Frage 1
Frage
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 ?
Antworten
-
H3PO4
-
H2PO4-
-
HPO42-
-
PO43-
Frage 2
Frage
What is the basic formula of Carbohydrates?
Antworten
-
Cn(OH)n
-
Cn(CO2)n
-
Cn(H2O)n
-
C(H2O)n
Frage 3
Frage
Which of these is not these is not a polysaccharide?
Antworten
-
Cellulose
-
Glycogen
-
Starch
-
Fructose
Frage 4
Frage
Long chains of single sugars covalently linked describes what types of carbohydrates?
Antworten
-
Oligosaccharides
-
Multisaccharides
-
Polysaccharides
-
Megasaccharides
Frage 5
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Which pair of molecules are epimers?
Frage 6
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Which of these structures is glucose?
Frage 7
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Galactose is a ___ epimer of glucose.
Frage 8
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Which one of these is a ketohexose
Antworten
-
Fructose
-
Glucose
-
Ribose
-
2-Deoxy-Ribose
Frage 9
Frage
Which of these is not true?
Antworten
-
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
Frage 10
Frage
During the cyclisation of Monosaccharides which is/are true?
Antworten
-
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
Frage 11
Frage
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?
Frage 12
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The disaccharide formed upon condesation of two glucose molecules via the 1-4 bond is called
Antworten
-
Trehalose
-
Sucrose
-
Maltose
-
Lactose
Frage 13
Frage
Which of these describes cellobiose
Antworten
-
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
Frage 14
Antworten
-
can be branched but cannot have multiple monomer types
-
cannot be unbrached
-
have defined molecular weights
-
with only two monomer types cannot be branched
Frage 15
Frage
Which one of these hetero-polysaccharides has the largest size
Antworten
-
peptidoglycan
-
agarose
-
hyaluronan
Frage 16
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which of these is used in Algae cell walls
Antworten
-
Peptidoglycan
-
hyaluronan
-
agarose
Frage 17
Frage
Glucose is stored in animals as
Antworten
-
Glucagon
-
Glycogen
-
Glucose
-
Insulin
-
Starch
Frage 18
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Glycogen is a polysaccharide in which glucose is joined by β-(1→4) linkages
Frage 19
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Glycogen is a polysaccharide in which glucose is joined by α-(1→6) linkages
Frage 20
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Which of the following is true
Antworten
-
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
Frage 21
Frage
hydrolysis of cotton occurs
Antworten
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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
Frage 22
Frage
Which of the following is not true
Antworten
-
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
Frage 23
Frage
Which of these lack enzymes that can hydrolyse D-glucose β (1→4) linkages
Antworten
-
Fungi
-
bacteria
-
termites
-
protozoa
Frage 24
Frage 25
Frage
Sephadex gels separate proteins by
Antworten
-
size
-
charge
-
polarity
-
shape
Frage 26
Frage
Which of these would you find in the first fractions after size exclusion chromatography
Antworten
-
acidic proteins
-
the smallest proteins
-
the largest proteins
-
basic proteins
Frage 27
Frage
which of these are homoglycans
Antworten
-
Agar
-
Dextrans
-
Peptidoglycan
-
None
Frage 28
Frage
Which of these can be linked to epichlorohydrin in sephadex beaded gels
Antworten
-
Agar
-
Agarose
-
Peptidoglycan
-
Dextran
Frage 29
Frage
Agar is a complex mixture of heteropolysaccharides containing modified
Antworten
-
Glucose units
-
Mannose units
-
Fructose units
-
None of the above
Frage 30
Frage
Which of these is false
Antworten
-
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
Frage 31
Frage
N-acetyl-galactosamine is a ___ epimer of N-acetyl-glucosamine
Frage 32
Frage
Where wold yo expect to find hyaluronate
Antworten
-
ECM of Cartilage
-
Hair
-
Nails
-
Horns
Frage 33
Frage
Which one of these glycosaminoglycans acts as a lubricant?
