Brainscape's Knowledge GenomeTM

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


See full index

AS Biology > Topic 3A - Exchange and transport systems > Flashcards

Topic 3A - Exchange and transport systems Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Give 3 examples that show that organisms need to exchange substance

A
  1. Cells need to take in oxygen (for aerobic respiration) and nutrients
  2. They also need to excrete waste products like CO2 anr urea
  3. Most organisms need to stay at same temp, so heat needs to be exchanged too
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The ease of exchanging substances depends on the organisms…

A

Surface area to volume ratio

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

Do smaller animals have higher or lower surface area: volume ratios?

A

They have higher surface area: volume ratios

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

In single-celled organisms, how are substances exchanged in/out of the cell?

A

Substances can diffuse directly into/out of the cell across the cell surface-membrane

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

In single-celled organism, why is diffusion rate quick?

A

Diffusion rate is quick because of the large SF and the small distances the substances have to travel

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

In multicellular organisms, why is diffusion across the outer membrane (into the environment) slow?

A
  1. Some cells are deep within the body - big distance between them and environment
  2. Large animals have low SF:V ratio - difficult to exchange enough to supply large volume of animal through relatively small outer surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are multicellular organisms specialised to exchange substances?

A

They use exchange organs e.g. lungs and a mass transport system

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

How is mass transport different in mammals and plants?

A

Mammals - refers to circulatory system, which uses blood to carry glucose and 02 around body. Also carries hormones , antibodies and waste like CO2

Plants - refers to transport of water and solutes in the xylem and phloem

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

How does the size of an animal affect heat exchange?

A

If animal too big - Hard to lose heat from body and SF: is small compared to volume

If animal too small - Heat is lost more easily as SA is large.

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

How does the shape of an animal affect heat exchange?

A
  1. Animals with compact shape have a smaller SA to volume ratio to minimise heat lose
  2. Animals with a less compact shape (sticky out bits) have a higher SA to volume ratio, increasing heat loss from their surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe some behavioural and physiological adaptions, that SMALL animals use, to aid exchange

A

1) High SA:V ratio means they tend to lose more water as it evaporates from their surface. So some desert animals have kidney structure adaptations to produce less urine
2) Small animals in cold areas need to eat high energy foods like nuts, to support metabolic rates
3) Small animals may have thick layers of fur or hibernate when its cold

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

Describe some behavioural and physiological adaptions, that LARGER animals use, to aid exchange

A
  • elephants have large flat ears to increase their SA, allowing them to lose heat
  • hippos spend much of the day in water, to help them lose heat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What factors increase the rate of diffusion across exchange surfaces?

A
  1. Large surface area
  2. Thickness (exchange surfaces are only 1 layer of epithelial)
  3. Steep concentration gradient of particles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why do fish need a counter current system for gas exchange?

A

Because there’s a lower conc of 02 in water than air, so they need special adaptations to get enough O2

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

Describe the counter-current system that fish use for gas exchange (diagram)

A
  1. H2O enters fish through mouth and out through gills
  2. Gills made of thin plates, gill filaments (for large SA)
  3. Filaments covered in lamellae, to increase SA more
  4. Lamellae have blood capillaries and thin surface layer of cells to speed up diffusion
  5. Blood and water flow in lamellae along opposite directions, maintaining large conc gradient between 2. Conc of O2 in water is always higher than in blood,so as much 02 as possible diffuses into blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What do insects use to exchange gases?

A

Tracheae - microscopic air-filled pipes

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

Describe how insects use tracheae to exchange gases

A
  1. Air enters tracheae through surface pores; spiracles
  2. Oxygen travels down conc gradients towards cells
  3. Tracheae branch off to smaller, thinner, permeable walls (tracheoles) and go to cells. O2 is diffused to cells
  4. CO2 moves down conc gradient to spiracles, to be released
  5. RAM to move air in and out spiracles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What gases do plants need for photosynthesis and respiration?

A

Photosynthesis - C02

Respiration - O2

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

What is the main gas exchange surface for dicotyledonous plants? (DIAGRAM)

A

The surface of mesophyll cells in the leaves

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

How are mesophyll cells adapted to their function?

