Transport in cells Flashcards
What is the concentration gradient
Difference in concentration between 2 areas
What is the correlation between concentration gradient and diffusion rate
The higher the concentration gradient the faster the rate of diffusion
Give 4 examples of diffusion
1) Oxygen and glucose into body cells from bloodstream (respiration)
2) CO2 into actively photosynthesising plant
3) Gas exchange in lungs
4) Simple sugars and amino acids from gut to cell membranes
There is a shallow concentration gradient between either side of the cell membrane.
If 3 particles move to the right side of the membrane but 7 move to the left then what is the net movement
The net movement is 4 particles to the left
In osmosis, there is a net movement of particles from a ______ solution (high water concentration), to a more _________ solution (low water concentration)
.Dilute
.Concentrated
What is the term for 2 solutions that have the same concentration
Isotonic
The term for a more concentrated solution (more solute less water) is _______
HypERtonic
—-
The term for a more dilute solution (more water less solution) is _______
HypOtonic
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What happens to an animal cell if the solution around it is:
A) hypotonic
B) hypertonic
A) Water will move into the cell via osmosis (cell swells and could burst)
B) Water moves out of the cell via osmosis (cell shrinks)
What is turgor pressure
When no more water can enter a cell because of pressure inside
What happens to cause turgor pressure
1) Water into plant cell
2) Vacuole swells
3) Cytoplasm pressed against cell wall
4) Cell rigid and so do leaves + stem
What happens to plant cells in a hypertonic solution
They lose water, become flaccid and wilts
What is plasmolysis
Clue: opposite of turgor pressure process
1) Plant cell placed in hypertonic solution
2) Water leaves cell
3) Vacuole + cytoplasm shrink
4) Membrane pulls away from cell wall
Why can plant tissue be used as an osmometer
It reacts very strongly to concentration of external solution
Why does active transport require energy from respiration
It acts against the concentration gradient
Give an example of active transport in plant roots
Root hair cells absorb mineral ions from dilute solutions in the soil
Give an example of active transport in the digestive system
Glucose can be absorbed from gut/(kidney tubules) against large concentration gradient
Give an example of active transport failure in people with cystic fibrosis
They have thick and sticky mucus in active transport system as mucus not working properly in mucus cells
What is the correlation between the surface are to volume ratio and the size of an organism
Surface area to volume ratio decreases as size increases
Why can single celled organisms perform all necessary exchanges with environment on their surface
They have a relatively large surface area to volume ratio
Why do larger organisms have efficient exchange surfaces
Because they have many cells that can’t make contact with the environment
Give the properties that an efficient exchange surface must have at least one of
1) large surface area
2) Thin membranes
3) Short diffusion path
4)
Give the properties that an efficient exchange surface must have
1) large surface area
2) Thin membranes
3) Short diffusion path
4) Efficient transport system
Give a way in which a gaseous exchange surface in an animal is ventilated
Oxygen absorbed by alveoli in lungs during breathing
