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Biology > Exchange > Flashcards

Exchange Flashcards

1
Q

The ___ and _______ rate of an organism affects the rate of exchange.

A

size, metabolic

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2
Q

What happens to the SA:V as a cell increases?

A

it decreases

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3
Q

How do you calculate SA:V ?

A

SA / V

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4
Q

Why do small, inactive organisms not have a specialised gas exchange?

A
  • Large SA to V

- Substances can diffuse in/out quick enough as substances don’t have to travel far to get to cells

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5
Q

what are the 3 reasons why large organisms need a specialised circulatory system

A
  • need to meet metabolic requirement
  • V increases at a faster rate than SA
  • Cells too far away from outer surface, too long for diffusion
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6
Q

Name the 4 features of specialised gas exchange

A
  • Large SA:V = increases exchange rate
  • Very thin = diffusion pathway short
  • selectively permeable = allow selected materials across
  • movement of internal (i.e. blood) and environmental medium (i.e. air) = allow diffusion gradient
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7
Q

describe gas exchange in a single celled organisms

A
  • no specialised gas exchange
  • large SA:V
  • short diffusion pathway
  • diffusion rapid enough to allow O2 (respiration) in and CO2 out (toxic)
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8
Q

name the 3 main parts of the tracheal system of an insect

A

spiracles, trachea, tracheoles

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9
Q

Name the 3 ways gases move in/out of tracheal system

A
  • ends of tracheoles filled with H2O
  • mass transport
  • Along a diffusion pathway
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10
Q

explain how the end of the tracheoles filled with H2O help gases move in/out of insect

A
  1. anaerobic respiration = lactate produced
  2. lactate soluble = lowers H2O potential of cells
  3. H2O moves into cells (osmosis)
  4. volume of H2O in tracheoles reduced
  5. air drawn in further
  6. liquid diffusion pathway = diffusion rapid
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11
Q

explain mass transport of gases in an insect

A
  1. contraction of muscles squeeze trachea
  2. mass movement of air in/out
  3. speeds up exchange of gases
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12
Q

explain how gases in insects move along a diffusion pathway

A
  1. cells respiring, O2 reduced = conc. reduced in tracheoles
  2. creates diffusion gradient = O2 diffuses into trachea/tracheoles
  3. CO2 produced = creates gradient in opposite direction
  4. CO2 leaves
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13
Q

Name the components of the specialised gas exchange in fish

A

gills (covered by operculum), gill filaments, gill arch, blood vessels, lamellae

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14
Q

explain countercurrent flow

A

blood and O2 flow in OPPOSITE directions so:

  • conc. of O2 in H2O always slightly more than blood, NEVER REACHES EQUILIBRIUM
  • diffusion gradient maintained across whole lamellae
  • ventilation (brings O2 to gills) allows mass transport = carrying O2 away: steep conc. gradient
  • 80% of O2 diffuses into blood
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15
Q

explain why co-current or parallel flow is not used

A
  • diffusion gradient maintained for only half distance across lamellae
  • no net diffusion (when conc. equilibrates)
  • only 50% of O2 diffuses into blood
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16
Q

why are these used in fish: gill filaments, lamellae, epithelium and blood vessels

A

gill filaments = increase SA
lamellae = increase SA further
epithelium = short diffusion pathway
blood vessels = conc. gradient

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17
Q

what processes in plants maintain the diffusion gradients?

A
  • photosynthesis (CO2 diffuses in from external air) and - respiration (O2 diffuses from external air)
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18
Q

Adaptation of leaves: In leaves diffusion takes place in ___ phase. Air spaces ______ compared to V of tissue. Many interconnecting __ spaces so gases readily come into contact with ________ cells. Large _____ ____ of _______ cells so there is rapid diffusion. Lots of ______, no cell far from a stoma = _____ diffusion pathway.

A
  1. gas
  2. large
  3. air
  4. mesophyll
  5. surface area
  6. mesophyll
  7. stomata
  8. stoma
  9. short
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19
Q

stomata are surrounded by ______ cells which open/close stomatal ________.

A

guard cells, aperture

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20
Q

an increase in _______ acid can trigger ____ ions to flow into _____ cell, _____ H2O potential. This increases ______ so guard cell ____ stomata.

