Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y1 AQA Biology - Burnley College (2024-25) > Exchange & Transport 3.3. > Flashcards

Exchange & Transport 3.3. Flashcards

1
Q

Digestion and absorption (AO1)

During digestion, large biological molecules are ____________________ to smaller molecules that can be absorbed across cell membranes.

A

hydrolysed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Digestion and absorption (AO1)

Amylase hydrolyses which bonds?

A

Glycosidic bonds
(in starch)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Digestion and absorption (AO1)

Where is amylase produced in the body?

A

Salivary glands

Pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Digestion and absorption (AO1)

Starch is hydrolysed into which disaccharide

A

Maltose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Digestion and absorption (AO1)

Maltase location

A

Membrane-bound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Digestion and absorption (AO1)

Membrane-bound

A

This means the enzyme is located in the cell surface membrane of epithelial cells lining the ileum of the small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Digestion and absorption (AO1)

Disaccharidase examples

A

Maltase
Sucrase
Lactase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Digestion and absorption (AO1)

Disaccharidase location

A

Membrane-bound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Digestion and absorption (AO1)

Describe the complete digestion of starch by a mammal (4 marks).

A

1. Hydrolysis;
2. (Of) glycosidic bonds;
3. (Starch) to maltose by amylase;
4. (Maltose) to glucose by disaccharidase/maltase;
5. Membrane-bound (disaccharidase/maltase);

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Digestion and absorption (AO1)

Process by which glucose and amino acids are absorbed into the blood via the epithelial cells of the small intestine

A

Co-transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Digestion and absorption (AO1)

Role of sodium-potassium
pump in co-transport

A

Actively transports sodium ions out of epithelial cell into the blood

This lowers the concentration of sodium ions inside the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Digestion and absorption (AO1)

TRUE or FALSE

Sodium ions are needed to absorb glucose and amino acids via co-transport

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Digestion and absorption (AO1)

Name of transport protein that allows sodium ions AND glucose OR amino acids into the epithelial cell

A

Co-transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Digestion and absorption (AO1)

TRUE or FALSE:

Sodium ions and glucose bind to the same site on the co-transporter

A

FALSE

(they bind to different sites, each with a specific and complementary shape)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Digestion and absorption (AO1)

Epithelial cells lining the ileum of mammals absorb glucose by co-transport with sodium ions. Explain how (3 marks).

A

1. Sodium ions actively transported from ileum cell into blood;

2. Lowers concentration of sodium ions, so they enter epithelial cells from lumen of small intestine;

(Sodium and glucose bind to co-transporter at different binding sites)

3. Glucose enters cell by facilitated diffusion along with sodium ions

4 This is co-transport;

5. Glucose then leaves epithelial cell and moves into blood via faciliated diffusion;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Digestion and absorption (AO1)

A

1 ATP hydrolysis releases energy;

2. This energy allows ions to be moved against a concentration gradient

OR allows active transport of sodium ions;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Digestion and absorption (AO1)

Epithelial cells contain ______________ to increase surface area for absorption

A

microvilli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Digestion and absorption (AO1)

Describe and explain two features you would expect to find in a cell specialised for absorption (2 marks).

A

1. Folded membrane/microvilli so large surface area for absorption;

2. Large number of co-transport/carrier/channel proteins so fast rate of absorption;

3. Large number of mitochondria so make more ATP by aerobic respiration;

4. Membrane-bound enzymes so maintains concentration gradient (for fast absorption);

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Digestion and absorption (AO1)

Section of small intestine where most absorption takes place

A

ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Digestion and absorption (AO1)

Protease examples

A

Endopeptidase
Exopeptidase
Dipeptidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Digestion and absorption (AO1)

Bond hydrolysed by proteases

A

peptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Digestion and absorption (AO1)

Endopeptidases hydrolyse ____________ peptide bonds within the polypeptide chain

A

internal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Digestion and absorption (AO1)

Exopeptidases hydrolyse the peptide bonds at the ________________ ends of the polypeptide chain

A

terminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Digestion and absorption (AO1)

Products of dipeptidase action

A

x2 amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Digestion and absorption (AO1)

TRUE OR FALSE

Dipeptidases are produced
in the stomach

A

FALSE

(They are membrane-bound enzymes located in the cell surface membrane of the ileum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Digestion and absorption (AO1)

The action of endopeptidases and exopeptidases can increase the rate of protein digestion. Describe how (2 marks).

