2. Transport Across Membranes Flashcards
Which chemicals are in the composition of cell membrane
Proteins and phospholipids
How are phospholipids arranged
In two layers
How are proteins arranged
Scattered between the two layers of phospholipids, or creating pores in the membrane
What is diffusion
A passive process by which molecules move from an area of high concentration to an area of low concentration, down a concentration gradient
What is osmosis
A passive process by which water moves from an area of high concentration to an area of low concentration, through a selectively permeable membrane
Describe osmosis in plant cells
When the higher concentration of water is outside the plant cell osmosis occurs, swelling it up - TURGOR
When the lower concentration of water is outside the plant cell osmosis occurs, shrinking the cell membrane from the cell wall - PLASMOLYSIS
Describe osmosis in animal cells
When the higher concentration of water is outside the animal cell osmosis occurs, and the cell bursts -HAEMOLYSIS
When the lower concentration of water is outside the animal cell osmosis occurs, and the cell shrivels up - CRENATION
What is the concentration gradient
The difference in concentration between two regions
What % of the body is water
70%
What enters and leaves our body by diffusion
Enters - glucose and oxygen
Leaves - carbon dioxide and waste products
What diffusion features do some organs have
Special surfaces for absorbing exchanging materials, which are usually adapted for rapid diffusion
Moist surface, as gases must dissolve
What is active transport
Movement of ions across membranes up a concentration gradient, from a lower concentration to a higher concentration
Specific protein molecules act as carriers and move them across the membrane
ENERGY comes from respiration
