Mcat Biochemistry (Chapter 8)

Front 1

fluid mosaic model

Back 1

accounts for the presence of lipids, proteins and carbohydrates in a dynamic, semisolid plasma membrane that surrounds cells

Front 2

lipid rafts

Back 2

collections of similar lipids with or without associated proteins that serve as attachment points for other biomolecules; serve roles in signaling

Front 3

flippases

Back 3

specific membrane proteins that maintain the bidirectional transport of lipids between the layers of the phospholipid bilayer in cells

Front 4

triacylglycerols and free fatty acids

Back 4

act as phospholipid precursors and are found in low levels in the membrane

Front 5

glycerophospholipids

Back 5

replace one fatty acid with a phosphate molecule, which is often linked to other hydrophilic groups

Front 6

cholesterol

Back 6

present in large amounts and contributes to membrane fluidity and stability

provides membrane fluidity by interfering with the crystal structure of the cell membrane and occupying space between phospholipid molecules

provides stability by cross-linking adjacent phospholipids through interactions at the polar head group and hydrophobic interactions at the nearby fatty acid tail

Front 7

waxes

Back 7

present in very small amounts, if at all; they are most prevalent in plants and function in waterproofing and defense

Front 8

proteins located within the cell membrane act as

Back 8

transporters, cell adhesion molecules and enzymes

Front 9

transmembrane proteins

Back 9

can have one or more hydrophobic domains and are most likely to function as receptors or channels

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embedded proteins

Back 10

most likely to be a part of a catalytic complex or involved in cellular communication

(in other words, most likely to have catalytic activity linked to nearby enzymes)

Front 11

membrane-associated (peripheral) proteins

Back 11

may act as recognition molecules or enzymes on the extracellular surface and be involved in signaling

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carbohydrates

Back 12

can form a protective glycoprotein coat and also function in cell recognition

Front 13

membrane receptors

Back 13

bind extracellular ligands and function as channels or enzymes in second messenger pathways

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cell-cell junctions

Back 14

regulate transport intracellularly and intracellularly

include:

gap junctions

tight junctions

desmosomes

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gap junctions

Back 15

allow for the rapid exchange of ions and other small molecules between adjacent cells

do not prevent paracellular transport of materials

found in discontinuous bunches around the cell

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tight junctions

Back 16

prevent paracellular transport, but do not provide intercellular transport

form bands around the cell

Front 17

desmosomes and hemidesmosomes

Back 17

anchor layers of epithelial tissue

Front 18

osmotic pressure

Back 18

a colligative property

the pressure applied to a pure solvent to prevent osmosis and is used to express the concentration of the solution

better conceptualized as a "sucking" pressure in which a solution is drawing water in, proportional to its concentration

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passive transport

Back 19

does not require energy because the molecule is moving down its concentration gradient or from an area with higher concentration to an area with lower concentration

includes:

simple diffusion

osmosis

facilitated diffusion

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simple diffusion

Back 20

does not require a transporter

small, nonpolar molecules passively move from an area of high concentration to an area of low concentration until equilibrium is achieved

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osmosis

Back 21

describes the diffusion of water across a selectively permeable membrane

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facilitated diffusion

Back 22

uses transport proteins to move impermeable solutes across the cell membrane

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active transport

Back 23

requires energy in the form of ATP or an existing favorable ion gradient

includes:

primary and secondary active transport

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primary active transport

Back 24

uses ATP or another energy molecule to directly transport molecules across a membrane

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secondary active transport (or coupled transport)

Back 25

harnesses the energy released by one particle going down its electrochemical gradient to drive a different particle up its gradient

includes:

symport

antiport

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symport

Back 26

type of secondary active transport in which the particles flow in the same direction across the membrane

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antiport

Back 27

type of secondary active transport in which the particles flow in opposite directions across the membrane

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pinocytosis

Back 28

the ingestion of liquid into the cell from vesicles formed from the cell membrane

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phagocytosis

Back 29

the ingestion of bacteria by phagocytes

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membrane potential

Back 30

maintained by the sodium-potassium pump and leak channels

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Nernst equation

Back 31

used to calculate the electrical potential created by one ion

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Goldman-Hodgkin-Katz voltage equation

Back 32

derived from the Nernst equation and used to calculate the resting potential of a membrane at physiological temperature

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outer mitochondrial membrane

Back 33

highly permeable to metabolic molecules and small proteins

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inner mitochondrial membrane

Back 34

surrounds the mitochondrial matrix, where the citric acid cycle produces electrons used in the electron transport chain and where many other enzymes important in cellular respiration are located

does not contain cholesterol

Front 35

examples of sphingolipids

Back 35

gangliosides

ceramide

sphingomyelin

cerebrosides

sphingolipids