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Question 1

Stages of mitosis and description of each

Answer 1

Interphase - the chromosomes copy themselves and extra sub cellular structures are made

Prophase - the nucleus starts to break down and spindle fibres appear

Metaphase: the chromosomes are lined up on the spindle fibres across the middle of the cell

Anaphase : the chromosome copies are seperated and move to opposite ends of the cell on spindle fibres

Telophase : a membrane forms around each set of chromosomes to form nuclei

Cytokinesis: a cell membrane forms to separate the two cells and two daughter cells are formed

Question 2

Asexual reproduction summary

Answer 2

• reproduction only requires one parent
• produces offspring that are clone
• asexual reproduction relies on mitosis

Question 3

Growth definition

Answer 3

The increase in size as a result of an increase in number or size of cells

Question 4

What is cell differentiation

Answer 4

The process that changes less specialised cells into more specialised ones

Question 5

A blood cell is a specialised cell . How is it adapted

Answer 5

• it has no nucleus allowing more space for red haemoglobin molecules .
• it has a large surface area which allows oxygen to diffuse in and out more quickly

Question 6

A fat cell is a specialised cell . How is it adapted ?

Answer 6

• the cytoplasm of fat cells is filled with large fat droplets . The fat is stored until the body needs energy

Question 7

What are nerve cells adapted to do

Answer 7

To carry electrical impulses from one place to another

Question 8

What allows plants to continue growing throughout their life

Answer 8

A group of cells near the end of each shoot called meristems . The cells in meristems divide rapidly by mitosis and contribute to length and differentiate to carry out unique functions

Question 9

Specialised plant cell and it’s features

Answer 9

A xylem cell : carries water throughout the plant

-Thickened wall to withstand water pressure
-Tiny pores in wall allow water and mineral salts to enter and leave the vessel
-No cytoplasm so vessel is empty
-loss of cell walls of two xylem cells to form a tube

Question 10

Stem cells definition

Answer 10

Cells that can divide repeatedly over a long period of time to produce cells that then differentiate

Question 11

Where are the stem cells found in plants

Answer 11

In the meristem

Question 12

Difference between plant and animal stem cells

Answer 12

Plant stem cells are usually able to produce any kind of specialised cell throughout the plants life however with animals all the cells differentiate as an embryo

Question 13

What is an adult stem cell and what does it do

Answer 13

Stem Cells in animals that can only produce the tissue around them . The adult stem cells in human tissue allow the tissues to grow or replace old or damaged cells

Question 14

What do embryonic stem cells do

Answer 14

Divide to produce more and more stem cells

Question 15

What happens once an embryo is three weeks old

Answer 15

The stems cells in the brain area start to differentiate

Question 16

Where is the cerebral cortex

Answer 16

It is at the front of the brain and is divided into two hemispheres .

Question 17

What happened to Phineas gage and what did it help prove

Answer 17

He was walking on a railway sight when dynamite exploded launching a pole straight into the front of the cerebral cortex at the front of his brain . After a few minutes unconscious he was able to get up and walk and talk again perfectly fine . However they found his personality changed . Before the accident he was kind and hard working but after he was lazy and irritable . This helped doctors learn that the cerebral cortex controls ur personality

Question 18

Where is the cerebellum and what does it do

Answer 18

It’s located at the base of the brain . It is divided into two halves and controls balance and posture.
It also controls the timing and fine controls of muscle activity making sure movements are smooth.

Question 19

Where is the medulla oblongata and what does it do

Answer 19

It controls ur heart rate and breathing rate and is also responsible for reflexes such as swallowing and vomiting . It is located at the bottom of the brain and the mass of neurons that make it up connects the brain to the spinal cord

Question 20

What’s the CNS

Answer 20

The central nervous system . It controls ur body and is made up of the brain and spinal cord .

Question 21

What do impulses in your body do

Answer 21

Allows all the parts of ur body’s to communicate using electric signals .

