250-259 Flashcards

1
Q

Covalent bonds:

A

Covalent bonds: Strong molecular interactions mediated by shared electrons.

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2
Q

Noncovalent bonds:

A

Noncovalent bonds: Weak, reversible molecular interactions

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3
Q

Van der Waals bonds:

A

Van der Waals bonds: A nonspecific attraction (occurs when any two

atoms are 3–4 Å apart).

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4
Q

water

A

Polar.

■ Triangular.

■ Highly cohesive.

■ Excellent solvent for polar molecules.

■ Weakens ionic and H-bonds.

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5
Q

Catalyzes the reaction between CO2 and H2O.

■ Extremely fast enzyme.

A

Carbonic Anhydrase

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6
Q

Located largely in erythrocytes and kidneys.

■ A metalloenzyme: contains zinc.

A

Carbonic Anhydrase

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7
Q

The total energy of a closed system is conserved.

A

First law of thermodynamic

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8
Q

The entropy of a closed system always increases.

A

■ Second law of thermodynamics

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9
Q

Direct calorimetry:

A

Direct measurement of the amount of heat produced

in a given system.

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10
Q

Indirect calorimetry:

A

Measurement of the amount of heat produced in

terms of inhaled O2 and exhaled CO2.

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11
Q

Highly specific catalysts for biochemical reactions.

■ Classified according to their mechanism of action.

A

enzymes

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12
Q

https://drive.google.com/open?id=0B8uJUY-tie8GbzB2bGljMl93NHc

A

https://drive.google.com/open?id=0B8uJUY-tie8GR1ZtdkU4VU50aVk

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13
Q

Composed of proteins combined with nonprotein structures (either

organic or inorganic) that aid in their function

A

Metallic Coenzymes

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14
Q

Coenzymes

■ Cofactors

■ Prosthetic groups

A

metallic coenzymes

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15
Q

Coenzyme:

A

Nonprotein portion of an enzyme.

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16
Q

Apoenzyme:

A

Protein portion of an enzyme. Catalytically inactive by itself.

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17
Q

Haloenzyme: ■

A

Complete, catalytically active enzyme.\

= Apoenzyme + Coenzyme

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18
Q

Isozymes:

A

Enzymes with subtle molecular differences that catalyze the

same reaction.

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19
Q

Oxidoreductases:

A

Catalyze redox reactions.

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20
Q

Transferases:

A

Catalyze the transfer of functional groups.

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21
Q

Hydrolases: ■

A

Catalyze bond cleavage by hydrolysis.

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22
Q

Isomerases:

A

Catalyze a change in molecular structure.

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23
Q

Lyases:

A

Catalyze bond cleavage by elimination.

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24
Q

Ligases:

A

Catalyze the union of two molecules.

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25
Q

Substrate-binding induces a conformational change in an enzyme.

■ The energy produced by these changes enables the reactions to progress

A

induced fit model

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26
Q

Increasing substrate concentration —- reaction rate only until the

—— —— sites are saturated.

A

Increasing substrate concentration increases reaction rate only until the

enzyme-binding sites are saturated.

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27
Q

Maximum reaction velocity (Vmax) is achieved when any further —-

in substrate concentration —— increase reaction rate.

A

Maximum reaction velocity (Vmax) is achieved when any further increase

in substrate concentration does not increase reaction rate.

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28
Q

The Michaelis constant (Km) is the substrate concentration when the initial

reaction velocity (vi) is —– of the maximum reaction velocity (Vmax).

A

The Michaelis constant (Km) is the substrate concentration when the initial

reaction velocity (vi) is half of the maximum reaction velocity (Vmax).

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29
Q

ΔG = ΔGP− ΔGS

A

Determines reaction direction.

■ If ΔGS > ΔGP, then ΔG will be negative and the reaction will proceed

spontaneously toward equilibrium.

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30
Q

Equilibrium is attained when ΔG = —-

A

Equilibrium is attained when ΔG = 0.

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31
Q

vi =

Vmax · [S]

Km + [S]

A

https://drive.google.com/open?id=0B8uJUY-tie8GU3FWZ1l6T3JJa3M

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32
Q

Reactions are based on their ΔG (see Table 5–2).■

A

Exergonic

■ Endergonic

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33
Q

A: Any reaction with enzyme present.

