Text Chapter 3: Membranes Flashcards Preview

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Flashcards in Text Chapter 3: Membranes Deck (25):
1

Macromolecules that Comprise the Plasma Membrane

phospholipids, cholesterol, proteins

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Phospholipid Bilayer (plasma membrame)

forms boundary to isolate cell contents form environment, restricts passage of hydrophilic substances across the membrane

3

Cholesterol (plasma membrane)

increases bilayer strength and flexibility, reduces membrane fluidity, reduces permeability to water-soluble substances

4

Transport Proteins

regulates movement of water-soluble substances
Channel Proteins- have pores that allow passage of ions and small water-soluble molecules
Carrier Proteins- bind to molecules and change shape for delivery across membrane

5

Receptor Proteins

docking site for molecules outside the cell, trigger internal cellular response

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Recognition Proteins

identification tags (carbohydrate chains aid in cell-cell recognition), cell-surface attachment sites

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Role of Carbohydrates when attached to Proteins and Lipids

carbohydrate chains aid in cell-cell recognition

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Diffusion

molecules move from an area of high concentration to an area of low concentration, molecules pass through the plasma membrane without the assistance of another molecule.

9

Osmosis

diffusion of water molecules from an area of high concentration to an area of low concentration across a differentially permeable membrane

10

Active Transport with Carrier

movement from an area of low concentration to an area of high concentration, energy and protein carrier required

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Endocytosis

surrounding the material with the plasma membrane, creating a vesicle that is transported into the cell, energy needed

12

Receptor-Mediated Endocytosis

material that binds to a receptor is enclosed in a vesicle and transported into the cell

13

Exocytosis

material enclosed in a vesicle is released from the cell when the vesicle fuses with the plasma membrane

14

Hypertonic Solution

solute concentrations are higher in the extracellular fluid, water diffuses out of cells

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Hypotonic Solution

solute concentrations are lower in the extracellular fluid, water diffuses into the cells (unlike plant cells, animal cells may explode in hypotonic solutions because they don’t have a cell wall to limit cellular expansion)

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Isotonic Solution

solute concentrations are balanced, water movement is balanced

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Tight Junction

fusion of proteins from membranes adjacent to cells, form a water-tight seal between cells like a caulking around tub

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Desmosome

transmembrane proteins link together to bridge space between cells, act like velcro and fasten cells together

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Gap Junction (animals)

pairs of channels connect insides of adjacent cells (animals)

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Plasmodesmata (plants)

connect insides of adjacent cells (plants)

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Channel Proteins

have pores that allow passage of ions and small water-soluble molecules (type of transport protein)

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Carrier Proteins

bind to molecules and change shape for delivery across membrane (type of transport protein)

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Plasma Membrane "Fluid"

a double layer of phospholipids

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Plasma Membrane "Mosaic"

a collection of proteins

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Low Concentration -----> High Concentration

endocytosis, exocytosis, receptor-mediated endocytosis, active transport