Question 1
Question
L’acide phosphorique est tri-basique, avec des valeurs de pKa de 2.14, 6.88 et 12.4. Quelle forme ionique est prédominante à pH = 5.9 ?
Answer
-
H3PO4
-
H2PO4-
-
HPO42-
-
PO43-
Question 2
Question
What is the basic formula of Carbohydrates?
Answer
-
Cn(OH)n
-
Cn(CO2)n
-
Cn(H2O)n
-
C(H2O)n
Question 3
Question
Which of these is not these is not a polysaccharide?
Answer
-
Cellulose
-
Glycogen
-
Starch
-
Fructose
Question 4
Question
Long chains of single sugars covalently linked describes what types of carbohydrates?
Answer
-
Oligosaccharides
-
Multisaccharides
-
Polysaccharides
-
Megasaccharides
Question 5
Question
Which pair of molecules are epimers?
Question 6
Question
Which of these structures is glucose?
Question 7
Question
Galactose is a ___ epimer of glucose.
Question 8
Question
Which one of these is a ketohexose
Answer
-
Fructose
-
Glucose
-
Ribose
-
2-Deoxy-Ribose
Question 9
Question
Which of these is not true?
Answer
-
Enantiomers are stereoisomers that are not mirror images
-
In sugars that contain the most chiral centers only the one that is the most distant from the caronyl carbon is designated as D or L
-
hemiacetals are formed by alcohols attacking aldehydes
-
Alcohol oxygen atom is nucleophilic
Question 10
Question
During the cyclisation of Monosaccharides which is/are true?
Answer
-
The carbon atom furthest from the former carbonyl atom becomes the anomeric carbon
-
The position of anomeric carbon's oxygen determines whether the anomer is α or β
-
The position of the anomeric carbon's hydroxyl group determines whether the anomer is α or β
-
The carbon atom furthest from the former carbonyl atom becomes the chiral center
Question 11
Question
Which of these are carbohydrates that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom?
Question 12
Question
The disaccharide formed upon condesation of two glucose molecules via the 1-4 bond is called
Answer
-
Trehalose
-
Sucrose
-
Maltose
-
Lactose
Question 13
Question
Which of these describes cellobiose
Answer
-
α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside
-
β-D-glucopyranosyl-(1→4)-β-D-glucopyranose
-
β-D-galactopyranosyl-(1→4)-α-D-glucopyranose
-
α-D-glucopyranosyl-(1→4)-β-D-glucopyranose
Question 14
Question
Polysaccharides...
Answer
-
can be branched but cannot have multiple monomer types
-
cannot be unbrached
-
have defined molecular weights
-
with only two monomer types cannot be branched
Question 15
Question
Which one of these hetero-polysaccharides has the largest size
Answer
-
peptidoglycan
-
agarose
-
hyaluronan
Question 16
Question
which of these is used in Algae cell walls
Answer
-
Peptidoglycan
-
hyaluronan
-
agarose
Question 17
Question
Glucose is stored in animals as
Answer
-
Glucagon
-
Glycogen
-
Glucose
-
Insulin
-
Starch
Question 18
Question
Glycogen is a polysaccharide in which glucose is joined by β-(1→4) linkages
Question 19
Question
Glycogen is a polysaccharide in which glucose is joined by α-(1→6) linkages
Question 20
Question
Which of the following is true
Answer
-
Amylose is the branched form of starch
-
α-amylase is a pancreatic enzyme that hydrolyses the α (1→4) linkages of starch
-
Glycogen has less α (1→4) linkages than starch
-
Glycogen has less α (1→6) linkages than starch
Question 21
Question
hydrolysis of cotton occurs
Answer
-
at the β (1→2) linkages of D-glucose
-
at the α (1→2) linkages of D-glucose
-
at the β (1→4) linkages of D-glucose
-
at the α (1→4) linkages of D-glucose
Question 22
Question
Which of the following is not true
Answer
-
Glycosidic bonds can freely rotate
-
more than 10^9 metric tonnes of cotton are produced/year
-
Starch can be coiled into a helical structure
-
Glycogen and amylopectin have only one reducing end
Question 23
Question
Which of these lack enzymes that can hydrolyse D-glucose β (1→4) linkages
Answer
-
Fungi
-
bacteria
-
termites
-
protozoa
Question 24
Question 25
Question
Sephadex gels separate proteins by
Answer
-
size
-
charge
-
polarity
-
shape
Question 26
Question
Which of these would you find in the first fractions after size exclusion chromatography
Answer
-
acidic proteins
-
the smallest proteins
-
the largest proteins
-
basic proteins
Question 27
Question
which of these are homoglycans
Answer
-
Agar
-
Dextrans
-
Peptidoglycan
-
None
Question 28
Question
Which of these can be linked to epichlorohydrin in sephadex beaded gels
Answer
-
Agar
-
Agarose
-
Peptidoglycan
-
Dextran
Question 29
Question
Agar is a complex mixture of heteropolysaccharides containing modified
Answer
-
Glucose units
-
Mannose units
-
Fructose units
-
None of the above
Question 30
Question
Which of these is false
Answer
-
Agarose can be used for growing bacteria
-
Agarose is a component of bacterial cell walls
-
Agarose can be used for DNA separation
-
Agar is a component of seaweed cell walls
Question 31
Question
N-acetyl-galactosamine is a ___ epimer of N-acetyl-glucosamine
Question 32
Question
Where wold yo expect to find hyaluronate
Answer
-
ECM of Cartilage
-
Hair
-
Nails
-
Horns
Question 33
Question
Which one of these glycosaminoglycans acts as a lubricant?
