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test 2 Flashcards

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Biology 101 flashcards
1
Q

What is selective permeability?

A

it allows some substances to cross it more easily than others

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2
Q

what is the plasma membrane?

A

is the boundary that separates the living cells from its surroundings

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3
Q

What does amiphipathic mean?

A

contains both hydrophobic and hydrophilic regions

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4
Q

are phospholipids amphipathic?

A

ye

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5
Q

what is a fluid mosaic model?

A

a membrane is a fluid structure with a “mosaic” of various proteins embedded in it.

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6
Q

what affects the fluidity of membranes?

A

cholesterol and the fatty acid makeup

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7
Q

what are peripheral proteins?

A

they are bound to the surface of the membrane

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8
Q

What are integral proteins?

A

they penetrate the hydrophobic core

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9
Q

what are transmembrane proteins?

A

they are integral proteins that span the membrane

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10
Q

What makes up the hydrophobic regions of an integral protein?

A

one or more stretches of nonpolar amino acids, often coiled into alpha helices

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11
Q

what are the 6 major functions of membrane proteins?

A

transport, enzymatic activity, signal transduction-relaying signals, cell-cell recognition, intercelluar joining, and attachment to the cytoskeleton and extracellular matrix

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12
Q

____ ______ molecules like hydrocarbons can dissolve in the lipid bilayer and pass through the membrane rapidly without involvement of proteins

A

small hydrophobic

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13
Q

What type of molecules go through transport proteins?

A

hydrophilic molecules including small ions and polar molecules

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14
Q

passive transport= _____, and goes tom ____ to _____ concentration.

A

diffusion, high to low

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15
Q

what goes through passive transport?

A

small hydrophobic molecules

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16
Q

What is facilitated diffusion?

A

transport proteins are used to transport ions, water, small hydrophilic molecules

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17
Q

what is active transport?

A

it takes energy and is not based on diffusion, it goes against concentration gradient

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18
Q

what is diffusion?

A

the tendency for molecules to spread out evenly into the availible space

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19
Q

what happens during dynamic equilibrium?

A

equal amount of molecules crossing over

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20
Q

what is osmosis?

A

the diffusion of water across a selectively permeable membrane, low to high

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21
Q

What is the ability of a surrounding solution to cause a cell to gain or lose water

A

tonicity

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22
Q

what is a solute concentration that is the same as that inside the cell; no net water movement across the plasma membrane

A

isotonic solution

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23
Q

what is the type of solution where the solute concentration is greater than that inside the cell; cell loses water

A

hypertonic solution

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24
Q

what is the type of solution where the solute concentration is less than that inside the cell; cell gains water

A

hypotonic solution

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25
Q

what is the control of solute concentrations and water balance and is a necessary adaption for life in such enviroments?

A

osmoregulation

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26
Q

What proteins provide corridors that allow a specific molecule or ion to cross the membrane and does not undergo any change when transporting?

A

channel proteins

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27
Q

what facilitates the diffusion of water?

A

aquaporins

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28
Q

what facilitates the diffusion of ions?

A

ion channels

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29
Q

what ion channels open or close in response to a stimulus?

A

gated channels

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30
Q

which proteins undergo a subtle change in shape that translocates the solute-binding site across the membrane?

A

carrier proteins

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31
Q

facilitated diffusion is ____ transport

A

passive

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32
Q

what is active transport?

A

moves substances against their concentration gradients; requires energy usually in the form of ATP

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33
Q

review the sodium potassium pump rn bitch

A

ok

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34
Q

what is the voltage difference across a membrane

A

membrane potential

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35
Q

what causes voltage?

A

differences in the distribution of positive and negative ions across a membrane

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36
Q

what drive the diffusion of ions across a membrane?

A

electrochemical gradient

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37
Q

what are the two combined forced in the electrochemical gradient?

A

chemical (ion’s concentration gradient) and electrical (the effect of the membrane potential on the ion’s movement)

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38
Q

what is an electrogenic pump?

A

a transport protein that generates voltage across a membrane

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39
Q

what is a proton ppump?

A

the main electrogenic pump of plants, fungi, and bacteria

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40
Q

what is the major electrogenic pump for animal cells?

