Download Ch. 7 Review Guide Membranes

CP BIO
CH. 7 CELL MEMBRANE AND TRANSPORT
REVIEW TOPICS
These are topics and vocabulary terms covered in this chapter which may appear on the chapter test. See
chapter guide, warm-ups, quick reviews, and text chapter 7 parts 3 and 4
Ch. 2 Enzymes –What are they? – protein catalysts
Why important? – speed reactions in cells
 Activation energy – to start a reaction, enzymes lower it
 Active site and substrate – what are they?
 Modes of enzyme action – lock-and-key, induced fit
 Conditions that affect enzyme action
o Temperature – warm increases rate; hot
denatures protein
o pH – narrow range, excess H+ or OH- break 3-D bonds
o concentration of enzyme or of substrate – limiting reactant
o inhibitors – slow enzyme action
 block active site or change molecule shape
7. 2 Cell Boundaries
 Cell membrane
o Lipid bilayer, Fluid Mosaic Model
o Phospholipid: hydrophobic and hydrophilic parts
o Membrane proteins – 6 kinds, cholesterol, carbohydrate tags
7.3 Cell Transport
 Passive transport – no cell energy/ solute moves DOWN a concentration gradient
 Diffusion – Small, nonpolar (O2, CO2, H2O)
o Facilitated diffusion – through a membrane transport protein
 Pores or channels – open passage through membrane
 Carriers – receive on one side of membrane, release on other
 Small, polar or charged (glucose, amino acids, ions, water)
o Osmosis – water across a membrane
 Osmotic pressure - force which makes water diffuse
 Isotonic – same solute concentration on both sides of membrane
 Water moves equally in both directions
 Natural state for animal cells; wilted for plant cells
 Hypotonic – low solute concentration on one side (high water
concentration)
 Water goes FROM hypotonic TO hypertonic
 If cell environment hypotonic:  water goes into cells
o Animal cells swell, may burst (lyse)
o Plant cells turgid
 Hypertonic – high solute concentration on one side (low water
concentration)
 Water goes TO hypertonic FROM hypotonic
 If cell environment hypertonic to cell:  water goes out of cells
o cytoplasm shrinks - plasmolysis
o Animal cells shrink, shrivel
o Plant cells – cytoplasm shrinks, but wall stays
 Active Transport – uses cell energy ATP
o Across membranes – AGAINST the gradient
 Protein “pumps” push particles to where they are already more
concentrated
 In intestine – absorb as many nutrients as possible
 In kidneys – remove as many wastes as possible
 Sodium-potassium pumps – nerve cells
o Bulk Transport – large particles and cells, in vacuoles or vesicles
 Endocytosis – bring IN to cell
 Phagocytosis – ‘cell eating’ – engulf food and enclose in
vacuole
o Amoeba, white blood cells
 Pinocytosis – ‘cell drinking’ – small folds in cell membrane
enclose drops of liquid
o Intestine lining
 Exocytosis – send OUT of cell
 vesicle filled with substance merges with cell membrane
 opens outside of cell to release substance
o glands that make hormones or enzymes
o contractile vacuoles