Answer
-
Chondrotin-4-sulfate
-
keratan sulfate
-
heparin
-
hyaluronate
Question 34
Question
which one of the has approximately 50'000 disaccharides per chain
Answer
-
hyaluronate
-
keratan sulfate
-
heparin
-
chondrotin-4-sulfate
Question 35
Question
Which one of these glycosaminoglycans consists of [galactose β(1,4) Glc-NAc6S] repeating disaccharides
Answer
-
hyaluronate
-
chondrotin-4-sulfate
-
heparin
-
keratan sulfate
Question 36
Question
Which of these repeating disaccharides make dermantan sulfate?
Answer
-
glucaronic acid and N-acetylglucosamine
-
glucaronic acid and N-acetylgalctosamine-4-sulfate
-
Iduronic acid and N-acetylgalactosamine-4-sulfate
-
Iduronic acid and N-acetylglucosamine
Question 37
Question
The cabohydrate attached to a protein in a Glycoconjugate attaches via...
Question 38
Question
Which of the following most likely contains the most glycosylated proteins (Glycoproteins)
Answer
-
Humans
-
E.coli
-
Ebola virus
-
Cats
Question 39
Question
O linked oligosaccharides are linked through the N terminus of the amino acid
Question 40
Question
In glycoproteins, sugars are attached either to the amide nitrogen atom in the side chain of asparagine (termed an N-linkage) or to the oxygen atom in the side chain of serine or threonine (termed an O-linkage)
Question 41
Question
Glycophorin A is the most important attachment site for which of the following parasites in order to enter erythrocytes
Answer
-
Plasmodium falciparum
-
Chilomastix mesnili
-
Entamoeba coli
-
Entamoeba dispar
Question 42
Question
Which of these sulfated glycosaminoglycans are attached to a protein anchored to a membrane lipid?
Question 43
Question
NB! Select all which are functions of polysaccharides
Answer
-
Labelling of proteins for destruction
-
Recognition sites for growth factors
-
recognition sites for bacteria
-
localization of certain proteins
Question 44
Question
Which one of these is not a main component of the extracellular matrix (ECM)
Answer
-
Proteoglycan aggregates
-
Collagen fibers
-
Elastin
-
Fatty acids
Question 45
Question
Which one of these in not a characteristic of Glycosaminoglycans
Question 46
Question
Plasmodium flaciparum requires which of these as an attachment site to enter erythrocytes
Answer
-
Glycophorin A
-
Hyaluronan
-
syndecan
-
Podocalyxin
Question 47
Question
Which of these about proteoglycans is not true
Answer
-
Proteoglycan aggregates are found in articula cartilage
-
Proteoglycans influence growth factor activation and adhesion
-
glycosaminoglycans are linked to the core protein from the anomeric carbon
-
proteoglycanaggregates form high friction material
Question 48
Question
Which of these are integral receptors for extracellular proteoglycans
Answer
-
Integrins
-
actin
-
collagen fibers
-
elastin
Question 49
Question
Which of these about enzymatic reactions is true
Answer
-
Enzymes directly affect equilibrium (∆G)
-
Entropy cost is paid during binding
-
enzymes increse reaction rates (κ ) by increasing (∆G)
-
slow reactions do not have high activtaion barriers
Question 50
Question
Rate of enzymatic reactions are affected by....? (Click all true)
Question 51
Question
Which one of these describes a micelle
Answer
-
individual units are wedge shaped
-
artificial carriers of molecules
-
individual units are cylindrical
-
composed lipid-based structures that form pliable sheets
Question 52
Question
Which of these is false
Answer
-
membranes vary from 3-10nm
-
membranes form spontaneously by noncovalent forces
-
membranes are symmetric
-
membranes can be found within cells
Question 53
Question
Which of these is true about fatty acids
Answer
-
Most natural fatty acids are branched
-
Saturated fatty acids have double bonds between carbons in the chain
-
Most natural fatty acids have an even number of C's
-
linoleic acid is a saturated fatty acid
Question 54
Question
Which of these is false about fatty acids
Answer
-
Fatty acids solubility decreases as the chain length increases
-
Melting point decrases as the chain length decreses
-
Melting point increases as the number of double bonds increases
-
unsaturated cis fatty acids have a lower melting point than saturated fatty acids
Question 55
Question
Omega-3 (ω-3) fatty acids have
Answer
-
a double bond between the 2nd and 3th carbon from the methyl end of the chain.