Question 22

What is a stimulus

Answer 22

Anything ur body is sensitive to including changes inside your body and in its surroundings

Question 23

What do receptor cells do

Answer 23

Detect stimuli

Question 24

What are sense organs

Answer 24

Eyes skin and ears that detect stimuli . They do this with receptor cells

Question 25

What do receptor cells do

Answer 25

Create impulses which usually travel to the brain. The brain then processes the information and can send impulses to other parts of the body to cause something to happen ( a response )

Question 26

What is neurotransmissions and where does it happen

Answer 26

The travelling, or transmission, of impulses is called neurotransmission and happens in neurones (nerve cells).

Question 27

Sensory neurone function

Answer 27

sensory neurone. Its function is to carry impulses from receptor cells towards the CNS.

Question 28

How are impulses transmitted

Answer 28

A receptor cell impulse passes into a tiny branch called a dendrite. It is then transmitted along the dendron and the axon. A series of axon terminals allow impulses to be transmitted to other neurones.

Question 29

How are sensory neurons adapted

Answer 29

Dendrons and axons are frequently long, to allow fast neurotransmission over long distances. There is also a fatty layer surrounding these parts, called the myelin sheath.
This electrically insulates a neurone from neighbouring neurones (e.g. in a nerve), stopping the signal losing energy.

Question 30

What does the eye contain

Answer 30

The eye is a sense organ that contains receptor cells found in a layer called the retina

Question 31

What are cones

Answer 31

Cones are receptor cells that are sensitive to the colour of light. Some cones detect red light, while others detect green or blue.

Question 32

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Answer 32

L

Question 33

What happens to the info from the cones

Answer 33

The information from all the cones is processed into full colour vision at the back of the cerebral hemispheres

Question 34

What are rods

Answer 34

Rods are receptor cells that detect differences in light intensity, not colour.

Question 35

Rods vs cones

Answer 35

Rods work well in very dim light whereas cones only work in bright light, which is why your colour vision is poor in dim light.

Question 36

What is the cornea

Answer 36

Clear colourless covering that focuses light

Question 37

The pupil

Answer 37

The pupil is the dark area in the middle of the eye, and is where light enters.
The amount of light entering the eye is controlled by muscles in the iris,
which can constrict the pupil (decrease its diameter or dilate it make it bigger). Bright light can damage the receptor cells in the retina.

Question 38

How are images created from light rays Entering the eye

Answer 38

Light rays entering the eye need to be focused onto a point in the retina to produce a clear image. Most focusing is done by the cornea, which bends (refracts) light rays to bring them together. The lens then fine-tunes the focusing. Ciliary muscles make the lens fatter to focus light from near objects and thinner to focus light from distant objects.

Question 39

Causes of short sightedness and long sightedness

Answer 39

Short sightedness - . This is because the rays of light from distant objects are focused in front of the retina

Long sightedness - rays of light from close objects are focused behind the retina

Question 40

What is a cataract and how to fix it

Answer 40

Cataract is a protein build up inside the lens that makes it cloudy . Full vision can be restored by replacing the clouded lens with a plastic one.

Question 41

What’s the cause of color blindness

Answer 41

People with colour-blindness have some cones that do not work properly and so have difficulty in seeing some colours.

Question 42

What do effectors do

Answer 42

When the brain coordinates a response to a stimulus, impulses are sent to effectors and these carry out an action. Effectors include muscles and glands

Question 43

What do motor neurons do

Answer 43

Motor neurons carry impulses to effectors . Doesn’t have a dendron and the dendrites are on the cell body .

Question 44

What is a relay neuron

Answer 44

Relay neurones are short neurones that are found in the spinal cord, where they link motor and sensory neurones. Doesn’t have a dendron and the dendrites are on the cell body

Question 45

What is a synapse

Answer 45

It is the tiny gap where one neuron meets another . When an impulse reaches an axon terminal a neurotransmitter substance is released into the gap . This is detected by the next neurone which generates a new impulses. In short a synapse is the tiny gal where neurotransmitters diffused into the next neuron

Question 46

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Question 47

The reflex arc steps

Answer 47

1) stimuli is detected by receptor cells
2) this then stimulates a sensory neurone which will carry an impulse to the spinal cord
3) in the spinal cord the impulse is then transferred to a relay neuron
4) the relay neuron then pases the impulse to a motor neuron
5) this then travels back out to the body to an effector which will cause an action based on the stimuli for example if you burn ur hand the effector would be ur wrist and the action the effector would be carrying out is moving ur wrist out the way.