A

1. Exopeptidases hydrolyse peptide bonds at the terminal ends of a polypeptide AND endopeptidases hydrolyse internal peptide bonds within a polypeptide;

2. This produces more surface area for faster hydrolysis;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Digestion and absorption (AO1)

Endopeptidases and exopeptidases are involved in the hydrolysis of proteins. Name the other type of enzyme required for the complete hydrolysis of proteins to amino acids.

A

Dipeptidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Digestion and absorption (AO1)

Similarities between co-transport of glucose and amino acids

A

Both require sodium ions to be actively transported out of the epithelia cell into blood;

Both require sodium ions to bind to a co-transporter to help faciliate diffusion;

Both glucose and amino acids enter the blood via facilitated diffusion;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Digestion and absorption (AO1)

Differences between co-transport of glucose and amino acids

A

Co-transporter for glucose has a different tertiary structure to co-transporter for amino acid

Channel/carrier protein for glucose has a different tertiary structure to channel/carrier protein for amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Digestion and absorption (AO1)

Describe the mechanism for the absorption of amino acids in the ileum (4 marks).

A

1. Sodium ions actively transported from ileum cell into blood;

2. Lowers concentration of sodium ions, so they enter epithelial cells from lumen of small intestine;

(Sodium and amino acids bind to co-transporter at different binding sites)

3. Amino acids enter cell by facilitated diffusion along with sodium ions

4. This is co-transport;

5. Amino acids then leaves epithelial cell and moves into blood via facilitated diffusion;

Note: these are the same steps as those involved in glucose absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Digestion and absorption (AO2)

A

1. No/less ATP produced OR No active transport;

2. Sodium (ions) not moved (into/out of cell);

3. No diffusion/concentration gradient for sodium (to move into cell with amino acid via co-transport);

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Digestion and absorption (AO1)

Bile contains bile salts, which ____________ fat droplets

A

emulsify

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Digestion and absorption (AO1)

Describe two functions of bile salts

A

1. Emulsify lipids;

2. Increases surface area for
faster lipase activity;

3. Form micelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Digestion and absorption (AO1)

Emulsification increases the ____________ of lipids for faster hydrolysis by lipases

A

surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Digestion and absorption (AO1)

Lipases hydrolyse triglycerides into ____________

A

Glycerol &
3 fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Digestion and absorption (AO1)

Describe the hydrolysis reactions involved in the digestion of triglycerides (2 marks).

A

1. Breaking of ester bonds;

2. By addition of water;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Digestion and absorption (AO1)

Explain the advantages of lipid droplets following emulsification.

A

1. Droplets increase surface areas for lipase action;

2. So faster hydrolysis triglycerides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Digestion and absorption (AO1)

Micelles are made up of……….

A

Bile salts & fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Digestion and absorption (AO1)

Explain the advantage of micelle formation

A

Micelles bring fatty acids to lining of the ileum epithelial cell;

This helps maintain concentration gradient of fatty acids;

Makes fatty acids soluble in water;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Digestion and absorption (AO1)

Describe the role of micelles in the absorption of fats into the cells lining the ileum (3 marks).

A

1. Micelles include bile salts and fatty acids;

2. Make the fatty acids more soluble in water;

3. Bring fatty acids to the lining of the ileum epithelial cells;

4. Maintain high(er) concentration of fatty acids at the lining of the ileum epithelia cells;

5. Fatty acids absorbed by diffusion;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Digestion and absorption (AO1)

Process by which fatty acids enter the ileum epithelial cell

A

Diffusion

42
Q

Digestion and absorption (AO1)

TRUE or FALSE:

Micelles enter the ileum epithelial cell by simple diffusion

A

FALSE

Fatty acids enter by simple diffusion

43
Q

Digestion and absorption (AO1)

Organelle that (re)synthesises triglyceride

A

Smooth endoplasmic reticulum

44
Q

Digestion and absorption (AO1)

Organelle that modifies proteins by combining them with triglycerides

A

Golgi body / apparatus

45
Q

Digestion and absorption (AO1)

Name of modified protein produced after lipid absorption

A

Chylomicron

46
Q

Digestion and absorption (AO1)

Lipids are absorpted directly into the blood OR lymph vessels

A

Lymph vessels

47
Q

Digestion and absorption (AO1)

Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels (5 marks).