A

They have a large surface area so faster diffusion rate

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

What are stomata and what do they do?

A

They are pores in the epidermis that allow gases to move in and out of leaf
- They open to allow exchange of gases and close to prevent water loss

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

What do guard cells do?

A

They control the opening and closing of stomata

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

What adaptations do insects have to reduce water loss?

A
  • They close their spiracles using muscles

- Waterproof, waxy cuticle around body & tiny hairs around spiracles to reduce water loss by evaporation

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

How are guard cells adapted to control water loss?

A
  • Water enters guard cells, making them turgid, and opening stomatal pore as usual
  • when plant is dehydrated, guard cells lose water and become flaccid, closing the pore
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Give 5 examples of xerophytic adaptations (DIAGRAM)

A
  1. Stomata sunken in pits that trap most air, reducing conc gradient of water between leaf & air and reducing water loss by evaporation
  2. Layer of ‘hairs’ on epidermis - to trap moist air
  3. Curled leaves with stomata in, to protect from wind
  4. Reduce number of stomata
  5. Waxy waterproof cuticles on leafs and stems
26
Q

Lungs are specialised organs for…

A

Gas exchange

27
Q

Describe the structure of the lungs

A
  1. When you breathe in, air enters the trachea
  2. Trachea splits into 2 bronchi (one goes to each lung)
  3. Bronchus branches into smaller tubes - bronchioles
  4. Bronchioles end in small ‘air sacs’ called alveoli
  5. Ribcage, intercostal muscles, diaphragm all work together to move air in and out
28
Q

How many layers of intercostal muscles are there?

A

3

29
Q

Define the terms ventilation, inspiration and expiration

A

Ventilation - breathing in and out
Inspiration - breathing in
expiration - breathing out

30
Q

Describe the process of inspiration

A
  1. External intercostal and diaphragm muscles contract
  2. So ribcage moves upwards & outwards and diaphragm flattens, increasing vol of thoracic cavity
  3. As volume of TC increases, lung pressure decreases (to below atmospheric pressure)
  4. Air moves from area of high pressure to area of low pressure so air flows down trachea and into lungs
31
Q

Is inspiration an active or passive process?

A

It’s an active process

32
Q

Describe the process of expiration?

A
  1. External intercostal and diaphragm muscles relax
  2. So ribcage moves downwards & inwards and diaphragm is curved, decreasing vol of thoracic cavity
  3. As vol of TC decreases, lung pressure increases (above atmospheric temp)
  4. Because of conc gradient, area moves out of lungs
33
Q

Can expiration be forced?

A

Yes

34
Q

What happens during forced expiration?

A
  1. During forced expiration, the external intercostal muscles relax whilst internal intercostal muscles contract
  2. This moves ribcage further down and in
  3. Movement of external & internal intercostal muscles are antagonising (opposing)
35
Q

Where does gaseous exchange take place in humans? (the specific part)

A

In the alveoli

36
Q

What are alveoli surrounded by?

A

They are surrounded by a network of capillaries

37
Q

Describe the diffusion of O2 and CO2 in the alveoli (DIAGRAM)

A
  1. O2 diffuses (down conc gradient) out of alveoli, across alveolar epithelium and capillary endothelium (type of epithelium that forms capillary wall), and into haemoglobin in the blood
  2. CO2 diffuses (down conc gradient) into the alveoli from the blood, and is breathed out
38
Q

What factors speed up the rate of diffusion in the alveoli?

A
  1. Thin exchange surface
  2. Large number of alveoli in lung (to give large SF)
  3. Steep conc gradient of O2 and CO2 between alveoli and capillaries (constantly maintained by flow of blood and ventilation
39
Q

Is expiration an active or passive process?

A

A passive process

40
Q

What do lung diseases affect?

A

They affect ventilation and gas exchange in lungs

41
Q

Define tidal volume (and what is the normal TD for adults?)