-
a double bond between the 3rd and 4th carbon from the methyl end of the chain.
-
a double bond between the 1st and 2nd carbon from the methyl end of the chain.
-
a double bond between the 2nd and 3nd as well as 3rd and 4th carbon from the methyl end of the chain.
Question 56
Question
Which of these is untrue
Answer
-
Triacylglycerols are polar
-
Triacylglycerols are non hydrated
-
Vegetable oils are composed of triacylglycerols with unsaturated fatty acids
-
Animal fats are composed of triacylglycerols with saturated fatty acids
Question 57
Question
which of these is a greasy solid at room tempreature
Question 58
Question
which of these is a sphingolipid
Question 59
Question
Which of these is the head group of phosphatidylserine
Question 60
Question
Which of these has a net charge of -4 at pH7
Question 61
Question
Which of these is the major component of most eukaryotic cell membranes
Answer
-
phophatidylcholine
-
phosphatidylglycerol
-
cardiolipin
-
phosphatidylethanolamine
Question 62
Question
a fatty acid is joined to sphingosine via an
Answer
-
ester linkage
-
amide linkage
-
glycosidic linkage
-
phosphodiester linkage
Question 63
Question
ganglioside GM2 has which of these as a head group
Question 64
Question
The blood groups are determined in part by the
Question 65
Question
The structure of sugars located on the head groups in glycosphingolipids is determined by an expression of specific glycosyltransferases. Individuals with a glycosyltransferase that transfers an N-acetylgalactosamine group will
Answer
-
will have the O antigen
-
A blood group
-
B blood group
-
AB blood group
Question 66
Question
which of thes is false
Answer
-
Cholesterol modulates cell membrane fluidity
-
Mammals can not synthesize cholesterol
-
cholesterol in loe density lipoproteins tend to deposit in arteries
-
most bacteria lack sterols
Question 67
Question
which of these polyketides is an antibiotic
Answer
-
erythromycin
-
amphotericin B
-
lovastatin
Question 68
Question
which of these lipids are hormone precursors
Answer
-
vitamins E and K
-
vitamins A and D
-
steroid hormones
-
eicosanoids
Question 69
Question
which of these lipids are paracrine hormones
Answer
-
phosphatidylinositols
-
vitamins A and D
-
vitamins E and K
-
Dienes
-
eicosanoids
Question 70
Question
which of these is true
Answer
-
cholesterol is predominant in mitochondrial membranes
-
galactolipids are abundant in animals
-
membranes have non-selective import and export across the membrane
-
archaebacteria have monolayer instead of a bilayer
Question 71
Question
which of these is a type 6 integral membrane protein
Question 72
Question
Which of these amino acid residues would you find predominantly in the transmembrane segments of membrane proteins
Question 73
Question
Proteins can be targeted to the INNER leaflet of the plasma
membrane by farnesylation. The primary sequence of the protein contains a signature for farnesylation which is
Question 74
Question
hutchinson-gilford progeria syndrome is caused by
Answer
-
palmitoylation defect
-
myristoylation defect
-
farnesylation defect
Question 75
Question
which of these are only found on the outside of cell membranes
Answer
-
proteins
-
lipids
-
carbohydrates
Question 76
Question
which of these statements about the physical properties of membranes is true
Answer
-
Permeable to large polar solutes and ions
-
Not permeable to small polar solutes and nonpolar
compounds
-
Permeability can be artificially increased by chemical
treatment
-
Exist in a single phase and cannot undergo phase
transitions
Question 77
Answer
-
cell membrane transition from the gel to fluid
-
cell membrane transition from the fluid to gel
-
cell membrane changed to become not permeable to large polar solutes
-
cell membrane changed to become permeable to small polar solutes and nonpolar compounds
Question 78
Question
Which of these statements on membrane fluidity is incorrect
Answer
-
is determined mainly by the fatty acid composition
-
more fluid membranes require shorter and more unsaturated fatty acids
-
At higher temperatures cells need more saturated fatty
acids to maintain fluidity
-
Gel phase means that the individual molecules do not move
around
Question 79
Question
which of these increase in membrane compisition percentage when temperatures increase
Answer
-
Myristic acid
-
palmitoleic acid
-
oleic acid
-
hydroxymyristic acid
Question 80
Question
Cell membranes of .... contain hopanols instead of sterols
Answer
-
animals
-
bacteria
-
plants
-
fungi
Question 81
Question
Membrane Dynamics: Transverse Diffusion.