A

sodium-potassium pump

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41
Q

what is cotransport?

A

it occurs when active transport of a solute indirectly drives transport of other substances

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42
Q

what is exocytosis?

A

where transport vesicles migrate to the membrane, fuse with it, and release their contents outside the cell

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43
Q

what is endocytosis?

A

where the cells takes in macromolecules by forming vesicles from the plasma membrane

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44
Q

what are the three types of endocytosis?

A

phagocytosis, pinocytosis, and receptor-mediated endocytosis

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45
Q

what happens in receptor-mediated endocytosis?

A

binding of ligands to receptor triggers vesicle formation

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46
Q

what is any molecule that binds specifically to a receptor site of another molecule?

A

ligand

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47
Q

what is metabolism?

A

the totality of an organisms’s chemical reactions and the sum of its anabolic and catabolic reactions

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48
Q

What is a anabolic reaction?

A

complex molecules are made from simple molecules; energy input is required

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49
Q

what is a catabolic reaction?

A

complex molecules are broken down to simpler ones and energy is released

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50
Q

what are catabolic pathways?

A

they release energy by breaking down complex molecules into simpler compounds

51
Q

what is cellular respiration?

A

the breakdown of glucose in the presence of oxygen; an example of a pathway of catabolism

52
Q

what are anabolic pathways?

A

they consume energy to build complex molecules from simpler ones; an example would be the synthesis of a protein from amino acids

53
Q

what is energy?

A

the capacity to cause change

54
Q

what is kinetic energy?

A

energy associated with motion

55
Q

what is potential energy

A

the energy that matter possesses because of its location or structure

56
Q

what is heat (thermal) energy?

A

the kinetic energy associated with random movement of atoms or molecules

57
Q

what is chemical energy?

A

the potential energy stored in chemical bonds available for release in a chemical reactions

58
Q

what is thermodynamics?

A

the study of energy transformations

59
Q

an ____ system, like liquid in a thermos, is unable to exchange energy or matter with its surroundings.

A

isolated

60
Q

in an ____ system, energy and matter can be transferred between the system and its surroundings.

A

open; some examples are organisms and cells

61
Q

what is the 1st law of thermodynamics?

A

energy can be transferred and transformed but it cannot be created nor destroyed; the energy of the universe is constant

62
Q

are energy transformations 100% efficient?

A

naw son

63
Q

what is the second law of thermodynamics?

A

every spontaneous energy transfer or transformation increases the entropy (disorder) of the universe

64
Q

what are spontatneous processes?

A

they occur without energy input; they can happen quickly or slowly

65
Q

when a process occurs without energy input then it must _____ the entropy of the universe

A

increase

66
Q

what is the energy that is available to do work called?

A

free energy or gibbs free energy

67
Q

what’s the equation of free energy?

A

delta g= g of products - g of reactants

68
Q

when is delta g positive?

A

when the products are greater; free energy is consumed

69
Q

when is delta g negative?

A

when the reactants are greater; free energy is released

70
Q

what is the other equation of free energy?

A

delta g= delta H-temp(delta s)

h=enthalpy, s=entropy

71
Q

processes with a ____ delta g are spontaneous

A

negative

72
Q

what is an exergonic reaction?

A

proceeds with a net release of free energy and is spontaneous

73
Q

what is an endergonic reaction?

A

it absorbs free energy from its surroundings and is non spontaneous

74
Q

what are the three main kinds of work by a cell?

A

chemical, transport, and mechanical

75
Q

what is energy coupling?

A

the use of an exergonic process to drive an endergonic one; mediated by atp

76
Q

what is atp?

A

the cell’s energy shuttle, composed of a ribose, adenine, and three phosphate groups

77
Q

how is energy released from atp?

A

when the terminal phosphate bond is broken by hydrolysis. the energy comes from the chemical change to a state of lower free energy

78
Q

the three types of celluar work (transport, chemical, and mechanical) are powered by ________.

A

the hydrolysis of atp

79
Q

how does atp drive endergonic reactions?

A

by phosphorylation, transferring a phosphate group to some other molecule. the recipient molecule is called phosphorylated intermediate

80
Q

atp hydrolysis leads to a change in ______

A

protein shape and binding ability

81
Q

what does atp do in trnasport work?

