Transport in cells Flashcards

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1
Q

how do particles in liquids and gases move?
what happens due to the particles’ continuous movement in liquids and gases?

A

continuously
particles will spread themselves evenly throughout a liquid or a gas.

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2
Q

state what is meant by ‘diffusion’:

A

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

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3
Q

what is important to state about the movement of particles during diffusion: (2)

A

particles:

-will move in both directions, but there will be a net movement from high to low concentration
-will end up evenly spread throughout the liquid or gas but will continue to move

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4
Q

describe what is meant by ‘solute’, ‘solvent’ and ‘solution’:

A

solute: the substance that will be dissolve

solvent: the liquid that the solute will be dissolved in

solution: mixture formed by solute and solvent

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5
Q

what is a concentration gradient?
describe the movement of particles during this process:

A

-the difference in concentration of a chemical (across a membrane)

-particles will move down a concentration gradient, from a high concentration to a low concentration.

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6
Q

examples of diffusion in biological systems: describe the process in a leaf (2)

palisade and spongy mesophyll

A

-oxygen moves out of the palisade mesophyll cells by diffusion into spongy mesophyll cells
-carbon dioxide moves into palisade mesophyll cells by diffusion from spongy mesophyll

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7
Q

examples of diffusion in biological systems: describe the process in the lungs (4)

A

-blood from the body high in carbon dioxide and low in oxygen
-carbon dioxide diffuses from high concentration in blood to low concentration in alveolus

-oxygen diffuses from high concentration in alveolus to low concentration in blood
-blood to the body high in oxygen and low in carbon dioxide

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8
Q

examples of diffusion in biological systems: describe the process in liver cells (3)

A

-high concentration of urea in liver cells
-low concentration of urea in blood vessel in liver
-urea is filtered from blood by the kidneys

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9
Q

what can the rate of diffusion be affected by? (3)

A

Concentration gradient,
temperature
Surface area of the cell membrane separating different regions

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10
Q

how does the ‘concentration gradient’ affects the rate of diffusion?

A

The greater the difference in concentration, the quicker the rate of diffusion

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11
Q

how does temperature affect the rate of diffusion? (2)

A

The higher the temperature, the more kinetic energy the particles will have,
-so they will move and mix more quickly

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12
Q

how does the ‘Surface area of the cell membrane separating different region’ affect the rate of diffusion?

A

The greater the surface area, the faster the rate of diffusion

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13
Q

how does diffusion occur in plants?

A

substances diffuse into and out of the bacterial cell across its surface

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14
Q

how does diffusion occur in multi-cellular organisms?

A

substances diffuse into the leaves and simple roots over their surface.

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15
Q

how odes a simple organisms need being determined by its volume cause a problem?

A

As organisms increase in size, their surface area does not increase at the same rate as their volume.

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16
Q

what is osmosis?

A

diffusion of water molecules, from a region of higher concentration to lower concentration, through a partially permeable membrane.

17
Q

describes the difference between a dilute solution and a concentrated solution: (2)

A

-A dilute solution contains a high concentration of water molecules,
-concentrated solution contains a low concentration of water molecules.

18
Q

what happens when the concentration of water is the same on both sides of the membrane? (2)

A

the movement of water molecules will be the same in both directions.
-There will be no net movement of water molecules.

19
Q

what do cells contain? and how will water be transported into and out of the cell?

A

-dilute solutions of ions, sugars and amino acids.
-since the cell membrane is partially permeable, water will move into and out of cells by osmosis.

20
Q

describe the process of osmosis in different plant cells: (3)
-Isolated plant cells
-root hair cells
-Leaf cells

A

-Isolated plant cells placed in a dilute solution or water will take in water by osmosis.
-If the soil is wet or moist then root hair cells will also take up water by osmosis.
-Leaf cells of land plants, unless it is raining or the humidity is high, will have a tendency to lose water.

21
Q

what do plant cells have outside the cell membrane? what is a feature of it? what does it do to the cell?

A

-a strong cellulose cell wall.
-fully permeable to all molecules.
-supports the cell and stops it bursting when it gains water by osmosis.

22
Q

what happens to the cell contents in pure water?
what do fully turgid cells support?

A

cell contents push against the cell wall and the cell becomes turgid.
-the stems of non-woody plants.

23
Q

what happens to the cell contents in concentrated solutions?
what does the cell membrane begin to do?
what does the cell become?

A

cell contents lose water by osmosis and the cells shrink.
The cell membrance starts to pull away from the cell wall.
The cell becomes flaccid.

24
Q

what happens to the cell membrane in VERY concentrated solutions?
what is this process called?

A

the cell membrane pulls away from the cell wall completely
-plasmolysis.