Cell transport Flashcards
What is surface area to body ratio?
Surface area (cm^2) : Volume (cm^3)
(Always have volume as 1)
Why is is surface area to body ratio important?
An organism needs to have a large enough surface area to absorb enough nutrients to sustain itself
What is diffusion?
When the particals of a solute go from an area of high concentration to a lower concentration. (Down the concentration gradient)
How to increase the rate of diffusion (3)?
- Large supply of blood (water for plants) to keep a steep concentration gradient
- Large surface area to increase the area a substance can diffuse over
- Thin cell wall to reduce the distance needed to travel
- moist surface to keep gasses trapped
- Higher temp
Where does diffusion happen in the body?
- the lungs (oxygen diffuses in carbon dioxide diffuses out)
- the small intestine ( e.g. glucose into the bloodstream)
How do the lungs work?
The intercostal muscles contract swinging the ribs up and out. The diaphragm flattens/ contracts leaving low pressure in the thoracic cavity. This cause air to rush in and oxygen in the alveoli diffuses into the blood. The abdominal cavity is squished by this and forces the diaphragm back up creating a higher pressure inside than out forcing the air out.
What is osmosis?
When water goes from an area of high concentration down the gradient to an area of low concentration via a partially permeable membrane.
What is a partially permeable membrane?
A membrane that lets some substances through but not others
What does Isotonic mean
When a solution is equally concentrated to the cells it encounters
What does flaccid (plant cell) mean
When the cell is dehydrated after being put is a HYPERTONIC solution due to water diffusing out of the cell down the concentration gradient. The cell membrane pulls away from the cell wall making it squishy but still retaining its shape.
What does flaccid (animal cell) mean
The cell is placed in a hypERtonic solution. Water diffuses out and the cell will shrivel and die in a process known as plasmolysis
What does turgid mean (plant cell)
The cell is placed in a HYPOTONIC solution meaning there is more water outside than inside the cell so the water diffuses in making the cell stiff and rigid and swollen but it wont explode due to the cell wall.
what does turgid mean (animal cell)
The cell is placed in a hypOtonic solution. Water diffuses into the cell via osmosis. The cell will bloat and often explode.
What is active transport
When solutes move up against the concentration gradient. It is an active process that uses a partially permeable membrane and transport protein which uses energy in the form of ATP (Adenosine triphosphate)
What is transported during active transport
Mineral ion- membranes don’t like charge
Glucose
Amino acids
