Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biology > Topic 3-organisms exchange substances with their environment > Flashcards

Topic 3-organisms exchange substances with their environment Flashcards

1
Q

why do multicellular organisms require specialised exchange surfaces

A

Longer diffusion pathway as there is lower SA:V

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

What are some features that make an efficient exchange surface?

A

large surface area and thin to ensure a short diffusion pathway (e.g. a leaf), good blood supply or ventilation for a steep gradient for exchange

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

how many pairs of gills does a bony fish have?

A

4 pairs

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

Describe the structure of a fish gas exchange system

A

4 pairs of gills, each is supported by an arch with gill filaments (long strands), which have lamallae on them. Blood and water (from ext. environment) flow across the lamallae in countercurrent directions (opposite directions). this allows gas exchange between the blood and water, creating a steep concentration gradient. the filaments are held apart by water, so in the absence of water they stick together and fish cant survive without oxygen.

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

Explain how the counter current mechanism in fish gills ensures the
maximum amount of the oxygen passes into the blood flowing through the
gills (3)

A
  1. Water and blood flow in opposite directions
  2. Blood is always passing the water
    which has a higher oxygen concentration
  3. Diffusion gradient is maintained throughout length of gill
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe and explain the advantage of the counter-current principle in gas
exchange across a fish gill. (3)

A
  1. Water and blood flow in opposite directions.
  2. Maintains diffusion concentrations of oxygen throughout length of gill
    3.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain two ways in which the structure of fish gills is adapted for efficient gas exchange (2)

A
  1. There is a large surface area because of the many filaments
  2. Thin surface so there is a short diffusion pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does ventilation work in fish

A

The fish opens its mouth, lowering the floor of the buccal cavity, water flows in. The fish closes its mouth, bucal cavity floor raises, pressure is increased, water is forced over the gill filaments.

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

What does the operculum do in fish

A

acts as a valve and pump, lets water out and pumps it in.

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

Describe ventilation in terrestrial insects

A

Oxygen is transported directly into tissues undergoing respiration, tracheoles supply tissues with oxygen they have spiracles which are the openings. Gases move in and out through mass muscle contraction and volume change in the tracheoles.

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

Explain three ways in which an insect’s tracheal system is adapted for
efficient gas exchange. (3)

A
  1. Trachioles have thin walls and are highly branched so short diffusion distance to cells
  2. Highly branched tracheoles means there is large surface area for gas exchange
  3. Trachioles provide tubes full of air so fast diffusion into insect tissues.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do you calculate surface area?

A

SA (㎠)= H x L x no.sides

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

What is the benefit of having a large number of stomata in a leaf?

A

All cells are a short distance to the stomata

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

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

A

Stomata close (1), less carbon dioxide for photosynthesis production (2)

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

what prevents friction between the lungs and the ribs?

A

a lubricating fluid is produced

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

Describe a feature of the airways which provides structural support

A

C shaped cartilage rings hold the trachea and bronchi open providing strutural support, but are incomplete to allow passage of food behind the trachea in the oesphoegus

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

What is the cartilage that makes the C shapes rings composed of?

A

Loose tissue including glandular and connective tissue, blood vessels, elastic fibres and smooth muscle

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

what is the inner lining of the trachea and bronchi composed of?

A

ciliated epithelium and goblet cells

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

why are the alveoli an efficient gas exchange surface?

A

only one cell thick, surrounded by capillaries which are also one cell thick so there is a short diffusion pathway. Constant blood supply from capillaries maintains steep concentration gradient

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

why is cartilage an important feature of the lungs?

A

Prevents lungs collapsing when pressure drops

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

what are ciliated epithelium and why do we have them

A

present in all airways, helps to move mucus towards the throat where it can be swallowed

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

what is the role of smooth muscle in mammalian gas exchange system

A

can contract to constrict the airways when necessary controlling the diameter thus controlling flow of air to and from alveoli

