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Biochemistry MCQ's
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Questions in this quiz (40)
1The redox centre of FAD is
- AFlavin mononucleotide (FMN)
- BNicotinamide
- CAdenosine
- DPhosphate
2Which of the following nucleotide triphosphates is often involved in signal transduction and also provides the energy for ribosomal translocation?
- ACTP
- BTTP
- CUTP
- DGTP
3Which monosaccharide provides the main source of energy for sperm cells?
- AGlucose
- BFructose
- CGalactose
- DMannose
4Which pathway(s) include phosphorylated seven carbon monosaccharides?
- ACalvin cycle
- BLeloir pathway
- CGlycogen synthesis
- DAll of the above
5The isomerisation of glucose 1-phosphate to glucose 6-phosphate occurs in which two pathways?
- ACalvin cycle and glycogen synthesis
- BLeloir pathway and Calvin cycle
- CLeloir pathway and glycolysis
- DLeloir pathway and glycogen synthesis
6Steroids
- AAre entirely hydrophobic molecules
- BOften act as hormones
- CCannot pass through cell membranes
- DAre mainly hydrophilic molecules
7The sequence of reactions: oxidation-hydration-oxidation occurs in which two pathways?
- Aβ-oxidation of fatty acids and tricarboxylic acid (Krebs’) cycle
- Bβ-oxidation of fatty acids and glycolysis
- CFatty acid synthesis and tricarboxylic acid (Krebs’) cycle
- DFatty acid synthesis and glycolysis
8The mobility of membrane phospholipids can be demonstrated by
- AIrradiating a leaf and watching the return of the green colour
- BObserving the molecules using an electron microscope
- CPaper chromatography of the lipids and staining
- DBleaching of fluorescently labelled phospholipids and watching the return of the fluorescence
9Cholesterol is an example of what class of molecule?
- ASterol
- BFatty acid
- CKetose monosaccharide
- DAldose monosaccharide
10In the Calvin cycle, how many molecules of carbon dioxide are required for the synthesis of one molecule of fructose 6-phosphate?
- A3
- B4
- C6
- D12
11In cellulose, the glucose residues are bonded together by:
- Aα(1→4) glycosidic bonds
- Bα(1→4) glycosidic bonds with α(1→6) glycosidic bonds approximately every tenth residue
- Cβ(1→4) glycosidic bonds
- Dβ(1→4) glycosidic bonds with β(1→6) glycosidic bonds approximately every tenth residue
12Which of the following is not a reducing sugar?
- ASucrose
- BMaltose
- CLactose
- DGalactose
13The carnitine cycle
- A“Fixes” atmospheric carbon dioxide into sugars
- BTransports fatty acids into the matrix of the mitochondria
- CTransports ATP out of the mitochondria
- DProduces NADH for use in oxidative phosphorylation
14Glycerol can be used as a source of energy by conversion to the glycolytic intermediate dihydroxyacetone phosphate. Per molecule of glycerol, this process:
- AProduces one molecule of NADH and consumes one molecule of ATP
- BProduces one molecule of ATP and consumes one molecule of NADH
- CProduces one molecule of NADH and consumes no molecules of ATP
- DProduces no molecules of NADH and consumes one molecule of ATP
15Fatty acid synthesis:
- ARequires NADH
- BRequires water as a reactant
- CAdds carbon atoms two at a time
- DAll of the above
16In enzyme kinetics, the ratio of constants kcat/Km:
- AIs a measure of the rate of acceleration carried out by the enzyme.
- BFor a given enzyme is independent of the substrate used.
- CHas units of concentration.
- DGives an idea of the enzymes catalytic efficiency.
17In enzyme catalysis, the term ‘approximation’ refers to:
- AA catalytic strategy facilitating transition state formation through covalent bond formation between the substrate and enzyme active site.
- BA catalytic strategy facilitating transition state formation through hydrogen bond formation and electrostatic bond formation between the substrate and enzyme active site.
- CA catalytic strategy facilitating transition state formation through interaction involving metal ions and substrate in the enzyme active site.
- DA catalytic strategy facilitating transition state formation through direct transfer of a proton to or from the substrate in the enzyme active site.
18Consider an enzyme that shows Michaelis-Menten kinetics where:
v0 = Vmax . [S] / (Km + [S])
If a substrate, S, is present at a concentration of 8 mM, and Km is 4 mM, the rate of reaction (v0) measured will be:- AHalf of Vmax
- BTwo thirds of Vmax
- CDouble Vmax
- DThree times Vmax
19Koshland’s induced fit model for enzyme-substrate complex formation:
- AMay explain why enzymes have particular substrate specificity.
- BMay explain why enzymes are able to catalyse chemical reactions that cannot be facilitated in any other way
- CMay explain why enzymes increase the rate of a reaction by reduction of the activation energy change for the reaction
- DMay explain why enzymes can effectively reduce the loss of energy from a chemical reaction as heat
20Enzymes:
- Aare chemically altered at the end of their reaction
- Bare involved in changing the equilibrium constant of the reaction that they
catalyse - Cbind their substrates at their active site(s)
- Dincrease the activation energy of the reaction they catalyse
21The Michaelis constant, Km:
- AIs a measure of the rate acceleration caused by the enzyme
- BFor a given enzyme is independent of the substrate used
- CHas units of concentration
- DGives an idea of the enzyme’s catalytic efficiency
22The Vmax of an enzyme catalysed reaction:
- AIs altered when a competitive inhibitor is present
- BCan be determined from the intercept on the x-axis of a Lineweaver-Burk plot
- CIs the maximum rate at which the enzyme can convert substrate into product
- DHas units of concentration
23Proteosome-mediated proteolysis:
- AIs controlled by serine protease enzymes.
