Cell Membranes Flashcards
What is a cell membrane?
It encloses everything in a cell.
Where does the cell membrane lie in a plant cell?
Again the inside of the cell wall.
What is a cell membrane made up of?
Protein and Lipids (fats) molecules
What is diffusion?
Diffusion is the movement of a substance from an area where it is HIGH concentration to where it is in a LOW concentration, until evenly spread.
Example of Diffusion?
-Oxygen entering a cell for respiration
-Carbon Dioxide leaves cell
-Digested food enters
What is the concentration gradient?
The difference in concentration that exists between an area of HIGH concentration and LOW concentration.
What is passive transport?
When diffusion requires NO energy input from cells.
What is osmosis?
Diffusion of WATER from an area where its in HIGH concentration to an area where it is in LOW concentration through a SELECTIVELY PERMEABLE MEMBRANE.
Is Osmosis passive transport?
Yes. It does not use up energy therefore it is passive.
OSMOSIS IN ANIMAL CELLS!!!
A. Red blood cell placed into pure water?
B. Placed into isotonic solution?
C. Placed into salt solution?
A. Water moves into cell - Cell bursts (Haemolysis)
B. Water moves in and out equally - No net change
C. Water does out of cell - Cell shrivels (Crenated)
OSMOSIS IN PLANT CELL!!!
A. Plant cell placed into pure water?
B. Placed into isotonic solution?
C. Placed in salt solution?
A. Water moves into cell - Cell becomes turgid
B. Water moves in and out equally - No net change
C. Water moves out of cell - Cell is plasmolyse
Passive transport examples ?
Diffusion and Osmosis require no energy
What happens in Passive transport?
Molecules simply move from an area of HIGH concentration to an area of LOW concentration.
What is Active transport?
The movement of molecules from an area of LOW concentration to an area of HIGH concentration against a concentration gradient.
Does Active transport require energy?
Yes!