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

what are 2 parts of ventilation

A

Inspiration and expiration

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

INSPIRATION
what are the internal and external intercostal muscles doing

A

External contract, internal relax.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Describe inspiration
Diaphragm contracts and flattens. Intercostal muscles cause volume of lungs to increase Ribs raise upwards Lowering the pressure. Pressure is higher externally, there is a steep concentration gradient and air is forced into the lungs, down the pressure gradient
25
EXPIRATION what are internal and external intercostal muscles doing
External relax, internal contract. (the first letter of the name of the process is the same as the first letter of the muscles that are relaxing).
26
Describe expiration
Rib cage is lowered. Diaphragm relaxes and raises upwards. Volume in the lungs is decreased, pressure is increased, air is forced out of the lungs.
27
what does a spirometer measure?
Lung volume
28
what is vital capacity
Max capacity of air that can be inhaled or exhaled in a single breath.
29
What are the internal intercostal muscles doing during inspiration?
relaxing
30
what are external intercostal muscles doing during expiration?
relaxing
31
what are internal intercostal muscles doing during expiration?
contracting
32
what are external intercostal muscles doing during inspiration?
contracting
33
what is the residual volume in the lungs
volume of air which is always present
34
what do goblet cells do
present in all airways, involved in mucus secretion to trap bacteria and dust
35
Describe and explain one feature of the alveolar epithelium that makes the epithelium well adapted as a surface for gas exchange. Do not refer to surface area or moisture in your answer. (2)
Single layer of cells (1) reduces diffusion distance (2)
36
Describe and explain one feature of the alveolar epithelium that makes the epithelium well adapted as a surface for gas exchange. Do not refer to surface area or moisture in your answer. (2)
Permeable (1) allows diffusion of oxygen and carbon dioxide (2)
37
The tidal volume in a person with emphysema is reduced compared with the tidal volume in a healthy person. Suggest and explain how a reduced tidal volume affects the exchange of carbon dioxide between the blood and the alveoli. (3)
Less carbon dioxide exhaled (1) So reduced concentration gradient between blood and alveoli (2) so slower movement of carbon dioxide out of blood (3)
38
Describe and explain the mechanism that causes lungs to fill with air (3)
Diaphragm contracts and external intercostal muscles contract, causes volume to increase and pressure to decrease, air moves into the lungs down the pressure gradient
39
Two solutions often used to stain tissues are haematoxylin solution and iodine solution. * Haematoxylin solution stains DNA a blue colour. * Iodine solution stains starch a blue-black colour. The scientist used haematoxylin solution and not iodine solution to stainthe lung tissue. Suggest why. (2)
The lung tissue doesnt contain starch (1), haematoylin makes the nucleus visible
40
If alveolar epithelium cells die inside the human body they are replaced by non-specialised, thickened tissue. Explain why death of alveolar epithelium cells reduces gas exchange in human lungs. (3)
Reduced surface area (1) increased distance for diffusion (2), reduced gas exchange (3)
41
Describe the pathway taken by an oxygen molecule from an alveolus to the blood. (2)
Diffuses across alveolar epithelium (1) into epithelium of capillary (2)
42
Explain how one feature of an alveolus allows efficient gas exchange to occur (2)
Alveolar epithelium is one cell thick (1) creating a short diffusion pathway (2).
43
Describe the gross structure of the human gas exchange system and how we breathe in and out. (6)
1. Trachea branches into bronchus then bronchioles with alveoli next to blood capillary. (2, correct names+order) 2. During inspiration, external intercostal muscles contract, diaphragm flattens and contracts (1) volume increases, pressure decreases, air moves into lungs down pressure gradient. During expiration diaphragm relaxes, external intercostal muscles relax, volume decreases and pressure increases, air moves out of lungs down pressure gradient.
44
Explain three ways in which an insect’s tracheal system is adapted for efficient gas exchange.
Tracheoles have thin walls so short diffusion distance to cells (1) Trachea provide tubes full of air so fast diffusion (2) Fluid in end of tracheoles moves out to tissues during exercise so larger surface area for gas exchange (3)
45
What is the definition of digestion?
Hydrolysis of large biomolecules into smaller molecules that can be absorbed across cell membranes
46
What enzyme breaks down carbohydrate polymers in the mouth?
amylase
47
What enzyme breaks down monosaccharides in the ileum?
maltases
48
what enzymes break down lipids?
lipases
49
how do lipases break down lipids?
hydrolysing the ester bond between the monogylcerides and fatty acid
50
where are products of digestion absorbed?
Cells lining the ileum (last part of small intestine), these are called epithelial cells
51
what is the epithelium?
lining of ileum (last part of small intestine)
52
what does amylase do?
Catalyses polysaccharides like starch into maltose
53
how does amylase catalyse starch into maltose?
hydrolyses the glycosidic bonds in a starch polymer
54
where is amylase produced?
salivary glands and pancreas
55
what enzymes break down disaccharides e.g. glucose
Membrane bound disaccharidases break down disaccharides into monosaccharides
56
Name 3 membrane-bound disaccharidases
Maltase, sucrase, lactase
57
why is amylase not a disaccharidase?
it breaks down starch which is a polysaccharide
58
what does lactase enzyme convert lactose into?
glucose+galactose
59
