cell transport

diffusion

particles spreading from an area of high concentration to an area of low concentration

what is the concentration of oxygen inside a cell?

low concentration

what is the concentration of oxygen outside of a cell?

high concentration

what direction does oxygen move in relation to the cell?

oxygen moves into the cell

how is oxygen used in the cell?

by the mitochondria for aerobic respiration which releases energy for the cell

what waste product does oxygen produce during respiration?

carbon dioxide

what concentration is carbon dioxide in the cell?

high concentration

what concentration is carbon dioxide outside the cell?

low concentration

what direction does carbon dioxide move out of the cell?

carbon dioxide moves out of the cell

what factors affect the rate of diffusion?

temperature, surface area, concentration gradient

how does temperature affect the rate of diffusion?

it increases the rate of diffusion as the particles have more kinetic energy and therefore move faster

how does surface area and concentration gradient affect the rate of diffusion?

increases it

how do a large organism and ratio of surface area to volume link?

the larger the organism the lower the ratio of surface area to volume?

what do multicellular organisms rely on?

multicellular organisms rely on diffusion to transport molecules like single celled organisms.

why is having a lower ratio of surface area to volume a big problem for larger organisms?

surface area is not large enough for volume meaning not enough oxygen is able to diffuse into all the cells especially cells that are in the centre of the organism

why is it hard for cells in larger organisms to get oxygen diffused into them?

they are too far away from the surface

in what ways are gills in fish adapted for diffusion?

bigger surface era, thin membrane, efficient blood supply

how do fishes gills have a larger surface area?

a large number of filaments

how do fishes gills having a thin membrane make them more effective for diffusion?

provides a short diffusion pathway

how does an efficient blood supply in fishes gills make them more effective for diffusion?

helps take oxygenated blood away and always the concentration gradient to remain high

how do fish get oxygen from the water into there gills?

water flows over gills and the oxygen is transported into the bloodstream

how does oxygen transported into the bloodstream get into the filaments of the fish?

deoxygenated blood passes into the filament and the oxygen diffuses the water into the blood

osmosis

diffusion of water

what type of solution is in a cytroplasm?

concentrated with a low concentration of water

what will happen to the cytroplasm when it is placed in water?

by the process of osmosis water from move from outside of the cell to inside

what will happen to an animal cell if it is placed in water?

the water moving into it will expand and maybe even burst

what will happen to an animal cell if it is placed in a concentrated solution?

the water moving out of it will cause it to shrink

what will happen to a plant cell if it is placed in water?

the water moving into it will cause it expand but not burst as the cell wall prevents it - cell is deemed turgid at this stage

what will happen to a plant cell if it is placed in a concentrated solution?

the water moving out of it will cause it to shrink - cell is deemed flaccid at this stage

what is active transport?

a process that moves material from an area of low concentration to an area of high concentration

what does active transport do to the concentration gradient?

it moves substances against the concentration gradient which requires energy

what does active transport allow for plants?

allows mineral ions found in soil to be absorbed from low concentrations which allows for important growth

what cell is specialised in order to carry out active transport?

root hair cell

what specialised functions allow the root hair cell to carry out active transport?

large vacole, large surface area, thin walls, lack of cuticles

how does the root hair cell having a large vacuole allow it to carry out active transport?

to store solutes

how does the root hair cell having a large surface area allow it to carry out active transport?

increases the rate of active transport

how does the root hair cell having think walls allow it to carry out active transport?

reduces the distance of diffusion

how does the root hair cell having a lack of a cuticle allow it to carry out active transport?

allows for the absorption of water

what carries out active transport within the cell membrane?

protein carriers

how is active transport carried out?

the substance binds to protein carries on the side with low concentration using energy from respiration to do so and release it onto the other side

what do specialised cells designed to carry out active transport need?

lots of mitochondria for energy

what is the first step of the osmosis required practical?

to peel the potato

why do we need to peel the potato in the osmosis required practical?

the potato skin could affect the process of osmosis

what is the second step of the osmosis required practical?

use a cork borer to produce 3 cylinders of potato

what is the third step of the osmosis required practical?

use a scalpel to cut them to the same length

why do we need to use a cork borer in the osmosis required practical?

using it allows the cylinders of potato to all be equal in diameter

what is the forth step of the osmosis required practical?

to measure the mass + length of each cylinder

what is the fifth step of the osmosis required practical?

place each potato cylinder in a test tube - the first one in 10 cm^3 of a 0.5 molar sugar solution, the second one in a 0.025 molar sugar solution and the last in distilled water

why is it important to use distilled water for this experiment rather than tap water?

because distilled water contains no dissolved substances which could have an affect on the rate of osmosis

what is the sixth step in the osmosis required practical?

leave the potato cylinders in water overnight

what is the seventh step in the osmosis required practical?

remove the cylinders from the tube and pat dry with paper towel

why do we need to pat the potato cylinders dry in the osmosis required practical?

in order to remove any surface moisture that could affect the results

what is the last step in the osmosis required practical?

measure the mass and lengths of the potato cylinders again, calculate the percentage change using the start and end results and plot a graph

why is it that the place that the x crosses the graph there is no change in mass?

the concentration outside the cell is the same as the concentration inside - no osmosis has taken place