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Biology > Topic 3 - Transport systems > Flashcards

Topic 3 - Transport systems Flashcards

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1
Q

What’s the definition of digestion ?

Digestion and Absorption

A

Larger biological molecules are broken down into smaller molecules which can move across cell membranes and be absorbed from the gut into the bloodstream to body cells

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2
Q

How are carbohydrates broken down ?

Digestion and Absorption

A

Amylase hydrolyses startch into maltose during a hydrolysis recation by adding a water molecule, breaking the glyocosodoc bonds.
Membrane bound disachharidases hydrolyse maltose into glucose during a hydrolysis reaction which adds water to break the glycosidic bonds.

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3
Q

Where is amylase produced?

Digestion and Absorption

A

salivary glands (secreted into the mouth)
pancreas (secreted into the small intestine)

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4
Q

Where are membrane bound disacharidases found ?

Digestion and Absorption

A

the epithelial cells of the ileum

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5
Q

How are lipids broken down ?

Digestion and Absorption

A

lipase enzyme hydrolyses the ester bonds by the addition of a water molecule in a hydrolysis reaction between lipids to form monoglycerides and fatty acids.

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6
Q

Where are lipases produced and found ?

Digestion and Absorption

A

produced in the pancreas
found in the small intestine

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7
Q

Where are bile salts produced and stored ?

Digestion and Absorption

A

produced in the liver and stored in the gall bladder

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8
Q

How are micelles formed ?

Digestion and Absorption

A

once the lipid is brown down, the monoglycerided and fatty acids stick with the bile salts to form micelles.
Monoglycerides and fatty acids are not very soluble, so micelles aid the transport of these substances to the cell surface membrane.

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9
Q

What are the two main peptidases ?

Digestion and Absorption

A

endopeptidases
exopeptidases

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10
Q

What is the role of endopeptidases ?

Digestion and Absorption

A

They hydrolyse the peptide bonds within a protein to form smaller proteins.

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11
Q

What is the role of exopeptidases ?

Digestion and Absorption

A

They hydrolyse the peptide bonds at the end of the protein molecules. To inccrease the surface area for Dipeptidades.

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12
Q

What is the role of dipeptidases ?

Digestion and Absorption

A

Dipeptidades hydrolyse the peptide bond between 2 amino acids (dipeptide), they’re often located in the cell surface membranes of the epithelial cells of the small intestine.

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13
Q

How are monosaccharides absorbed ?

Digestion and Absorption

A
  1. Sodium ions are actively transported out of the ileum epithelial cells into the blood by the sodium potassium pump, this creates a concentration gradient as there’s a high concentration of sodium ions in the lumen compared to the epithelial cells.
  2. Sodium ions diffuse from the lumen into the epithelial cells down their concentration gradient via the co transporters
  3. The co transporters bonded to glucose/galactose and sodium, meaning that glucose molecule is carried into the cell causing the concentration of glucose in the epithelial cells to increase.
  4. glucose diffuses out of the cells into the blood stream down it’s concentration gradient in a protein channel by facilitated diffusion.

Fructose is absorbed via facilitated diffusion

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14
Q

How are amino acids absorbed ?

Digestion and Absorption

A
  1. Sodium ions are actively transported out of the ileum epithelial cells into the blood by the sodium potassium pump, this creates a concentration gradient as there’s a high concentration of sodium ions in the lumen compared to the epithelial cells.
  2. Sodium ions diffuse from the lumen into the epithelial cells down their concentration gradient via the co transporters
  3. The co transporters bonded to amino acids and sodium, meaning that amino acid molecule is carried into the cell causing the concentration of amino acid in the epithelial cells to increase.
  4. amino acids diffuses out of the cells into the blood stream down it’s concentration gradient by facilitated diffusion.
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15
Q

how are monoglycerides and fatty acids absorbed ?

Digestion and Absorption

A

micelles help move them into the epithelial cells where they’re transported to the ER and the golgi apparatus to be recombined and form triglycerides.
Triglycerides combine with cholesterol and lipoproteins to form chilomicrons.
chilomicrons move out of the cell by exocytosis and enter the lacteals of the villi.

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16
Q

What does blood transport ?

