C/P Review Flashcards

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1
Q

What does A represent?

A

Activation energy without enzyme present

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2
Q

What does B represent?

A

Lowered activation energy due to an enzyme being present

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3
Q

A molecule that REDUCES is a ____ agent

A

oxidizing agent

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4
Q

List 3 ways in which you can see if a molecule has been oxidized

look for….

A
  1. additional oxygens
  2. fewer hydrogens
  3. carbons that have additional bonds to oxygen
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5
Q

Proteins that are more stable have [higher/lower] melting points

A

Higher

higher melting point = more stability

If a question is asking which protein is more stable, it is likely the one with a higher melting point, so look for this info

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6
Q

If a molecule is gaining electrons to carry, it is being [reduced/oxidized]

A

Reduced

reduction = gaining electrons to REDUCE the CHARGE

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7
Q

The process of changing from an optically active compound into an optically inactive compound or mixture. Optically active compounds (which consist of only one enantiomer) are converted into an equal mixture of enantiomers with zero optical activity.

A

racemization

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8
Q

True or False

Racemeization requires substitution at a chiral center

A

True

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9
Q

An achiral compound with several chiral centres but no optical activity due to an internal plane of symmetry. Superimposable on its mirror image

A

meso-compound

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10
Q

The ability of a substance to rotate the plane of polarization of a beam of light that is passed through it.

A

optical activity

Compounds that are optically active contain molecules that are chiral, unless it is a meso-compound

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11
Q

Name the isomeric relationship

____ rotate the plane of polarized light in opposite directions

A

Enantiomers

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12
Q

Organic compounds in which two chiral carbons are present and those two are similar. Have zero net rotation of plane polarised light.

A

mesomer

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13
Q

A process in which the configuration of an atom is changed. If the atom in question is a stereocenter, ____ usually (but not always) changes R absolute configuration into S, and S into R. ____ can also convert cis into trans, or trans into cis.

A

inversion of configuration

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14
Q

If the chiral carbon is not changed in the reaction, a molecule’s sterochemistry is conserved

A

conservation of sterochemistry

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15
Q

chiral centers are ____ hybridized

A

sp3

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16
Q

the Rf of a compound represents the distance traveled by the [solvent front/compound] divided by the distance traveled by the [solvent front/compound]

A

the Rf of a compound represents the distance traveled by the compound divided by the distance traveled by the solvent front

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17
Q

A lower Rf value suggests that the molecule in question is more [polar/nonpolar] and therefore [more/less] traveling bc the molecule has [lower/higher] affinity for the stationary phase

A

A lower Rf value suggests that the molecule in question is more polar and therefore less traveling bc the molecule has higher affinity for the stationary phase

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18
Q

True or False

Enzymes can affect ΔS

A

False. ΔS is the change in entropy. Enzymes do not affect thermodynamics at ALL.

If a question asks if an enzymes affect anything involved in the Gibbs Free energy equation the answer is NO

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19
Q

What’s the acronym that can help you remember the colors of vivisble light in order of increasing energy and frequency.

A

ROYGBV

400nm-700nm

Violet has the shortest wavelength and the highest frequency in the visible range

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20
Q

An order of chemical reaction in which the rate of the reaction depends on the concentration of only one reactant, and is proportional to the amount of the reactant.

A

1st order kinetics

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21
Q

chemical reactions wherein the sum of the exponents in the corresponding rate law of the chemical reaction is equal to two. The rate of such a reaction can be written either as r = k[A]2, or as r = k[A][B].

A

second order kinetics

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22
Q

A chemical reaction in which the rate is constant & independent of the concentration of the reactants

A

zeroth order reactions

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23
Q

globular proteins are [water/lipid] soluble, which means that amino acids wiht hydro[phobic/hilllic] side chains are found on their exterior

A

water-soluble, hydrophillic

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24
Q

When G > 0, a reaction is [spontaneous/nonspontaneous]

A

**non**spontaneous

## Footnote

Given **ΔG = ΔH - TΔS**. When a problem gives you a hypothetical reaction and asks you determine its spontaneity given its H, T, or S values, just imagine large values in this equation

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25
Q

A value of K(eq) > 1 suggests that the ΔG° is [greater than/less than] 1

A

If Keq > 1, then ΔG° < 1

ΔG° = –RTlnKeq

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26
Q

What is the equation for determining the pH of a substance given its concentration of hydrogens?

