CB8- Exchange And Transport In Animals

Question 1

Metabolism

Answer 1

All the chemical reactions in your body that occur to maintain life

Question 2

Why do organisms exchange substances with their environment?

Answer 2

The body needs vital substances so it will take these in and then get rid of the waste products.

Question 3

What are two examples of exchange in organisms?

Answer 3

1. The kidneys remove urea which is a poison produced by the break down of amino acids.
2. Cells need oxygen for aerobic respiration which then produced carbon dioxide as a waste product.

Question 4

How do substances move in an out of the body?

Answer 4

Diffusion

Question 5

How does the rate of diffusion increase?

Answer 5

1. Large surface area giving the particles more room to diffuse
2. Thin cell membranes create a shorter distance that particles need to diffuse across

Question 6

How does the surface area:volume ratio operate?

Answer 6

• When a cell has a larger surface area:volume ratio the surface area will be larger than the volume meaning that every part of the cell will receive the substance quickly
• if the surface area:volume ratio is small, the volume will be significantly larger than the surface area meaning that the rate of diffusion will take much longer

Question 7

What is exchange like in single-celled organisms?

Answer 7

• Single called organisms have larger surface area:volume ratios, therefore diffusion happens at a much faster rate, and they can solely depend on it for transportation and exchange.

Question 8

What is exchange in multicellular organisms like?

Answer 8

• multicellular organisms have smaller surface area:volume ratios since they are much larger and have more volume compared to surface area.
• this means that they cannot only rely on diffusion because it will not be enough to reach all parts of the cell
• therefore multicellular organisms need specialised exchange surfaces to reach all parts of a cell
• for example the lungs as a whole would have a smaller surface area:volume ratio making transport very difficult, so it has millions of alveoli which increases the overall surface areas while keeping the volume the same

Question 9

What adaptations do specialised exchange surfaces need to have?

Answer 9

1. Large surface areas:volume ratios
2. Thin membranes for fast diffusion
3. Permeable so the substance is able to pass through
4. A diffusion gradient

Question 10

What is the alveolus?

Answer 10

Tiny air sacs that lie on the end of bronchus that are used in gas exchange.

Question 11

How does the alveolus work? (Detailed)

Answer 11

• in the main structure of the alveolus carbon dioxide moves out, while oxygen moves in
• the lining of the alveolus is only one cell thick making diffusion easy for the oxygen within to diffuse out into the surrounding capillaries (also one cell thick lining) and then into the bloodstream where it will reach the red blood cells, then bind to the haemoglobin to create oxyhaemoglobin.
• within the surrounding capillaries, blood will enter with a higher level of carbon dioxide compared to oxygen, but as it travels across the co2 will diffuse into the alveoli where it will be removed as waste. This is because there is a lower concentration of CO2 inside the alveolus compared to the capillaries.
• this makes the travelling blood have a lower co2 concentration before entering the rest of the body.
• by moving along the capillaries are able to maintain a low concentration allowing there to be a concentration gradient for diffusion to occur

Question 12

How is the alveolus adapted for this gas exchange?

Answer 12

• large surface area- with the general shape of the alveolus but also the large amount of alveoli that remains within
• very thin- (one cell thick) creating a short diffusion distance
• moist lining- allows gases to dissolve and then diffuse
• very good blood supply- since there are many capillaries surrounding it
• good ventilation- good supply of air via breathing allowing lots of oxygen to enter

Question 13

What is blood?

Answer 13

Blood is a tissue intended to act as a large transport system all around the body.

Question 14

What is the function of red blood cells and how does it fulfil these functions?

Answer 14

• red blood cells are intended to carry oxygen around all parts of the body reaching necessary body cells
• red blood cells contain haemoglobin which contains iron
• when reaching the lungs haemoglobin binds with oxygen (that has diffused from the alveolus into the capillaries) and forms oxyhemoglobin.
• oxyhemoglobin then travels with the blood eventually reaching body tissues in which the substance will separate back to its original forms oxygen and haemoglobin

Question 15

How are red blood cells adapted for their function?

