Cell Membrane The cell membrane Controls what comes out and in of the cell It also provides protection The composition is a double layered sheet called a Bilipid layer This lipid bilayer is made up of two ID: 639326
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Slide1
The cell membrane
All
cells are surrounded by a thin flexible barrier known as the Cell Membrane.The cell membrane Controls what comes out and in of the cell. It also provides protection.The composition is a double layered sheet called a Bi-lipid layer.This lipid bi-layer is made up of two layers of Lipids (fats)
One of the most important parts of the cell is its
Membrane
, which separates the cell from its surroundings.Slide2Slide3
The cell membrane
The lipid bi-layer is what gives cell membranes a
unique structure that forms a strong barrier between the cell and its surroundings.In addition to lipids most cell membranes contain Protein molecules that are embedded in the lipid bi-layer. There are also receptor molecules that are attached to the protein molecules. Slide4
Protein Channels
The proteins act as pumps and channels
moving materials into and out of the cell and act as receptor molecules for any hormone or other chemical message that need to get into the cell.The carbohydrates act like chemical Reading cards allowing cells to communicate with each other. Slide5
Look at the roots of the protein labels (
hydrophilic & hydrophobic).What do you think they mean?Slide6
Passage of materials through the cell membrane…
hWhat does the cell membrane do?1. It protects the cell2.
It allows things in and out of the cell3. It is Semi-Permeable (not everything can get across it)4. It has 2 layers (It is like a protein sandwich)5. The proteins are for transporting things across
LIPID
PROTEIN
LIPIDSlide7
DIFFUSION
Diffusion
is the movement of materials from a high concentration to a low concentration until there is equilibrium
(
no
energy is used to do
this)
.Slide8
Why does diffusion occur?
The reason for this is so
all the molecules can be in equilibrium.Diffusion can also only occur across a cell membrane if there is a concentration gradient. (This is when material is higher on one side of the membrane than on the other). Slide9
Facilitated Diffusion
is when protein channels in the cell membrane help the movement of molecules across the membrane.
Osmosis is the diffusion of Water across a membrane from High to low concentration.[[No Energy used]] Slide10
inside cell
outside cell
Which way will fat move?
low
high
fat
fat
fat
fat
fat
fat
fat
fat
fat
fat
DiffusionSlide11
sugar
sugar
sugar
sugar
sugar
sugar
sugar
sugar
sugar
sugar
sugar
low
high
Which way
Will sugar
Move?
DiffusionSlide12
What are the effects of Osmosis?
If you place a cell in a solution (mixture of 2 substances)
three things can happen:
1.
ISOTONIC SOLUTION
When the concentration of water is the same inside and outside cell
2
.
HYPOTONIC SOLUTION
When
there is a higher concentration of water outside cell, so water moves into cell
3.
HYPERTONIC SOLUTION
W
hen
there is a higher concentration of water inside cell, so water moves out of cell Slide13
Isotonic Solution
Isotonic Solution
Balanced conditionsno difference between cell & environmentexample: bloodproblem: nonewater flows across membrane equally, in
both directions
volume of cell
doesn't
changeSlide14
Hypotonic Solution
Hypotonic Solution
Freshwater a cell in fresh waterexample: Paramecium problem: gains water, swells & can burstwater continually enters Paramecium cellsolution: contractile vacuole
pumps water out of cellSlide15
Hypertonic Solution
Hypertonic Solution
Saltwater a cell in salt waterexample: shellfishproblem: lose waterplasmolysis in plantsshrinking cell
solution
: take up waterSlide16
Methods of Transport
Passive transport: movement from High to low concentration.
No energy is used.This is also called Simple diffusionActive transport:movement from low to high concentration. A. needs energy
B
. opposite of simple diffusion Slide17
Active Transport
Analyze this animation. Explain what you see happening.
Now add the following words to your explanation:
Solution
Molecules
Cell membrane
Protein channel
ATP
Active Transport
High concentration
Low concentrationSlide18
SIMPLE DIFFUSION
Move
from HIGH to LOW concentration“passive transport”no energy needed
Do the animations below portray active or passive transport?
How do you know?Slide19
ACTIVE TRANSPORT
Cells
may need molecules to move against concentration differenceneed to pump “uphill”from LOW to HIGH using ATP
protein pump
requires energy ATP
ATP
Do the animations below portray active or passive transport?
How do you know?Slide20
diffusion
facilitated
diffusion
active
transport
ATP
Transport Summary
Analyze the three forms of transport across a membrane below.
Identify
and
Explain
the forms of transport for each red arrow!Slide21
Transport Vocab
Pinocytosis
- cell drinking-engulfing small particles. Phagocytosis- cell engulfing- Lysosomes fuse with a bacteria for digestion Cyclosis- Movement of the cytoplasm