Transport

Question 1

Why can unicellular organisms rely on diffusion for the movement of substances in and out of their cells?

Answer 1

-because they have a high SA : V ratio and therefore can obtain all the substances they need as the volume of the organism determines the number of substances that need to be taken in

Question 2

Why do lungs have a large surface area?

Answer 2

-to allow maximum diffusion of oxygen into your blood, and carbon dioxide into the air

Question 3

What is the small intestine adapted for?

Answer 3

• for exchanging nutrients between digested food in the small intestine and the blood

Question 4

What are the 4 specialised exchange surfaces?

Answer 4

• small intestine
• lungs
• root
• leaves

Question 5

What is the role of the xylem?

Answer 5

• transports water and minerals from the soil after being absorbed by the root hair cell
• Water molecules in the xylem stick together, drawing water up the stem
• Once it reaches the leaves, the majority of water evaporates and the water vapour diffuses out through open stomata

Question 6

Why do plants need water?

Answer 6

• for photosynthesis
• for support
• to transport materials

Question 7

How are xylem cells adapted to take up water?

Answer 7

• they are made up of a series of connected dead xylem cells.
• The end walls of the dead cells are broken to allow water to move through.

Question 8

What is translocation?

Answer 8

• the process by which food produced in photosynthesis is transported from the leaves to the growing regions of plants and storage organs via the phloem
• a bidirectional movement (up and down phloem)

Question 9

How is the phloem adapted to transport sucrose and amino acids?

Answer 9

-made up of columns of elongated cells that have holes in the end walls.
These holes allow cell sap (contains sucrose and amino acids) to pass between the cells.

Question 10

What strengthens the cell walls of xylem cells?

Answer 10

-lignin

Question 11

How does plasma transport CO2?

Answer 11

• Carbon dioxide is a waste product made by cells in respiration.
• It is dissolved in the plasma, and transported to the lungs where it is breathed out

Question 12

How does plasma transport heat energy?

Answer 12

• Because plasma is a liquid, it can easily carry heat energy around the body.
• When we are too hot or too cold, our blood flow changes to increase or decrease the amount of heat energy we lose from our bodies

Question 13

How does plasma transport hormones?

Answer 13

-Hormones such as insulin and sex hormones are transported around the body dissolved in the plasma

Question 14

How does plasma transport urea?

Answer 14

-Urea is dissolved in the blood plasma, and then passes out of the body in urine

Question 15

What is urea?

Answer 15

-a substance made in the liver from excess protein

Question 16

How does plasma transport digested food?

Answer 16

• absorbed into the blood from the small intestine.

- They are transported, dissolved in the plasma, to the parts of the body where they are needed

Question 17

What is another name for red blood cells?

Answer 17

-erythrocytes

Question 18

How are red blood cells adapted?

Answer 18

-small size so they can pass through the capillaries
-biconcave shape creates a large surface area and allows for the rapid diffusion of oxygen
-no nucleus which allows more room for haemoglobin which maximises the amount of oxygen they can carry
-

Question 19

How does the antibody lock on to the antigen?

Answer 19

-has a complementary shape and causes the antigens to cluster so the phagocytes can ingest them

Question 20

What are the 3 types of blood vessels?

Answer 20

-veins, arteries, capillaries

Question 21

What is the function of an artery?

Answer 21

-transport blood away from the heart to the organs. They all carry oxygenated (contains oxygen) blood (apart from the pulmonary artery). Their structure is adapted to perform their function in the body

Question 22

What are the adaptations of arteries?

Answer 22

• he walls have elastic fibres, allowing them to stretch and spring back
• Artery walls have thick layers of muscle. This makes them strong and able to cope with the high pressure at which blood is pumped out by the heart

Question 23

What is the function of a vein?

Answer 23

• form when capillaries join up after passing through the body.
• They transport deoxygenated (contains no oxygen) blood (apart from the pulmonary vein) from the organs back to the heart

Question 24

What are the adaptations of veins?

