Thursday 1/30/14
AIM: How is the structure of the plasma
membrane related to its function?
DO NOW: In complete sentences, explain
why every cell has a cell membrane.
Homework: The cell handout
Functions
Helps to maintain balance or homeostasis
within the cell
Boundary between cell and its
environment
Selectively permeable: allows some to
pass and others are kept out
The Plasma Membrane YouTube
How is the cell membrane
constructed?
The cell membrane
Plasma membrane
Phospholipid bilayer
Embedded with
proteins and
cholesterol molecule
Membrane proteins: help
molecules move across the
membrane
Integral proteins: big enough to span both
layers of the membrane
Peripheral proteins: only found on the
surface of the membrane
– Usually only span one layer of phospholipids
How do fibrous proteins,
globular proteins and
cholesterol create a fluid
mosaic?
How do membrane proteins
assist in protecting the cell?
Membrane proteins
Fibrous proteins: receptors
Glycoproteins:cell to cell recognition or
identification
Pore proteins: passive transport
Channel proteins: active transport
Thursday 12/6/12
AIM: How does the plasma membrane regulate
movement of molecules into and out of the cell?
DO NOW:Explain the difference between
hydrophobic and hydrophillic. Which part of the
cell membrane is hydrophobic? Hydrophillic?
HOMEWORK: Textbook read pages 175-177.
answer the reading check questions on pages
175 and 176. Question 3 on page 177
POP QUIZ
1- What are the 2 other names for the cell
membrane?
2- why is it important for the cell
membrane to be partly hydrophobic and
partly hydrophillic?
Why is it important for the
membrane to be partly
hydrophobic and partly
hydrophillic?
The cell membrane
How does the structure of the
membrane relate to its function?
Construction of the Cell
Membrane Wisconsin Online
Structure of a phospholipid
Why does the membrane need
cholesterol?
Helps stabilize the membrane
Dissolve in the hydrophobic tail to make
the membrane liquid
Cell Membrane proteins
Integral proteins
– Function is to help
molecules move
across the membrane
– Span both layers of
phospholipids
Peripheral proteins
– Function in cell top cell
recognition
– Also assist in
molecular movement
– Only span one layer of
the phospholipid
bilayer
Period 7 friday 12/8/12
Glycoproteins
Part carbohydrate (glyco)
Part protein
These are peripheral
Help in cell to cell recognition
Fluid Mosaic model
Individual phospholipids
are not bonded
Fluid because
phospholipids move
within the membrane
At the same time,
proteins in the
membrane also move
among the
phospholipids
These proteins create a
mosaic model
Why is the plasma membrane
selectively permeable?
In complete sentences explain what you
would do in the following situation: You are
at a dance that contains 100 kids within 1
hour the dance fills up with 800 kids and
you can hardly move. What would you do
and why?
How do molecules move across
the plasma membrane?
Transport
Passive: molecules move from a high to
low concentration
Active: molecules move from low to high
concentration
Transport across the membrane
cytoplasm has different
molecules and ions.
Some easily pass through
the plasma membrane
into the cell.
These include water,
oxygen and glucose
molecules, and sodium
and chloride ions.
Passive Transport
Small lipid soluble molecules move from a
crowded area to a less crowded area
Down the concentration gradient
No energy is required
Passive transport
Passive transport
Simple diffusion
Osmosis
Facilitated diffusion
Assessment
Use your notes to design a well organized
table using the parts and the functions that
build the plasma membrane
Diffusion
Movement is driven
by concentration
gradient
Molecules move from
an area of high
concentration to low
concentration
Solute concentration
is equal
Facilitated diffusion
Some molecules are
too big to passively
diffuse
So they need the help
of carrier proteins
Transport is still
driven by a
concentration
gradient
What are the different types
of transport?
Passive and active
How are passive and active
transport different?
Passive: driven by
concentration gradient
Active: driven by ATP
Osmosis
Simple diffusion of
water
From an area of
higher
concentration to a
region where they are
in a lower
concentration
Isotonic: equal movement of water
into and out of cell
Hypotonic solution: net water
movement into the cell
Hypertonic: net movement of water
out of the cell
Friday 11/18/05
Aim: Why does the cell use energy to move
molecules across the cell membrane?
Do Now: Use your table from yesterday or
create a new table organizing the osmotic
environments and the flow of water in each. In a
third column of your table, draw a picture of each
using an x to represent solute molecules and o
to represent water molecules.
Homework: study for tuesdays exam
How does the concentration
gradient determine the
direction of molecule
movement across the cell
membrane?
Active transport
Movement of substances against a
concentration gradient
From low to high
Needs energy
Membrane proteins use energy to move
individual molecules
How does active transport differ
from facilitated diffusion?
Monday 11/21/05
AIM: How does the cell use energy to
transport molecules across the plasma
membrane?
DO NOW: Use the picture displayed to
explain the process:
Homework: Internet Project #
1
How is active transport different
from passive transport?
Passive transport does
not need energy to move
molecules from high to
low concentration
Active Transport uses
energy to move
molecules against the
concentration gradient
Why is active transport necessary
for homeostasis?
Certain molecules need to enter or leave
the cell against their concentration
gradient
12/5/07 Wednesday
AIM: How do molecules actively cross the
cell membrane?
DO NOW: Create a Venn diagram
showing the differences between active
and passive transport
HW: textbook page 197 Questions 6 and
21
Northland College Education
Biology Animation
Transport processes
Requiring ATP
Active transport
Endocytosis: cell uses energy to carry
molecules inside
Exocytosis: remove contents from the cell
Ion pumps
Co-transport
Active transport
Endocytosis: intake of
particles or fluids in to
the cell
Pinocytosis: cell
drinking
Phagocytosis: cell
eating
Phagocytosis in an ameba
Ion Transport
Cotransport
movement of 2
solutes together
often moves 1 solute
passively & other
actively
Exocytosis
Type of active transport that removes
molecules from the cell
Uses the help of The ER and Golgi bodies
to make vesicles
Vesicles then travel to the cell membrane
and release the contents
Assessment
In your notebooks draw the picture
depicted below and explain how molecules
move in the direction of the arrows