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The cell consists of what 3 major parts?
Nucleus, Cytoplasm, cell membrane (plasma membrane)
What does it mean if a cell can choose what to regulate in and out of the cell to maintain integrity?
Selectively permeable
The cell membrane consists of a bilayer of what?
Phospholipid molecules
What are the parts of a phospholipid molecules?
Polar heads, fatty acid tails, lipid tails
What molecules can move through the membrane easily?
O2, H2O, CO
What type of proteins does are in the cell membrane?
Globs, Rods, Fibers
Can water molecules pass through the membrane?
No- they need help from channel proteins
What is the function of carbohydrates?
Cell recognition and adhesion
What is the function of cholesterol?
Stabilize the membrane
What is the difference between passive and active mechanisms?
Passive- does not require energy
Active- uses cellular energy
What are the 4 types of passive mechanisms?
Diffusion, facilitated diffusion, osmosis, filtration
Diffusion
Molecules move from an area of high concentration to an area of low concentration until EQUILIBRIUM occurs.
Ex: Sugar or food dye
Facilitated Diffusion
Another form of diffusion where molecules move from an area of high concentration to an area of low concentration, but there is a selectively permeable membrane involved hindering the process.
Needs a helper protein
Glucose needs what to travel?
A carrier protein
Osmosis
Diffusion with water
What are the three types of osmosis?
Isotonic, hypertonic, hypotonic
Isotonic
Same outside and inside
Hypertonic
Higher osmosis pressure than body fluids
Cells shrink
Hypotonic
Lower osmosis pressure
Cells would swell
Filtrated Diffusion
Forces molecules thru membranes by hydrostatic pressure.
Used to separate solids from water
Explain the difference between diffusion and osmosis.
Both concentrations move from high to low, but osmosis uses a selective membrane.
Active Mechanism
Moves from low to high concentration region
Needs energy (atp)
Active transport
Career proteins with ATP live molecules across membrane
“Pumps”
Examples of pumps
Sugars, Amino Acids, Sodium, Potassium, Calcium.
What are two other processes that use cellular energy without crossing cell?
Endocytosis and exocystosis
Endocytosis
Pinocytosis- may take in water and the particles dissolved in it. (“cell drinking”)
PhagocytosiS- solids instead of liquids.(“cell eating”)
Receptor mediated endocytosis specific substances can enter
Exocytosis
Vesicle fuses with the membrane to expel substances from the cell.
Ex. Secretion of certain hormones.