Quiz
BioChemistry Quiz
Perguntas do quiz (121)
1L’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 ?
- AH3PO4
- BH2PO4-
- CHPO42-
- DPO43-
2What is the basic formula of Carbohydrates?
- ACn(OH)n
- BCn(CO2)n
- CCn(H2O)n
- DC(H2O)n
3Which of these is not these is not a polysaccharide?
- ACellulose
- BGlycogen
- CStarch
- DFructose
4Long chains of single sugars covalently linked describes what types of carbohydrates?
- AOligosaccharides
- BMultisaccharides
- CPolysaccharides
- DMegasaccharides
5Which pair of molecules are epimers?
- AD-Glucose and D-Galactose
- BD-Glucose and L-Glucose
- CThreose and Erythrose
- DD-Glucose and D-Gulose
6Which of these structures is glucose?
- A
- B
- C
- D
- A
7Galactose is a ___ epimer of glucose.
- AC1
- BC2
- CC3
- DC4
8Which one of these is a ketohexose
- AFructose
- BGlucose
- CRibose
- D2-Deoxy-Ribose
9Which of these is not true?
- AEnantiomers are stereoisomers that are not mirror images
- BIn 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
- Chemiacetals are formed by alcohols attacking aldehydes
- DAlcohol oxygen atom is nucleophilic
10During the cyclisation of Monosaccharides which is/are true?
- AThe carbon atom furthest from the former carbonyl atom becomes the anomeric carbon
- BThe position of anomeric carbon's oxygen determines whether the anomer is α or β
- CThe position of the anomeric carbon's hydroxyl group determines whether the anomer is α or β
- DThe carbon atom furthest from the former carbonyl atom becomes the chiral center
11Which of these are carbohydrates that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom?
- AFuranoses
- BPyranoses
12The disaccharide formed upon condesation of two glucose molecules via the 1-4 bond is called
- ATrehalose
- BSucrose
- CMaltose
- DLactose
13Which of these describes cellobiose
- Aα-D-glucopyranosyl-(1→2)-β-D-fructofuranoside
- Bβ-D-glucopyranosyl-(1→4)-β-D-glucopyranose
- Cβ-D-galactopyranosyl-(1→4)-α-D-glucopyranose
- Dα-D-glucopyranosyl-(1→4)-β-D-glucopyranose
14Polysaccharides...
- Acan be branched but cannot have multiple monomer types
- Bcannot be unbrached
- Chave defined molecular weights
- Dwith only two monomer types cannot be branched
15Which one of these hetero-polysaccharides has the largest size
- Apeptidoglycan
- Bagarose
- Chyaluronan
16which of these is used in Algae cell walls
- APeptidoglycan
- Bhyaluronan
- Cagarose
17Glucose is stored in animals as
- AGlucagon
- BGlycogen
- CGlucose
- DInsulin
- EStarch
18Glycogen is a polysaccharide in which glucose is joined by β-(1→4) linkages
- AVerdadeiro
- BFalso
19Glycogen is a polysaccharide in which glucose is joined by α-(1→6) linkages
- AVerdadeiro
- BFalso
20Which of the following is true
- AAmylose is the branched form of starch
- Bα-amylase is a pancreatic enzyme that hydrolyses the α (1→4) linkages of starch
- CGlycogen has less α (1→4) linkages than starch
- DGlycogen has less α (1→6) linkages than starch
21hydrolysis of cotton occurs
- Aat the β (1→2) linkages of D-glucose
- Bat the α (1→2) linkages of D-glucose
- Cat the β (1→4) linkages of D-glucose
- Dat the α (1→4) linkages of D-glucose
22Which of the following is not true
- AGlycosidic bonds can freely rotate
- Bmore than 10^9 metric tonnes of cotton are produced/year
- CStarch can be coiled into a helical structure
- DGlycogen and amylopectin have only one reducing end
23Which of these lack enzymes that can hydrolyse D-glucose β (1→4) linkages
- AFungi
- Bbacteria
- Ctermites
- Dprotozoa
24Chitin
- Ais a heteropolymer
- Bconsists of β (1→2) linkages of N-acetyl-D-glucosamine
- Cis insoluble
- Donce acetlated forms Chitosan
25Sephadex gels separate proteins by
- Asize
- Bcharge
- Cpolarity
- Dshape
26Which of these would you find in the first fractions after size exclusion chromatography
- Aacidic proteins
- Bthe smallest proteins
- Cthe largest proteins
- Dbasic proteins
27which of these are homoglycans
- AAgar
- BDextrans
- CPeptidoglycan
- DNone
28Which of these can be linked to epichlorohydrin in sephadex beaded gels
- AAgar
- BAgarose
- CPeptidoglycan
- DDextran
29Agar is a complex mixture of heteropolysaccharides containing modified
- AGlucose units
- BMannose units
- CFructose units
- DNone of the above
30Which of these is false
- AAgarose can be used for growing bacteria
- BAgarose is a component of bacterial cell walls
- CAgarose can be used for DNA separation
- DAgar is a component of seaweed cell walls
31N-acetyl-galactosamine is a ___ epimer of N-acetyl-glucosamine
- AC3
- BC2
- CC4
- DC6
32Where wold yo expect to find hyaluronate
- AECM of Cartilage
- BHair
- CNails
- DHorns
33Which one of these glycosaminoglycans acts as a lubricant?
