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bio 120 midterm > lecture 6 > Flashcards

lecture 6 Flashcards

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Biology 101 flashcards
1
Q

what is the structure of the cell membrane

A

fluid mosaic model, its a fluid mosaic of lipids with proteins embedded, and membrane is asymmetrical

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2
Q

what evidences supports fluid mosaic model

A

membranes are not rigid, consist of fluid lipid bilayer in which proteins embedded and float freely, and human and mouse cell experiment

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3
Q

why is the membrane asymmetric

A

proteins on one half are structurally and functionally distinct from other half

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4
Q

what is the lipid composition of cell membrane

A

phospholipid is most dominant, head group has glycerol linked to types of alcohol or amino acid phosphate group, tail has two long chains of hydrocarbon fatty acid

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5
Q

what is a fatty acid

A

a carboxylic acid with long chain of hydrocarbon, and an even number from 4- 28

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6
Q

what makes phospholipids amphipathic molecules

A

hydrophilic (“water-loving”) or polar end and a hydrophobic (“water-fearing”) or nonpolar end

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7
Q

how do you maintain a proper fluidity

A

depends on lipid density, composition and temp.

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8
Q

how do you adjust fatty acid composition

A

change with temperature

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9
Q

what influences membrane fluidity

A

cholesterol is essential structural components of animal cell membrane, it acts as membrane buffer

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10
Q

what are the two distinct categories of membrane proteins

A

-integral membrane proteins
-peripheral membrane proteins

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11
Q

glycolipids

A

-cell-cell interactions
-immune response
-blood types

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12
Q

what are cell-cell interactions

A

the direct interactions between cell surfaces that play a crucial role in the development and function of multicellular organisms.

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13
Q

what is immune responses

A

function in interaction between leukocytes and endothelial cells in inflammation

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14
Q

what is blood type

A

four main blood type determined by oligosaccharide attached to specific glycolipid on surface of red blood cell

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15
Q

what is the key function of membrane protein

A

transport, signal transduction, enzymatic activity, and attachment/ Recognition

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16
Q

how do we know protein are inserted into membrane?

A

integral membrane protein are embedded in phospholipid bilayer
-are transmembrane proteins composed of nonpolar amino acids usually coiled into alpha helices held by covalent bonds

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17
Q

peripheral membrane proteins

A

most located on cytoplasmic side of membrane, made up of polar and nonpolar amino acids, and held together by noncovalent bonds like hydrogen and ionic bonds

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18
Q

membranes are semipermeable

A

permeable to non-polar or hydrophobic molecules, impermeable to large and polar molecules

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19
Q

what does permeability depend on

A

solubility, charge, and solute size

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20
Q

how do molecules move through membranes

A

diffusion and osmosis

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21
Q

what is diffusion

A

movement of molecules from high concentration to lower concentration

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22
Q

what is osmosis

A

diffusion of solvents through semipermeable membrane

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23
Q

what are the two types of membrane transport

A

-active and passive transport

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24
Q

what is passive transport

A

-doesn’t require energy
-high concentration to low concentration

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25
Q

what is active transport

A

-low-concentration to high concentration
-requires direct/indirect input of ATP

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26
Q

what two types of diffusion does passive transport break down into

A

-simple and facilitated diffusion

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27
Q

what is simple transport

A

-substances pass through phospholipids
-rate of diffusion depends on concentration difference

28
Q

what is facilitated diffusion

A

spontaneous, and ions cross biological membrane

29
Q

what are properties of facilitated diffusion

A

-follow concentration gradients
-high diffusion rate
-limited binding capacity
-high substrate specificity

30
Q

what are three main examples of facilitated diffusion

A

channel proteins=aquaporin
ion channel protein= K+ voltage-gated channel
carrier protein= glocuse transporter

31
Q

how does water move through the membrane

A

by osmosis which is a passive passage

32
Q

what is tonicity

A

it is an example of membrane passage by osmosis

33
Q

tonicity (flow of water in and out of cell) has three groups, what are they

A

hypotonic, isotonic, and hypertonic

34
Q

what is a hypertonic solution

A

osmotic flow out of the cell

35
Q

what is hypotonic solution

A

osmotic flow into cell

36
Q

what is isotonic solution

A

no osmotic flow

37
Q

what are channel proteins: aquaporin (ex. of facilitated diffusion)

A

integral membrane protein that forms pore in membrane

38
Q

what are ion channel protein: ion voltage-gate channel (ex. facilitated diffusion)

A

switches between open and closed and intermediate states, this involves changing 3-D shape

39
Q

what are carrier proteins

A

bind to specific single solute and transport across lipid bilayer

39
Q

what are carrier proteins

A

bind to specific single solute and transport across lipid bilayer

40
Q

active transport has two types

A

-primary active tranport
-secondary active transport

41
Q

what is primary active transport

A

-moves positively charge ions
-Na+/K+ pump
-h+ pumps
-ca2+ pumps

42
Q

what do Na+-K+ pumps do

A

regulate cellular volume
-help maintain right concentration of ions (cell swell automatically activates pump)

43
Q

what is membrane potential

A

difference in ion concentration creates difference of charge between exterior and interior part of membrane

44
Q

what are a secondary source of energy

A

electrical gradient

45
Q

what are a secondary source of energy

A

electrical gradient

46
Q

what are electrical gradients

A

provide energy to transport glucose, amino acid, and other nutrients, known as secondary active transport

47
Q

what are the two forms of secondary active transport

A

sodium-calcium exchanger, and sodium-hydrogen antiporter

48
Q

what are sodium-hydrogen antiporter

A

transport Na+ into cell and H+ out

49
Q

what is sodium-calcium exchanger

A

uses energy stored in electrochemical gradient of Na+ by allowing it to flow down gradient across plasma membrane exchange for calcium out of cell

50
Q

what are the three main functions of Na+-K+ pump

A
  • maintain isotonicity cell volume by pumping out calcium
    -create a difference in charge between exterior and interior
    -create electrochemical gradient to provide energy to move molecules against concentration gradient
51
Q

what transports larger substance

A

exocytosis

52
Q

what is exocytosis

A

energy-dependent process which large molecule bulks transported out of cell

53
Q

what are 3 main function of endocytosis

A

-pinocytosis
-receptor mediated endocytosis
-phagocytosis

54
Q

what is pinocytosis (endocytosis)

A

extracellular fluid and molecules within it

55
Q

what are receptor-mediated endocytosis

A

small vesicles coated with cytosolic protein

56
Q

what are phagocytosis

A

bind and internalize large particles

57
Q

how is tissue stability acheived

A

cell junctions and extracellular matrix

58
Q

what are tight junctions (impermeable and tissue stability)

A

rows of transmembrane proteins that bind to corresponding membrane protein of adjacent cell

59
Q

what are tight junctions (impermeable and tissue stability)

A

rows of transmembrane proteins that bind to corresponding membrane protein of adjacent cell

60
Q

what is a gap junction

A

intercellular channels directly communicate cytoplasm of two cells, allowing passage (ions+small molecules)

61
Q

what is anchoring junction

A

link of cytoskeleton with extracellular matr

61
Q

what is anchoring junction

A

link of cytoskeleton with extracellular matr

62
Q

what stages do membrane receptors link extracellular signals with cellular responses

A

-reception
- transduction
-response

63
Q

what is kinases

A

adds chemical called phosphates to other molecules

bio 120 midterm (10 decks)

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