Spontaneous flips of individual lipids from one leaflet to another are rare because...
Answer
-
the hydrophobic head group must transverse the hydrophilic tail region of the membrane
-
membrans are rigid and individual lipids cannot move at all
-
the charged head group must transverse the hydrophobic tail region of the membrane
Question 82
Question
Which is false about flippases
Answer
-
catalyze transverse diffusion
-
catalyze lateral diffusion
-
use ATP
-
move lipids against the concentratiion gradient
Question 83
Question
Tick ALL that are true!!
Answer
-
Membrane Lipid Rafts contain clusters of glycosphingolipids with longer-than-usual tails
-
Membrane Lipid Rafts are more ordered than the rest of the membrane
-
Membrane fusion can only occur through protein mediation
-
Passive diffuision of polar molecules across cell membranes has a high activation barrier
Question 84
Question
Which of these is a membrane receptor that detects light
Answer
-
opsin
-
insulin receptor
-
acetylcholine receptor
-
maltoporin
Question 85
Question
Which of these is a membrane receptor that detects neurotransmitters
Answer
-
opsin
-
acetylcholine receptor
-
maltoporin
-
insulin receptor
Question 86
Question
Cystic fibrosis (Mucoviscidose) is caused by
Answer
-
a mutation to a Cl- ion channel in epithelial cells
-
a mutation to a K+ ion channel in epithelial cells
-
a mutation to a Na+ ion channel in epithelial cells
-
a mutation to a Ca2+ ion channel in epithelial cells
Question 87
Question
Tick ALL that are correct
Answer
-
Energy of ATP hydrolysis can be used to drive protons through the membrane
-
Energy of the proton gradient can be used to synthesize ATP
-
Primary active transport is a form of active transport across a biological membrane in which a transporter protein couples the movement of an ion (typically Na+ or H+) down its electrochemical gradient to the uphill movement of another molecule or ion against a concentration/electrochemical gradient.
-
glucose is cotransported with Na+ in intestinal epithelial cells
Question 88
Question
Which of these plasma proteins is the most abundant
Answer
-
transferrin
-
ceruloplasmin
-
immunoglobulins
-
albumin
Question 89
Question
What is labelled as B?
Answer
-
blood
-
plasma
-
White blood cells
-
ficoli
Question 90
Question
What is labelled as D
Answer
-
Plasma
-
White blood cells
-
Ficoli
-
white blood cells
Question 91
Question
Which of these are not a hematopoietic cells
Answer
-
eosinophils
-
basophils
-
neutrophils
-
thrombocytes
Question 92
Question
Which of these is derived from lymphoid stem cells
Answer
-
erythrocytes
-
T cells
-
basophil
-
neutrophil
Question 93
Question
Which one of these leukocytes secretes histamine and mediates inflammation
Answer
-
neutrophils
-
basophils
-
eosinophils
-
macrophages
Question 94
Question
Which of these leukocytes produces Ab (antibodies)
Answer
-
Neutrophils
-
T cells
-
B cells
-
Macrophages
Question 95
Question
Where is myoglobin found
Answer
-
in the bone marrow
-
freely circulating in the blood
-
in skeletal and striated muscles
-
restricted to erythrocytes
Question 96
Question
which of these is false
Answer
-
myogloblin stores oxygen in the cytoplasm and delivers it to mitochondrion
-
hemoglobin is restricted to erythrocytes
-
Heme (B) is the oxygen binding molecule found only in hemoglobin
-
the distal histidine of the myglobin protein hydrogen bonds with oxygen bound to the protein
Question 97
Question
Consider a process in which a ligand (L) bind reversibly to a site in a protein (P). After some time, the process will reach equilibrium where the Ka (association rate constant) and Kd (dissociation rate constant) rates are equal. which of these equations represents the equilibrium.
