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biology year 1 > exchange and transport systems A > Flashcards

exchange and transport systems A Flashcards

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1
Q

how does an organism’s size relate to their surface area to volume ratio?

A

the larger the organism, the lower the surface area to volume ratio.

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2
Q

Relationship between SA:V (and thus the size of an organism) and metabolic rate

A

-Rate of heat loss / heat lost per unit body mass increases as SA:V increases
-i.e. more heat lost per unit body mass in smaller animals with a high SA:V
-So they need a higher metabolic rate / faster respiration
-To generate enough heat to maintain a constant body temperature i.e. replace lost heat

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3
Q

Exchange and transport in unicellular organisms

A

-can rely on diffusion to exchange substances
-short diffusion pathway from cell surface to centre of cell
-larger SA;V ratio
-microvilli can increase SA;V ratio further

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4
Q

exchange and transport in multicellular organisms

A

-need exchange and transport systems
-long diffusion pathway from body surface to centre of body so diffusion would take much too long
-smaller SA:V ratio so cannot exchange enough substances through surface

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5
Q

relationship between body shape/size and heat exchange

A

-body shape can increase SA:V ratio (large ears) or decrease SA:V ratio (round shape)
-smaller organisms have faster heat loss through their surface because of higher SA:V ratio

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6
Q

what is a metabolic rate and how is it measured

A

=amount of energy used up by an organism in a given amount of time
-often measured by measuring oxygen uptake

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7
Q

why do active organisms have a higher metabolic rate

A

-use up more ATP in a given amount of time
-need more oxygen per unit of body mass

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8
Q

a small animal with a higher SA:V have ……… heat loss per gram of body mass, so have a …… rate of metabolism which…… heat

A

1.faster
2.faster
3.releases

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9
Q

Adaptations of gas exchange surfaces: across the body surface of a single-celled organism

A

-Thin, flat shape and large surface area to volume ratio
- Short diffusion distance to all parts of cell for rapid diffusion eg. of O2 / CO

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10
Q

why cant insects use their bodies as an exchange surface?

A

have a waterproof chitin exoskeleton and a small SA:V ratio in order to conserve water

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11
Q

Describe the tracheal system of an insect

A
  1. Spiracles = pores on surface that can open / close to allow diffusion
  2. Tracheae = large tubes full of air that allow diffusion
  3. Tracheoles = smaller branches from tracheae, permeable to allow gas exchange with cells
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12
Q

adaptations for gas exchange ( tracheal system of an insect)

A

-Tracheoles have thin walls =Short diffusion distance to cells
-High numbers of highly branched tracheoles=Short diffusion distance to cells and large SA for gas exchange
-Tracheae provide tubes full of air=Fast diffusion
-Fluid in end of tracheoles moves out during exercise = larger SA
-Contraction of abdominal muscles changes pressure in body causing air to move in / out=Maintains concentration gradient for diffusion of O2 / CO2

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13
Q

how is the tracheal system of an insect adapted to reduce water loss

A

-Thick waxy exoskeleton=Increases diffusion distance so less evaporation
-Spiracles can open & close=Open to allow oxygen in and carbon dioxide out. Close to reduce water loss by evaporation
-Tiny hairs around spiracles=Trap most air → reduce water potential gradient → less water lost by evaporation

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14
Q

explain the process of gas exchange in insects

A

-gases move in and out of the tracheae through the spiracles
-diffusion gradient allows oxygen to diffuse into the body tissue while waste CO2 diffuses out
-contraction of muscles in the tracheae allows mass movement of air in and out

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15
Q

why cant fish use their bodies as an exchange surface

A

have a waterproof,impermeable outer membrane and a small SA:V ratio

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16
Q

what are the adaptations for gas exchange in gills of fish

A

-Each gill made of many filaments covered with many lamellae =Increase surface area for diffusion
-Thin lamellae wall =Short diffusion distance between water / blood
-Lamellae have a large number of capillaries=Remove O2 and bring CO2 quickly → maintains concentration gradient

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17
Q

counter current exchange system maximise oxygen absorbed by the fish, what happens in counter current flow

A
  1. Blood and water flow in opposite directions
    through/over lamellae
  2. So oxygen concentration always higher in water than blood near
  3. So maintains a concentration gradient of O2 between water and blood
  4. For diffusion along whole length of lamellae
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18
Q

why cant water and blood flow in the same direction

A

equilibrium would be reached, so oxygen wouldn’t diffuse
into blood along the whole gill plate.

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19
Q

adaptations for gas exchange of dicotyledonous plants

A

-Many stomata=Large surface area for gas exchange (when open) but can close to reduce transpiration
-Spongy mesophyll cells contain air spaces=Large surface area for gases to diffuse through
-thin= short diffusion pathway

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20
Q

what is a xerophyte

A

a plant adapted to live in very dry,windy,warm conditions

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21
Q

adaptations of xerophytic plants to reduce water loss

A

*thicker waxy cuticle = Increases diffusion distance so less evaporation
*Sunken stomata in pits,Rolled leaves,Hairs=
-‘Trap’ water vapour / protect stomata from wind
- So water potential gradient between leaf and air decreased
- So less evaporation
*Spines / needles=Reduces surface area to volume ratio

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22
Q

what is the structure of the lungs

A

*Trachea → windpipe from mouth
* Bronchi → branch off from trachea, one bronchus to each lung
* Bronchioles → branch off from bronchi, smaller tubes
* Alveoli → tiny air sacs at the end of bronchioles where gas
exchange occurs
* Surrounded by the ribcage and intercostal muscles

23
Q

how are lungs adapted for gas exchange

A

-Many alveoli / capillaries=Large surface area
-Alveoli / capillary walls are thin=Short diffusion distance
-Ventilation / circulation=Maintains concentration gradient

24
Q

The essential features of the alveolar epithelium as a surface over which gas exchange takes place

A
  • Thin / flattened cells / one cell thick → short diffusion distance
  • Folded → large surface area
  • Permeable → allows diffusion of oxygen and carbon dioxide
  • Moist → gases can dissolve
  • Good blood supply from network of capillaries → maintains concentration gradient
25
Q

How does gas exchange occur in the alveoli? ( oxygen)

A
  • Oxygen diffuses from alveoli
  • Down its concentration gradient
  • Across the alveolar epithelium
  • Across the capillary endothelium
  • Into the blood (in haemoglobin)
26
Q

How does gas exchange occur in the alveoli? ( carbon dioxide)

A
  • Carbon dioxide diffuses from capillary
  • Down its concentration gradient
  • Across the capillary endothelium
  • Across the alveolar epithelium
  • Into the alveoli
27
Q

Explain why death of alveolar epithelium cells reduces gas exchange in
human lungs.

A
  1. Reduced surface area;
  2. Increased distance for diffusion;
  3. Reduced rate of gas exchange;
28
Q

what is ventilation

A

the mechanism of breathing

29
Q

state how inspiration ( breathing in) occurs

A
  1. External intercostal muscles contract, internal intercostal muscles relax (antagonistic) → ribcage moves up / out
  2. Diaphragm muscles contract → flattens
  3. Increasing volume in thoracic cavity (chest)
  4. Decreasing pressure in thoracic cavity
  5. Air moves into lungs down pressure gradient
30
Q

state how expiration (breathing out) occurs

A
  1. Internal intercostal muscles can contract, external intercostal muscles relax → ribcage moves down / in
  2. Diaphragm relaxes → moves upwards
  3. Decreasing volume in thoracic cavity
  4. Increasing pressure in thoracic cavity
    5.Air moves out of lungs down pressure gradient
31
Q

why is inspiration an active process

A

requires energy

32
Q

is expiration an active process

A

no, passive process

33
Q

why is ventilation needed

A
  • Maintains an oxygen concentration gradient
  • Brings in air containing higher concentration of oxygen
  • Removes air with lower concentration of oxygen
34
Q

what is tidal volume

A

Volume of air in each breath

35
Q

what is ventilation rate

A

Number of breaths per minute

36
Q

what is forced expiratory volume ( FEV)

A

Maximum volume of air a person can breathe out in 1 second

37
Q

Forced vital capacity (FVC)

A

Maximum volume of air a person can breathe out in a single breath

38
Q

what two things does lung disease affect

A

-ventilations
-gas exchange

39
Q

how does lung disease have an effect on ventilation

A

● Reduce lung elasticity (eg. fibrosis - build-up of scar tissue) → lungs expand / recoil less
○ Reducing volume of air in each breath (tidal volume)
○ Reducing maximum volume of air breathed out in one breath (forced vital capacity)
● Narrow airways / reduce airflow in & out of lungs (eg. asthma - inflamed bronchi)
○ Reducing maximum volume of air breathed out in 1 second (forced expiratory volume)
● Reduced rate of gas exchange → increased ventilation rate to compensate for reduced oxygen in blood

40
Q

how does lung disease have an effect on gas exchange

A

-Thicker tissue in alveoli (e.g. fibrosis)→ increased diffusion distance
-Walls of alveoli break down → reduced surface area
-Reduce lung elasticity → lungs expand / recoil less → reduces concentration gradients of O2 / CO2

41
Q

what does an overlap in standard deviation mean

A

differences in means are likely to be due to chance

42
Q

what does no overlap in standard deviation mean

A

differences in means are likely to be significant

43
Q

what are the 3 statistical tests to analyse/ interpret data

A

Correlation coefficient,Student’s t test and Chi squared

44
Q

when do we use a correlation coefficient

A

when examining an association between 2 sets of data

45
Q

when do we use a student t test

A

when comparing means of 2 sets of data

46
Q

when do we use a chi squared test

A

when data are categoric

47
Q

what were the restrictions on tobacco and smoking

A

-tobacco should carry a health warning label
-British medical association called for a ban on smoking in public places

48
Q

what were the restrictions on sources of air pollution

A

-clean air programme for Europe
-clean power for transport

49
Q

A student was dissecting a pair of pig lungs . her teacher told her to inflate the lungs with a bicycle pump.
Q. explain why she shouldn’t inflate lungs by blowing into them

A

because she would end up sucking up the stale air from inside the lungs into her mouth

50
Q

A student was dissecting a pair of pig lungs . her teacher told her to inflate the lungs with a bicycle pump.
Q.give one safety precaution the student should take while inflating the lungs

A

-put the lungs inside a plastic bag while she inflates them
-this helps prevent bacteria being released into the air

51
Q

A student was dissecting a pair of pig lungs . her teacher told her to inflate the lungs with a bicycle pump.
Q. once the lungs are inflated, the student stops pumping air into them. describe and explain what the student would expect to see next

A

the lungs would deflate by themselves because of the elastin in the walls of the alveoli

52
Q

how can you make sure that the dissecting tools are safe to use?

A

check they are clean,sharp and free from rust

53
Q

what are two ethical issues that might be raised regarding dissections

A

-some believe its morally wrong to kill animals
-animals used for dissections may not be raised in a humane way or killed in a humane way

biology year 1 (10 decks)

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