Transport in cells Flashcards
Name the three types transport that happen in cells
Active transport
Osmosis
Diffusion
define diffusion
The net movement of molecules from where they are at a higher concentration to where they are at a lower concentration. The molecules diffuse down the concentration gradient
What factors affect the rate of diffusion
Surface area
Diffusion distance
Temperature
Why would diffusion happen quicker if the temperature is warmer ?
The molecules will have more energy
What is net movement
When substances may diffuse in both directions
Define osmosis
The net movement of water molecules only across a partially permeable membrane down their concentration gradient
Define passive
No energy required
What happens to the red blood cell if it is concentrated
Small
no water inside the blood cell
What happens to the red blood cell is very dilute and has a salt solution
The red blood cell will explode
If the plant cell contains a concentrated salt solutionv then it is ?
Rigid
If the plant cells concentration is the same as the cell then the plant cell will be ?
perfect
If the plant cell is very dilute and contains a salt solution then what shape would it be ?
Rigid
Define active transport
The movement of substances into and out of cells against the concentration gradient
Two examples of active transport
Absorption of minerals from soil water by plant roots
Absorption of glucose sugar in the small intestine
What features do all animal exchange surfaces have In common ?
Large surface area - More space for substance across which substances can move
short distance - Are thin , only one cell thick and often flattened cells
Concentration gradient - designed to maintain a steep gradient
What is the job of the small intestine ?
To absorb nutrients eg glucose some absorbed by diffusion but active transport is needed to absorb against the concentration gradient
Name the main exchange surface for a Mammal
Lungs
Name the main exchange surface for a fish
Gills
Name the main exchange surface for a plant
Leaves
small intestine exchange surface ?
Short diffusion distance created due to being only one cell thick
Capillary inside means that as soon as molecules enter the blood they will be transported away to maintain a high concentration
Large surface area created by villi and micro villi means more area for absorption of small food molecules
Lungs gills exchange surface ?
The fish ventilates so that a flow of water occurs across the gills this helps to maintain high concentration
Large surface area created by lots of plates
Gill lamellae are just one cell thick this creates a short diffusion distance
Mammals lungs exchange surface ?
A large surface area is created by millions of alveoli which are one cell thick covered by a capillary network
There is a short diffusion distance because the alveoli and capillary walls are just one cell thick
A steep diffusion distance gradient is created by the capillary network