- AChondrotin-4-sulfate
- Bkeratan sulfate
- Cheparin
- Dhyaluronate
34which one of the has approximately 50'000 disaccharides per chain
- Ahyaluronate
- Bkeratan sulfate
- Cheparin
- Dchondrotin-4-sulfate
35Which one of these glycosaminoglycans consists of [galactose β(1,4) Glc-NAc6S] repeating disaccharides
- Ahyaluronate
- Bchondrotin-4-sulfate
- Cheparin
- Dkeratan sulfate
36Which of these repeating disaccharides make dermantan sulfate?
- Aglucaronic acid and N-acetylglucosamine
- Bglucaronic acid and N-acetylgalctosamine-4-sulfate
- CIduronic acid and N-acetylgalactosamine-4-sulfate
- DIduronic acid and N-acetylglucosamine
37The cabohydrate attached to a protein in a Glycoconjugate attaches via...
- AThe C6 carbon
- BThe anomeric carbon
- CThe furthest carbon from the anomeric carbon
- DThe C2 carbon
38Which of the following most likely contains the most glycosylated proteins (Glycoproteins)
- AHumans
- BE.coli
- CEbola virus
- DCats
39O linked oligosaccharides are linked through the N terminus of the amino acid
- AVerdadeiro
- BFalso
40In 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)
- AVerdadeiro
- BFalso
41Glycophorin A is the most important attachment site for which of the following parasites in order to enter erythrocytes
- APlasmodium falciparum
- BChilomastix mesnili
- CEntamoeba coli
- DEntamoeba dispar
42Which of these sulfated glycosaminoglycans are attached to a protein anchored to a membrane lipid?
- Asyndecans
- Bglypicans
43NB! Select all which are functions of polysaccharides
- ALabelling of proteins for destruction
- BRecognition sites for growth factors
- Crecognition sites for bacteria
- Dlocalization of certain proteins
44Which one of these is not a main component of the extracellular matrix (ECM)
- AProteoglycan aggregates
- BCollagen fibers
- CElastin
- DFatty acids
45Which one of these in not a characteristic of Glycosaminoglycans
- ANegatively charged
- BC5 oxidation
- Cone monomer is either N-acetyl-glucosamine or N-acetyl-galactosmine
- Dfound in connective tissue
46Plasmodium flaciparum requires which of these as an attachment site to enter erythrocytes
- AGlycophorin A
- BHyaluronan
- Csyndecan
- DPodocalyxin
47Which of these about proteoglycans is not true
- AProteoglycan aggregates are found in articula cartilage
- BProteoglycans influence growth factor activation and adhesion
- Cglycosaminoglycans are linked to the core protein from the anomeric carbon
- Dproteoglycanaggregates form high friction material
48Which of these are integral receptors for extracellular proteoglycans
- AIntegrins
- Bactin
- Ccollagen fibers
- Delastin
49Which of these about enzymatic reactions is true
- AEnzymes directly affect equilibrium (∆G)
- BEntropy cost is paid during binding
- Cenzymes increse reaction rates (κ ) by increasing (∆G)
- Dslow reactions do not have high activtaion barriers
50Rate of enzymatic reactions are affected by....? (Click all true)
- Aconcentration of enzyme
- Bconcentration of substrate
- Ctemperature
- Dshape of enzyme
- Eshape of substrate
51Which one of these describes a micelle
- Aindividual units are wedge shaped
- Bartificial carriers of molecules
- Cindividual units are cylindrical
- Dcomposed lipid-based structures that form pliable sheets
52Which of these is false
- Amembranes vary from 3-10nm
- Bmembranes form spontaneously by noncovalent forces
- Cmembranes are symmetric
- Dmembranes can be found within cells
53Which of these is true about fatty acids
- AMost natural fatty acids are branched
- BSaturated fatty acids have double bonds between carbons in the chain
- CMost natural fatty acids have an even number of C's
- Dlinoleic acid is a saturated fatty acid
54Which of these is false about fatty acids
- AFatty acids solubility decreases as the chain length increases
- BMelting point decrases as the chain length decreses
- CMelting point increases as the number of double bonds increases
- Dunsaturated cis fatty acids have a lower melting point than saturated fatty acids
55Omega-3 (ω-3) fatty acids have
- Aa double bond between the 2nd and 3th carbon from the methyl end of the chain.
