1B Transport in Cells Flashcards
Whats the definition of diffusion
The spreading out of particles from an area of high concentration to an area of lower concentration
How does dissolved substances eg.oxygen move in and out of cells by diffusion
They diffuse through cell membranes as they are small enough
What affects the rate of diffusion
- Temperature
- Concentration
- Surface Area
Why is the rate of diffusion faster when the concentration is higher
The net movement from one side is greater
Why is the rate of diffusion faster when the temperature is higher
The particles have move energy
Why is the rate of diffusion faster when the surface area is higher
More particles can move through at once
What is osmosis
The movement of water molecules through a partially permeable membrane from an area of high water concentration to an area of lower water concentration
How do you investigate the different concentrations of sugar/salt solution on potato cells
Place identical potato cylinders in a beaker of concentrated sugar solution(eg1.omol/dm3) and in a beaker of pure water. Leave for 24hrs then measure percentage change in mass after drying off.
How do you calculate the rate of osmosis
Divide change in mass by time taken (g/min)
How do you calculate the percentage change in plant tissue mass
(change in mass/ original mass) x 100
What does the point when the line of best fit crosses the x -axis mean when investigating the effect of sugar solution in potato cells
Where the concentration of sugar is same in and out of the potato. You can estimate the concentration of solution inside the potato
What is active transport
Movement of particles against a concentration gradient using energy by respiration
How does the structure of the root hair cell help it absorb mineral ions and water
It has a big surface area
What do root hair cells use active transport for and why
To absorb mineral ions as they need it for healthy growth
What does the gut absorb into the blood by active transport and why
Sugar for use in cellular respiration
What out of diffusion, osmosis and active transport requires energy
Active transport
What are some examples of substances that move in and out of cells by diffusion
Oxygen and carbon dioxide or transferred between cells and The environment during gas exchange
Why can gases and dissolved substances diffuse directly into the cell across the cell membrane is in a single celled organism
They have a large surface area compare to the volume so enough substances can be changed to supply the body
Why do you multi cellular organisms have specialised Exchange services/transport systems
They have a smaller surface area: volume ratio so not enough substances can diffuse supply The volume
How’s the exchange services adapted to maximise effectiveness
- thin membrane-short distance to diffuse
- large surface area-lots of substances diffuse at once
- Exchange services have a lot of blood vessels-to get stuff into/out of the blood quickly
- gas exchange and animals are often ventilated-air moves in and out
How is alveoli adapted to maximise the exchange of gases in the lungs in mammals
An enormous surface area
Moist lining for dissolving gases
Very thin walls
Good blood supply
How does villi adapt to aid the absorption of nutrients in the gut
A single layer of cells are cells
Very good blood supply to assist quick absorption
How are leaves adapted to maximise the exchange of gases in plants
-stigmata underneath leaf-carbon dioxide in and oxygen/water out
-flatten shape-increases area so it’s more affective
– Air spaces inside leave – increases area so more chance of CO2 to get into cells
How are girls adapted to maximise the exchange of gases in fish
Water containing outage and enter for your mouth and out through gills
- made of thin plates(Gill filaments)
- Gill filaments covered in teeny structures called lamellae
- blood flow through lamellae is in One Direction and water in opposite direction
- large concentration gradient between water and blood