The Cardiac Cycle

A

Respiratory gases
products of digestion
metabolic waste
hormones

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17
Q

What is the function of the coronary arteries ?

The Cardiac Cycle

A

They supply the heart muscle with oxygenated blood and glucose

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18
Q

What is the pericardium ?

The Cardiac Cycle

A

It encloses the heart to protect it from over expansion and infection

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19
Q

What’s the pulmonary circuit ?

The Cardiac Cycle

A

Blood is pumped to the lungs to pick up oxygen

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20
Q

What is the systemic circuit ?

The Cardiac Cycle

A

oxygenated blood is pumped around the body

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21
Q

What are the walls of the heart made out of ?

The Cardiac Cycle

A

Cardiac muscle with doesn’t tire however it requires oxygen

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22
Q

What is systole ?

The Cardiac Cycle

A

contraction of heart muscles

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23
Q

What is diastole ?

The Cardiac Cycle

A

Relaxation of the heart muscles

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24
Q

Why do the ventricles have thicker muscles than the atria ?

The Cardiac Cycle

A

They pump blood across longer distances so the contraction needs to be stronger

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25
Q

What are the bicuspid and tricuspid valves ?

The Cardiac Cycle

A

They link the atria to the ventricles.
They close when there’s a higher pressure in the ventricles than the atria to prevent the backflow of blood from the ventricles into the atria.
They open when there’s a larger pressure in the atria than the ventricles to allow blood to flow through to the ventricles

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26
Q

What are the semi-lunar valves ?

The Cardiac Cycle

A

They are valves between the ventricles and the aorta and pulmonary artery.
They close when there’s a higher pressure in the atria than the ventricles to prevent the backflow of blood into the ventricles from the aorta and pulmonary artery
They open when there’s a higher pressure in the ventricles than the atria to allow blood to flow through the aorta and the pulmonary artery

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27
Q

What are the function of cords in relation to the heart ?

The Cardiac Cycle

A

They connect the atrioventricular valves to the ventricles to stop them from being forced into the atria during contraction

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28
Q

What are the 3 steps of the cardiac cycle ?

The Cardiac Cycle

A

atrial systole
ventricular systole
diastole

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29
Q

Explain what happens during atrial systole

The Cardiac Cycle

A

The muscles of the atria contract and the ventricles relax.
This decreases volume and increases pressure of the atria. This causes the bicuspid and tricuspid valves to open to allow blood to flow through to the ventricles. The semi-lunar valves close to prevent the back flow of blood from the aorta and pulmonary artery to the ventricles. Pressure decreases

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30
Q

What happens during ventricular systole ?

The Cardiac Cycle

A

The muscles of the ventricles contract and the atrial muscles relax. This decreases the volume and increases the pressure of the ventricles. This causes the bicuspid and tricuspid valves to close to prevent the back flow of blood from the ventricles to the atria. The semi-lunar valves open to allow blood to flow through the pulmonary artery and aorta

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31
Q

What happens during diastole ?

The Cardiac Cycle

A

the ventricles and atria both relax. The high pressure in the aorta and pulmonary artery causes the semi lunar valves to close to prevent the backflow of blood from the arteries to the ventricles. Blood flows to the body and lungs. Blood starts to flow through the vena cava and pulmonary vein.

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32
Q

What is the function of the arteries ?

The Cardiac Cycle

A

They transport blood to the rest of the body

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33
Q

Explain the structure of the arteries

The Cardiac Cycle

A

They have thick muscular walls and have elastic tissue to allow for stretching at contraction and recoil at relaxation. This helps to maintain the high pressure.
The inner lining (endothelium) is folded allowing the artery to stretch to help maintain the high pressure. It is also smooth to be streamlined for blood flow. They have smaller lumen then veins.

34
Q

What are arterioles ?

The Cardiac Cycle

A

Arteries divide into smaller vessels called arterioles. They form a network across the body. They provide demanding cells with blood by the smooth muscle contracting to cause constriction, which restricts blood flow and decreases the diameter of the lumen. Or the smooth muscle relaxes to allow dilation, full blood flow, which increases the diameter of the lumen.

35
Q

What is the function and structure of veins ?