- Ba double bond between the 3rd and 4th carbon from the methyl end of the chain.
- Ca double bond between the 1st and 2nd carbon from the methyl end of the chain.
- Da double bond between the 2nd and 3nd as well as 3rd and 4th carbon from the methyl end of the chain.
56Which of these is untrue
- ATriacylglycerols are polar
- BTriacylglycerols are non hydrated
- CVegetable oils are composed of triacylglycerols with unsaturated fatty acids
- DAnimal fats are composed of triacylglycerols with saturated fatty acids
57which of these is a greasy solid at room tempreature
- Atriacylglycerols with unsaturated fatty acids
- Btriacylglycerols with saturated fatty acids
58which of these is a sphingolipid
- A
- B
- A
59Which of these is the head group of phosphatidylserine
- A
- BA
- CB
- DC
- ED
- FE
- A
60Which of these has a net charge of -4 at pH7
- Aphosphatidylcholine
- Bcardilipin
- Cphosphatidylglycerol
- Dphosphatidylinositol 4,5- biphosphate
61Which of these is the major component of most eukaryotic cell membranes
- Aphophatidylcholine
- Bphosphatidylglycerol
- Ccardiolipin
- Dphosphatidylethanolamine
62a fatty acid is joined to sphingosine via an
- Aester linkage
- Bamide linkage
- Cglycosidic linkage
- Dphosphodiester linkage
63ganglioside GM2 has which of these as a head group
- Aglucose
- Bgalactose
- Cdi, tri, or tetrasaccharide
- Dcomplex oligosaccharide
64The blood groups are determined in part by the
- Atype of sugars located on the head groups in glycosphingolipids
- Btype of sugars located on the head groups in glycolipids
- Ctype of sphingolipids
- Dtype of galactolipids
65The 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
- Awill have the O antigen
- BA blood group
- CB blood group
- DAB blood group
66which of thes is false
- ACholesterol modulates cell membrane fluidity
- BMammals can not synthesize cholesterol
- Ccholesterol in loe density lipoproteins tend to deposit in arteries
- Dmost bacteria lack sterols
67which of these polyketides is an antibiotic
- Aerythromycin
- Bamphotericin B
- Clovastatin
68which of these lipids are hormone precursors
- Avitamins E and K
- Bvitamins A and D
- Csteroid hormones
- Deicosanoids
69which of these lipids are paracrine hormones
- Aphosphatidylinositols
- Bvitamins A and D
- Cvitamins E and K
- DDienes
- Eeicosanoids
70which of these is true
- Acholesterol is predominant in mitochondrial membranes
- Bgalactolipids are abundant in animals
- Cmembranes have non-selective import and export across the membrane
- Darchaebacteria have monolayer instead of a bilayer
71which of these is a type 6 integral membrane protein
- A
- B
- C
- D
- A
72Which of these amino acid residues would you find predominantly in the transmembrane segments of membrane proteins
- ATyr
- BThr
- CSer
- DPro
73Proteins 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- ACaaX
- BMaaX
- CCaX
- DMaX
74hutchinson-gilford progeria syndrome is caused by
- Apalmitoylation defect
- Bmyristoylation defect
- Cfarnesylation defect
75which of these are only found on the outside of cell membranes
- Aproteins
- Blipids
- Ccarbohydrates
76which of these statements about the physical properties of membranes is true
- APermeable to large polar solutes and ions
- BNot permeable to small polar solutes and nonpolar
compounds - CPermeability can be artificially increased by chemical
treatment - DExist in a single phase and cannot undergo phase
transitions
77Heating causes
- Acell membrane transition from the gel to fluid
- Bcell membrane transition from the fluid to gel
- Ccell membrane changed to become not permeable to large polar solutes