A

1. Micelles contain bile salts and fatty acids;

2. Make fatty acids more soluble in water
OR Bring fatty acids to lining of ileum epithelial cells
OR Maintain high concentration of fatty acids at lining of ileum epithelial cells;

3. Fatty acids absorbed by diffusion;

4. Triglycerides (re)formed in smooth endoplasmic reticulum;

5 Chylomicrons produced in Golgi body;

6. Vesicles containing chylomicrons move to cell surface membrane via exocytosis;

48
Q

Surface area to volume ratio (AO1)

As an organism gets ____________, the smaller the surface area : volume ratio.

A

larger

49
Q

Surface area to volume ratio (AO1)

The smaller the organism, the ____________ surface area : volume ratio.

A

larger

50
Q

Surface area to volume ratio (AO1)

Explain the advantage for larger animals of having a specialised system that facilitates oxygen uptake (2 marks).

A

1. Larger organisms have a smaller surface area : volume (ratio);
OR accept converse

2. (Specialed exchange) system provides a shorter diffusion pathway / enables faster diffusion;

51
Q

Surface area to volume ratio (AO2)

In large cells of U. marinum, most mitochondria are found close to the cell-surface membrane. In smaller cells, the mitochondria are distributed evenly throughout the cytoplasm.

Use this information and your knowledge of surface area to volume ratios to suggest an explanation for the position of mitochondria in large U. marinum cells (2 marks).

A

1. Larger cells have smaller surface area to volume ratio;

2. The diffusion distance/pathway is longer;
OR slower diffusion (to mitochondira)
OR
Less/no oxygen diffuses (to mitochondria)

i.e. mitochondria close to the membrane = faster diffusion of oxygen

52
Q

Surface area to volume ratio (AO1)

What adaptations to cells or specialised exchange surfaces enable a FASTER rate of diffusion?

A

1. Large surface area
2. Large concentration gradient
3. Short diffusion distance

53
Q

Surface area to volume ratio (AO1)

For smaller organsisms with a larger surface area : volume ratios, what is the main disadvantage?

A

heat loss

(via the larger surface area)

54
Q

Surface area to volume ratio (AO1)

How do smaller organisms compensate for heat loss?

A

increased metabolic activity
e.g. respiration

55
Q

Surface area to volume ratio (AO1)

By-product of increased respiration that allows smaller organisms to maintain an optimal body temperature

A

heat

56
Q

Surface area to volume ratio (AO2)

Mammals such as a mouse and a horse are able to maintain a constant body temperature.

Use your knowledge of surface area to volume ratio to explain the higher metabolic rate of a mouse compared to a horse.

A

1. Mouse is smaller so larger surface area to volume ratio;

2. Faster heat loss OR lose more heat easily (per gram/in relation to body size);

3. Faster rate of respiration/metabolism releases heat;

57
Q

Surface area to volume ratio (Maths)

How to calculate the
surface area : vol ratio?

A

Divide the surface area by volume

Always present like this “X : 1”

For exampe, if SA = 25cm^2, volume = 5cm^3.

SA : VOL = 25 / 5 = 5 : 1

58
Q

Surface area to volume ratio (Maths)

Calculate SA : VOL ratio

Surface area = 17cm^2

Volume = 34cm^3

A

Working: 17 / 34

Answer: 0.5 : 1

59
Q

Surface area to volume ratio (Maths)

Complete Table 1. State your calculated volume and surface area : volume ratio to 2 significant figures.

A
60
Q

Gas Exchange (AO1)

How does oxygen enter a single-celled organism e.g. amoeba?

