T1 transport in cells Flashcards Preview

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Flashcards in T1 transport in cells Deck (17)
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1
Q

what is diffusion

A

net movement of particles from an area of higher concentration to an area of lower concentration

2
Q

three main factors affecting the rate of diffusion

A

concentration gradient - larger, faster

temperature - higher, faster

surface area - larger, faster

3
Q

give examples of substances transported by diffusion in the lungs and the kidney

A

lungs: O2 diffuses into blood from the lungs and CO2 diffuses into the lungs from the blood, both down their concentration gradient
kidney: urea diffuses from cells into blood plasma so it can be excreted in urine

4
Q

how are single-celled organisms adapted for diffusion

A

large surface area to volume ratio - maximises the rate of diffusion of molecules to meet the organism’s needs

5
Q

how is surface area to volume calculated

A

=number of sides x (side length x side width)

volume = length x width x depth

ratio = surface area : volume

6
Q

what 4 factors increase the effectiveness of a gas exchange surface

A

large surface area

thin membrane (short diffusion path)

efficient blood supply

ventilation

7
Q

what is osmosis

A

movement of water from a dilute solution to a concentrated solution through a partially permeable membrane

8
Q

what is meant when a solution is isotonic to a cell

A

concentrations of the external and internal solutions are the same

9
Q

what is meant when a solution is hypertonic to a cell

A

concentration of the external solution is higher than that of the internal solution (inside cell)

10
Q

what is meant when a solution is hypotonic to a cell

A

concentration of the external solution is lower than that of internal solution

11
Q

what may happen when an animal cell is placed in a hypotonic solution

A

water moves into the cell, causing it to burst

12
Q

what may happen when an animal cell is placed in a very hypertonic solution

A

water moves out of the cell, causing it to shrivel up

13
Q

how do plant leaves and stems remain rigid

A

turgor pressure - water moves in by osmosis, causing the vacuole to swell and the cytoplasm to press against the cell wall

14
Q

what may happen when a plant cell is placed in a very hypertonic solution

A

water moves out of the cell by osmosis and the vacuole and cytoplasm decrease in size

cell membrane may pull away from the cell wall, causing the cell to become plasmolysed

15
Q

what is active transport

A

movement of molecules from a more dilute solution to a more concentrated solution against a concentration gradient, using energy from respiration

16
Q

how do plant root hair cells use active transport

A

take up mineral ions from a more dilute solution in soils.

ions such as magnesium and nitrates are required for healthy growth

17
Q

how is active transport used to absorb the products of digestion

A

transport glucose from a lower concentration in the gut to a higher concentration in the blood

glucose is then transported to the tissues where it can be used in respiration