cell membrane and cell transport notes. ca standard cell biology 1. a. students know cells are...
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CELL MEMBRANE AND CELL TRANSPORT NOTES
CA Standard
Cell Biology1. a. Students know cells are enclosed
within semipermeable membranes that regulate their interaction with their surroundings.
What is the cell membrane?
The cell membrane regulates what enters and leaves the cell and also provides protection and support.
The structure of the cell membraneThe cell membrane
consists of a lipid bilayer (lipid = fat; bi=2) plus proteins that straddle the bilayer. Attached to the proteins are carbohydrates.
Many of these proteins are channels and pumps that allow substances through or not!
Draw the cell membrane, color and label it. (p.182)
Cell Membrane
You should be able to answer these questions:
1. Describe the structure of the cell membrane.
2. How do molecules get into and out of the cell?
3. What is selective permeability?
4. What is diffusion and how does it work?
5. What is facilitated diffusion and how does it work?
6. What is active transport and how does it work?
7. What is osmosis and how does it work?
8. What is the function of transport proteins?
Transport through the Cell Membrane
Cell membranes are selectively permeable (semipermeable).
Permeable- ability to pass through a membrane
Impermeable- can’t pass throughSelectively Permeable (semipermeable)-
some things can pass through and some can’t
Type of Transport
Transport Protein Used?
Direction of movement
Requires Energy input
from cell?
Classification of transport?
Simple Diffusion
Facilitated Diffusion
Active Transport
Copy the chart into your notes
Transport Through the Membrane
Simple
Diffusion
Facilitated
Diffusion
Active
Transport
Simple Diffusion
No transport protein usedMovement WITH the
concentration gradient (high to low)
No additional cell energy required
PASSIVEExamples: water, carbon
dioxide and oxygen
Type of Transport
Transport Protein Used?
Direction of movement
Requires Energy input
from cell?
Classification of transport?
Simple Diffusion
NO With concentration
gradient
(high to low)
NO PASSIVE WATER,
CO2, O2
Facilitated Diffusion
Active Transport
Solution- a liquid with one or more substances dissolved in it
Solvent- the liquid that the solute is dissolved in
Solute- the substance dissolved in a solution
Concentration- how strong it is the solute/volume (percentage)
Think of living cells like little bags of solutions surrounded by a semipermeable membrane!
For the cell to survive, the concentration of solutes must stay within a safe range to maintain homeostasis.
Concentration Gradient- when there is a difference in concentrationsHigh concentration: more particlesLow concentration: fewer particles
In diffusion, particles move from high to low concentration to reach an equal concentration (equilibrium) on each side.
Facilitated Diffusion
Transport protein used: carrier protein or channel protein
Movement WITH the concentration gradient (high to low)
No additional cell energy requiredPASSIVEExample: Glucose molecules
Type of Transport
Transport Protein Used?
Direction of movement
Requires Energy
input from cell?
Classification of transport?
Simple Diffusion
NO With concent.
gradient
NO PASSIVE WATER,
CO2, O2
Facilitated Diffusion
Yes: Channel Proteins or Carrier Proteins
With concent. gradient
NO PASSIVE GLUCOSE
Active Transport
Carrier Proteins
Channel Proteins
Passive Transport: Facilitated Diffusion
Active Transport
Transport protein used: carrier proteinMovement AGAINST the concentration
gradient (low to high)Additional cell energy requiredACTIVEExample: Sodium-Potassium Pump:
pumps Na+ ions out of cell and K+ ions into cell
Type of Transport
Transport Protein Used?
Direction of movement
Requires Energy
input from cell?
Classification of transport?
Simple Diffusion
NO With concent.
gradient
NO PASSIVE WATER,
CO2, O2
Facilitated Diffusion
Yes: Channel Proteins or Carrier Proteins
With concent. gradient
NO PASSIVE GLUCOSE
Active Transport
Yes: Carrier Proteins
Against concent. gradient
YES ACTIVE Na+ and
K+ ions
Active Transport
Active Transport
Other Types of Active Transport
Endocytosis – the process of taking material into the cell by folding in pockets of the cell membrane into pouches called vesicles Phagocytosis – endocytosis involving large solid
particlesPinocytosis – endocytosis involving liquid
Exocytosis – the process of removing material out of the cell where vesicles merge with the cell membrane to release contents
Endocytosis and Exocytosis
Osmosis- the diffusion of water
No transport protein used
With the concentration gradient (high to low)
No additional cell energy required
Passive
Concentration StrengthIsotonic – the solution and the cell have the
same concentration strength Hypotonic – the solution has a lower
concentration than the cellHypertonic – the solution has a higher
concentration strength than the cell
Osmotic Pressure
Osmotic Pressure is the pressure that water exerts on the hypertonic side of a selectively permeable membrane.
It can be problematic for living cells because they can burst from over-inflation with water or shrivel up from loss of water.
Red Blood Cells in a Hypertonic Solution
Plants and Osmosis
Applications of OsmosisWater overdose/intoxicationPenicillin kills bacteriaHigh concentration of fertilizer kills plantsWater enters the roots of plantsWhy drinking salt water can kill youWhy putting salt on a slug or snail kills itHow dialysis machines workThe preservation of foods in salt brines (olives,
fish vegetables) kills bacteriaDesalination works by reverse osmosisRefresh wilted salad greens by putting in water
Osmosis Worksheet10 points
Diffusion and Osmosis in Living Systems
40 pts
Cell Quiz1. What are two differences between prokaryotes and eukaryotes?
2. An animal cell is a prokaryotic/eukaryotic cell. (circle the correct answer)
3. When preparing a wet mount, the cover slip should be put on at an angle to avoid ______.
4. The ______ contains the DNA and controls the cell.
5. Diffusion is the movement of molecules from a ______ to a _______ concentration.
6. If a cell has 95% water and it is placed in a hypertonic solution, water will move out of/into the cell. (circle the correct answer)
7. _________ are where photosynthesis occurs in plant cells.
8. A bacteria is a prokaryotic/eukaryotic cell. (circle the correct answer)
9. On high power, more/less of the cell can be seen. circle the correct answer)
10. What two things happen to an image when viewed under a microscope?
11. Choose and explain one of the following: endocytosis, phagocytosis, pinocytosis, or exocytosis.