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Bio > Bio ch 5 > Flashcards

Bio ch 5 Flashcards

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Biology 101 flashcards
1
Q

what is the plasma membrane

A

the boundary between the living cell and the environment

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2
Q

what is a fluid mosaic

A

how biologists describe the structure of membranes

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3
Q

what is the structure of membranes

A

a bilayer of phospholipids with embedded and attached proteins

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4
Q

what does cholesterol do in animal cell membranes

A

helps stabilize the membrane at warm temperatures but also keeps the membrane fluid at warmer temperatures

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5
Q

what are the 6 major functions performed by membrane proteins

A 
enzymatic activity
cell to cell recognition
intercellular junctions
transport
signal transduction
attachment to the cytoskeleton and extracellular matrix
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6
Q

what is selective permeability

A

allowing some substances to cross more easily then others

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7
Q

what is a phospholipid

A

made of a hydrophilic head made of an alcohol and a phosphate group and and two hydrophobic tails made of chains of fatty acids

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8
Q

how do phospholipids get their kinked tails

A

double bonds

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9
Q

what gets through the phospholipid bilayer fairly easily

A

non polar molecules (O2, CO2, lipids)

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10
Q

what needs the help of proteins to get through the phospholipid bilayer

A

polar molecules

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11
Q

what is a glycoprotein

A

a carbohydrate attached to a protein

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12
Q

what is a glycolipid

A

a carbohydrate attached to a lipid

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13
Q

what is the function of glycoproteins and glycolipids

A

they are used as receptor molecules, binding with hormones or neurotransmitters to trigger a series of chemical reactions within the cell itself.

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14
Q

what is signal transduction

A

the message-transfer process in which a a protein functions as a receptor for a signaling molecule from another cell. The binding of this signaling molecule triggers a change in the protein, which relays the message to the cell, activating molecules that perform specific functions

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15
Q

what is passive transport

A

diffusion across a membrane with no energy investment

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16
Q

what is diffusion

A

the tendency for particles of any kind to spread out evenly in an available space; they spread from high concentration to low concentration - down the concentration gradient

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17
Q

how can ions and non polar molecules diffuse across the hydrophobic interior of a membrane

A

if they are moving down their concentration gradients and if they have transport proteins to help them cross

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18
Q

what is an example of passive transport

A

it happens in the lungs with CO2 and O2

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19
Q

what is facilitated diffusion

A

when polar molecules can diffuse across its concentration gradient with the help of a transport protein

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20
Q

what does a transport protein do

A

create an avenue for travel for polar molecules and/or may change its shape, polarity or charge

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21
Q

what is osmosis

A

Diffusion of water across a selectively permeable membrane to obtain equal concentration of solute

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22
Q

what is tonicity

A

loss or gain of water in a cell

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23
Q

isotonic

A

when the concentration of solute in the cell is equal to the concentration of solute outside the cell

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24
Q

hypotonic

A

when the concentration of solute in the cell is more than the concentration of solute outside the cell

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25
Q

hypertonic

A

when the concentration of solute in the cell is less than the concentration of solute outside the cell

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26
Q

what is osmoregulation

A

the control of water balance that an animal uses to survive in a hypnotic or hypertonic environment to prevent excessive uptake or loss of water

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27
Q

what happens to an animal cell placed in a hypotonic solution

A

it will burst (lyse)

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28
Q

what happens to an animal cell placed in hypertonic solution

A

it will shrivel and could die from water loss

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29
Q

what happened to an animal cell placed in isotonic solution

A

the volume remains constant

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30
Q

why are water balance issues somewhat different for plant cells

A

because of their cell walls

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31
Q

what happens to a plant cell placed in an isotonic solution

A

it is limp, flaccid

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32
Q

what happens to a plant cell placed in hypotonic solution

A

it is turgid, very firm, and this is the healthy state for most plant cells

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33
Q

what happens to a plant cell placed in hypertonic solution

A

it shrivels and its plasma membrane pulls away from the cell wall

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34
Q

what is plasmolysis

A

when a plant cell loses water, shrivels, and its plasma membrane pulls away from the cell

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35
Q

is facilitated diffusion active or passive transport

A

passive

36
Q

what are two ways transport proteins help polar molecules or ions diffuse through the membrane

A
  1. by providing a hydrophilic channel that some molecules or ions use as a tunnel through the membrane
  2. by binding the ion/molecule, changing shape, and releasing it on the other side
37
Q

what is active transport

A

a cell must expend energy to move a solute against its concentration gradient

38
Q

what supplies the energy for active transport

A

ATP

39
Q

describe the active transport process

A
  • Solute in cell binds attaches to a transport protein
  • ATP phosphorylates the protein
  • Transport protein changes shape and releases solute onto other side of the cell
  • Phosphate group detaches and transport protein returns to its normal shape
40
Q

what does active transport allow for

A

a cell to maintain internal concentrations of small molecules and ions that are different concentrations in its surroundings (examples are potassium ions and sodium ions)

41
Q

what is exocytosis

A

exports bulky materials like proteins or polysaccharides

42
Q

how does exocytosis work

A

Big molecules in vesicles fuse with plasma membrane and then spill its contents outside of the cell.