A

the volume of air in each breath - usually between 0.4 dm^3 and 0.5 dm^3 for adults

42
Q

Define ventilation rate (and what is the normal VR for a healthy person?)

A

The number of breaths per min. For a healthy person at rest, it’s about 15 breaths

43
Q

Define Forced expiratory volume (FEV1)?

A

The max vol of air that can be breathed out in 1 sec

44
Q

Define forced vital capacity (FVC)?

A

Max vol of air that is possible to breathe forcefully out of lungs after a really deep breath in

45
Q

1dm^3 is equal to…

A

1 litre

46
Q

What’s a spirometer?

A

It is a machine that scientists use to measure the volume of air breathed in and out

47
Q

What can you work out from the graph produced by a spirometer?

A

You can work out tidal volume, ventilation rate and other measures of breathing

48
Q

How does pulmonary tubercolosis cause a reduction in tidal volume?

A
  1. TB bacteria causes immune system cells to build wall around bacteria in lungs. This forms small hard lumps called tubercles
  2. Infected tissue within tubercle dies and gaseous exchange surface is damaged so TV is reduced
  3. TB also causes fibrosis, furthering reducing TV
49
Q

What are the common symptoms of pulmonary tubercolosis

A
  1. Coughing up blood and mucus
  2. Chest pains
  3. Shortness of breath and fatigue
50
Q

What is fibrosis?

A

Fibrosis is the formation of scar tissue in lungs, as a result of an infection or exposure to substances like asbestos or dust
- scar tissue is thicker and less elastic than normal lung tissue

51
Q

What are the consequences of fibrosis?

A
  1. Lungs are less able to expand, so can’t hold asmuch air - reduced TV and FVC
  2. Reduction in rate of gaseous exchange - diffusion is slower across thicker scarred membrane
52
Q

What are the symptoms of fibrosis?

A 
FIBROSIS
1. Shortness of breath
2.Dry cough 
3 Chest pain
4. Fatigue and weakness
53
Q

Why do fibrosis sufferers have a faster ventilation rate than normal?

A

Because they need to get enough air into their lungs to oxygenate their blood.

54
Q

What is asthma?

A

Respiratory disease where airways become inflamed and irritated (usually because of allergic reaction or pollen/dust)

55
Q

What happens during an asthma attack?

A
  1. Smooth muscle lining the bronchiole contracts and large amount of mucus is produced
  2. This causes constriction of airways and reduces the diameter of the airways , making it difficult for sufferer to breathe.
    - Air flow in and out of lungs is reduced, so less O2 enters alveoli and moves into blood. Reduced air flow means FEV1 is severely reduced
56
Q

What are the symptoms of an asthma attack?

A
  • Wheezing
  • shortness of breath
  • tight chest
57
Q

What can an asthma attch be relieved by and how does this work?

A

By drugs in inhalers, which cause the muscle in the bronchioles to relax, opening up the airways

58
Q

What is emphysema?

A

A lung disease caused by smoking or long-term exposure to air pollution - foreign particles in smoke become trapped in alveoli

59
Q

How do foreign particles in smoke damage the alveoli?

A
  1. Causes inflammation, attracting phagocytes to the area. Phagocytes produce an enzyme that breaks down elastin (protein in walls of alveoli)
  2. Elastin is elastic and helps alveoli return to its shape after inhaling/exhaling air
  3. Loss of elastin means alveoli cant recoil to expel air as well (so air is trapped in alveoli)
  4. Also leads to destruction of alveoli walls, which reduces surface area of alveoli, so rate of gaseous exchange decreases
60
Q

What are the symptoms of emphysema?

A
  • Wheezing
  • shortness of breath
  • increased ventilation rate as they try to increase the amount of oxygen reaching the lungs
61
Q

Summarise the general effect of diseases like TB, fibrosis, asthma and emphysema?

A
  1. All reduce the rate of gas exchange in alveoli
  2. Less oxygen can diffuse into blood so body cells receive less oxygen and rate of aerobic respiration is reduced.
  3. Therefore, less energy is released and sufferers feel tired and weak

AS Biology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions