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Biology Year 1 > Chapter 6 - Exchange > Flashcards

Chapter 6 - Exchange Flashcards

1
Q

Who has a larger surface area to volume ratio out of a mouse and an elephant?

A

Mouse

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2
Q

What are the 2 possible scenarios that might be asked about in relation to surface area to volume ratio

A
  • The absorption of oxygen in single celled organisms

- Heat conservation/loss between mammals

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3
Q

How does extreme enter a single celled organism or a flatworm

A

Direct diffusion

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4
Q

What is a single celled organisms SA:VOL like

And how does oxygen diffuse into it

A

Very high SA:VOL

O2 observed through membrane

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5
Q

What does it mean if a mammal has a higher SA:VOL than another?

A

They lose more heat per gram of body weight

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6
Q

What does a mammal have to do if it loses more heat per gram of body mass

A
  • Requires a faster rate of respiration

- As it needs more oxygen to maintain body temperature

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7
Q

How does an elephants rate of respiration differ to a mice?

A

Elephants is slower as they don’t need as much oxygen to maintain body temperature due to a smaller SA:VOL

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8
Q

What does the rate of diffusion for gas exchange depend upon? (Fick’s law)

A

Surface area of membrane
Diffusion distance (thickness)
Concentration gradient

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9
Q

What is fick’s law

A

Rate of diffusion is proportional to

Surface area x concentration difference/diffusion distance

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10
Q

Explain how gas exchange occurs in insects

A
  • Air enters through spiracles into trachea
    Trachea divide into tracheoles
  • Oxygen diffuses does concentration gradient along tracheoles
  • Tracheoles are closely surrounded by cells so oxygen diffuses into cells
  • Ventilation occurs, where air in trachea and tracheoles is replaced to maintain concentration gradient of oxygen between air and cells
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11
Q

What are examples of water loss adaptations in insects

A
  • Body is covered by waxy cuticle to reduce evaporation

- Insects can close spiracles

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12
Q

Why are insects not able to grow to a large size?

A

Insects rely on diffusion to exchange gases directly between the environment and its cells, therefore a short diffusion pathway is needed
This means that they can’t grow to a much larger size

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13
Q

What is the way in which gas exchange in fish occurs referred to as

A

Counter current flow

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14
Q

What is meant by counter current flow

A

Water and blood moving in opposite directions

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15
Q

What is the purpose of counter current flow

A
  • A high concentration gradient can be maintained across the entire surface, water is always next to blood with a low oxygen concentration
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16
Q

What are some adaptations that increase efficiency of diffusion in fish

A
  • Filaments and lamellae have a large surface area
  • Thin epithelium(short diffusion distance
  • Circulation of blood, means that deoxygenated blood replaces oxygenated blood to maintain concentration gradient
  • Ventilation of water means that oxygen is not lost by diffusing back into water
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17
Q

What are dicotyledonous plants

A

Plants with leaves

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18
Q

Explain gas exchange in dicotyledonous plants

A
  • Air enters through stomata

- Gas exchange of CO2 and O2 occurs in mesophyll

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19
Q

What is an adaptation of mesophyll and why is this

A

They are spongy, so can increase surface area

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20
Q

How are dicotyledonous plants adapted to reduce water loss and how does this happen

A
  • Guard cells can open and close stomata
  • If a plant has a lot of water, cells are hard
  • If it has a lack of water, cells are flacid, and if guard cells are flacid they close the stomata
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21
Q

What is a xerophytic plant

A

A plant in dry conditions eg cacti

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22
Q

What are 5 adaptations of xerophytic plants

A
  • Curled leaves (spikes)
  • Stomata sunken in pits
  • Hairs on epidermis of leaf (bottom)
  • Thick waxy cuticle
  • Few stomata
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23
Q

How do curled leaves, sunken stomata and hairs on epidermis help to reduce water loss

A
  • Reduces ventilation of air
  • Therefore water vapour accumulates within the leaf (outside stomata)
  • This decreases diffusion gradient for water vapour
  • Reduces water loss
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24
Q

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

A
  • Reduces evaporation of water from leaf, thus reduces water loss
25
Q

How does having fewer stomata reduced water loss for xerophytic plants

A

Fewer stomata mean there is less opportunity for water loss via stomata

26
Q

What are the adaptations for efficient gas exchange in humans? (Surface area)

A
  • Alveoli at end of bronchioles
  • Large number of them
  • They have a folded membrane to increase surface area
  • Many small capillaries to increase surface area
27
Q