Answer 15

• large surface areas to maximise the rate of diffusion
• biconcave shape which also enhances the large surface area to absorb oxygen
• no nucleus which maximises volume, allowing for a larger quantity or oxygen to be held
• thin membrane so gases can easily diffuse through
• small, narrow and flexible so they can fit through narrow vessels.

Question 16

What are the function of white blood cells?

Answer 16

• defends against infections and pathogens
• it does this through the immune system which contains things like lymphocytes and phagocytes that undergo phagocytosis

Question 17

How are white blood cells adapted to their functions?

Answer 17

• lymphocytes can produce antibodies against antigens that lie on microorganisms/pathogens
• phagocytes can change shape in order to entrap, engulf and digest a pathogen
• white blood cells will increase in numbers to fight a disease

Question 18

What are blood platelets?

Answer 18

• blood platelets are small fragments of cells with no nucleus
• they help blood to clot at wounds preventing excessive bleeding and pathogens from entering the blood stream

Question 19

What is plasma?

Answer 19

The liquids that carry everything in the blood like red blood cells, white blood cells, platelets, carbon dioxide, urea, glucose, amino acids, hormones and many more.

Question 20

What is the purpose of arteries?

Answer 20

• arteries pump blood away from the heart
• they then divide into capillaries

Question 21

What are some features of arteries making them well adapted to their function?

Answer 21

• artery walls are extremely thick and elastic as they pump blood out of the heart which creates very high pressure (this increase in pressure in the arteries is your ‘pulse’ rather than the actual beating of the heart)
• the walls of arteries are very thick compared to the actual lumen
• very thick layers of muscle to increase strength but also the elastic fibres which continuously stretch and contract in order to make the blood flow more smoothly

Question 22

What is the purpose of capillaries?

Answer 22

• arteries will divide to become capillaries, very fine networks that travel through tissues and between cells
• they are used to transport substances around the body

Question 23

How are capillaries well adapted to their roles?

Answer 23

• super tiny and narrow so they can squeeze in between gaps in cells so they can reach every part of the body
• have thin permeable walls so that substances can diffuse easily and in a shorter time period
• the constant movement within capillaries also maintains a concentration gradient allowing diffusion of substances to occur
• walls of capillaries are one cell thick creating a short diffusion distance.

Question 24

What is the purpose of veins?

Answer 24

• veins take blood back into the heart and are capillaries after they have joined back together

Question 25

How are the veins adapted in order to fulfil their role?

Answer 25

• veins have lower pressure compared to arteries so the walls will not be as thick or strong as it is not withstanding immense pressure
• it has a bigger lumen creating greater blood flow
• contains heart VALVES which help the blood flow in the correct direction
• blood in the veins will also move via basic movements of the skeletons muscles.

Question 26

What is a heart attack?

Answer 26

A heart attack is when blood stops flowing to muscles in some part of the heart causing it to break down and no longer function.

Question 27

What is a double circulatory system like?

Answer 27

• Mammals have double circulatory systems which involve blood pumping around the body in two different circuits
• the first circuit carries deoxygenated blood to the lungs in order to become oxygenated
• in the second circuit the heart pumps oxygenated blood all around the other organs to deliver oxygen to all body cells
• the double circuit is advantageous as it reaches the heart twice, increasing efficiency

Question 28

What are single circulatory systems like?

Answer 28

• single circulatory systems are found within fish and involve only one circuit which carries deoxygenated blood from the heart to the gills where it becomes oxygenated and then to the organs
• not very efficient as the blood uses a lot of pressure to reach the gills and then travels slowly to other organs.

Question 29

Describe the movement within the right side of the heart.

