Quiz
Proteins 1
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Questions in this quiz (33)
1Peptide bonds are strong
- ATrue
- BFalse
2Amino acids exist in non- ionic form in nature.
- ATrue
- BFalse
3PH and dissociation constants dictate the ionic form is [blank_start]ALWAYS[blank_end] present in solution
- AALWAYS
4Pka= the PH in which something capable of ionisation is [blank_start]half[blank_end] dissociated.
- Ahalf
- Bfully
5Amino Pka at PH [blank_start]10.0[blank_end]
- A9.5-10.0
- B5.0
- C2.2-3.0
6Acid Pka at PH [blank_start]10.0[blank_end]
- A9.5-10.0
- B5.0
- C2.2-3
7At normal PH of 7, the zwitteron is [blank_start]never[blank_end] present
- Anever
- Balways
- Coften
8At PH ABOVE the Pk of an ACIDIC side chain,
the SIDE CHAIN is ................... charged.- Apositive
- Bnegative
- Cneutral
9for a BASE at PH BELOW Pka of a basic side chain, that side chain is always ....
- Aprotonated and negative
- Bdeprotonated and positive
- Cprotonated and positive
- Ddeprotonated and negative
10Remember that in a protein the alpha amino and alpha carboxyl are taken up in a peptide bond,
you only find N+ and COO-- ATrue
- BFalse
11PI: Isoelectronic point of a protein
- Athe PH at which the protein carries positive charge so this tells you whether the protein is acidic or basic
- Bthe PH at which the protein carries no net charge so this tells you whether the protein is acidic or basic
- Cthe PH at which the protein carries negative charge so this tells you whether the protein is acidic or basic
12Histone is a [blank_start]...........[blank_end] protein
- Aacidic
- Bbasic
13The PH inside the nucleus is 7.3 , histone has a PI of around 10, so inside the nucleus it is going to be [blank_start].............[blank_end] charged
and therefore it will be attracted to the [blank_start]...............[blank_end] charge of the DNA , which is why histones bind to DNA- Apositively
- Bnegative
14At PH above a PI of a protein which has got PI of less than 7, the protein is always [blank_start]negatively[blank_end] charged. Below the PH of protein which has a PI of more than 7, it will be [blank_start]positively[blank_end] charged.
- Anegatively
- Bpositively
15D- amino acids predominate in nature
- ATrue
- BFalse
16In proteins the pKa's of the carboxyl and amino groups can be ignored and cancel each other out at the N and C terminus.
In proteins only the side-chain pKa's influence the charge of the protein.
Protein charge is thus PH dependent- ATrue
- BFalse
17Protein charge is PH dependent
- ATrue
- BFalse
18In proteins the side-chain Pka's does not vary, it is independent of the environment in which they sit
- ATrue
- BFalse
19Order these amino acids with aliphatic R groups from no to most hydrophobic.
[blank_start]Leucine[blank_end], [blank_start]Valine[blank_end], [blank_start]Glycine[blank_end], [blank_start]Isoleucine[blank_end], [blank_start]Alanine[blank_end]- ALeucine
- BGlycine
- CIsoleucine
- DAlanine
- EValine
- FValine
- GGlycine
- HLeucine
- IAlanine
- JIsoleucine
- KGlycine
- LLeucine
- MIsoleucine
- NAlanine
- OValine
- PIsoleucine
- QValine
- RAlanine
- SGlycine
- TLeucine
- UAlanine
- VLeucine
- WValine
- XIsoleucine
- YGlycine
20Because both the alpha and beta-carbon atoms of isoleucine are asymmetric it has [blank_start].....[blank_end] chiral centres,
it therefore has [blank_start].....[blank_end] possible stereoisomers- A2
- B4
21You are expected to find ALIPHATIC R groups, [blank_start]..........[blank_end] a protein. Unless the protein has a binding site
for a hydrophobic molecule, in which case you will find it in that binding site. It could also be part of
a multi subunit protein where the subunits seem to interact by [blank_start].............[blank_end] interaction- Aoutside
- Binside
- Chydrophobic
- Dhydrophilic
22Generally when talking about globular proteins (which are monomeric), you will find ALIPHATIC R groups [blank_start]........[blank_end]
- Ainside
- Boutside
23Glycine is expected to be at the sharp ends because it does not have a bulky R group,
rather a small side chain, that's why there are lots of glycine in collagen (helical protein with lots of tight terms in it)- ATrue
- BFalse
24Aspartate and Glutamate often used in catalysis as [blank_start].............[blank_end] catalyst because they have [blank_start]..............[blank_end] a proton and have become a conjugate base (their pKa is 4.0-4.5) . You find them on the surface, active site or binding sites.
- Abase
- Bacid
- Cgained
- Dlost
25Select three amino acids with basic R groups:
1. H[blank_start].........[blank_end] I[blank_start]........[blank_end]. ion
2. I[blank_start]..........[blank_end] A[blank_start]........[blank_end] ion
3. A[blank_start]........[blank_end] G [blank_start].........[blank_end] ion- Aistidine
- Bmidazolium
- Cysine
- Dlkylammonium
- Erginine
- Fuanidinium
26What is the most basic of 20 amino acids?
[blank_start].....[blank_end]- Aarginine
27Which protein loves to bind metal ions?
H[blank_start]..........[blank_end] and G[blank_start]...........[blank_end]- Aistidine
- Blutamine
28Threonine
- Ahas two chiral centres and thus have four stereoisomers
- BEssentially hydrophobic. OH group does not appreciably ionise at physiological pH
- Ccan form disulphide bridges in proteins
- Dis one of the more hydrophobic amino acids
29Serine
- Adoes appreciably ionise at physiological pH. Essentially hydrophilic
- Bhas two chiral centres and thus can have four stereoisomers
- Ccan form disulphide bridges in proteins
- Dis one of the more hydrophobic amino acids
30Methionine
- Acan form disulphide bridges in proteins
- Bdoes not appreciably ionise at physiological pH. Essentially hydrophilic
- Chas two chiral centres and thus can have four stereoisomers
- Done of the more hydrophobic amino acids
31Under what conditions would we get a disulphide bond?
Under [blank_start].....[blank_end] conditions- Aoxidising
32The OH from Serine, Threonine and Tyrosine are used for [blank_start]phosphorylation[blank_end] in metabolic processes
- Aphosphorylation
33Who devised the plot for allowed torsion angles in a protein?
[blank_start]...........[blank_end]- ARamachandran
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- Quiz on Proteins 1, created by Margaret-Estefani Conde Paredes on 23/11/2016.
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