Answer 24

• thinner walls than the artery as the blood is lower pressure
• wider cross section than arteries- Low pressure hinders blood flow. This means that veins have a wider cross section through which blood can flow to counteract this
• have valves to prevent the backflow of blood

Question 25

What are capillaries?

Answer 25

-Arteries branch into much smaller vessels, called capillaries. Capillaries have thin walls and pass very close to the body cells

Question 26

What are the functions of a capillary?

Answer 26

- waste products, such as carbon dioxide, move out of the cells and into the blood - exchange of materials between blood and tissue cells

Question 27

What are the steps of the heart pumping?

Answer 27

- Blood enters the heart via the atria. - Once filled with blood, the atria contract, forcing blood down into the ventricles below - When the ventricles contract, they force blood to exit the heart

Question 28

Why might someone be fitted with an artificial pacemaker?

Answer 28

- A group of cells in the right atrium act as a pacemaker to control the heart's beating. - Irregular heart rates can be corrected using electrical devices, known as artificial pacemakers

Question 29

Why is the left ventricle thicker than the right ventricle?

Answer 29

- The left ventricle wall is much thicker than the right because it has to force blood out of the heart at a higher pressure, because the blood has to travel further (around the whole body). - The right ventricle only has to pump blood to the lungs

Question 30

Why does the heart pump faster during exercise?

Answer 30

-Muscle cells use up more energy (released in respiration) during exercise, so they need to respire at a faster rate. The heart pumps faster to circulate oxygenated blood to muscle tissues

Question 31

How does the heart rate change under the influence of adrenaline?

Answer 31

-adrenaline is a hormone that triggers the so-called ‘fight or flight’ response, preparing the body to move and think quickly in response to danger. -Adrenaline increases heart rate and blood pressure. This means that there is an increase in blood flow around the body, specifically to the muscle cells

Question 32

What is coronary heart disease?

Answer 32

-when the coronary arteries become more narrow because of a build-up of fatty deposits. This reduces blood flow and leads to a lack of oxygen being supplied to the heart muscle

Question 33

Which factors increase the risk of coronary heart disease?

Answer 33

-overweight, smoking, a diet high in saturated fats, lack of exercise

Question 34

What is the double circulatory system?

Answer 34

-blood vessels, blood and the heart

Question 35

Describe the double circulatory system.

Answer 35

- Deoxygenated blood from the body enters into the right atrium of the heart - This deoxygenated blood is pumped out of the heart and towards the lungs by the right ventricle - At the lungs, the deoxygenated blood exchanges carbon dioxide for oxygen. This is how it becomes oxygenated - Oxygenated blood returns to the left atrium of the heart - This oxygenated blood is pumped out of the heart and to the body by the left ventricle - The oxygenated blood gives its oxygen to body cells in exchange for carbon dioxide. - The blood becomes deoxygenated and returns to the heart

Question 36

What is the role of the vena cava?

Answer 36

-the heart receives deoxygenated blood from the body through it

Question 37

What is the role of the pulmonary vein?

Answer 37

-The heart receives oxygenated blood from the lungs through it

Question 38

What is the role of the aorta?

Answer 38

-The heart pumps out oxygenated blood to the body through the aorta

Question 39

What is the role of the pulmonary artery?

Answer 39

-The heart pumps out deoxygenated blood to the lungs through the pulmonary artery

Question 40

What are the coronary arteries?

Answer 40

-they supply the heart muscle with oxygenated blood

Question 41

What is the hepatic artery?

Answer 41

- Supplies oxygenated blood to the liver | - Takes deoxygenated blood away from the liver, back to the heart

Question 42

What is the renal vein?

Answer 42

-Filtered blood leaves the kidneys through the renal vein

Question 43

What is the hepatic portal vein?

Answer 43

-Brings nutrient-rich blood from the gut to the liver

Question 44

What is the renal artery?

Answer 44

-Blood arrives at the kidneys to be filtered through the renal artery