Bio Stuff 2
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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What is diffusion?
Natural movement of particles from a higher concentration to a lower concentration (to create equilibrium)
How does rate of diffusion work?
It can be increased by adding energy or molecular movement (stirring or adding heat)
What parts of cells can diffusion of water or solutes occur in?
Cytoplasm or cell membrane
What is a concentration gradient?
A difference in concentration; involves molecules or ions of a single type, drives diffusion and osmosis.
What is passive diffusion?
When no energy is needed.
How does the cell membrane determine what comes through its membrane?
Particle size, charge, and solubility in lipids.
What is Osmosis?
Diffusion of water; able to pass through if there is a concentration gradient across the cell even if a solute cannot pass
Passive transport
Energy is not required
Hypertonic solution
Solution that a higher concentration of solutes than the cell and a lower water concentration . Water will leave the cell for the hypertonic solution.
Hypotonic solution
Solution had a lower concentration of the solutes than the cell, higher concentration of water. Water will enter the cell.
Isotonic Solution
Equal concentration, no net water movement, already equalized.
Can all substances pats through the lipid bilayer via diffusion?
No, only substances that are soluble in lipids.
What does soluble mean?
Able to be dissolved in; form a solution with another substance.
Facilitated diffusion
Passive movement of molecules along the concentration gradient; e.g., transport of glucose and amino acids into the cell from the blood stream.
Carrier proteins
Provide hydrophilic molecules to move down the concentration gradient.
What are channel proteins?
Acts like a pore; lets water molecules or small ions quickly
What does going down a concentration gradient mean?
Going from high to low concentration