■ B: Equilibrium —– of the reaction.

■ Enzymes have— —- on reaction equilibrium

A

A: Any reaction with enzyme present.

■ B: Equilibrium constant of the reaction.

■ Enzymes have no effect on reaction equilibrium

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34
Q
A

https://drive.google.com/open?id=0B8uJUY-tie8GOUVDUUlxSV9lSjA

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35
Q

rxn rate

A

Determined by the activation energy.

■ Attaining activation energy requires an increase in reactant kinetic energy.

36
Q

Kinetic energy is largely influenced by —– and substrate ——

■ Enzymes —- the activation energy of a reaction, —— the rate

A

Kinetic energy is largely influenced by temperature and substrate concentration.

■ Enzymes lower the activation energy of a reaction, accelerating the rate

37
Q

Negative

Released

A

G

nrg flow

= exergonic

38
Q

Positive

Required

A

G

nrg flow

=endergonic

39
Q

https://drive.google.com/open?id=0B8uJUY-tie8GZ1lmejcxcVQxVW8

A

https://drive.google.com/open?id=0B8uJUY-tie8GUVJHdHNPTDhjUGc

40
Q

Inhibitor and substrate compete for the same binding site.

■ Inhibition can be reversed with increased substrate concentration.

A

comp. inh.

41
Q

No effect on Vmax.

■ Km is increased

A

comp. inh

42
Q

comp inh

A

https://www.google.com/search?rlz=1C5CHFA_enUS763US763&biw=1379&bih=749&tbm=isch&sa=1&q=competitive+inhibition+graph&oq=competitive+inhibition+graph&gs_l=psy-ab.3..0l2j0i5i30k1l2.9067.10098.0.10219.6.6.0.0.0.0.172.643.0j5.5.0….0…1.1.64.psy-ab..1.5.641….0.sdGbc8vRG_4#imgrc=uKXNNJ82kEt77M:

43
Q

non comp inh

A

https://www.google.com/search?rlz=1C5CHFA_enUS763US763&biw=1379&bih=749&tbm=isch&sa=1&q=non+competitive+inhibition+graph&oq=non+competitive+inhibition+graph&gs_l=psy-ab.3..0.69599.70182.0.70391.4.4.0.0.0.0.124.456.0j4.4.0….0…1.1.64.psy-ab..0.4.454…0i13k1j0i7i30k1j0i8i7i30k1j0i13i5i30k1j0i5i30k1.0.vyq3HplZf8s#imgrc=ji_YDOEADuS4xM:

44
Q

Inhibitor and substrate bind simultaneously.

■ The two binding sites do not overlap.

A

non comp inh

45
Q

Inhibition cannot be reversed with increased substrate concentration.

■ Vmax is decreased

A

non comp inh

46
Q

No effect on K

A

non comp inh.

47
Q

non comp injh

A

Inhibitor binds only after the substrate is bound first.

■ The two binding sites do not overlap

48
Q

Vmax is decreased.

■ Km is decreased

A

non comp inh

49
Q

Inhibitor ——- alters the molecular structure of an enzyme, prohibiting

its continued activity.

A

Inhibitor irreversibly alters the molecular structure of an enzyme, prohibiting

its continued activity.

50
Q

cov modification

A

Reversible or irreversible enzymatic

modification alters enzyme conformation,

thus affecting its activity

51
Q

cov modification

A

Phosphorylation (kinases)

■ Dephosphorylation (phosphatases)

■ Methylation (methyltransferases

52
Q

Allosteric enzyme:

A

Allosteric enzyme: A regulatory enzyme that has both an active site (for the

substrate) and an allosteric site (for the effector).

53
Q

If the effector is present, it binds to the —- —–causing a conformational

change to the —- site, which then changes (increases or decreases)

the enzymatic activity

A

If the effector is present, it binds to the allosteric site causing a conformational

change to the active site, which then changes (increases or decreases)

the enzymatic activity

54
Q

If no effector is present, the enzyme can still act on substrate —–y (via

the active site) to produce product.