Antworten
-
Chondrotin-4-sulfate
-
keratan sulfate
-
heparin
-
hyaluronate
Frage 34
Frage
which one of the has approximately 50'000 disaccharides per chain
Antworten
-
hyaluronate
-
keratan sulfate
-
heparin
-
chondrotin-4-sulfate
Frage 35
Frage
Which one of these glycosaminoglycans consists of [galactose β(1,4) Glc-NAc6S] repeating disaccharides
Antworten
-
hyaluronate
-
chondrotin-4-sulfate
-
heparin
-
keratan sulfate
Frage 36
Frage
Which of these repeating disaccharides make dermantan sulfate?
Antworten
-
glucaronic acid and N-acetylglucosamine
-
glucaronic acid and N-acetylgalctosamine-4-sulfate
-
Iduronic acid and N-acetylgalactosamine-4-sulfate
-
Iduronic acid and N-acetylglucosamine
Frage 37
Frage
The cabohydrate attached to a protein in a Glycoconjugate attaches via...
Frage 38
Frage
Which of the following most likely contains the most glycosylated proteins (Glycoproteins)
Antworten
-
Humans
-
E.coli
-
Ebola virus
-
Cats
Frage 39
Frage
O linked oligosaccharides are linked through the N terminus of the amino acid
Frage 40
Frage
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)
Frage 41
Frage
Glycophorin A is the most important attachment site for which of the following parasites in order to enter erythrocytes
Antworten
-
Plasmodium falciparum
-
Chilomastix mesnili
-
Entamoeba coli
-
Entamoeba dispar
Frage 42
Frage
Which of these sulfated glycosaminoglycans are attached to a protein anchored to a membrane lipid?
Frage 43
Frage
NB! Select all which are functions of polysaccharides
Antworten
-
Labelling of proteins for destruction
-
Recognition sites for growth factors
-
recognition sites for bacteria
-
localization of certain proteins
Frage 44
Frage
Which one of these is not a main component of the extracellular matrix (ECM)
Antworten
-
Proteoglycan aggregates
-
Collagen fibers
-
Elastin
-
Fatty acids
Frage 45
Frage
Which one of these in not a characteristic of Glycosaminoglycans
Frage 46
Frage
Plasmodium flaciparum requires which of these as an attachment site to enter erythrocytes
Antworten
-
Glycophorin A
-
Hyaluronan
-
syndecan
-
Podocalyxin
Frage 47
Frage
Which of these about proteoglycans is not true
Antworten
-
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
Frage 48
Frage
Which of these are integral receptors for extracellular proteoglycans
Antworten
-
Integrins
-
actin
-
collagen fibers
-
elastin
Frage 49
Frage
Which of these about enzymatic reactions is true
Antworten
-
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
Frage 50
Frage
Rate of enzymatic reactions are affected by....? (Click all true)
Frage 51
Frage
Which one of these describes a micelle
Antworten
-
individual units are wedge shaped
-
artificial carriers of molecules
-
individual units are cylindrical
-
composed lipid-based structures that form pliable sheets
Frage 52
Frage
Which of these is false
Antworten
-
membranes vary from 3-10nm
-
membranes form spontaneously by noncovalent forces
-
membranes are symmetric
-
membranes can be found within cells
Frage 53
Frage
Which of these is true about fatty acids
Antworten
-
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
Frage 54
Frage
Which of these is false about fatty acids
Antworten
-
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
Frage 55
Frage
Omega-3 (ω-3) fatty acids have
Antworten
-
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.