The Cardiac Cycle

A

Veins carry blood back to the heart at a lower pressure. They have a larger lumen. They have little muscular or elastic tissue. Veins contain valves to stop the backflow of blood. The blood flow is helped by the contraction of body muscles surrounding them.

36
Q

What is the function of capillaries ?

The Cardiac Cycle

A

Arterioles branch into capillaries.
They exchange substances such as glucose and oxygen with cells.
They have no elastic or muscular tissue. They have a small lumen which is the width of one blood cell.

37
Q

How are capillaries adapted for efficient exchange ?

The Cardiac Cycle

A

They’re always close to cells in exchange tissues to decrease the diffusion pathway.
Their walls are one cell thick to decrease the diffusion pathway.
There are a large number of capillaries to increase surface area for exchange.

38
Q

Why can veins be described as organs ?

The Cardiac Cycle

A

They’re made of different tissues.

39
Q

Explain how tissue fluid is made.

Tissue Fluid

A

At the arteriole end of the capillary there is a high hydrostatic pressure which is bigger than the osmotic effect, it causes small molecules like water to move out of the vessel to from tissue fluid.
As there is less volume of water in the capillary, at the venule end of the vessel there is a lower hydrostatic pressure.
As plasma proteins remain in the plasma, there is a low water potential causing some fluid to move back into the vessel by osmosis.
The remaining tissue fluid is drained into the lymphatic system which transports it to the circulatory system.

40
Q

What type of proteins are Red Blood cells ?

Haemoglobin

A

Globular proteins.

41
Q

Describe the structure of haemoglobin .

Haemoglobin

A

It has a quaternary structure due to its 4 polypeptide chains. Each chain has a haem group which contains 1 iron ion and gives haemoglobin its red colour. Each iron ion binds to a oxygen molecule.

42
Q

What does partial pressure of oxygen/carbon dioxide mean ?

Haemoglobin

A

the pressure it exerts in a mixture of gases

43
Q

Describe the process of haemoglobin loading oxygen.

Haemoglobin

A

At the lungs, there is high partial pressure of oxygen, causing haemoglobin to have high affinity for oxygen, so oxygen loads onto haemoglobin to form oxyhaemoglobin
At respiring tissues, there is low partial pressure of oxygen, causing haemoglobin to have low affinity to oxygen, so oxyhaemoglobin unloads to form haemoglobin.

44
Q

When is there a high saturation of oxygen with haemoglobin ?

Haemoglobin

A

When partial pressure of oxygen is high, haemoglobin has a high affinity for oxygen, so oxygen loads to it. As a result, haemoglobin has a high saturation of oxygen.
It is the opposite for low saturation.

45
Q

What does the dissociation curve show in relation to haemoglobin ?

Haemoglobin

A

It shows the saturation of oxygen in haemoglobin at any partial pressure given.

46
Q

Why is the dissociation curve an S-shape ?

Haemoglobin

A

When haemoglobin combines to the first oxygen molecule it is more difficult. But afterwards, its shape alters, making it easier for other oxygen molecules to combine (it turns into Fe3+). But as haemoglobin becomes saturated it gets harder for more oxygen molecules to combine. The shallow parts at the beginning and end show where it is harder, when the curve is steeper, that’s where it is easiest for oxygen to load to haemoglobin.

47
Q

What is the Bohr effect ?

Haemoglobin

A

When cells respire they produce carbon dioxide which increases the partial pressure of CO2.
This increases the rate of oxygen unloading (oxyhaemoglobin dissociates into haemoglobin).
So the dissociation curve shifts to the right.
The saturation of haemoglobin with oxygen is lower at a given partial pressure of oxygen, meaning more oxygen is being released.

48
Q

What adaptation do organisms that live in environments with low concentration of oxygen ?

Haemoglobin

A

They have haemoglobin with high oxygen affinity.
The dissociation curve is shifted left.

49
Q

What adaptation do organisms that are very active have ?

Haemoglobin

A

They have haemolgobin with a lower oxygen affinity.

50
Q

How do atheromas form and what do they cause ?

Cardiac Disease

A

If damage occurs to the smooth lining of the artery, white blood cells and lipids from the bloodstream clump together under the lining forming fatty streaks. Over time, more white blood cells, lipids and connective tissues build up and harden forming fibrous plaque called atheroma. This plaque partially blocks the lumen of the artery and restricts blood flow, causing pressure to increase.