A

If no effector is present, the enzyme can still act on substrate normally (via

the active site) to produce product.

55
Q

A form of feedback regulation in which an enzyme of a —- —-

is controlled by the end product of that same pathway. (See Figure 5–7.)

A

A form of feedback regulation in which an enzyme of a metabolic pathway

is controlled by the end product of that same pathway. (See Figure 5–7.)

56
Q

Often catalyzes a committed step early in a metabolic pathway.

■ Simple Michaelis–Menten kinetics are not followed.

A

allosteric rxn

57
Q

Proenzyme (zymogen):

A

Proenzyme (zymogen): Catalytically inactive enzyme precursor.

58
Q

Proteases cleave the protein fragment (propeptide) of the zymogen, —–

the enzyme

A

Proteases cleave the protein fragment (propeptide) of the zymogen, activating

the enzyme

59
Q

Trypsinogen 2 Trypsin

A

Enteropeptidase

60
Q

Fibrinogen 2 Fibrin

A

Thrombin

61
Q

The most fundamental carbohydrate; required for carbohydrate metabolism,

storage, and cellular structure.

A

glucose

62
Q

If carbohydrates are not absorbed by dietary intake, they are generally converted

to glucose in the liver.

A

glucose

63
Q

Monosaccharides:

A

The simplest carbohydrates.

64
Q

Number of carbon atoms:

A

Trioses, tetroses, pentoses, hexoses, heptoses

65
Q

Functional group:

A

Aldoses (aldehyde) or ketoses (ketone)

66
Q

6–2).

■ Reducing sugars: Contain —– groups that are oxidized to

—–. For example: glucose, fructose, galactose, maltose,

lactose.

A

6–2).

■ Reducing sugars: Contain aldehyde groups that are oxidized to

carboxylic acids. For example: glucose, fructose, galactose, maltose,

lactose.

67
Q

D-form:

A

Hydroxyl group on right. Most common form.

68
Q

L-form:

A

Hydroxyl group on left.

69
Q

Disaccharides:

A

Glycosidic condensation of two monosaccharides

70
Q

Maltose →

A

glucose + glucose; via maltase

71
Q

Sucrose →

A

glucose + fructose; via sucrase

72
Q

Lactose →

A

glucose + galactose; via lactase.

73
Q

Oligosaccharides:

A

Glycosidic condensation of 2–10 monosaccharides

74
Q

■ Polysaccharides:

A

■ Polysaccharides: Glycosidic condensation of >10 monosaccharides.

75
Q

polysach

A

Mostly used as storage molecules or cellular structural components.

■ Can be linear or branched

76
Q

https://drive.google.com/open?id=0B8uJUY-tie8GOUNvV0RIU3ZuMVU

A

https://drive.google.com/open?id=0B8uJUY-tie8GVXQ4cHprT0dzbzQ

77
Q

A homopolymer of glucose l

STARCH

A

inked by a–1, 4 glycosidic bonds.

78
Q

STARCH

A

The major glucose storage molecule in plants.

79
Q

Contains unbranched helical amylose (15–20%) and branched (a–1, 6)

amylopectin (80–85%).

A

STARCh

80
Q

Amylases:

A

The key enzymes in starch catabolism

81
Q

Dextrins:

A

D-glucose polymer intermediates in starch hydrolysis. “Limit

dextrins” are the fragments that remain following hydrolysis

82
Q

https://drive.google.com/open?id=0B8uJUY-tie8GWVZRS0VOUmQwQ2c

A

https://drive.google.com/open?id=0B8uJUY-tie8GQnlFMVBBVGZ6bFE

83
Q

glycogen

A

A homopolymer of glucose linked by a-1, 4 glycosidic bonds.

■ The major glucose storage molecule in animals

84
Q

glycogen

A

■ Contains numerous branch points via a-1, 6 glycosidic linkages.

85
Q

https://drive.google.com/open?id=0B8uJUY-tie8GZmRzNm9xSlZTaHM

A

https://drive.google.com/open?id=0B8uJUY-tie8GY1VNMG5aWXJjd1k

86
Q
A