movement of substances through cells Flashcards
What does a high concentration gradient mean
The difference between the concentrations of both areas is very large
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration due to their kinetic energy across a concentration gradient
What are four factors that can affect diffusion
Temperature
Distance
Concentration gradient
Surface area to volume ratio
Describe how temperature affects the rate of diffusion
The higher the temperature the more kinetic energy
So more collisions
So faster the rate of diffusion
Will diffusion be quicker with a high concentration gradient or a low concentration gradient?
High concentration gradient
Will rate of diffusion be faster in high surface area to volume ratio or low surface area to volume ratio
And explain why
High surface area to volume ratio (eg 6:1)
Because there will be more space for diffusion to occur across less space relative to its size
Explain why humans are made of many cells rather than one
Entire Human body has low surface area to volume ratio
so diffusion would happen slowly
and oxygen would not be able to be supplied to the body fast enough
So single cells provide high surface area to volume ratios so diffusion happens quickly
What restricts the free movement of particles to move outside a cell
The partially permeable cell membrane
Explain three ways in which diffusion helps living organisms
- helps obtain nutrients (——
- helps in gas exchange for respiration—–) (——
- helps get rid of waste products——)
Which molecule for respiration moves through a leaf and where does enter from and where are they transported to?
Oxygen enters through the stomata and is transported to the mitochondria
Does diffusion require energy
No
Name two molecules that can not pass through the semi permeable membrane
and two that can
Starch and proteins CANT
glucose and amino acids CAN
Give an example of a cell adapted to diffusion and how it is adapted
The villi of the small intestine
It is folded so has an increased surface area to volume ratio
What is Osmosis
The diffusion of particles from a dilute solution to a concentrated solution across a semi permeable membrane
What is the water potential of a dilute solution
High water potential
What is the name given to two solutions with the same osmotic pressure
Isotonic solution
If a plant cell is placed in dilute solution, describe the movement of water and the name given to what happens to the cell
Water will move into the cell
Because water moves from dilute solutions(High water potential to concentrated solutions (low water potential )
cell becomes TURGID
If an animal cell is placed in dilute water, explain the movement of water and the name given to what happens to it
Water moves into the cell
Because water moves from dilute solutions(High water potential to concentrated solutions (low water potential )
This process is called LYSIS
If an animal cell is placed in concentrated solution of water, explain the movement of water and the name given to what happens to it
Water will move out
Because water moves from a more dilute solution(High water potential)to a more concentrated solution (low water potential)
Cell becomes CRENATED
If a plant cell is placed in concentrated solution of water, explain the movement of water and the name given to what happens to it
Water will move out of the cell
Because water moves from a more dilute solution(High water potential)to a more concentrated solution (low water potential)
The cell becomes FLACID
What is the name given to a plant cell that has lost toon,ugh water through osmosis
It become PLASMOLYSED