AP Biology Study Guide

Matter

anything that takes up space and has mass

element

a substance that cannot be broken down into other substances by chemical reactions

compound

a substance consisting of two or more difference elements combined in a fixed ratio

CHOPN

Carbon, Hydrogen, Oxygen, Phosphorous, Nitrogen

Selective permeability

the ability of membranes to regulate the substances that enter and exit

hydrophilic head orient towards…

the aqueous environments

hydrophobic tails orient…

facing inwards away from the aqueous environments

amphipathic

having both hydrophobic and hydrophilic parts

What does the plasma membrane do?

separates internal cell environment from external environment

What is the name of the model used to describe the structure of a cell membrane?

Fluid Mosaic Model

What does “Fluid” mean in the Fluid Mosaic Model?

the membrane is held together by weak hydrophobic interactions and can therefore move and shift

What does “Mosaic” mean in Fluid Mosaic Model

it’s compromised of many macromolecules, with the surface resembling a mosaic painting

What affects fluidity?

temperature and amount of unsaturated fatty acids (the hydrocarbon tails)

______ helps maintain fluidity at high and low temperatures

Cholesterol

What are the major categories of proteins in the membrane?

Integral proteins and Peripheral proteins