A

pH = -log[(H+)]

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27
Q

Given that the stomach contains 0.21N HCl, what is the concentration of hydrogens? What is the pH?

A

H+ concentration = 0.21N
pH = -log(0.21)

N in the context of acids is = to H+ per liter of solution.
Remember: pH = -log[H+]

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28
Q

In a fractional distillation, two molecules may have very similar molecular weight but have different levels of….

(there can be multiple answers)

A

intermolecular forces and branching

IMF takes importance

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29
Q

If lung elastance is the resistance to stretch, would increased elastance be counteracted by increased pressure per unit volume OR increased work by the intercostal muscles?

A

increased work by the intercostal muscles

increased elastance = breathing will take more work

to counteract decreased lung compliance (the ability of the lungs to expand), work done by the muscles to expand the lungs must increase

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30
Q

Energy stored in an object due to a force that temporarily changes its shape, such as squashing or stretching

A

elastic energy

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31
Q

Arteries are more elastic than veins becuase…

A

Because of their thicker walls

remember: elasticity is the ability of an object or material to resume its normal shape after being stretched or compressed; stretchiness.

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32
Q

The ability of an object or material to resume its normal shape after being stretched or compressed; stretchiness.

A

elasticity

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33
Q

Decibles are measured on a log scale, thus an increase of 10dB is a ____ increase, and an increase of 20dB is a ____ increase

A

10x, 20x

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34
Q

Proteases are ____, cleaving only L-amino acids

A

sterospecific

L-amino acids are naturally occuring ones

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35
Q

threonine and serine both have [polar/nonpolar] uncharged side chains that contain ____ groups

A

polar uncharged sidechains that contain hydroxyl groups

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35
Q

What is the trend of the acceleration at part 7 given the graph?

A

The acceleration is increasing in the negative direction

the velocity's slope is getting steeper, meaning the magnitude of the acceleration is increasing, but in the opposite direction
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36
Q

work = ….

A

Power (watts) x Time (seconds)

in Joules or KJ

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37
Q

In a cation exchange chomatography, the mobile phase will have [positve/negative] ions binding to the beads

A

positive

cation exchange chromatography has (-) charged resin

cation refers to the ATTRACTED molecule

38
Q

Resistance can be found via Ohm’s law, which is….

A

V = IR

Voltage = Current x Resistance

would be R = V x I to find resistance

39
Q

What’s the difference between ΔG°rxn and G‡?

A

ΔG°rxn refers to Gibbs free energy, where G‡ refers to activation energy.

Enzymes only affect G‡

40
Q

What are the two ways in which we could increase the rate of a catylytic reactionn?

A

1.) Increasing substrate concentration
2.) Increasing enzyme concentration

41
Q

The reaction rate when the enzyme is fully saturated by substrate, indicating that all the binding sites are being constantly reoccupied

A

Vmax

adding susbstate beyond this point will have no effect on reaction rate as the enzyme active sites are saturated
JW Article

42
Q

The substrate concentration at which the reaction is half of the Vmax

A

Km

43
Q

Given this equation, what happens to Km when the substrate concentration is very high?

A

When S is very high, we can ignore Km, simplifying the equation to V0 = Vmax

44
Q

Enzymes are increasingly binding to substrate, increasing the velocity of the reaction. What reaction order is this?

A

1st order

45
Q

All of the enzyme’s active sites are occupied by substrate. Adding more substrates at this point is not changing the reaction’s velocity. What order of kinetics is this?

A

0th order

46
Q

True or False

Enzyme-substrate reactions are reversible

A

True

E + S ⇌ ES

47
Q

What happens to Km when V0 is equal to half of Vmax?