- Dcell membrane changed to become permeable to small polar solutes and nonpolar compounds
78Which of these statements on membrane fluidity is incorrect
- Ais determined mainly by the fatty acid composition
- Bmore fluid membranes require shorter and more unsaturated fatty acids
- CAt higher temperatures cells need more saturated fatty
acids to maintain fluidity - DGel phase means that the individual molecules do not move
around
79which of these increase in membrane compisition percentage when temperatures increase
- AMyristic acid
- Bpalmitoleic acid
- Coleic acid
- Dhydroxymyristic acid
80Cell membranes of .... contain hopanols instead of sterols
- Aanimals
- Bbacteria
- Cplants
- Dfungi
81Membrane Dynamics: Transverse Diffusion.
Spontaneous flips of individual lipids from one leaflet to another are rare because...- Athe hydrophobic head group must transverse the hydrophilic tail region of the membrane
- Bmembrans are rigid and individual lipids cannot move at all
- Cthe charged head group must transverse the hydrophobic tail region of the membrane
82Which is false about flippases
- Acatalyze transverse diffusion
- Bcatalyze lateral diffusion
- Cuse ATP
- Dmove lipids against the concentratiion gradient
83Tick ALL that are true!!
- AMembrane Lipid Rafts contain clusters of glycosphingolipids with longer-than-usual tails
- BMembrane Lipid Rafts are more ordered than the rest of the membrane
- CMembrane fusion can only occur through protein mediation
- DPassive diffuision of polar molecules across cell membranes has a high activation barrier
84Which of these is a membrane receptor that detects light
- Aopsin
- Binsulin receptor
- Cacetylcholine receptor
- Dmaltoporin
85Which of these is a membrane receptor that detects neurotransmitters
- Aopsin
- Bacetylcholine receptor
- Cmaltoporin
- Dinsulin receptor
86Cystic fibrosis (Mucoviscidose) is caused by
- Aa mutation to a Cl- ion channel in epithelial cells
- Ba mutation to a K+ ion channel in epithelial cells
- Ca mutation to a Na+ ion channel in epithelial cells
- Da mutation to a Ca2+ ion channel in epithelial cells
87Tick ALL that are correct
- AEnergy of ATP hydrolysis can be used to drive protons through the membrane
- BEnergy of the proton gradient can be used to synthesize ATP
- CPrimary 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.
- Dglucose is cotransported with Na+ in intestinal epithelial cells
88Which of these plasma proteins is the most abundant
- Atransferrin
- Bceruloplasmin
- Cimmunoglobulins
- Dalbumin
89What is labelled as B?
- Ablood
- Bplasma
- CWhite blood cells
- Dficoli
90What is labelled as D
- APlasma
- BWhite blood cells
- CFicoli
- Dwhite blood cells
91Which of these are not a hematopoietic cells
- Aeosinophils
- Bbasophils
- Cneutrophils
- Dthrombocytes
92Which of these is derived from lymphoid stem cells
- Aerythrocytes
- BT cells
- Cbasophil
- Dneutrophil
93Which one of these leukocytes secretes histamine and mediates inflammation
- Aneutrophils
- Bbasophils
- Ceosinophils
- Dmacrophages
94Which of these leukocytes produces Ab (antibodies)
- ANeutrophils
- BT cells
- CB cells
- DMacrophages
95Where is myoglobin found
- Ain the bone marrow
- Bfreely circulating in the blood
- Cin skeletal and striated muscles
- Drestricted to erythrocytes
96which of these is false
- Amyogloblin stores oxygen in the cytoplasm and delivers it to mitochondrion
- Bhemoglobin is restricted to erythrocytes
- CHeme (B) is the oxygen binding molecule found only in hemoglobin
- Dthe distal histidine of the myglobin protein hydrogen bonds with oxygen bound to the protein
97Consider 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.