Answer 29

• the body will send deoxygenated blood via the vena cava(a huge vein)
• this will then enter the right atrium where it will continuously fill up until the muscles contract, pushing the blood down the valve and to the right ventricle
• the same process will happen again and the blood which be sent up the pulmonary artery
• the pulmonary artery will send the deoxygenated blood to the lungs to become oxygenated

Question 30

Describe the movement within the left side of the heart.

Answer 30

• the lungs will send oxygenated blood to the pulmonary vein
  -the blood from here will then travel to the left atrium, filling up and then being sent down to the left ventricle
• within the left ventricle the blood will fill up, eventually travelling up the aorta where the oxygenated blood will travel around the rest of the body

Question 31

How does the left chamber of the heart differ to the right chamber?

Answer 31

The left chamber has stronger, thicker muscles as it has to send oxygenated blood all throughout the body and withstand high pressure rather than just travelling to the lungs.

Question 32

What are coronary arteries and where are they located?

Answer 32

• coronary arteries branch out of the aorta and spread out into the heart muscles
• they provide oxygen to the muscle cells of the heart
• this oxygen will then be used for energy to create contractions

Question 33

How do you work out the cardiac output?

Answer 33

Cardiac output= heart rate x stroke volume

Question 34

What is the cardiac output?

Answer 34

The total volume of blood pumped by a ventricle each minute.

Question 35

What is the heart rate?

Answer 35

The number of times the heart beats per minute.

Question 36

What is the stroke volume?

Answer 36

The volume of blood pushed into the aorta each beat.

Question 37

What is respiration?

Answer 37

• Respiration is the release of energy that occurs as a result of the break down of glucose molecules
• it is an exothermic reaction that takes place in the mitochondria

Question 38

What is the energy from respiration used for?

Answer 38

Metabolic processes such as:
- movement of muscles
- maintaining body temperature
- breaking down products eg. The breakdown of protein into amino acids

Question 39

What is aerobic respiration?

Answer 39

• when oxygen is used for respiration
• an efficient way to transfer energy from glucose

Question 40

What is the word equation for aerobic respiration?

Answer 40

Glucose + oxygen -> carbon dioxide + water

Question 41

What is anaerobic respiration? (Animals)

Answer 41

• when oxygen is not present for respiration
• occurs when oxygen is not present and is being used up at a faster rate than it can be replaced
• not efficient as it does not completely break down glucose leading to a smaller transfer in energy
• causes a build up of lactic acids which can cause cramps

Question 42

How does anaerobic respiration occur in plants?

Answer 42

Instead of having a product of lactic acids, it produces ethanol and carbon dioxide instead.

Question 43

How does the body get the reactants for respiration

Answer 43

• through the circulatory system the lungs provide oxygen via breathing that is able to diffuse into the capillaries via the alveolus. This is then in the plasma.
• in the small intestines glucose will be absorbed in the blood stream
• the blood will now have both glucose and oxygen and be able to travel to body cells so that they can respirate.

Question 44

What happens during exercise that triggers anaerobic respiration?

Answer 44

• muscles need more energy so the rate of aerobic respiration increases
• muscles take in more oxygen and glucose from the blood
• heart beats faster in order to get more blood to the muscle cells
• breathing increases in order to increase oxygen diffusion in the lungs
  Through all of this oxygen is used up faster that it can be replaced.

Question 45

Explain the steps for investigating respiration.

Answer 45

1. Get 2 boiling tube with sodalime granules
2. Cover with cotton wool
3. In one tube place living organism and in the second control tube don’t
4. Seal with capillary tube
5. Place both in a water bath to increase the temperatures to respirate
6. Then put coloured liquids into the end of capillary tube
7. Wait five minutes and measure how much it has moved
8. Repeat with different temperatures

Question 46

Why is soda lime used in the investigation?

Answer 46

It absorbs carbon dioxide a product of respiration.

Question 47

Why is cotton wool placed in the test tube?

Answer 47

Soda lime is incredibly corrosive and should not be in contact with the eyes.