A

Km = [S]

Remember, Km is the substrate concentration at which the reaction is half of the Vmax
video

48
Q

Name the enzyme inhibition

Induces conformational change that prevents the enzyme from forming products

A

Non-competitive inhibition

non-competitive inhibition changes enzyme ACTIVITY

The binding of this allosteric inhibitor changes the conformation of the enzyme so the enzyme-substrate complex cannot perform catylytic activity. This means the enzyme cannot catylyze a reaction to form a product.

49
Q

Where do non-competitive inhibitors bind, and what is their effects on Km and Vmax?

A
  • Bind at allosteric site (any region other than active site)
  • Does not affect Km
  • Decreases Vmax

Non-competitive inhibitors don’t affect the affinity of the enzyme for its substrate (Km) because the active site is not competed for by the inhibitor
However, the Vmax is decreased because increasing the substrate concentration will not overcome the inhibition

50
Q

Name the enzyme inhibition

This Lineweaver-Burk plot is for which type of inhibition?

A

Noncompetitive

Km unaffected, Vmax reduced
51
Q

Name the type of inhibition

Only binds to an enzyme when a substrate is present

A

Uncompetitive inhibition

only binds to ES complex

This inhibitor complex forms mostly under concentrations of high substrate and the ES-I complex cannot release product while the inhibitor is bound, thus result in reduced Vmax.
Km is reduced because an enzyme’s affininity for its substrate increases

52
Q

True or False

In both non-competitive and uncompetitive inhibition, the amount of product that is formed decreases

A

True

Note: the Vmax of both of these inhibitions decreases. For noncompetive inhibition, this is because the enzyme’s catylytic activity is hindered. In uncompetitive inhibiton, this is because the substrate stays bound to the enzyme

53
Q

A low Km value means….

A

Only a small amount of substrate is needed to saturate the enzyme, indicating a high affinity for substrate.

54
Q

Why does an enzyme’s affinity for its substrate increase with uncompetititve inhibition?

Why does Km decrease with uncompetitive inhibition?

A

Because the inhibitor binds to the enzyme-substrate complex and then changes the enzyme’s conformation, it makes it incredibly difficult for the substrate to become unbound from the enzyme (substrate gets stuck!). Thus, the apparent affinity of the substrate for the enzyme is dramatically increased

55
Q

This Lineweaver-Burk plot is for which type of inhibition?

A

Uncompetitive inhibition

56
Q

This Lineweaver-Burk plot is for which type of inhibition?

A

Competitive inhbition

57
Q

In competitive inhibition, why does the Vmax stay the same while the Km increases?

A

The reaction can eventually reach its Vmax, but it takes a higher concentration of substrate to get it there. The extra substrate makes the substrate molecules abundant enough to consistently “beat” the inhibitor to the enzyme.

58
Q

A reaction with a large positve ΔH and a large negative ΔS would indicate that the chemical reaction is [spontaneous/not spontaneous]

A

Not spontaneous.

Given the ΔG = ΔH - TΔS, a large positive ΔH minus a large negative number gives a large positive number as a result, and a positive ΔG means that the reaction is not spontaneous

59
Q

How can you tell if a molecule is being reduced?

A

A molecule gains a bond to hydrogen

60
Q

____ has more entropy than liquids

A

Gases

entropy = disorder gases have more disorder because their molecules are bouncing all over the place

61
Q

The change in heat for a given phase is represented by the equation….

A

q=mcΔT

If a substance is changing phases, this equation’s realionships are no longer valid.

62
Q

A problem says you have to find the highest period of a sound wave. What equation would you use?

A

f = 1/T where f is frequency and T = period

63
Q

What equation represents the relationship between power and intensity? Power and energy?