What are the adaptations for efficient gas exchange in humans? (Concentration gradient)

A
  • Ventilation through breathing replaces air with high CO2 and low O2 concentration
  • Circulation of blood, deoxygenated blood is replaced by blood with high CO2 and low O2 concentration
  • Both increase concentration gradient
28
Q

What are the adaptations for efficient gas exchange in humans? (Diffusion distance)

A
  • Thin epithelia In alveoli and capillaries
  • One cell thick
  • Short diffusion pathway
29
Q

What is meant by tidal volume

A

Volume of air breathed in or out per breath at rest

30
Q

What is meant by ventilation/breathing rate

A

Number of breaths per minute

31
Q

What is meant by pulmonary ventilation

A

Total volume of air breathed in per minute

32
Q

Calculation for pulmonary ventilation

A

Tidal volume x breathing rate

33
Q

What is meant by oxygen consumption

A

Volume of oxygen used per min

34
Q

What is meant by vital capacity

A

Maximum volume of air that can be exhaled after maximum volume of air inhaled

35
Q

What is meant by residual volume

A

Volume of air that can’t be breathed out after maximum inhale and exhale

36
Q

What is the effect of exercise on tidal volume

A

Increases, deeper breaths

37
Q

What is the effect of exercise on breathing rate

A

Increase, faster breaths

38
Q

What is the effect of exercise on pulmonary ventilation

A

Increase, more breaths per min

39
Q

What is the effect of exercise on oxygen consumption

A

Increases, due to more respiration

40
Q

Draw a spirometer trace and label it with vital capacity, residual volume and tidal volume

A

Snapchat memories 14 nov

41
Q

Explain the mechanics of breathing for inspiration

A
  • Diaphragm contracts (flattens)
  • External intercostal muscles contract, rib cage moves up and out
  • Increasing volume of thorax (chest cavity)
  • Decreases air pressure in thorax, so air moves in from high to low pressure
42
Q

Explain the mechanics of breathing for expiration

A
  • Diaphragm relaxes (becomes domed)
  • External intercostal muscles relax
  • Rib cage moves down and in
  • Decreases volume of thorax
  • Increases air pressure in thorax
  • Air moves out from high to low pressure
43
Q

Explain the mechanics of breathing for forced expiration

A
  • Internal intercostal muscles contract
  • Pulls rib cage down more and faster
  • Internal and external intercostal muscles are an antagonistic pair
44
Q

What is meant by digestion

A

Large biological molecules are hydrolysed (broken down) by enzymes into smaller molecules that can be absorbed across a cell membrane

45
Q

Explain digestion of carbohydrates

A
  • Amylase hydrolyses glycosidic bonds in starch (polysaccharide)
  • Form maltose (disaccharide)
  • Maltase hydrolyses glycosidic bonds in maltose
  • Form 2 glucose molecules
46
Q

How are carbohydrates absorbed

A

After being digested into glucose, they are absorbed by co-transport with sodium ions

47
Q

Where is amylase found and where is it made

A

Found in saliva

Made in pancreas

48
Q

Where is maltase made

A

Small intestines

49
Q

What is sucrose broken down into

A

Glucose and fructose

50
Q

What is lactose broken down into

A

Glucose and galactose

51
Q

Explain the digestion of lipids

A
  • A lipid droplet (triglyceride) is emulsified by bile salts
  • Emulsified means make them smaller, thus increase SA:VOL
  • Lipase (enzyme) breaks the emulsified lipid droplets down into a monoglyceride and 2 fatty acids
52
Q

What are micelles

A

Tiny droplets of monoglycerides and fatty acids

54
Q

Where are bike salts produced

A

Liver

55
Q

What are the three ways that proteins are broken down

A

Endopeptidase
Exopeptidase
Membrane bound dipeptase

56
Q

What does endopeptidase do

A

Hydrolyses peptide bonds within a polypeptide

57
Q

What does exopeptidase do

A

Hydrolyses peptide bonds at the end of polypeptides

58
Q

What does membrane bound dipeptase do

A

Hydrolyse the peptide bonds between dipeptides

59
Q

Explain how amino acids are absorbed

A
  • Co-transport with sodium
  • sodium pumped out
  • Low concentration of sodium
  • Sodium diffuses in via carrier protein
  • Amino acids are also absorbed via co-transport (against concentration gradient)
60
Q

How are lipids absorbed

A
  • Once broken down into micelles, these release monoglycerides close to surface of the cell
  • These are small non-polar molecules so diffuse in to epithelium of cell

Biology Year 1 (10 decks)

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