A

Simple diffusion
(across the cell-surface membrane)

61
Q

Gas Exchange (AO1)

What adaptations does the single-celled single-celled amoeba have for a faster rate of gas exchange?

A

Large surface area to volume ratio;

Short diffusion distance;

62
Q

Gas Exchange (AO1)

Describe how gas exchange occurs in a single-celled organism and explain why this method cannot be used by large, multicellular organisms?

A

1. Diffusion across the cell surface membrane;

2. Larger organisms have a smaller surface area : volume ratio;

3. Diffusion pathway would be too long OR
Diffusion would be too slow;

63
Q

Gas Exchange (AO2)

Name the process by which oxygen reaches the cells inside the body of a tubifex worm shown below.

A

Simple diffusion

64
Q

Gas Exchange (AO2)

Using the information provided below, explain how two features of the body of the tubifex worm allow efficient gas exchange.

A

1. Thin/small so short diffusion pathway;

2. Flat/small so large surface area to volume ratio

65
Q

Gas Exchange (AO1)

Name of insect gas exchange system

A

the tracheal system

66
Q

Gas Exchange (AO1)

Location of gas exchange in the tracheal system

A

tracheoles

67
Q

Gas Exchange (AO1)

TRUE or FALSE:
Tracheoles supply oxygen direct
into insect tissues

A

TRUE

68
Q

Gas Exchange (AO1)

Name the structure through which gases enter and leave the body of an insect.

A

spiracles

69
Q

Gas Exchange (AO1)

Adaptations of tracheoles for efficient gas exchange

A

1. Highly branched so provide a large surface area for faster rate of diffusion

2. Their walls are thin so there is short diffusion distance;

3. Supply tissues (e.g. muscle fibres) so diffusion is direct into cells

70
Q

Gas Exchange (AO1)

Describe how atmospheric oxygen reaches respiring cells in an insect

A

1. Oxygen enters the insect through spiracles and into the tracheae.

2. Spiracles close

3. Oxygen diffuses (down a conc gradient) through the tracheae into the tracheoles (where gas exchange occurs)

4. Oxygen is delivered directly to respiring tissues

71
Q

Gas Exchange (AO1)

Explain the movement of oxygen into the gas exchange system of an insect when it is at rest
(3 marks).

A

1. Oxygen used in (aerobic) respiration;

2. (so) oxygen (concentration) gradient (established);

3. (so) oxygen diffuses in;

72
Q

Gas Exchange (AO1)

Explain the role of abdominal pumping in insects during gas exchange

A

Movement of the insect body by its muscles;

Increases pressure so forces carbon dioxide out (via
spiracles which open);

Maintains concentration gradient of carbon dioxide and oxygen;

73
Q

Gas Exchange (AO1)

Insects must balance minimising ___________ loss with efficient gas exchange.

A

water

74
Q

Gas Exchange (AO1)

Describe and explain how the insect gas exchange system limits water loss (2 marks).

A

1. Exoskeleton is impermeable to water so reduces water loss.

2. Spiracles close to prevent water loss

3. Small hairs around the spiracles

75
Q

Gas Exchange (AO1)

Describe and explain how the structure of the insect gas exchange system provides cells with sufficient oxygen (4 marks).

A

1. Spiracles, tracheae, tracheoles;

2. Spiracles allow diffusion (of oxygen)

OR (Oxygen) diffusion through tracheae/tracheoles;

3. Tracheoles are highly branched so large surface area for exchange;

4. Tracheole walls thin so short diffusion distance (to cells)

5. Tracheole walls are permeable to oxygen/air;

76
Q

Gas Exchange (AO1)

A

F = Filament

G = Lamella(e)

77
Q

Gas Exchange (AO1)

Gills have many finger-like projections called gill ____________.

A

filaments

78
Q

Gas Exchange (AO1)

Each gill filament has many _____________

A

lamellae

(singular lamella)

79
Q

Gas Exchange (AO1)

Lamellae contain ____________ and are the site of gas exchange.

A

capillaries

80
Q

Gas Exchange (AO1)

The capillaries bring ___________ blood to the lamellae.