A
  1. abscisic
  2. K+
  3. stomata
  4. lowering
  5. turgor
  6. opens
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21
Q

How does a thick waxy cuticle reduce H2O loss in xerophytic plants

A

waterproof so less H2O escapes i.e. holly

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22
Q

how does hairy leaves and stomata in pits/grooves reduce H2O loss

A

traps still/moist air. H2O potential gradient reduced both in/out leaf. Reduces evap. i.e. pine trees

23
Q

how does the rolling up of leaves reduce H2O loss

A

traps still air. High water potential. No water potential gradient between in/out of cell. No water loss. i.e. marram grass

24
Q

how does reducing SA:V of leaves reduce H2O loss

A

as a smaller SA:V slower rate of diffusion i.e. pine needles

25
How do insects limit H2O loss (4 ways)
- Small SA:V (minimise area where H2O is lost) - waterproof cuticle covering exoskeleton - spiracles closed majority of time - tiny hairs around spiracles, humid = trap H2O
26
The trachea is supported by what and what 2 cells line the wall of the trachea?
+ supported by C-shaped rings of cartilage - goblet cells = secrete mucus - ciliated epithelial cells = moves mucus up to pharynx where it goes down oesophagus to stomach
27
describe the bronchi
- 2 divisions of trachea - have muscle and ciliated cells. - Have cartilage but amount decreases as bronchi gets smaller
28
What 3 part make up the alveoli?
- collagen - elastic fibres - epithelial cells
29
why do alveoli contain elastic fibres
so they can stretch when filled and recoil so CO2 can be expelled
30
Is this true or false: gases move from an area of low pressure to high pressure
false: gases move from an area of high to low pressure
31
describe what happens during inspiration/inhalation
1. external intercostal muscles contract 2. diaphragm contracts/flattens 3. volume of thorax increases 4. atmospheric pressure is greater than inside lungs 5. air moves down a concentration gradient into lungs
32
describe what happens during expiration/exhalation
1. internal intercostal muscles contract 2. diaphragm relaxes 3. volume of thorax decreases 4. atmospheric pressure lower than inside lungs 5. air moves down concentration gradient out of lungs
33
define tidal volume and its units
volume of air inspired with each breath at rest - dm3
34
define ventilation rate and its units
no. of breaths in 1 min. min-1
35
define pulmonary ventilation rate and its units
total volume of air moved into lungs in 1 min. dm3 min-3
36
define total lung capacity
total volume of air contained in the lung at the end of max. inhalation
37
define vital capacity
max. volume of air a person can expel after max. inhalation in 1 breath
38
define residual volume
volume of gas remaining in lung at end of max. exhalation
39
define the equation for pulmonary ventilation
tidal volume x ventilation rate
40
define the equation for cardiac output
stroke volume x heart rate
41
Alveoli have a single layer of _________ cells whereas blood capillaries have a single layer of ________ cells
1. epithelium | 2. endothelium
42
- Red blood cells pass ______ through capillaries = ______ time for ______. - Red blood cells _______ against capillary wall and walls are very ___ = diffusion pathway _______ - Alveoli and pulmonary capillaries have large ______ ____. - ______ flow thru capillaries = maintains ______ - breathing and ______ of the heart = ________ and circulating the blood keeps ____ conc. gradient
1. slowly, more, diffusion 2. flatten, thin, short 3. surface area 4. blood, gradient 5. pumping, ventilating, steep
43
define Ficks law and what does it mean
diffusion = SA x Difference in conc. gradient / length of diffusion pathway - diffusion is directly proportional to SA and difference in conc. - inversely proportional to length of pathway
44
What does pulmonary fibrosis do and why does it make it harder to take in O2?
- reduces elasticity in lungs = lung recoil decreases + alveoli can't expand/contract/recoil + smaller SA = less O2/CO2 exchanged, conc. gradient decreases
45
What does asthma do and why does it make it harder to take in O2?
- inflammation of bronchi/bronchioles, more mucus produced + increased resistance to air flow = smaller volume of air into lungs/alveoli + so decrease in O2 conc. diffusion of O2 decreases
46
What does emphysema do and why does it make it harder to take in O2?
- elastin protein in lungs damaged = reduces elasticity + alveoli unable to expand/recoil/stretch + less O2 enters/less CO2 leaves = decrease in CO2/O2 conc. gradient + SA for diffusion decreases, less diffusion
47
name the 5 main risk factors for lung disease
smoking, pollution, genetic makeup, infections, occupation i.e. miner
48
When analysing data: just because there is a _______ does not imply _______. Does not show a specific variable ____ the other due to the fact that there are other ______. Also there is normally a delay between cause and ______.
1. correlation 2. causation 3. causes 4. factors 5. effect
49
what are the 2 things you need to do to prove a specific factor causes an outcome
1. a hypothesis to explain current correlation | 2. perform experiments to prove causal relationships
50
Name at least 3 restrictions on the sources of smoking
- reducing tobacco products - health warnings on packaging - ban on advertising smoking - minimum age of smoking - smoking banned in areas/places
51
____ transport maintains the final ______ gradients that bring substances to/from the cell membranes of individual cells. Also maintains a stable environment (____ fluid)
mass, diffusion, tissue
52
What 2 cells is the bronchioles made up of?
muscle cells lined with epithelial cells | muscle constrict = control air flow
53
where does gas exchange take place?
the alveolar epithelium
54
why do alveoli have a large SA and very thin walls?
increase rate of diffusion

Biology (25 decks)

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