B1 Cell Biology Flashcards
What is diffusion?
The spreading out of particles with a net movement from a high concentration to a low concentration
Why is oxygen needed in the body?
It is needed for respiration in cells
Why does oxygen move into a cell?
There is a high concentration outside the cell as it is surrounded by blood from the lungs.
Why does carbon dioxide move out of the cell?
There is a high concentration of carbon dioxide in the cell
What is carbon dioxide in the body?
A waste product of respiration
What is urea?
A waste product produced in cells
Why does urea move out of the cell?
There’s a high concentration in the cell so if users through the membrane into blood plasma
What factors increase the rate of diffusion?
A higher surface area
A greater concentration gradient
High temperature
What is surface area to volume ratio?
A measure of how large an organism surface area is compared to its volume.
Why can single celled organisms use diffusion to get all the gases?
They have a large surface area to volume ratio
What happens when an organisms gets larger?
Surface area to volume ratio falls
Why can multicellular organisms not use diffusion to get gases?
The surface area to volume ratio is not large enough so oxygen cannot diffuse to the centre of the organism
What adaptation do gills have?
Large surface area
Thin membrane
High blood flow
What is osmosis?
The movement of water molecules over a partially permeable membrane from an area of high concentration to an area of low concentration
What is active transport?
The movement of particles against concentration gradient using energy transferred during respiration
How do plants use active transport?
It allows minerals in areas of low concentration in the soil to move into the root hair cells against a concentration gradient
How is active transport used in digestion?
When there is a low concentration of nutrients in the gut but higher concentration of nutrients in the blood.
What is the difference between active transport and diffusion?
Active transport uses energy while diffusion is passive.