what does maltase convert maltose into?
glucose+glucose
60
what does amylase convert starch into?
maltose
61
what does sucrase convert sucrose into?
glucose+fructose
62
what are the two categories of enzymes that break down carbohydrates?
membrane bound disaccharidases and amylases
63
Where in the body do sucrose and lactose get hydrolysed into maltose by membrane bound disaccharidases?
In the duodenum
64
where does protein digestion start?
in the stomach
65
what are the two processes of lipid digestion?
chemical-lipase physical-bile salts
66
where is lipase produced and secreted into
pancreas, secreted into duodenum and ileum
67
how are lipids digested by lipase?
ester bond is hydrolysed in the triglyceride: triglyceride--> monoglyceride+fatty acid
68
in lipid digestion, what happens before lipase action?
bile salts emulsify lipids to form many small droplets called micelles which provide a larger surface area to enable faster hydrolysis action by lipase
69
where are bile salts produced
liver
70
what are lipids coated in (which forms an emulsion?)
bile salts
71
Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels (5)
1. Micelles contain bile salts, monoglycerides and fatty acids 2. Brings fatty acids and monogyclerides to cells lining the ileum 3. Fatty acids and monogylcerides are absorbed by diffusion 4. Triglycerides are reformed in cells 5. Vesicles move to cell membrane
72
what are micelles? (contains 4 things)
vesicle containing bile salts, monogylcerides, glycerol and fatty acids
73
Describe the role of micelles in the absorption of fats into the cells lining the ileum (3)
1. Micelles include bile salts and fatty acids 2. This makes the fatty acids more soluble in water 3. Brings fatty acids to the lining of the ileum, maintains higher conc. of fatty acids to the lining of the ileum 4. Fatty acids are absorbed by diffusion
74
Describe the role of enzymes in the digestion of proteins in a mammal (4)
1. Endopeptidases hydrolyse peptide bonds between amino acids in the middle of a polypeptide 2. Exopeptidases hydrolyse peptide bonds between amino acids at the end of a polypeptide 3. Depiptidases act between two amino acids
75
By which process do fatty acids and glycerol enter the intestinal epithelial cell?
Diffusion
76
Explain the advantages of lipid droplet and micelle formation (3)
1. Droplets increase surface area for lipase action 2. So faster hydrolysis of triglycerides 3. Micelles carry fatty acids and glycerol through membrane to intestinal epithelial cell
77
How is the golgi apparatus involved in the absorption of lipids? (3)
1. Modifies triglycerides 2. Combines triglycerides with proteins 3. Forms vesicle for release
78
Cells lining the ileum of mammals absorb the monosaccharide glucose by co-transport with sodium ions. Explain how (3)
1. Sodium ions actively transported from ileum cell to blood 2. Maintains diffusion gradient for sodium to enter from small intestine 3. Glucose enters by facilitated diffusion with sodium ions
79
is haemoglobin water soluble?
yes
80
what type of molecule is haemoglobin?
a globular protein
81
describe the structure of haemoglobin
2 beta polypeptide chains and 2 alpha helices, each chain/helix has a haeme group and iron
82
how does haemoglobin carry oxygen in the blood?
Oxygen binds to each haem group, so each haemoglobin molecule contains 4 oxygen molecules
83
what does the affinity of oxygen for haemoglobin mean?
How easily haemoglobin binds to oxygen, in an area with a high oxygen concentration, (e.g. lungs) affinity for oxygen will be higher and the haemoglobin will attract more oxygen
84
what does partial pressure of oxygen mean?
the concentration of oxygen, the greater the dissolved concentration of oxygen in a cell, the higher the partial pressure. so the capillary next to the alveoli will have a high partial pressure of oxygen.
85
describe the relationship between partial pressure of oxygen and the affinity of oxygen for haemoglobin
As partial pressure increases, the affinity of oxygen for haemoglobin also increases (oxygen will bind to the haemoglobin tightly)
86
What is 'loading' in the lungs?
loading is when the partial pressure of oxygen is high and the affinity of oyxgen for haemoglobin is high so the oxygen binds to the haemoglobin
87
What happens to haemoglobin during respiration?
During respiration oxygen is used up, so partial pressure of respiring cells decreases, decreasing the affinity of oxygen for haemoglobin. As a result, haemoglobin unloads the oxygen into the respiring cell. After unloading, the haemoglobin returns to the lungs.
88
Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind. Explain why (2)
Binding of first oxygen changes tertiary structure of haemoglobin, uncovering another haem group for the second oxygen to bind to. (increase in saturation=increase in affinity)
89
what do dissassociation curves illustrate?
the change in haemoglobin as partial pressure changes
90
what causes the steep increase in dissasociation curves?
Initially, the curve is shallow because it is hard for the first oxygen to bind, then when the tertiary stucture of the haemoglobin changes and more haem groups are uncovered, affinity increases causing a steep increase in saturation
91
what causes dissasociation curves to flatten out?
once 3 oxygens have binded to the haemoglobin the likelihood of a fourth oxygen finding a binding site is low
92
how does foetal haemoglobin differ from adult haemoglobin?
has a higher affinity for oxygen as the partial pressure is lower because the blood has to reach the placenta
93
What is the bohr effect?
In the presence of carbon dioxide, the affinity of haemoglobin for oxygen decreases, causing the oxygen to be released
94
give 2 factors that can affect the affinity of oxygen to haemoglobin?
partial pressure of oxygen partial pressure of carbon dioxide

biology (8 decks)

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