- BIs a key part of the control mechanism in the eukaryote cell cycle
- CIs a key part of the control mechanism in the prokaryote cell cycle
- DIs controlled by ubiquinone activating enzymes.
24The Alanine Cycle:
- AIs completely located in the mitochondrial matrix.
- BFacilitates transport of ammonia produced in the liver to the muscles where it can be used in anabolic processes - preventing the exposure of free ammonium to other components of eukaryote tissues.
- CFacilitates transport of ammonia produced in the muscles to the liver where it can be effectively removed from the body - preventing the exposure of free ammonium to other components of eukaryote tissues.
- DIs located in the cell membrane of muscle cells.
25Which of the following is a Redox Centre of Mitochondrial Respiratory Chain Enzymes?
- ANADPH
- BSuccinate
- COxygen
- DFMN, flavin
26In Photosynthesis energy of light Quanta is captured by a molecule of:
- APlastoquinone
- BOxygen
- CChlorophyll
- DCytochrome c
27What is the overall equation for a light phase of Photosynthesis?
- A18CO2+ 2 NADPH + 3 ATP + light → 2 NADPH + 3 Glucose + 3 ADP + 18O2
- B2 H2O + 2 NADP+ + 3 ADP + 3 Pi + light → 2 NADPH + 2 H+ + 3 ATP + O2
- C2 H2O + 2 NAD+ 2 Pi → 2 NADPH + 2 H+ + O2 + light
- DCO2 + light + H2O → Glucose + O2
28Uncouplers inhibit Mitochondrial Oxidative Phosphorylation due to:
- AInhibition of respiratory chain
- BTheir ability to translocate protons and dissipate the membrane potential
- CInhibition of ATP-hydrolysis
- DInhibition of glycolysis
29Which of the following statements about light phase of Photosynthesis is incorrect?
- AProton-translocating ATP-synthase of thylakoid membrane can synthesise ATP
- BPhotosystem I and II can capture light quanta
- CThe thylakoid membrane is negatively charged on the lumen side
- DThe proton motive force can be used for active transport
30In biochemical pathways the metabolic cycles are:
- ACompounds which occur at cross-over or branching points in metabolic pathways
- BInitial substrates which feed into metabolic pathways
- CCompounds which catalyse the individual steps in a metabolic pathway
- DMetabolic hubs which allow the use and re-use of relatively small numbers of molecules
31Protein degradation is an example of which type of biochemical pathway?
- AAnabolic
- BCatabolic
- CAmphibolic
- DHyperbolic
32Which of the following is true of endotherms?
- AThey generate most of their heat through internal processes
- BThey get most of their heat from the environment
- CThey generate most of their heat from external processes
- DThey cannot regulate their body temperature
- AThey generate most of their heat through internal processes
33Which ONE of the following statements are true for the sympathetic nervous system?
- AIt prepares us for strenuous muscular activity
- BIt prepares us for relaxing (non-strenuous) activity
- CIt is one of 3 autonomic nervous systems
- DIt is a part of the endocrine system
34Diabetes insipidus is a disease caused by:
- AA lack of insulin
- BA lack of ADH
- CA lack of oxytocin
- DAn excess of insulin
35Cyclic AMP is:
- AAn activator of pyruvate kinase C
- BAn activator of protein kinase A
- CThe product of adenylate kinase
- DAn activator of phosphofructokinase-1
36Phosphofructokinase-1 Activity is:
- Astimulated by citrate
- Binhibited by citrate
- Cinhibited by AMP
- Dinhibited by fructose 2,6-bisphosphate
37Glycogen Phosphorylase is:
- Ainhibited by AMP
- Bactivated by phosphorylation
- Cactivated by glucose
- Dinhibited by phosphorylation
38Protein Kinase A:
- Ais an allosteric enzyme
- Bis activated by ADP
- Cphosphorylates glycogen phosphorylase
- Dphosphorylates phosphorylase kinase
39Cancer cells produce large amounts of Lactate even in the presence of Oxygen because they:
- ALack mitochondria
- BLack the gene for citrate synthase
- CPossess an over-active glycerol phosphate shuttle
- DHave a defective glycerol phosphate shuttle
40We know relatively little about the metabolism of the liver fluke. What is the most realistic prediction about galactose metabolism in this organism compared to the one we know about in humans?
- AIt will follow the Leloir pathway like in humans
- BIt will follow a different pathway because it is a parasite
- CIt will follow a different pathway because it eats different food
- DWe cannot make any realistic predictions
Information
- Description
- Papers covered; - August 2013
- Author
- tj.sloan
- Language
- English
- Views
- 76
- History
- Created on 2 Feb 2015 · updated on 14 Jun 2016
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