B4 - Organising Animals and Plants - Complete

Question 1

What does the human circulatory system comprise of?

Answer 1

The blood, the blood vessels, and the heart

Question 2

What does the blood consist of?

Answer 2

Mostly plasma, with white and red blood cells suspended within it, as well as substances that have dissolved within it

Question 3

Give 2 examples of substances your blood plasma carries around the body

Answer 3

Waste carbon dioxide, urea from your kidneys

Question 4

Give 2 adaptations of red blood cells to make them well suited to their job

Answer 4

They are biconcave discs, giving them an increased surface area to volume ratio for diffusion / They are packed with haemoglobin, which binds to oxygen - making oxygen transfer easy / They have no nucleus, so there is more space for haemoglobin

Question 5

What is the job of red blood cells?

Answer 5

To carry oxygen throughout the body’s tissues

Question 6

What are 2 types of white blood cells?

Answer 6

Phagocytes, which engulf invading bacteria and viruses, and lymphocytes, that produce antitoxins against the poisons of microorganisms

Question 7

What are platelets?

Answer 7

Small fragments of cells that have no nucleus and float around in the blood

Question 8

What is the function of platelets?

Answer 8

To help clot and block up wounds in order to stop infection and protect the new skin that is being built underneath

Question 9

What chemical process must take place when a cut is clotting and what is it controlled by?

Answer 9

Fibrinogen into fibrin, which is controlled by enzymes

Question 10

What are the three main types of blood vessel?

Answer 10

Arteries, veins and capillaries

Question 11

Describe an artery and how it works

Answer 11

An artery carries blood away from the heart and into the body’s tissues - meaning it is often bright red and oxygenated. Arteries expand and contract as blood passes through them and have thick walls containing muscle and elastic fibres. They are highly pressurised, and as a result very dangerous if cut

Question 12

Describe a vein and how it works

Answer 12

Veins carry blood away from the organs and back to the heart. They do not have a pulse, their blood is deoxygenated and so often more of a deep red or purple, and they have thinner walls than arteries. Veins also have valves to prevent the back flow of blood through its pathways

Question 13

What are capillaries and what do they do?

Answer 13

Capillaries are a type of blood vessel that are very small have very thin walls. Substances can easily diffuse in and out of them and they cover all of the parts of the body that a large blood vessel such as a vein or an artery could not

Question 14

Humans have a double circulatory system, what does this mean?

Answer 14

We have one transport system that carries blood to and from the heart and muscles, and one that goes to and from the heart and lungs

Question 15

Why is it positive that humans have a double circulatory system?

Answer 15

It makes it very efficient

Question 16

How is the heart itself supplied with oxygen?

Answer 16

The coronary arteries

Question 17

Why and how is the heart separated? (in terms of pumps)

Answer 17

Into two different parts: for the two different sectors of our circulatory system (one pumps to the lungs and back, the other to the body and back)

Question 18

Internally, how is the heart separated?

Answer 18

Into atria and ventricles

Question 19

What are the main blood vessels that bring blood in and out of the heart, and which is which?

Answer 19

The Vena Cava is the main vein that brings deoxygenated blood back to the heart, and the Aorta is the main artery: taking oxygenated blood back out into the muscles and organs of the body

Question 20

What is the main blood vessel that takes deoxygenated blood to the lungs from the heart?

Answer 20

The pulmonary artery

Question 21

What are valves and what are their purpose?

Answer 21

Valves prevent the back flow of blood

Question 22

What happens in coronary heart disease?

Answer 22

The coronary arteries that supply the blood with oxygen get blocked by deposited fats - making them thinner and eventually blocking the oxygen flow to the heart: causing a heart attack

Question 23

What are two ways of solving the problem of coronary heart disease?

Answer 23

A stent / blood thinners (statins) / a bypass /

Question 24

What is a stent and how is it put in place?

Answer 24

A stent is a tiny metal mesh that can be used to open up a blocked or thinned coronary artery. It is inserted with a balloon which is inflated: opening up both the artery and stent at the same time, which then holds the artery open, allowing blood to flow freely through

Question 25

What is a heart bypass and how does it work?