Frage 56
Frage
Which of these is untrue
Antworten
-
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
Frage 57
Frage
which of these is a greasy solid at room tempreature
Frage 58
Frage
which of these is a sphingolipid
Frage 59
Frage
Which of these is the head group of phosphatidylserine
Frage 60
Frage
Which of these has a net charge of -4 at pH7
Frage 61
Frage
Which of these is the major component of most eukaryotic cell membranes
Antworten
-
phophatidylcholine
-
phosphatidylglycerol
-
cardiolipin
-
phosphatidylethanolamine
Frage 62
Frage
a fatty acid is joined to sphingosine via an
Antworten
-
ester linkage
-
amide linkage
-
glycosidic linkage
-
phosphodiester linkage
Frage 63
Frage
ganglioside GM2 has which of these as a head group
Frage 64
Frage
The blood groups are determined in part by the
Frage 65
Frage
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
Antworten
-
will have the O antigen
-
A blood group
-
B blood group
-
AB blood group
Frage 66
Frage
which of thes is false
Antworten
-
Cholesterol modulates cell membrane fluidity
-
Mammals can not synthesize cholesterol
-
cholesterol in loe density lipoproteins tend to deposit in arteries
-
most bacteria lack sterols
Frage 67
Frage
which of these polyketides is an antibiotic
Antworten
-
erythromycin
-
amphotericin B
-
lovastatin
Frage 68
Frage
which of these lipids are hormone precursors
Antworten
-
vitamins E and K
-
vitamins A and D
-
steroid hormones
-
eicosanoids
Frage 69
Frage
which of these lipids are paracrine hormones
Antworten
-
phosphatidylinositols
-
vitamins A and D
-
vitamins E and K
-
Dienes
-
eicosanoids
Frage 70
Frage
which of these is true
Antworten
-
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
Frage 71
Frage
which of these is a type 6 integral membrane protein
Frage 72
Frage
Which of these amino acid residues would you find predominantly in the transmembrane segments of membrane proteins
Frage 73
Frage
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
Frage 74
Frage
hutchinson-gilford progeria syndrome is caused by
Antworten
-
palmitoylation defect
-
myristoylation defect
-
farnesylation defect
Frage 75
Frage
which of these are only found on the outside of cell membranes
Antworten
-
proteins
-
lipids
-
carbohydrates
Frage 76
Frage
which of these statements about the physical properties of membranes is true
Antworten
-
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
Frage 77
Antworten
-
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
Frage 78
Frage
Which of these statements on membrane fluidity is incorrect
Antworten
-
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
Frage 79
Frage
which of these increase in membrane compisition percentage when temperatures increase
Antworten
-
Myristic acid
-
palmitoleic acid
-
oleic acid
-
hydroxymyristic acid
Frage 80
Frage
Cell membranes of .... contain hopanols instead of sterols
Antworten
-
animals
-
bacteria
-
plants
-
fungi
Frage 81
Frage
Membrane Dynamics: Transverse Diffusion.
Spontaneous flips of individual lipids from one leaflet to another are rare because...
Antworten
-
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
Frage 82
Frage
Which is false about flippases
Antworten
-
catalyze transverse diffusion
-
catalyze lateral diffusion
-
use ATP
-
move lipids against the concentratiion gradient
Frage 83
Frage
Tick ALL that are true!!
Antworten
-
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
Frage 84
Frage
Which of these is a membrane receptor that detects light
Antworten
-
opsin
-
insulin receptor
-
acetylcholine receptor
-
maltoporin
Frage 85
Frage
Which of these is a membrane receptor that detects neurotransmitters
Antworten
-
opsin
-
acetylcholine receptor
-
maltoporin
-
insulin receptor
Frage 86
Frage
Cystic fibrosis (Mucoviscidose) is caused by
Antworten
-
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
Frage 87
Frage
Tick ALL that are correct
Antworten
-
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
Frage 88
Frage
Which of these plasma proteins is the most abundant
Antworten
-
transferrin
-
ceruloplasmin
-
immunoglobulins
-
albumin
Frage 89
Frage
What is labelled as B?
