The properties of lipids
Cell membranes have this typical layered structure because of the chemical properties of
the lipids that make up the membrane.
This *flexible structure forms a strong *barrier between the cell and its surroundings.
The cell membra
One of the most important functions of the cell membrane is to keep the cell's internal
conditions relatively *constant.
In order to maintain this condition of homeostasis, the cell membrane must control the
transport of materials into o
Driven by differences in solute concentration, the net movement of water into or out of a
cell produces a force known as osmotic pressure
Almost always hypertonic
Because cells contain a variety of solutes such as:
Sugars, proteins, salts
Predicting the direction of osmosis in cells
The direction of water movement into or out of a cell can have dire consequences on the
survival of a cell. By knowing the concentrations of solute and solvent on the inside and
outside of a cell, we ca
Introduction to cell transport
Transport is the name of the life process in which materials are exchanged between and
organism and its environment.
What types of materials need to be transported into or out of living cells?
Transport can be as simple as m
the process by which particles move from an area of high concentration to an area of
The process of diffusion drives the movement of many molecules which move across cell
Suppose a substance is present in unequal
What will happen to the concentration gradient over time as diffusion continues?
High gradient low gradient no gradient
Once the concentration of the substance on both sides of the cell membrane is the same
Equilibrium is reached
Particles of the solution will continue to move across the membrane in almost equal
numbers, so there is no further *net change to the concentration of the solutions inside or
outside the cell.
This is defined to in fact
Process in which molecules that cannot directly diffuse across the cell membrane pass
through special protein channels
Red blood cells have protein carriers to allow glucose to pass in/out of the cell.
There are hundreds of exam
Some proteins form * channels and pumps to help move material across the cell
B) some proteins *
attach directly to the cytoskeleton (internal support of the cell), enabling cells to respond
to their environment by using their membranes
Biology 20: Module 1: Lesson 2
MODULE 1: LESSON 2 ASSIGNMENT
This Module 1: Lesson 2 Assignment is worth 56 marks. The value of each assignment
and each question is stated in the left margin.
Lesson 2 Assignment: Energy Flow Throug