A

deoxygenated

81
Q

Gas Exchange (AO1)

Site of gas exchange in fish gills

A

lamellae

(singular lamella)

82
Q

Gas Exchange (AO1)

Explain two ways in which the structure of fish gills is adapted for efficient gas exchange.

A

many gill filaments/lamellae provide a large surface area;

lamellae have a thin epithelium for short diffusion distance (between water and blood)

83
Q

Gas Exchange (AO1)

Describe and explain the counter current mechanism in fish gills.

A

1. Water and blood flow in opposite directions;

2. Maintains diffusion/concentration gradient of oxygen

3. Diffusion along length of lamellae / filament / capillary;

84
Q

Gas Exchange (AO2)

A

(Difference)
1. More cells (between water and capillary/ blood)
OR Wider/thicker lamella/filament/epithelieum;

(Explanation)
2. Longer diffusion pathway/distance

  1. (So) slower gas exchange
    OR (So) slower absorption of oxygen
    OR (So) slower rate of diffusion;
85
Q

Gas Exchange (AO1)

Draw and label a cross section
of leaf tissue

A
86
Q

Gas Exchange (AO1)

Why is the concentration of carbox dioxide low in the palisade mesophyll cell?

A

Used in photosynthesis

87
Q

Gas Exchange (AO1)

Through which structures does carbon dioxide enter the leaf.

A

stomata

(Singular stoma)

88
Q

Gas Exchange (AO1)

What cells open and close the stomata?

A

guard cells

89
Q

Gas Exchange (AO1)

Describe how carbon dioxide in the air outside a leaf reaches mesophyll cells inside the leaf (3 marks).

A

1. Carbon dioxide enters via stomata;

2. (Stomata opened by) guard cells;

3. Diffuses through air spaces (in the spongy mesophyll layer);

4. Down diffusion/concentration gradient;

90
Q

Gas Exchange (AO1)

Describe and explain how the leaf is adapted for efficient gas exchange.

A

1. They are flat so have larger surface area to volume ratio

2. Contain many stomata which allow air to move in and out of the leaf

3. Air spaces in the spongy mesophyll so short distance pathway
(between air spaces the palisade mesophyll cells)

91
Q

Gas Exchange (AO1)

TRUE or FALSE:

Water is lost from the leaf via the stomata due to transpiration

A

TRUE

92
Q

Gas Exchange (AO1)

How do plants minimise water loss?

A

At night, the guard cells close the stomata so less transpiration;

Upper & lower surfaces have a waxy cuticle which increases diffusion distance / impermeable to water;

93
Q

Gas Exchange (AO1)

Group of plants adapted to live in dry conditions

A

Xerophytes

94
Q

Gas Exchange (AO1)

List the adaptations of xerophytes to dry conditions

A

Small leaves
Spines
Rolled leaves
Stomata in pits
Hairs
Thick waxy cuticle

95
Q

Gas Exchange (AO1)

How does a small leaf reduce water loss in xerophytes?

A

Smaller surface area so reduced number of stomata

96
Q

Gas Exchange (AO1)

How does a thick waxy cuticle reduce water loss in xerophytes?

A

Increased diffusion distance so reduces transpiration

97
Q

Gas Exchange (AO1)

How do spines reduce water loss in xerophytes?

A

Reduces the surface area : volume ratio

98
Q

Gas Exchange (AO1)

What features of a xerophyte reduce the water potential gradient by trapping water vapour?

A

Hairs;
Stomata in pits;
Rolled leaves;

99
Q

Gas Exchange (AO2)

A

Species B (no mark)
1. Smaller surface area so less evaporation ;

2. Thicker leaves so greater diffusion distance (for water);

3. Fewer stomata so less diffusion / evaporation (of water);

4. Smaller surface area to volume ratio so less evaporation.

100
Q

Gas Exchange (AO2)

Use your knowledge of gas exchange in leaves to explain why plants grown in soil with very little water grow only slowly (2 marks).

A

1. Stomata close (to reduce water loss);

2. Less carbon dioxide (uptake) for less photosynthesis;

Y1 AQA Biology - Burnley College (2024-25) (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions