Protein section 1

MrSujg
Quiz by MrSujg, updated more than 1 year ago
MrSujg
Created by MrSujg over 4 years ago
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Description

1st year Biochemistry and molecular biology Quiz on Protein section 1, created by MrSujg on 11/19/2015.

Resource summary

Question 1

Question
FOUR MAJOR FUNCTIONAL GROUPS:
Answer
  • Binding
  • Modification
  • Catalysis
  • Switching
  • Inhibition
  • Structural
  • Physiological

Question 2

Question
How is amide bond formed
Answer
  • dehydration
  • addition
  • hydrolysis
  • oxidation
  • reduction

Question 3

Question
The acidity of the carboxylic acid is due to....
Answer
  • stability of the carboxylate anion relative to the acid
  • the charge of the carboxylate residue
  • overall bonding
  • charge distribution

Question 4

Question
when the charge of the carboxylate resides two equivalent electronegative oxygens the structure is called
Answer
  • resonance form
  • protonated form
  • chiral form
  • assymetric form

Question 5

Question
pKa values vary somewhat depending on
Answer
  • the temperature of the solution
  • the precise molecular structure
  • the environment in which the acid-base chemistry is taking place.
  • how homogenous is the solution

Question 6

Question
The corresponding carboxylate anion is more stable in the presence of the adjacent, positively charged, ammonium ion, therefore
Answer
  • the carboxylic acid group of glycine is more acidic than a simple carboxylic acid since
  • the simple carboxylic acid is more acidic than the carboxylic acid group of glycine

Question 7

Question
The effect of environment on pKa is particularly important in non-polar conditions such as..
Answer
  • the interior of a protein
  • the outer part of the protein
  • the acidic part of the protein
  • the basic part of the protein

Question 8

Question
What stereoisomers predominate in nature
Answer
  • L-amino acids
  • D-amino acids

Question 9

Question
Into which groups can amino acids be divided
Answer
  • amino acids with hydrocarbon side chains
  • carboxylic acid side chains
  • amide side chains
  • acyclic with basic N containing side chains
  • hydroxyl functional groups
  • suphur containing side chains
  • nitrogen heterocycles and proline
  • hydrophilic side chains
  • hydrophobic side chain
  • phosphorus containing side chains

Question 10

Question
Which amino acid imparts unusual structural flexibility
Answer
  • Glycine
  • Serine
  • Proline
  • Guanine

Question 11

Question
What amino acid has two chiral centres due to the both of its α and β- carbons being asymmetric, and therefore has four possible stereoisomers.
Answer
  • Isoleucine
  • Valine
  • Glutamine
  • Cysteine

Question 12

Question
Confer negative charge on proteins because their side chains are ionised at pH 7, under physiological conditions acidic side chains exist as the conjugate base
Answer
  • aspartate
  • glutamate
  • arginine
  • histidine

Question 13

Question
The most basic of the 20 amino acids.
Answer
  • Histidine
  • Lysine
  • Arginine
  • Asparagine

Question 14

Question
The pKa of this protein is around pH 7 and thus at physiological pH it can act as either an acid or a base. This makes it especially important in acid-base catalysis and it has an important role to play in many enzymes. It also forms complexes with zinc in proteins which has importance for both structure and mechanism.
Answer
  • Histidine
  • Tryptophan
  • Methionine
  • Glutamine
  • Alanine

Question 15

Question
Fill in the blanks
Answer
  • Histidine
  • Arginine
  • Proline
  • Methionine
  • Isoleucine
  • Histidine
  • Proline
  • Arginine
  • Methionine
  • Isoleucine

Question 16

Question
Contains a non-polar methyl thioether group. This makes it one of the more hydrophobic amino acids

Question 17

Question
The hydroxymethyl group of this amino acid does not appreciably ionise at physiological pH. Essentially hydrophilic.

Question 18

Question
The side chain is somewhat hydrophobic, but also extremely reactive. It is polarisable and can lose its proton to bercome the thiolate anion. Can form disulphide bridges in proteins.

Question 19

Question
Has two chiral centres and thus can have four stereoisomers

Question 20

Question
The formation of disulphide bonds in proteins is an important [blank_start]secondary[blank_end] structural feature. This helps to impart [blank_start]stability[blank_end] and conformational rigidity to some proteins
Answer
  • secondary
  • primary
  • teriary
  • quaternary
  • stability
  • acidity
  • reactivity
  • inertness

Question 21

Question
This amino acid is unique in that its three carbon side chain is bonded to both the α carbon and the α amino group. The heterocyclic pyrrolidine ring created restricts the geometry of polypeptides.
Answer
  • proline
  • tyrosine
  • aspertate
  • valine

Question 22

Question
This amino acid has a hydroxyl function associated with the phenol ring. Acid base chemistry is facilitated as the ring enhances the stability of the conjugate base. It can sometimes act as an acid.
Answer
  • tyrosine
  • proline
  • tryptophan
  • phenyalanine

Question 23

Question
[blank_start]Phe, Tyr and Trp[blank_end] are all highly aromatic and can absorb UV light at 280nm. Proteins have an optical density at 280nm because of these side chains
Answer
  • Phe, Tyr and Trp
  • Ser, Thr and Cys
  • Val, Leu, Ile
  • Lys, Arg, His

Question 24

Question
drag the appropriate amino acid to the blank space
Answer
  • Proline
  • Histidine
  • Isoleucine
  • Arginine
  • Tyrosine

Question 25

Question
The more [blank_start]hydrophobic[blank_end] amino acids have a tendency to be sequestered away from the solvent towards the [blank_start]centre[blank_end] of protein molecules. This provides one of the major driving forces for protein [blank_start]folding[blank_end]
Answer
  • hydrophobic
  • hydrophilic
  • centre
  • inner part
  • outer part
  • folding
  • binding
  • inhibition

Question 26

Question
[blank_start]Hydrophilic[blank_end] residues tend to interact with the solvent more easily via [blank_start]hydrogen[blank_end] bonding and thus can be on the [blank_start]outside[blank_end] of proteins.
Answer
  • Hydrophilic
  • hydrophobic
  • hydrogen
  • covalent
  • outside
  • inside

Question 27

Question
Under [blank_start]physiological[blank_end] conditions this effectively restricts the [blank_start]peptide[blank_end] bond to one of two configurations: cis or trans To minimise steric crowding due to close proximity of bulky groups on th carbonyl carbon and the nitrogen the [blank_start]trans[blank_end] form is favoursed, except where [blank_start]PROLINE[blank_end] is involved.
Answer
  • physiological
  • cellular
  • peptide
  • ionic
  • trans
  • cis
  • Proline
  • Histidine

Question 28

Question
Proline has an [blank_start]alkyl[blank_end] chain rather than a [blank_start]hydrogen[blank_end] atom as the [blank_start]second[blank_end] substituent on nitrogen In amides containing proline the [blank_start]cis[blank_end] form is not dramatically disadvantaged In proteins about [blank_start]10%[blank_end] of all peptide bonds involving proline are cis.
Answer
  • alkyl
  • carboxyl
  • hydrogen
  • oxygen
  • second
  • third
  • cis
  • trabs
  • 10%
  • 15%
  • 5%

Question 29

Question
THE SHAPE OF POLYPEPTIDES IS DEFINED BY [blank_start]ROTATION[blank_end] ABOUT THE C-N AND C-C BONDS
Answer
  • ROTATION
  • SPIN
  • SIDE CHAIN
  • MOMENTUM

Question 30

Question
All atoms around the peptide bond lie in a [blank_start]planar[blank_end] conformation. This rotation is described by the torsion angles φ Phi between [blank_start]C-N[blank_end] and ψ Psi between [blank_start]C-C.[blank_end] If all psi and phi angles are the same the peptide assumes a [blank_start]repeated[blank_end] structure. For certain combinations of angles this can take the form of a [blank_start]helical stucture (the alpha helix)[blank_end] or a beta-sheet structure. Clearly the peptide structure exhibits [blank_start]flexibility[blank_end] and this is important for the complex [blank_start]structure[blank_end] of proteins.
Answer
  • planar
  • primary
  • cis
  • trans
  • C-N
  • C-C
  • C-C.
  • C-N.
  • repeated
  • saturated
  • helical stucture (the alpha helix)
  • coil structure
  • flexibility
  • motitlity
  • structure
  • binding

Question 31

Question
What characteristic of atoms and groups of atoms limits the possible psi and phi torsion angles that the backbone of the polypeptide chain can adopt without causing protruding R groups to bump into each other.
Answer
  • The physical size
  • The chemical properties
  • The amount
  • The flexibility

Question 32

Question
The Ramachandran plot shows the allowed
Answer
  • psi and phi angles
  • carboxyl and amino groups
  • secondary structure of the protein
  • binding of the protein

Question 33

Question
Label the chemical structure
Answer
  • Side chain
  • Alpha carbon
  • alpha-amino group
  • alpha-carboxylate

Question 34

Question
Amino acids with basic R groups
Answer
  • Lysine
  • Histidine
  • Arginine
  • Phenylalanine
  • Valine
  • Serine
  • Aspargine
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