Bio Test #4

What are the parts of the cell membrane?

phospholipid bilayer, protein, transport protein, phospholipid, cholesterol, charbohydrate

What does the cell membrane do?

it regulates what enters and leaves the cell and provides protection and support to the cell

Phospholipids

structural components of membranes

Transport proteins

form channels and pumps to help move materials across the membrane

Receptor proteins

recognize and bind to substances at the cell surface

fluid mosaic

because of constant movement in the bilayer, the pattern of the lipids and proteins is constantly changing

Homeostasis

cells maintain a stable internal environment, even when the external environment is constantly changing

Permeability of the Membrane

lets some substances pass through more readily than others and some materials are not allowed to enter at all. It can control the speed at which molecules are allowed to enter

the Concentration Gradient

in the absence of other forces, materials will tend to move from an area of high concentration to an area of lower concentration

Diffusion

movement of molecules from a region of high concentration to a region of low concentration

Osmosis

movement of water across a membrane from a region of high concentration to a region of low concentration

aquaporin

membrane protein that acts as a channel to move water across the cell membrane

isotonic solution

the concentration of solutes outside and inside the cell are equal. the concentration of water is the same on the inside and the outside of the cell.

hypertonic solution

the concentration of solute molecules outside the cell is higher than the concentration of solutes inside the cell.

Plasmolysis

too much water moves out and the cell collapses

Hypotonic

the concentration of solute molecules outside the cell is lower than the concentration of solutes inside the cell

Cytolysis

too much water moves into the cell, and the cell membrane ruptures because of the water pressure

facilitated diffusion

type of passive transport used for molecules that don’t readily diffuse through membranes

Carrier proteins/transport proteins

help molecules pass through the membrane more easily

active transport

the cell moves materials from an area of low concentration to an area of higher concentration (requires energy called ATP, moves against concentration gradient)

Endocytosis

a cell takes material into the cell by infolding the cell membrane

two types of endocytosis

phagocytosis and pinocytosis

Phagocytosis

the engulfing of large food particles

Pinocytosis

the cell surrounds and engulfs droplets of extracellular fluid.

Exocytosis

the cell releases large amounts of material to the outside of the cell.

Passive transport

substance moves from high to low concentration across a cell membrane(doesn’t require energy)

types of passive transport

diffusion, osmosis, facilitated diffusion

types of active transport

endocytosis and exocytosis (or just use a protein)

types of osmosis

isotonic, hypertonic, hypotonic

turgor pressure

the force within the cell that pushes the plasma membrane against the cell wall