Test on cell transport Flashcards
What is Diffusion?
Diffusion is the tendency of molecules to spread into an available space to equalize the concentration gradient.
Controlled/Facilitated Diffusion?
- No Energy
- Only occurs at certain points along cell membrane called “channels”
- Channels are usually specific to one or a few types of molecules
Simple/Passive Diffusion?
- No energy
- Happens across cell membrane
- From high concentration to low concentration (“down the concentration gradient”)
What is Osmosis?
- Simple diffusion of water
What is active transport?
- requires energy
- Happens only at specific channels
- From low to high concentration (“against the concentration gradient”)
Explain semi-permeability
- Allowing passage of certain, especially small, molecules or ions but acting as a barrier to others.
- It allows important nutrients to enter the cell, while preventing other foreign or un-needed things to enter the cell.
Concentration gradient
the gradual difference in the concentration of solutes.
What is the function of the cell membrane?
Acts as a barrier and decides what goes in and out of cell.
endocytosis?
Endocytosis is an energy-using process by which cells absorb molecules (such as proteins) by engulfing them. Then forms a vacuole with engulfed molecule within.
phagocytosis?
endocytosis for solids
pinocytosis?
endocytosis for liquids
receptor mediated endocytosis?
only certain molecules fit into the receptors (coated vesicles), so once they fill up it makes the coated vesicle large and drift into the rest of the cell.
What is exocytosis?
opposite of endocytosis. Vesicles containing molecules fuse to cell membrane and ‘spit out’ contents
What are the levels of cellular organization from smallest to largest?
cell-tissue-organ-organ system-organism
Define independent variable
variation does not depend on that of another.