Answer
-
kd [P].[L] = ka [PL]
-
ka [P].[L] = kd [PL]
-
[P].[L] = [PL]
-
ka [P].[L] > kd [PL]
Question 98
Question
Which of these statements is false
Answer
-
when the first binding event increases affinity at the remaining sites it is called positive cooperativity
-
when the first binding event decreases affinity at the remaining sites it is called negative cooperativity
-
oxygen binds to heme better than carbon monoxide
-
nH( hill coefficient) > 1 equals positive cooperativity
Question 99
Question
Cooperativity can be described as
Answer
-
positive homotropic regulation
-
negative homotropic regulation
-
positive heterotropic regulation
-
negative heterotropic regulation
Question 100
Question
Which of these statement on hemoglobin is false
Answer
-
oxygen binding triggers a tense to relaxed state conformational change
-
tense state has a higher affinity for oxgen than the relaxed state
-
conformational change from the T state to the R state invloves breaking ion pairs between the alpha1-beta2 interface of hemoglobin
-
2,3 -Bisphosphoglycerate is a negative heterotropic regulator of hemoglobin function
Question 101
Question
which of these is a non-phosphorylated nitrogenous base
Answer
-
nucleoside
-
nucleotide
-
nucleobase
-
nucleomide
Question 102
Question
Which side are the purines
Question 103
Question
Which color is encircling where a glycosidic bond between the nitrogenous base and the sugar would be present
Answer
-
red
-
green
-
blue
-
none of the above
Question 104
Question
Which letter represents deoxyadenylate
Question 105
Question
Which letter represents deoxythymidylate
Question 106
Question
Which letter represents deoxyguanylate
Question 107
Question
Which letter is representing cytidylate (CMP)
Question 108
Question
Which of these statements about the purine and pyrimidine bases is true
Question 109
Question
In nucleotides the pentose ring is attached to the nucleobase via a
Answer
-
β -N-Glycosidic Bond
-
α -N-Glycosidic Bond
-
Hydrogen bond
-
none of the above
Question 110
Question
In DNA structure there is free rotation about
Answer
-
C-1’-N-glycosyl bond
-
C-2’-N-glycosyl bond
-
C-3’-N-glycosyl bond
-
C-4’-N-glycosyl bond
Question 111
Question
How many base pairs do you find in the A form of DNA
Question 112
Question
The aromaticity of the nucleotide bases and their dipole moments is important for which interactions in DNA
Answer
-
Van der Waal forces in base stacking
-
link between base and sugar in a nucleotide
-
the link between two different nucleotides
-
interstrand bonding and complementarity
Question 113
Question
Figure A represents which type of DNA secondary structure
Answer
-
hairpin
-
mirror image
-
palindrome
-
cruciform
Question 114
Question
Figure C represents which type of DNA secondary structure
Answer
-
Cruciform
-
Palindrome
-
Hairpin
-
Mirror image
Question 115
Question
DNA sequences with a very high proportion of G residues forms which unusual DNA structure found on chromosome telomeres
Answer
-
tetraplex DNA
-
triplex DNA
-
inverted repeats
-
cruciforms
Question 116
Question
Which of these are a quaternary DNA structure
Answer
-
Chromatin
-
hairpin
-
supercoil
-
Triplex
Question 117
Question
In mammals ____ Functions as an autocoid, or "local hormone"
Answer
-
Adenosine
-
Guanine
-
Cytosine
-
Thymine
Question 118
Question
Which one of these is an RNase enzyme that prevents inbreeding of plants
Answer
-
S-RNase
-
RNase-P
-
Dicer
-
None of the above
Question 119
Question
_____ is an enzyme that cleaves double-stranded RNA into oligonucleotides
Question 120
Question
Why would animal cells need an enzyme that cleaves double-stranded RNA into oligonucleotides
Answer
-
processessing tRNA precursors
-
protection from viral genomes
-
using RNA as an energy source
-
using RNA in Coenzymes
Question 121
Question
RNA would be unstable in which of the conditions listed below