A

atp phosphorylates transport proteins

82
Q

whart does atp do in mechanical work?

A

atp binds noncovalently to motor proteins and then is hydrolyzed

83
Q

what is a catalyst?

A

a chemical agent that speeds up a reaction without being consumed by the reaction

84
Q

what is an enzyme?

A

a catalytic protein in cells

85
Q

what is the initial energy needed to start a chemical reaction?

A

energy of activation or activation energy

86
Q

how do enzymes work?

A

they catalyze reactions by lowering the activation energy

87
Q

in both endergonic and exergonic reactions, ____ are needed to lower the energy of activation

A

enzymes

88
Q

do enzymes change free energy?

A

no!

89
Q

are enzymes substitutes for atp coupling?

A

hell no!

90
Q

what is a substrate?

A

the reactant that an enzyme acts on

91
Q

what forms when an enzyme binds to its substrate?

A

enzyme-substrate complex

92
Q

what is the region on the enzyme where the substrate binds?

A

active site

93
Q

what is induced fit?

A

brings chemical group of the active site into positions that enhance their ability to catalyze the reaction

94
Q

how can the active site lower an activation energy barrier?

A

orienting substrates correctly, straining substrate bonds, providing a favorable microenviroment, covalently but transiently bonding to the substrate

95
Q

what factors can affect an enzymes activity?

A

environmental factors like temperature and pH

96
Q

what are cofactors?

A

nonprotein enzyme helpers

97
Q

what is an organic cofactor called?

A

coenzyme, include vitamins

98
Q

what are competitive inhibitors?

A

they bind to the active site of an enzyme, competing with the substrate

99
Q

what are non competitive inhibitors?

A

they bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

100
Q

what would happen if a cell’s metabolic pathways were not tightly regulated?

A

chemical chaos

101
Q

what is allosteric regulation?

A

may either inhibit or stimulate an enzymes activity

102
Q

when does allosteric regulation occur

A

when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site

103
Q

what are aollsterically regulated enzymes are of?

A

polypeptide subunits

104
Q

what is feedback inhibition?

A

the end product of a metabolic pathway shuts down the pathway; prevents a cell from wasting chemical resources by synthesizing more product than needed

105
Q

what is localization?

A

structures within the cell help bring order to metabolic pathways, some enzymes act as structural components of membranes

106
Q

the breakdown of organic molecules and catabolic pathways are generally ____

A

exergonic

107
Q

what is aerobic respiration?

A

consumes organic molecules and oxygen and yields ATP

108
Q

what respiration consumes compounds other than fermentation is in oxygen

A

anaerobic

109
Q

what is fermentation?

A

a partial degradation of sugars that occurs as part of aerobic respiration in absence of available oxygen

110
Q

how do catabolic pathways release stored energy?

A

by breaking down complex molecules (oxidizing organic fuels)

111
Q

the transfer of _____ during chemical reactions releases energy stored in organic molecule?

A

electrons

112
Q

what are chemical reactions that transfer electrons between reactants?

A

redox reactions

113
Q

what happens in oxidation?

A

a substance loses electrons,

114
Q

what happens in reduction?

A

a substance gains electrons,

115
Q

what is the electron donor called?

A

reducing agent

116
Q

what is the electron acceptor called?

A

oxidizing agent

117
Q

what are the 3 stages of cellular respiration?

A

glycolysis, pyruvate oxidation and citric acid cycle, and oxidative phosphorylation

118
Q

what is glycolysis?

A

breaks down glucose into 2 molecules of pyruvate in the cytoplasm

119
Q

what is pyruvate oxidation and citric cycle?

A

completes the breakdown of glucose in the mitochondrial matrix

120
Q

what is oxidative phosphorylation?

A

accounts for most of the atp synthesis on the mitochondrial cristae

121
Q

oxidative phosphorylation is powered by _____ reactions and account or ~___% of the ATP generated

A

redox; 90

122
Q

glycolysis occurs in 2 major phases

A

energy investment and energy payoff

123
Q

look at the energy investment and payoff diagram

A

okie dokie yo

bio 212 (3 decks)

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