- Akd [P].[L] = ka [PL]
- Bka [P].[L] = kd [PL]
- C[P].[L] = [PL]
- Dka [P].[L] > kd [PL]
98Which of these statements is false
- Awhen the first binding event increases affinity at the remaining sites it is called positive cooperativity
- Bwhen the first binding event decreases affinity at the remaining sites it is called negative cooperativity
- Coxygen binds to heme better than carbon monoxide
- DnH( hill coefficient) > 1 equals positive cooperativity
99Cooperativity can be described as
- Apositive homotropic regulation
- Bnegative homotropic regulation
- Cpositive heterotropic regulation
- Dnegative heterotropic regulation
100Which of these statement on hemoglobin is false
- Aoxygen binding triggers a tense to relaxed state conformational change
- Btense state has a higher affinity for oxgen than the relaxed state
- Cconformational change from the T state to the R state invloves breaking ion pairs between the alpha1-beta2 interface of hemoglobin
- D2,3 -Bisphosphoglycerate is a negative heterotropic regulator of hemoglobin function
101which of these is a non-phosphorylated nitrogenous base
- Anucleoside
- Bnucleotide
- Cnucleobase
- Dnucleomide
102Which side are the purines
- AA
- BB
103Which color is encircling where a glycosidic bond between the nitrogenous base and the sugar would be present
- Ared
- Bgreen
- Cblue
- Dnone of the above
104Which letter represents deoxyadenylate
- AA
- BB
- CC
- DD
105Which letter represents deoxythymidylate
- AA
- BB
- CC
- DD
106Which letter represents deoxyguanylate
- AA
- BB
- CC
- DD
107Which letter is representing cytidylate (CMP)
- AA
- BB
108Which of these statements about the purine and pyrimidine bases is true
- ACytosine is found in both DNA and RNA
- BNeutral molecules at pH 7
- CGuanine pKa at N7 is 2.4
- Dall the above
109In nucleotides the pentose ring is attached to the nucleobase via a
- Aβ -N-Glycosidic Bond
- Bα -N-Glycosidic Bond
- CHydrogen bond
- Dnone of the above
110In DNA structure there is free rotation about
- AC-1’-N-glycosyl bond
- BC-2’-N-glycosyl bond
- CC-3’-N-glycosyl bond
- DC-4’-N-glycosyl bond
111How many base pairs do you find in the A form of DNA
- A10.5
- B11
- C12
- D13
112The aromaticity of the nucleotide bases and their dipole moments is important for which interactions in DNA
- AVan der Waal forces in base stacking
- Blink between base and sugar in a nucleotide
- Cthe link between two different nucleotides
- Dinterstrand bonding and complementarity
113Figure A represents which type of DNA secondary structure
- Ahairpin
- Bmirror image
- Cpalindrome
- Dcruciform
114Figure C represents which type of DNA secondary structure
- ACruciform
- BPalindrome
- CHairpin
- DMirror image
115DNA sequences with a very high proportion of G residues forms which unusual DNA structure found on chromosome telomeres
- Atetraplex DNA
- Btriplex DNA
- Cinverted repeats
- Dcruciforms
116Which of these are a quaternary DNA structure
- AChromatin
- Bhairpin
- Csupercoil
- DTriplex
117In mammals ____ Functions as an autocoid, or "local hormone"
- AAdenosine
- BGuanine
- CCytosine
- DThymine
118Which one of these is an RNase enzyme that prevents inbreeding of plants
- AS-RNase
- BRNase-P
- CDicer
- DNone of the above
119_____ is an enzyme that cleaves double-stranded RNA into oligonucleotides
- AS-RNase
- BDicer
- CRNase P
120Why would animal cells need an enzyme that cleaves double-stranded RNA into oligonucleotides
- Aprocessessing tRNA precursors
- Bprotection from viral genomes
- Cusing RNA as an energy source
- Dusing RNA in Coenzymes
121RNA would be unstable in which of the conditions listed below
- ApH 1
- BpH 3
- CpH 6
- DpH 10
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