Antworten
-
blood
-
plasma
-
White blood cells
-
ficoli
Frage 90
Frage
What is labelled as D
Antworten
-
Plasma
-
White blood cells
-
Ficoli
-
white blood cells
Frage 91
Frage
Which of these are not a hematopoietic cells
Antworten
-
eosinophils
-
basophils
-
neutrophils
-
thrombocytes
Frage 92
Frage
Which of these is derived from lymphoid stem cells
Antworten
-
erythrocytes
-
T cells
-
basophil
-
neutrophil
Frage 93
Frage
Which one of these leukocytes secretes histamine and mediates inflammation
Antworten
-
neutrophils
-
basophils
-
eosinophils
-
macrophages
Frage 94
Frage
Which of these leukocytes produces Ab (antibodies)
Antworten
-
Neutrophils
-
T cells
-
B cells
-
Macrophages
Frage 95
Frage
Where is myoglobin found
Antworten
-
in the bone marrow
-
freely circulating in the blood
-
in skeletal and striated muscles
-
restricted to erythrocytes
Frage 96
Frage
which of these is false
Antworten
-
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
Frage 97
Frage
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.
Antworten
-
kd [P].[L] = ka [PL]
-
ka [P].[L] = kd [PL]
-
[P].[L] = [PL]
-
ka [P].[L] > kd [PL]
Frage 98
Frage
Which of these statements is false
Antworten
-
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
Frage 99
Frage
Cooperativity can be described as
Antworten
-
positive homotropic regulation
-
negative homotropic regulation
-
positive heterotropic regulation
-
negative heterotropic regulation
Frage 100
Frage
Which of these statement on hemoglobin is false
Antworten
-
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
Frage 101
Frage
which of these is a non-phosphorylated nitrogenous base
Antworten
-
nucleoside
-
nucleotide
-
nucleobase
-
nucleomide
Frage 102
Frage
Which side are the purines
Frage 103
Frage
Which color is encircling where a glycosidic bond between the nitrogenous base and the sugar would be present
Antworten
-
red
-
green
-
blue
-
none of the above
Frage 104
Frage
Which letter represents deoxyadenylate
Frage 105
Frage
Which letter represents deoxythymidylate
Frage 106
Frage
Which letter represents deoxyguanylate
Frage 107
Frage
Which letter is representing cytidylate (CMP)
Frage 108
Frage
Which of these statements about the purine and pyrimidine bases is true
Frage 109
Frage
In nucleotides the pentose ring is attached to the nucleobase via a
Antworten
-
β -N-Glycosidic Bond
-
α -N-Glycosidic Bond
-
Hydrogen bond
-
none of the above
Frage 110
Frage
In DNA structure there is free rotation about
Antworten
-
C-1’-N-glycosyl bond
-
C-2’-N-glycosyl bond
-
C-3’-N-glycosyl bond
-
C-4’-N-glycosyl bond
Frage 111
Frage
How many base pairs do you find in the A form of DNA
Frage 112
Frage
The aromaticity of the nucleotide bases and their dipole moments is important for which interactions in DNA
Antworten
-
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
Frage 113
Frage
Figure A represents which type of DNA secondary structure
Antworten
-
hairpin
-
mirror image
-
palindrome
-
cruciform
Frage 114
Frage
Figure C represents which type of DNA secondary structure
Antworten
-
Cruciform
-
Palindrome
-
Hairpin
-
Mirror image
Frage 115
Frage
DNA sequences with a very high proportion of G residues forms which unusual DNA structure found on chromosome telomeres
Antworten
-
tetraplex DNA
-
triplex DNA
-
inverted repeats
-
cruciforms
Frage 116
Frage
Which of these are a quaternary DNA structure
Antworten
-
Chromatin
-
hairpin
-
supercoil
-
Triplex
Frage 117
Frage
In mammals ____ Functions as an autocoid, or "local hormone"
Antworten
-
Adenosine
-
Guanine
-
Cytosine
-
Thymine
Frage 118
Frage
Which one of these is an RNase enzyme that prevents inbreeding of plants
Antworten
-
S-RNase
-
RNase-P
-
Dicer
-
None of the above
Frage 119
Frage
_____ is an enzyme that cleaves double-stranded RNA into oligonucleotides
Frage 120
Frage
Why would animal cells need an enzyme that cleaves double-stranded RNA into oligonucleotides
Antworten
-
processessing tRNA precursors
-
protection from viral genomes
-
using RNA as an energy source
-
using RNA in Coenzymes
Frage 121
Frage
RNA would be unstable in which of the conditions listed below