Quiz
Biochem Midterm March 2020
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Questions in this quiz (46)
1in cation exchange the stationary phase is positively charged
- ATrue
- BFalse
2What is the purpose of B mercaptotethanol in the anfinsen experiment
- AReducing agent
- BBreaking disulphide bonds
- CBreak/prevents H bonds
- DBreaks/prevents ionic bonds
3Hydroxy proline has [blank_start]2[blank_end] important roles in collagen
- A2
4an amino acid with an amino group in its side chain (pka 6) will be [blank_start]neutral[blank_end] at pH 7
- Aneutral
- Bnegative
- Cpositive
5the P50 of hemoglobin/myoglobin is
- Athe oxygen saturation at 50 mmHg PO2
- Bthe partial pressure of oxygen at 50% saturation
62,3-bisphosphoglycerate decreases affinity for oxygen in hemoglobin
- ATrue
- BFalse
7decreasing the affinity for oxygen in hemoglobin would do what to the oxygen binding curve?
- ACurve would shift up
- Bcurve would shift down
- Ccurve would shift left
- Dcurve would shift right
8What is (approximately) the PI of this amino acid?
- A2.3
- B9.6
- C6
- D1.0
9What is happenning at the labeled spot? This is the titration curve of an amino acid with an amino group in the side chain.
- ACOO- in amino acid is protonated
- BNh2 in side chain is protonated
- Cnh2 in Amino acid is protonated
10Edman degradation uses a [blank_start]chemical[blank_end] to remove residues [blank_start]1[blank_end] at a time
- Achemical
- BAmino acid specific protein
- C1
- D2
- E5
11Order these steps in an Edman Degredation...
[blank_start]1.[blank_end] terminal amino acid reacts with phenyl isothiocyanate
[blank_start]4.[blank_end] cyclic compound is identified
[blank_start]2.[blank_end] basic conditions lead to a cyclic structure forming
[blank_start]3.[blank_end] acid and heat cause release of terminal amino acid from peptide- A1.
- B2.
- C3.
- D4.
- E2.
- F3.
- G4.
- H1.
- I3.
- J4.
- K2.
- L1.
- M3.
- N1.
- O4.
- P2.
12Anion exchange has a negative stationary phase
- ATrue
- BFalse
13Rate of enzyme converting substrate to product = [blank_start]Kcat[blank_end]
Rate of enzyme binding to substrate = [blank_start]Kon[blank_end]
Rate of enzyme releasing substrate = [blank_start]Koff[blank_end]
Enzyme affinity for substrate = [blank_start]Km[blank_end]- AKcat
- Bkon
- CKOff
- DKm
14Vo is obtained by taking the slope at the [blank_start]beginning[blank_end] go the [P] vs time graph
- Abeginning
- Bplateau
- Cmidpoint
15When concentration of substrate is very high, Vo is [blank_start]equal to[blank_end] Vmax.
- Aequal to
- Blarger than
- Cless than
16When concentration of substrate is equal to the affinity constant, Vo is [blank_start]twice[blank_end] Vmax.
- Atwice
- Bhalf
- Cequal to
17When [enzyme] changes, which of these also changes?
- AVmax
- BKm
- CKcat
- DVo
18what is true about the specificity constant?
- Adepends of rate of catalysis and affinity
- Blow number is means it is a "good" enzyme
- CA high Km will give a high specificity constant
- D=Kcat/Km
19what are the six major classes of enzymes
- AOxidoreductases, transferases, Oxidases, protonases, ligases, hydroxylases
- BOxidoreductases, transferases, Hydrolyases, ligases, Isomerases, lyases
- CLyases, Oxidases, hydroxylases, Lipases, amylases, ligases
- Dtransferases, isomerases, carbohydrases, hydrolyases, oxireductases, ligases
20For enzymes that require a cofactor, the enzyme alone is called a(n) [blank_start]apo[blank_end] enzyme, and the enzyme cofactor complex is called a(n) [blank_start]holo[blank_end] enzyme
- Aapo
- Bprosthetic
- CHolo
- DFunctional
21Cofactors can be either vitamins or minerals
- ATrue
- BFalse
22∆G is the difference between free energy of product and reactants
- ATrue
- BFalse
23A non-spontaneous reaction is exergonic
- ATrue
- BFalse
24the more negative the ∆G, the faster the reaction
- ATrue
- BFalse
25What can affect ∆G?
