transport in cells Flashcards

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1
Q

What is diffusion

A

The random movement of particles from an area of high concentration to an area of low concentration

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2
Q

How do you calculate net movement

A

Particles moving in - particles moving out

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3
Q

What is net movement

A

The general movement of particles

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4
Q

What are the factors that determine the rate diffusion

A

Concentration gradient, surface area and diffusion distance

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5
Q

How does the concentration gradient affect the rate of diffusion

A

The greater the concentration gradient the quicker diffusion takes place

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6
Q

How does temperature affect the rate of diffusion

A

As the gas or solution heats up the particles gain more kinetic energy and move around faster, this increases the random movement of the particles enabling them to diffuse more rapidly

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7
Q

How does surface area affect the rate of diffusion

A

Our membranes are partially permeable, so by increasing the surface area through which the particles can move through diffusion will be faster

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8
Q

How does size compare to surface area to volume ratio

A

The larger the organism the smaller the surface area to volume ratio

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9
Q

List 3 adaptions for exchange

A

Increasing the surface area, so more particles can move at once
Have a short diffusion distance the particles have to travel
Increase the steepness of the concentration gradient to speed up the net flow of particles

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10
Q

How are lungs adapted for exchange

A

1)a large number of small alveoli creates a large surface area for rapid diffusion of gases
2) A rich capillary blood supply brings french blood to the alveoli maintaining a steep concentration gradient
Ventilation refreshes the air in the lungs to maintain a step concentration gradient
3)a thin alveolar wall gives the shortest diffusion distance for the gasses

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11
Q

How are the small intestines adapted for exchange

A

1)They have thousands of villi which in turn have numerous microvilli on their surface for large surface area
2) they have rich capillary lood supply to remove absorbed nutrients and maintain a steep concentration gradient
3)the walls are only one cell thick to keep the diffusion distance short

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12
Q

How are plant roots adapted for exchange

A

1)The tip of the roots are covered in root hair cells which increase their surface area for absorption
2) transpiration in the leaves continuously pulls water up the plant creating a steep concentration gradient
3) there is only a short distance from the edge of the root to the xylem in the middle

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13
Q

How are plant leaves adapted for exchange

A

1)There are stomata at the bottom of the leaf to allow carbon dioxide to diffuse into the leaf and oxygen out
2) the thin leaf shape minimises the diffusion distance for gasses
3) the air spaces in the spongy layer exposes a large surface area for gaseous exchange

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14
Q

What is osmosis

A

The net movement of water from a dilute solution to a strong solution across a partially permeable membrane

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15
Q

Osmosis model answer plan

A

1.Identify the hyper/hypotonic solution
2.State which way the water moves
3โ€ฆ..by osmosis through a partially permeable membrane
4.Describe the result eg swells up / shrivells up

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16
Q

What will happen to an animal cell when the solution is hypotonic to it

A

Water will enter the cells and can cause them to burst

17
Q

What will happen to an animal cell if the solution is hypertonic to it

A

Water will leave the cells, causing them to shrivel up

18
Q

What will happen to an animal cell when the surrounding solution is isotonic to it

A

(if the surrounding solution is the same concentration to the cell it is isotonic)
Under these conditions there will be no movement of water so the cells will remain the same size

19
Q

What will happen to a plant cell if it is placed in a hypotonic solution

A

Water will enter the cell causing the vacuole to swell up and pushing the cytoplasm against the cell wall
The wall will push back preventing the cell from bursting
The cell becomes swollen and turgid

20
Q

What will happen if a plant cell is placed in a hypertonic solution

A

Water will leave the cell via osmosis, the cell membrane will be pulled away from the cell wall in a process called plasmolysis

21
Q

Tears are hypotonic to blood, a student mixes tears and blood and looks at it through a microscope what would she see

A

Red blood cells swelling and possibly bursting

22
Q

Why does grass remain upright

A

Due to turgor pressure, the internal pressure exerted by the contents of plant cells due to the presence of water in the vacuole

23
Q

In a drip, an infused, one uses physiologic water (=0.9% NaCl) instead of pure water. Why is that?

A

Because this means it would have the same concentration of solute (be isotonic) to the blood, if pure water were used it would be hypotonic compared to the blood causing them to swell and potentially burst

24
Q

How does diffusion distance affect the rate of diffusion

A

The shorter the diffusion distance the faster the rate of diffusion will be.

25
Q

What do you call a swollen blood cell and plant cell?

A

animal cell - lysed
Plant cell - turgid

26
Q

What do you call a shrivelled plant and animal cell

A

Animal cell - crenated
Plant cell- plasmolysed

27
Q

What is active transport

A

The movement of a substance from an area of low concentration to an area of high concentration across a partially permeable membrane. It requires energy

28
Q

How do you calculate percentage change in mass

A

Subtract final mass from original mass
Divide by original mass
Multiply by 100

29
Q

Why is it important all potato pieces come from the same potato

A

To ensure initial water content and solute concentration are relatively consistent

30
Q

Why is it important all potato pieces come from the same potato

A

To ensure initial water content and solute concentration are relatively consistent

31
Q

Explain 2 ways which active transport differs from diffusion

A

Active transport requires energy while diffusion doesnโ€™t
Active transport moves substances against their concentration gradient while diffusion moves substances down the concentration gradient

32
Q

Why are plants not able to rely on diffusion to absorb mineral ions from the soil

A

Because the concentration of mineral ions in the soil is often lower than the concentration inside plant cells

33
Q

Why are plants not able to rely on diffusion to absorb mineral ions

A

Because the concentration of mineral ions in the soil is often lower than the concentration inside plant cells

34
Q

Explain why plants need mineral ions

A

To regulate their internal processes

35
Q

Emphysema is a disease that weakens and breaks down the walls of the alveoli explain why someone with this disease may suffer from lower energy levels during physical exercise

A

Because it weakens and breaks down the walls of the alveoli, therefore reducing their surface area for gas exchange leading to lower oxygen uptake and higher carbon dioxide retention causing lower energy levels during physical exersize

36
Q

What is the function of the stomata

A

To allow plants to take in carbon dioxide for photosynthesis and to release oxygen

37
Q

What is the function of the stomata

A

To allow plants to take in carbon dioxide for photosynthesis and to release oxygen

38
Q

Give one function of the ribs

A

To protect the organs in the chest cavity eg lungs