43
Q

what is endocytosis

A

the process in which a cell takes in a large molecule and forms a vesicle or vacuole in plasma energy

44
Q

what are the 3 types of endocytosis

A

phagocytosis, pinocytosis, and receptor-mediated endocytosis

45
Q

what is phagocytosis

A

a type of endocytosis in which a cell engulfs a particle by wrapping extensions around it called pseudopodia and packaging it within a membrane closed sac large enough to be a vacuole

46
Q

what is pinocytosis

A

a type of endocytosis in which a cell gulps droplets of fluid into tiny vesicles; it is non-specific - it takes in any and all solutes dissolved in the droplets

47
Q

what is receptor mediated endocytosis

A

a highly selective form of endocytosis; the plasma membrane indents to form a coated pit with receptor proteins for specific molecules. the coated pit then pinches closed to form a vesicle that carries the molecules into the cytoplasm

48
Q

what is energy

A

the capacity to cause change or perform work

49
Q

what are the 2 basic forms of energy

A

kinetic and potential

50
Q

what is kinetic energy

A

the energy of motion

51
Q

what is heat (thermal energy)

A

a type of kinetic energy associated with the random movement of atoms or molecules

52
Q

what is potential energy

A

energy that matter possesses as a result of its location or structure

53
Q

what is chemical energy

A

the potential energy available for release in a chemical reaction

54
Q

what is thermodynamics

A

the study of energy transformations that occur in a collection of matter

55
Q

what is an open system

A

it exchanges both energy and matter with its surroundings

56
Q

what is the 1st law of thermodynamics

A

energy cannot be created or destoryed

57
Q

what is entropy

A

a measure of disorder

58
Q

what is the 2nd law of thermodynamics

A

energy conversions increase the disorder of the universe

59
Q

what is the fuel source for cells

A

sugar

60
Q

what 2 molecules are necessary to create the fuel for cells

A

glucose and oxygen

61
Q

what happens in cellular respiration

A

chemical energy stored in organic molecules is covered to a form that the cell can use to perform work

62
Q

what is an exergonic reaction

A

a chemical reaction that releases energy

63
Q

what is an example of an exergonic reaction

A

wood burning

64
Q

what is an endergonic reaction

A

they yield products that are rich in potential energy

65
Q

what is an example of an endergonic reaction

A

photosynthesis

66
Q

what is metabolism

A

the total of an organism’s chemical reactions

67
Q

what is a metabolic pathway

A

a series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds

68
Q

what is the metabolic pathway of cellular respiration

A

a sequence of reactions that slowly releases the potential energy stored in sugar

69
Q

what is energy coupling

A

the use of energy released from exergonic reactions to drive essential endergonic reactions

70
Q

how does the ATP cycle provide energy

A

energy released in exergonic reactions is used to regenerate ATP from ADP. In this endergonic process, a phosphate group is bonded to ADP. The hydrolysis of ATP releases energy that drives endergonic reactions

71
Q

how is the ATP cycle an example of energy coupling

A

in the ATP cycle, it uses energy released from exergonic reactions to drive endergonic reactions

72
Q

what are the 3 main types of cellular work driven by ATP

A

mechanical, chemical, transport

73
Q

what is activation energy

A

the amount of energy needed for a reaction to take place

74
Q

what are enzymes

A

proteins that act as biological catalysts

75
Q

what do enzymes do

A

speed up a reaction by lowering the activation energy

76
Q

what is a substrate

A

the specific reactant that an enzyme acts on; it fits into a region of the enzyme called an active site

77
Q

what is an active site

A

typically a pocket or a groove on the surface of the enzyme; where the reaction takes place

78
Q

what makes enzymes specific

A

their active sites fit only specific substrate molecules

79
Q

what is induced fit

A

strain on the bonds to hold in certain orientation

80
Q

what are the optimal conditions for enzymes

A

temps of close to our body temp and pHs close to neutrality

81
Q

what are cofactors

A

nonproteins that help enzymes by binding to the active site and functioning in catalysis

82
Q

what are coenzymes

A

cofactors that are organic molecules

83
Q

what is an enzyme inhibitor

A

it interferes with an enzyme’s activity

84
Q

what is a competitive inhibitor

A

Binds covalently to active site so it is irreversible

85
Q

how can competitive inhibition be overcome

A

by increasing the concentration of the substrate, making it more likely that a substrate molecule rather than an inhibitor will be nearby when an active site becomes vacant

86
Q

what is a noncompetitive inhibitor

A

binds somewhere on the enzyme and changes the shape of the enzyme so that the active site no longer fits the substrate

87
Q

what is a feedback inhibitor

A

catalysis is blocked by its own products

Bio (9 decks)

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