- ATemperature
- Bcatalyst
- C[reactant]
- D[product]
26Can ∆G be zero?
- ATrue
- BFalse
27∆G‡ is
- Athe free energy of the transition state
- Bthe difference in free energy of the reactants and products
- Caffected by the addition of an enzyme/catalyst
28Which of these amino acids are ionizable?
- ALysine
- BGlutamine
- Ctryptophan
- DCysteine
- EArginine
29KD (Dissociation constant) is used to compare affinity in [blank_start]non-catalytic[blank_end] reactions. KD = [blank_start]Koff[blank_end]/[blank_start]Kon[blank_end]
- Anon-catalytic
- Bcatalytic
- CKoff
- DKon
- EKon
- FKoff
30The upper limit of Kcat/Km (specificity constant) is ...
- A10^-5 /s/M
- B10^9 /s/M
- C10^14 /s/M
31Which of these amino acids can H bonds, but are not ionizable?
- AW
- BS
- CY
- DC
- EN
- FQ
- GK
- HR
32Which amino acids are neutral in charge, no matter the pH?
- AAla
- BGly
- CLeu
- DPhe
- ELys
- FAsp
33The first amino acid in all proteins is [blank_start]methionine[blank_end]
- Amethionine
- Bcysteine
- Ctryptophan
- Dthreonine
34Methionine can be oxidized to [blank_start]methionine sulfoxide[blank_end]
- Amethionine sulfoxide
35free amino acids at neutral pH exist predominantly in the [blank_start]zwitterionic[blank_end] form
- Azwitterionic
36Amino acid composition analysis
[blank_start]1.[blank_end] peptide is hydrolyzed into individual amino acids using heat and acid
[blank_start]2.[blank_end] amino acids are separated by ion exchange or high pressure liquid chromatography
[blank_start]3.[blank_end] amount of amino acids measured- A1.
- B2.
- C3.
37Edman degradation can be used for peptides as long as 100 amino acids long
- ATrue
- BFalse
38Mass spectrometry measures [blank_start]acceleration[blank_end] of [blank_start]ionized[blank_end] molecules in the [blank_start]gas[blank_end] phase as they move through an electric field to determine [blank_start]mass[blank_end]
- Aacceleration
- Bvelocity
- Cionized
- Dneutral
- Egas
- Fliquid
- Gsolid
- Hmass
- Iidentity
39Mass spectrometry can be used to sequence proteins
- ATrue
- BFalse
40alpha carbons of amino acids in a peptide bond are usually...
- Acis
- Btrans
- Cparallel
- Dperpendicular
41What are stabilizing forces in secondary structure but not tertiary structure in a protein?
- Aionic attractions between opposite charged side chains
- BH bonds between oxygen of the backbone carbonyl and the hydrogen of the backbone amine
- CH bonds between side chains
- Dhydrophobic interactions between non polar side chains
42Fetal hemoglobin has 2 alpha subunits and 2 [blank_start]gamma[blank_end] subunits as opposed to Adult hemoglobin which has 2 alpha and 2 [blank_start]beta[blank_end]
- Agamma
- Bbeta
43tertiary structure is formed by interactions between R groups
- ATrue
- BFalse
44Quaternary structure is made by interactions between subunits
- ATrue
- BFalse
45Which of these features are true about the structure of collagen
- AMade of 3 polypeptides each arranged in a left hand helix
- BEvery 4th residue is a glycine
- Crich in proline and hydroxyproline
- Dthe 3 chains arrange in a right hand helix around each other
46Myoglobin is mainly hydrophobic in the interior
- ATrue
- BFalse
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- Quiz on Biochem Midterm March 2020, created by lyndsey chesham on 03/03/2020.
- Author
- lyndsey chesham
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- English
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