Osmosis & Plant Transport Flashcards

1
Q

Concentration gradient


3 marks

A

Difference in concentration between;

  • 2 solutions
  • different cells
  • or cells + a surrounding solution.

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2
Q

Flaccid

1 mark

A

Lacking turgor.

Lacking in stiffness or strength. Soft + floppy.

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3
Q

Humidity

2 marks

A

Amount of water vapour in the atmosphere measured as a percentage.

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4
Q

Potometer

1 mark

A

Device used to measure the rate of water uptake by a plant.

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5
Q

Selectively Permeable

1 mark

A

Property of a membrane that controls the movement of molecules depending on their size.

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6
Q

Transpiration

2 marks

A

Loss of water from leaves by evaporation through the stomata.


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7
Q

Turgid

1 mark

A

Having turgor; enlarged and swollen with water.


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8
Q

Visking tubing

2 marks

A

An artificial, partially-permeable membrane used in osmosis + diffusion experiments.

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9
Q

(Selectively/) Semi-permeable membrane

2 marks

A
  • Allows some small substances to pass through

- Prevents larger substances.

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10
Q

Cell wall permeability

2 marks

A

Fully permeable - does not control what enters + leaves cell.

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11
Q

Cell membrane structure

2 marks

A

Rigid - provides a plant cell with support + keeps non-woody plants upright.

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12
Q

Osmosis in Cells depends on

1 mark

A

Concentration of water surrounding it.

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13
Q

Animal cells - osmosis

2 marks

A

When water moves into an animal cell - cell membrane stretches + cell gets bigger.

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14
Q

Example of an Animal Cell

1 mark

A

Red blood cell

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15
Q

Lysis

1 mark

A

Cell membrane bursts due to excess water intake.

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16
Q

Membrane stretches - gets bigger, then bursts due to excess water intake

(1 mark)

A

Lysis

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17
Q

Turgidity in plant cells

5 marks

A

Water diffusing into a plant cell = vacuole gets bigger, pushing cell membrane against the cell wall.

Force of this increases turgor pressure within cell making it firm or turgid.

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18
Q

When vacuole expands cell membrane is pushed against cell wall - pressure created by cell wall during osmosis in the Cells…does what?

(2 marks)

A

Stops too much water entering + prevents cell lysis.

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19
Q

If plants do not receive enough water

2 marks

A

Cells cannot remain turgid + plant wilts.

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20
Q

Cells that are not turgid

1 mark

A

Are flaccid.

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21
Q

Plasmolysis

1 mark

A

When too much water moves out of a plant cell + cell contents shrink - pulling the cell membrane away from the cell wall.

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22
Q

Cell state unlikely to survive

1 mark

A

Plasmolysed cell

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23
Q

Transpiration

4 marks

A

Evaporation of water from spongy mesophyll cells

- followed by diffusion of water through the air spaces + out of the stomata.

24
Q

Transpiration stream

2 marks

A

Water in a plant that exits the leaf into the atmosphere

  • providing a continuous stream of water.
25
Q

Importance of transpiration stream

5 marks

A

Provides;

  • leaves with continuous supply of water (for photosynthesis).
  • plant cells with support from turgor.
  • water for transpiration.

Continually transports minerals from roots, to leaves + other parts of plant.

26
Q

If water availability is limited - plants…

1 mark

A

Will need to reduce transpiration.

27
Q

How to reduce transpiration.

2 mark

A

Stomata close (lower side of leaf)

28
Q

Effect of surface area (non-environmental factor) on transpiration.

(2 marks)

A

Smaller leaves will contain less stomata - causing a decrease in transpiration.

29
Q

Effect of wind speed on transpiration.

3 marks

A

Higher wind speed - increase rate of evaporation

Causing an increase in transpiration.

30
Q

Effect of temp on transpiration.

3 marks

A

Higher temp - will increase the rate of evaporation

Causing an increase in transpiration.

31
Q

Increase rate of evaporation

1 mark

A

Increased rate of transpiration.

32
Q

Effect of humidity on transpiration

3 marks

A

Higher humidity level - will reduce the rate of evaporation

causing a decrease in transpiration.

33
Q

Decreased rate of evaporation

1 mark

A

Decreased rate of transpiration.

34
Q

Effect of light intensity on transpiration.

3 marks

A

Darkness will cause the stomata to close - causing a decrease in transpiration.

35
Q

Smaller leaves will contain less stomata causing a decrease in transpiration:
How can we change this factor Experimentally?

(1 mark)

A

Remove leaves.

36
Q

Higher wind speed will increase the rate of evaporation causing an increase in transpiration:
How can we change this factor experimentally?

(1 mark)

A

Use a fan.

37
Q

Higher temp will increase the rate of evaporation causing an increase in transpiration.
How can we change this factor experimentally?

(1 mark)

A

Use a heater.

38
Q

Higher humidity level will reduce the rate of evaporation causing a decrease in transpiration:
How can we change this factor experimentally?

(2 marks)

A

Place a clear, plastic bag over the plant shoot.

39
Q

Darkness will cause the stomata to close causing a decrease in transpiration:
How can we change this factor experimentally?

(1 mark)

A

Use a lamp.

40
Q

If less is water being lost through transpiration.

1 mark

A

Plant will absorb less water at the roots.

41
Q

Potometer

2 marks

A

Apparatus designed to measure water uptake in a leafy shoot.

42
Q

2 types of potometer

2 marks

A

Bubble potometer + Weight potometer.

43
Q

Water is transpired from ______ .

1 mark

A

Leaves

44
Q

_____ absorbs water from the potometer.

1 mark

A

Shoot

45
Q

What can be used to calculate the rate of water uptake?

2 marks

A

Distance the air bubble moves in a certain period of time

46
Q

What can the movement of air bubbles (under time constraints) be used to measure?

(1 mark)

A

Rate of water uptake by Plant.

47
Q

Potometer - the apparatus

7 marks

A

Set up under water - prevent entry of unwanted air bubbles.

Junction between shoot + potometer is sealed - prevent air leaks.

Apparatus reset using reservoir/syringe so water uptake in the same leafy shoot can be measured – making the investigation more reliable.

48
Q

What is the junction between the shoot and potometer sealed usually sealed with?

(1 mark)

A

Petroleum jelly

49
Q

Why is the potometer set up under water?

1 mark

A

Prevent entry of unwanted air bubbles.

50
Q

Potometer is reset using the 1._________ or 2._______ so that water uptake in the same leafy shoot can be measured.

(2 marks)

A
  1. Reservoir

2. Syringe

51
Q

Why is the junction between the shoot + potometer sealed?

1 mark

A

Prevent air leaks.

52
Q

Examples of factors that the potometer can investigate

4 marks

A

Light intensity,
humidity,
temp
+ wind speed

53
Q

When investigating the effect of an environmental factor what is important?

(1 mark)

A

All others factors are kept constant to ensure the experiment is valid.

54
Q

Weight potometer - how to use:

6 marks

A

Apparatus + plant weighed + left for a period of time.

When reweighed the amount of water lost by the plant can be calculated.

Top pan balance that measures to 2 decimal points provides great accuracy.

55
Q

What provides great accuracy when using a weight potometer?

1 mark

A

Top pan balance that measures to 2 decimal points.

56
Q

Potometer can measure the amount of water taken up by a leafy shoot but cannot provide

(3 marks)

A

An accurate value for the amount of water transpired

  • because some water will be used in photosynthesis + to provide turgor.
57
Q

Potometer can measure

1 mark

A

Amount of water taken up by a leafy shoot.