answer 22

-Skeletal muscle is voluntary muscle (needs conscious thought to control it)
Smooth muscle is involuntary muscle (unconsciously controlled)
-cardiac muscle is myobenic and contracts on its own

Question 23

Nueromusculsr junctions

Answer 23

• Synapse between motor nuerone and muscle cell
• synapse releases nuerotransmitters acetylcholine which triggers depolarisation
• acetylcholine binds to post synaptic receptors making it release ACHE stored in clefts which breaks down the acetylcholine after the action potential has passed