51
Q

What is coronary heart disease ?

Cardiac Disease

A

The coronary arteries have lots of atheromas, which restricts blood flow to the heart muscle and can cause myocardial infraction.

52
Q

What is the scientific term for a heart attack ?

Cardiac Disease

A

Myocardial infarction

53
Q

How does myocardial Infarction affect the heart ?

Cardiac Disease

A

It can cause damage and death of the heart muscle.
If large areas of the heart are affected, complete heart failure can occur which is often fatal.

54
Q

What are symptoms of myocardial infarction ?

Cardiac Disease

A

Chest and upper body pain
shortness of breath
sweating

55
Q

Why can high blood cholesterol levels increase the risk of CVD ?

Cardiac Disease

A

Cholesterol is one of the main components of the fatty deposits that form atheromas, which lead to coronary heart disease and also myocardial infarction.

56
Q

What 3 things in a poor diet can increase the risk of CVD?

Cardiac Disease

A

High cholesterol levels - one of the main components of the fatty deposits that form atheromas.
High in saturated fats - associated with high blood cholesterol levels.
High in salt - increases blood pressure.

57
Q

What are risk factors to high blood pressure (causing CVD) ?

Cardiac Disease

A

Overweight
excessive alcohol consumption
not exercising

58
Q

What causes pH to reduce from 7.4 to 7.2 in tissues ?

Haemoglobin

A

Respiring tissues produce carbon dioxide.
This CO2 dissolves in the blood forming carbonic acid which dissociates,leaving H+ ions abd lowering the pH.

59
Q

For a fetus, the oxygen dissociation curve is to the left of the mothers, how is this an advantage for the foetus ?

Haemoglobin

A

Haemoglobin has a higher affinity for oxygen so it can load more readily at a lower partial pressure. Oyxgen moves from the mother to the fetus.

60
Q

What is the function of the Xylem ?

Xylem

A

Xylem tissue transport waster and mineral ions in a solution from the roots of the plants to the leaves.

61
Q

Describe the structure of Xylem

Xylem

A

Xylem consist of xylem vessels which are long tube like structurees which are formed from dead cells joined end to end. There are no end walls, allowing for water and mineral ions to pass through the middle easily. The walls of the cells are made of lignin which is waterproof, however pits are formed where there is no lignin, this allows water to move from one vessel to an adjacent vessel.

62
Q

What is transpiration ?

Xylem

A

Loss of water from a plant’s surface

63
Q

What is a transpiration stream ?

Xylem

A

The movement of water from the roots of the plant to the leaves where it evapourates.

64
Q

How does a transpiration stream work ?

Xylem

A

Water evaporates from the stomata when they open , it moves down the concentration gradient by diffusion. This creates tension, pulling more water up to the leaves. Water molecules are cohesive meaning the column of water in the xylem moves upwards from the roots, enters the stems and up to the leaves where it will diffuse out of. Trunk diameter decreases.

65
Q

What 4 things affect transpiration rate ?

Xylem

A

Wind
Light
Humidity
Temperature

66
Q

How does light affect transpiration rate ?

Xylem

A

The lighter it is, the faster the transpiration rate, this is because the stonata open when it gets light to let in carbon dioxide for photosynthesis - allowing for water to diffuse down its concentration gradient into the atmoshphere and evapourate . When its dark, stomata close so theres little transpiration.

67
Q

How does temperature affect transpiration rate ?

Xylem

A

as temperature increases, water molecules are given more kinetic energy , so they diffuse out of cells faster, this creates a large concntration gradient causing water to difffuse out of the stomata faster, increasing transpiration rate.

68
Q

How does humidity affect transpiration rate ?

Xylem

A

The lower the humidity, the faster the transpiration rate because dry air around the leaf increases the concentration gradient between the leaf and the atmosphere, this increases the transpiration rate.

69
Q

How does wind affect transpiration rate ?

Xylem

A

The windier it is, the faster the transpirationrate because lots of air movement blows away water molecules from the stomata, increasing the concentration gradient and therfore, the rate of transpiration.

