Chapter 4: Organising Animals and Plants

Question 1

What are the three types of blood vessels

Answer 1

Artery
Vein
Capillaries

Question 2

How much blood does the average person have?

Answer 2

Between 4.7 and 5 litres of blood

Question 3

How many red blood cells are there in the human body

Answer 3

5 million

Question 4

Information about red blood cells?

Answer 4

• They carry oxygen around the body.
• They have no nucleus, making more space for haemoglobin.
• They are biconcave disc.
• They are packed with haemoglobin which binds to the oxygen.

Question 5

Why are red blood cells biconcave?

Answer 5

Being concave gives them an increased surface area to increase the rate of diffusion of oxygen into the blood and alveoli.

Question 6

What is plasma?

Answer 6

Your blood plasma is a yellow liquid . The plasma transports all of your blood cells and some other substances around your body.

Question 7

What are white blood cells?

Answer 7

White blood cells make up part of the bodies defence system against harmful micro-organisms. It also has a nucleus unlike the red blood cell.

Question 8

What are lymphocytes?

Answer 8

They form antibodies against microorganisms.

Question 9

What are Phagocytes?

Answer 9

They engulf and digest invading bacteria and viruses.

Question 10

What are platelets?

Answer 10

They clot the blood at the site of the wound.

This produces a network of protein fibres that capture red blood cells and more platelets to form a jelly like clot.

Question 11

What is blood clotting?

Answer 11

Blood clotting is a series of enzyme controlled reactions that result in converting fibrinogen to fibrin.

Question 12

What makes up the human circulatory system?

Answer 12

The blood
Blood vessels
Heart

Question 13

How do substances diffuse in and out of the blood

Answer 13

The capillaries

Question 14

What do valves in the heart do?

Answer 14

They prevent back-flow and ensure that blood flows in the right direction

Question 15

Why is the circulatory system in humans described as a double circulatory system

Answer 15

The first is made up of the right ventricle. It pumps deoxygenated blood to the lungs to take in oxygen. The blood then returns to the heart.
The second then pumps the oxygenated blood around the body

Question 16

Name the 4 chambers of the heart

Answer 16

Right and left atrium

Right and left ventricle

Question 17

What is the function of the coronary arteries?

Answer 17

To provide blood for the heart

Question 18

Why can enzymes be described as biological catalysts

Answer 18

Because they are produced by the body

Question 19

Name the tubes that split of the trachea

Answer 19

Bronchus

Question 20

Describe the role that the alveoli play in gas exchange

Answer 20

Carbon dioxide diffuses out of the blood whilst oxygen diffuses in

Question 21

Why does the heart have a pacemaker and where is it

Answer 21

So that the heart beats regularly it is a small group of cells in the right atrium that control your heartbeat by producing an electrical pulse causing the muscle sto contract

Question 22

What is an artificial pacemaker?

Answer 22

It is a small device that is implanted under the sling with a wire connecting it to the heart. It produces small electrical impulses causing the muscle to contract to keep the heart beating regularly

Question 23

How are arteries adapted to carry blood away from the heart

Answer 23

They pump blood out at high pressure
They are strong and elastic
The walls are thick compared to the lumen
They contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back

Question 24

Describe how capillaries are adapted for their function

Answer 24

They run really close to individual cells to exchange substances such as food and oxygen, carbon dioxide.
They are permeable
They are only one cell thick it increase the rate of diffusion because it reduces the distance it happens

Question 25

Describe how veins are adapted to carry blood back to the heart

Answer 25

They have a bigger lumen | They have valves to keep blood flowing in the right direction

Question 26

What is a lumen?

Answer 26

The space inside the blood vessel for blood to flow

Question 27

Why don't red blood cells have nucleus ?

Answer 27

So there is more room for carrying oxygenp

Question 28

What are statins?

Answer 28

Statins are drugs that can reduce the amount of bad cholesterol present in the bloodstream. It slows down the rate of fatty deposits forming

Question 29

Give two advantages of statins.

Answer 29

By reducing the amount of bad cholesterol it can reduce the risk of strokes, heart disease and heart attacks. It can increase the amount of good cholesterol in the blood and can destroy bad cholesterol.