Answer 25

A heart bypass is when a doctor takes an artery from a different part of your body and transfers to the heart, where they use it to ‘bypass’ the blocked artery - allowing blood to flow freely through the diversion, rather than getting blocked up in the original route. This operation can, however, run the risk of death and is very expensive

Question 26

What are two treatments for problematic heart valves?

Answer 26

Replacements taken from pigs and other animals: these work extremely well and do not require any kinds of drugs to work, or mechanical valves made from things such as titanium and polymers that do not wear out, but do require drugs to stop blood clotting around them

Question 27

What problems can a faulty natural pacemaker cause?

Answer 27

If the heart beats too slowly, the person can feel winded and out of breath, but if it beats to fast it won’t pump it around properly

Question 28

What is an artificial pacemaker and how does it work?

Answer 28

An artificial pacemaker replaces the job of your real pacemaker and stimulates the heart with strong electric signals so that it beats regularly and the way it should

Question 29

What is 1 positive and 1 negative of a pacemaker?

Answer 29

They extended your life and help your heart significantly if you were experiencing problems, but you must have regular check ups with the doctor to make sure it is working right

Question 30

What are artificial hearts used for?

Answer 30

Artificial hearts are used for patients who have a heart problem and need a replacement, but have to wait for a correct tissue donor. They can keep people alive until then, but are currently not good enough to warrant a full time solution

Question 31

What problem makes artificial hearts dangerous for full time replacement?

Answer 31

The blood could clot around it: resulting in death

Question 32

Why do we breathe?

Answer 32

Other than to stay alive and supply us with oxygen, it allows the lungs to ventilate and a steep concentration gradient so that diffusion in and out of our lungs can take place quickly

Question 33

What two muscle structures regulate the air moving in and out of your lungs?

Answer 33

The diaphragm and the intercostal muscles (the ones between your ribs)

Question 34

What are alveoli?

Answer 34

Small structures within your lungs that have high concentrations of capillaries: allowing for lots of oxygen and carbon dioxide diffusion to take place

Question 35

Why is the gas exchange in our lungs or effective?

Answer 35

As the blood coming into the lungs is almost always high in carbon dioxide and low in oxygen, resulting in a high concentration gradient to and from the blood and allowing the diffusion exchange to be rapid

Question 36

What is the function of epidermal tissues in plants?

Answer 36

They cover the surfaces of the plants and often secrete a waxy substance that waterproofs them

Question 37

What is the function of the spongy mesophyll layer in plants?

Answer 37

This layer has large surface areas and air pockets for gas exchange to place, as well as a few chloroplasts for photosynthesis (although the gas exchange is its main job)

Question 38

What is the function of the palisade mesophyll layer in plants?

Answer 38

The palisade mesophyll layer is when the majority of a plant’s photosynthesis takes place, with many chloroplasts

Question 39

What does xylem transport?

Answer 39

Water and dissolved mineral ions

Question 40

What does phloem transport?

Answer 40

Dissolved food from the leaves around the plant

Question 41

What are stomata and what are their function?

Answer 41

Stomata are holes that can open or close to allow for gas exchange to take place, and therefore allowing for the disposal of and taking in of oxygen and carbon dioxide for and from photosynthesis

Question 42

What are stomata controlled by?

Answer 42

The guard cells around them

Question 43

Other than oxygen and carbon dioxide, what can be lost when the stomata open?

Answer 43

Water vapour due to diffusion out of the cells surrounding the stomata, in a process called transpiration

Question 44

What is the transpiration stream and why does it take place?

Answer 44

The transpiration stream is a result of water moving up through a plant to replace that that has been lost through transpiration. However, this is then often lost as a result of transpiration: resulting in a constant stream of water moving throughout the plant

Question 45

What are 2 factor that effect the rate of transpiration?

Answer 45

Temperature / Humidity / Light intensity / Amount of air movement

Question 46

Why does any factor that effects photosynthesis effect the rate of transpiration?

Answer 46

As the stomata open and close as a result of the amount of photosynthesis that takes place: i.e. if more photosynthesis takes place = stomata open more = more transpiration

Question 47

Why does wilting take place?

Answer 47

As a defence mechanism to stop the plant from having lots of surface area and therefore too much more evaporation taking place. It will remain like this until the temperature drops, the sun sets, or it rains

Question 48

What piece of equipment is most often used to show the rate of transpiration and the effects of different factors on it?

Answer 48

A potometer