A

I = P/A, P = W/t, thus W = Pt = IAt

I = intensity P = power A =area of surface W = work t = time spent listening to sound

64
Q

occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes

A

constructive interference

65
Q

when two waves overlap in such a way that they cancel each other out

A

destructive interference

66
Q

photons have a ____ charge

A

trick question, NO CHARGE

(regardless of what decay its from). Magnetic fields only affect CHARGED particles

67
Q

the ____ of any system is equal to the pH where exactly **half **of the compound in solution is in the protonated form and half is in the deprotonated form

A

pKa

68
Q

Deprotanation occurs at [high/low] pH and [acidic/basic] conditions

A

Deprotanation occurs at high pH and basic conditions

69
Q

a portion of a molecule, which may be a functional group, or describe a portion of a molecule with multiple functional groups which share common structural aspects

A

moiety

70
Q

indicates the total number of pi bonds and rings within a molecule

A

degrees of unsaturation

for an MCAT problem, you can just look at the number of bonds that change in the portion of the molecule undergoing transformation, and the number of rings that change
It is important to note that the removal of two protic hydrogens does not result in increasing the degree of unsaturation if the charges are localized on individual atoms

71
Q

a molecule during a transformation gains 1 pi bonds and loses 1 ring. What is the degree of unsaturation?

A

0

72
Q

a chemical addition reaction in which a nucleophile forms a sigma bond with an electron-deficient species.

A

nucleophillic addition

These reactions are considered very important in organic chemistry since they enable the conversion of carbonyl groups into a variety of functional groups

73
Q

An electron rich species that can donate a pair of electrons

A

nucleophile

74
Q

an electron poor species that can accept a pair of electrons

A

electrophile

75
Q

____ substances are Lewis acids (compounds that accept electron pairs), and many of them are Brønsted acids (compounds that donate protons).

A

electrophilic

76
Q

____ increases going down the periodic table due to greater size and polarizability

A

Nucleophilicity

77
Q

stronger nucleophiles make reaction go [faster/slower]

A

Faster

78
Q

A D-sugar has an [R/S] configuration at the last stereocenter in the molecule, while an L-sugar has the [R/S] configuration.

A

A D-sugar has an R configuration at the last stereocenter in the molecule, while an L-sugar has the S configuration.

79
Q

IV administration allows a drug to bypass the ____ , the primary organ responsible for drug metabolism

A

liver

80
Q

True or False

Drug absorption is poor through the oral and rectal mucosa

A

True

81
Q

A problem asks you to find the angle between the pole of a swing carousel that’s moving people in a circular motion and the people sitting in the swing chairs. What equation would you use to solve this problem?

A

Torque = τ = Fd sinθ

F is the force creating torque, d is the distance from the force to the rotation point, and θ is the angle between F and d.

82
Q

What is the relationship between Force and Mass

A

F = ma

83
Q

A force pointing into the center of the circle

A

centripedal force

84
Q

the apparent outward force on a mass when it is rotated

A

centrifugal force

Think of a ball on the end of a string that is being twirled around, or the outward motion you feel when turning a curve in a car.

85
Q

All mammallian amino acids except the achiral glycine, all have an L configuration, which corresponds to an [R/S] stereocenter at the alpha carbon.

A

S stereocenter

86
Q

True or False

All things undergo forces from higher potential energy to lower

A

True

87
Q

Equation for change in potential energy given a charge

A

ΔPE= qΔd

change in potential energy = charge x change in distance between electrical field/electric plates

88
Q

Where do electrical field lines point?

A

Away from a positive charge and towards a negative point

89
Q

Equation for 2nd order rate law

A

r = k[A]2

90
Q

Name the 5 factors that affect the dissociation constant of hemoglobin

A
  1. pH
  2. temperature
  3. carbon dioxide (CO2)
  4. 2,3-BPG
  5. carbon monoxide (CO)

adding any significant acid or base can affect the pH!

91
Q

True or False

Cells require the same number of NAD+ electron carriers compared to FAD electron carriers, in order to harvest ATP from fatty acids

A

Cells require more than twice the number of NAD+ electron carriers compared to FAD electron carriers, in order to harvest ATP from fatty acids

92
Q

Fatty acid catabolism starts in the ____, and is mostly performed in the ____

A

starts in the cytosol, performed in mitochondrial matrix

fatty acid catabolism = beta oxidation