Question 30

Give two disadvantages of statins

Answer 30

Statins are a long term drug and must be taken regularly. | Side effects include headaches, kidney failure, liver damage and memory loss

Question 31

What is a artificial heart?

Answer 31

A heart that is made out of plastic and metal that is a replacement for damage or dead heart. It is implanted through surgery and takes the job of pumping blood through the body whilst a donor is found

Question 32

What are the problems with artificial hearts

Answer 32

The device such as the mechanical motor can fail. Blood doesn't flow as well and can cause clotting. The patient has to take drugs to thin their blood and is dangerous if they are injured because it is easier for them to bleed out.

Question 33

How can faulty heart valves lead to poor circulation?

Answer 33

If a valve is stiff and won't open properly | If a valve is loose and leaking blood in the wrong direction it means blood doesn't circulate as effectively.

Question 34

How can faulty heart valves be treated?

Answer 34

Faulty heart valves can be treated by replacing them with either a mechanical or biological valve. Valves from other humans, cows and pigs are used or are man made

Question 35

Name all of the plant tissues

Answer 35

``` Epidermal tissue Palisade mesophyll tissue Spongy mesophyll tissue Xylem Phloem Meristem tissue ```

Question 36

What is epidermal tissue?

Answer 36

This tissue covers the whole plant. It is covered with a waxy cuticle, it helps to reduce water loss by evaporation. They are transparent

Question 37

What is palisade mesophyll tissue?

Answer 37

This is the part of the tissue where most photosynthesis happens. It contains lots of chloroplasts. They are near the top of the leaf where they can get most of the light

Question 38

What is spongy mesophyll tissue

Answer 38

It contains big air spaces to allow gases to diffuse in and out of cells. It increases the rate of diffusion of gases

Question 39

What is meristem tissue?

Answer 39

It is the undifferentiated cells at the tips of shoots and roots that can change into any other cell

Question 40

What is the lower epidermis

Answer 40

The lower part of the leaf. It contains stomata which diffuse carbon dioxide into the leaf. They are controlled by gaurd cells

Question 41

What are xylem?

Answer 41

They are made of dead cells joined end to end with no walls between them. They are strengthen with a material called lignin. They carry water and minerals from the roots to the leaves and stem. The movement of water from the roots to the leaf through the xylem is called the transpiration stream

Question 42

What are phloem?

Answer 42

They are made of columns of living cells. They have small pores in the end walls to allow sao to flow through. They transport food mainly dissolved sugars from the leaves to the rest of the plant. The transport goes in both directions. The process is called translocation.

Question 43

List the 4 main things that affect transpiration

Answer 43

Light intensity Temperature Air flow humidity

Question 44

Name the cell that opens and closes the stomata

Answer 44

Guard cells

Question 45

Why is transpiration affected by light intensity?

Answer 45

The brighter the light the higher the rate of diffusion. The darker it gets the slower the rate of diffusion is. Photosynthesis can't happen in dark so they don't need to be open. Very little water can escape because they're closed

Question 46

Why does air flow affect the rate of transpiration?

Answer 46

The better the air flow around a leaf the greater the transpiration rate. This is because if there isn't wind then the water vapour will collect around the leaf. If this happens transpiration happens slower because there isn't as much of a concentration gradient However if there is wind the rate of diffusion speeds up because of the concentration gradient

Question 47

How does temperature affect the rate of transpiration?

Answer 47

The warmer it is the faster transpiration happens

Question 48

Why does humidity affect the rate of transpiration?

Answer 48

The drier it is around a leaf the faster transpiration happens. If it is humid then there is a low concentration gradient between the leaf and the air so it happens slowly

Question 49

How are guard cells adapted and what do they do?

Answer 49

When the plant has lots of water the guard cells go plump and turgid this makes the stomata open so gases can be exchanged for photosynthesis. When the plant is low on water the cells become flaccid causing the stomata to close. They are sensitive to light and close at night. There are more stomata on the lower surface because it's cooler and it won't lose as much water.