70
Q

What does a potometer measure ?

Xylem

A

The water uptake of a plant, but it assumes that water uptake is directly linked to water loss (transpiration rate)

71
Q

How would you use a potometer ?

Xylem

A
  1. Cut a shoot underwater to prevent air bubbles from entering the xylem. Cut it diagonally to increase the surface area.
    2.Assemble the potometer underwater and insert the shoot underwater so that no air can enter.
    3.Remove tha apparatus from the water but keep the end of the capillary tube submerged in water. Check tha apparatus is water tight and air tight.
    4.Dry the leaves, allow time for the shoot to acclimatise and then shut the tap.
    5.Remove the end of the capillary tube from the beaker of water until one air bubble has forme, then re submerge it in the beaker.
    6.Record the starting postion of the air bubble, start a stop eatch and record the distance of the bubble every hour for 6 hours. The rate of the air bubble movement is an estimate of the transpiration rate.
72
Q

What is the function of translocation ?

Phloem

A

The movement of solutes (amino acids and sucrose) from sources to sinks in a plant.

73
Q

What is a source ?

Phloem

A

Where the solute are loaded onto the phloem ( high concentration), for example the leaf.

74
Q

What is a sink ?

Phloem

A

Where solutes are removed from the phloem (Low concentration), for example roots.

75
Q

How is the concentration gradient of solutes between sources and sinks maintained ?

Phloem

A

Enzymes chnage the solutes at the sink by breaking them down or building them into something else. For example in potatos enzymes convert sucrose into stratch at the sinks, this maintains a low concentration of sucrose so that it can continue to move down the concentration gradient from the source to the sink.

76
Q

Explain mass flow theory

Phloem

A

Active transport is used to actively load the solutes from the companion cells into seive tubes o the phloem at the source, e.g. the leaf.

This lowers the water potential of the seive tubes so water moves in by osmosis from the xylem and companion cells.

This causes a high pressure in the sieve tubes at the source of the phloem.

At the sink end solutes are removed to be used up.

This increases the water potential causing water to move out of the cells by osmisis.

This creates a lower pressure at the seive tubes in the sink end of the phloem.

This results in a prssure gradient from the source end to the sink end.

This gradient causes a movement of solutes from the high pressure in the sources to the low pressure at the sinks.

When the solutes reach the sink, they can be used up (respiration) or stored (starch).

77
Q

How is the rate of translocation Increased ?

Phloem

A

The higher the concentration of solutes at the source, the higher the rate of translocation.

78
Q

Explain why the mass flow theory is supported

Phloem

A

If a ring of bark is removed from a tree brank, a large bludge is formed above it. This buldge has a high concentration of sugars compared to the smaller buldge below the ring. This proves that there is a downward movement of sugars.
C14 radioactive isotope can be used to track the movement of organic substances in a plant
Pressure in the phloem can be investiagated using aphins. Sap flows out quicker towards the top of the branch compared to the bottom. This porves that there is a pressure gradient from the sources to the sinks.
If a metabolic inhibitor is added, transloaction stops. This shows that it requires active transport.

79
Q

Explain why the mass flow theory is rejected

Phloem

A

Sugar travels to more than one sink, not just the one with the highest water potential.
Sieve plated will act as a barrier to solutes. High pressure and speed would be needed to over come this barrier.

80
Q

Explain how you would show mass flow theory by using a radioactive isotope.

Phloem

A

surround a plant in a container and pump the 14C radioactive isotope into the conatainer
The carbon will be incorperated into the plants organic subatsnces produced (photosynthesis sugars) and transported by translocation.
Movement of the organic substances can be tracked by tracking 14C using an autoradiograph. The plant is placed on photographic film and if there is 14C present, the film will turn black.
This demonstrates the movement of solutes from sources in the leaves to sinks towards the roots.

81
Q

Why is it a bad assumption that water uptake is equivalent to the rate of transpiration ?

Xylem

A

some water will be used to keep cells turgid, for photosynthesis and other chemical reaction.
some water will be created from aerobic respiration.

82
Q

how would you workout the heart rate of something ?

A

The time taken for one cycle (peak to peak).
60 divided by the cycle time.

Biology (14 decks)

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