THE CARBOHYDRATE RIBOSE CONTAINS HOW MANY CARBON ATOMS?
3
4
5
6
SUCROSE IS A DISACCHARIDE OF:
Glucose and fructose
Maltose and glucose
Glucose and galactose
Fructose and galactose
THE BEST DESCRIPTION FOR FATTY ACIDS IS:
Hydrophobic
Hydrophilic
Amphipathic
Anglophobic
GLYCOGEN CONTAINS WHICH TYPES OF GLYCOSIDIC BONDS BETWEEN GLUCOSE RESIDUES?
α(1→4) and α(1→6)
β(1→4) and α(1→6)
α(1→4) and β(1→6)
β(1→4) and β(1→6)
THE CONFORMATION OF THE POLYSACCHARIDE CHAINS IN CELLULOSE IS NORMALLY:
Helical
Random coil
Zig-zag
Linear
THE REDOX CENTRE IN NAD+ IS:
Nicotine
Nicotinamide
Flavin mononucleotide
Flavinoid
WHICH NUCLEOTIDE TRIPHOSPHATE IS COMMONLY INVOLVED IN RIBOSOMAL TRANSLOCATION AND SIGNAL TRANSDUCTION?
CTP
TTP
UTP
GTP
IN LIVING CELLS, ATP IS USUALLY FOUND IN COMPLEX WITH WHICH ION?
Na+
Ca2+
Hg2+
Mg2+
IN THE LELOIR PATHWAY OF GALACTOSE METABOLISM, GALACTOSE IS PHOSPHORYLATED TO GIVE:
Galactose 1-phosphate
Galactose 6-phosphate
Glucose 1-phosphate
Glucose 6-phosphate
THE MAIN CARBOHYDRATE “FUEL” OF SPERM CELLS IS:
Glucose
Galactose
Fructose
Maltose
WHICH PATHWAY RESULTS IN THE GREATEST OVERALL DIRECT GENERATION OF ATP UNDER AEROBIC CONDITIONS?
Glycolysis
The tricarboxylic acid (Krebs) cycle
Oxidative phosphorylation
Gluconeogenesis
FOR THE COMPLETE OXIDATIVE METABOLISM OF ONE MOLECULE OF GLUCOSE UNDER AEROBIC CONDITIONS, HOW MANY TIMES DOES THE TRICARBOXYLIC ACID CYCLE “TURN”?
0
1
2
FOR EACH MOLECULE OF ACETYL COENZYME A (AcCoA) WHICH ENTERS THE TRICARBOXYLIC ACID CYCLE, HOW MANY MOLECULES OF CARBON DIOXIDE ARE RELEASED?
UNDER ANAEROBIC CONDITIONS, YEAST METABOLISE GLUCOSE TO:
Ethanol via acetic acid
Acetic acid via ethanol
Acetaldehyde (ethanal) via ethanol
Ethanol via acetaldehyde (ethanal)
THE PRODUCTS OF THE LIGHT REACTIONS OF PHOTOSYNTHESIS IN GREEN PLANTS INCLUDE:
NADH, oxygen and a proton motive force
NADPH, water and an electromotive force
NADPH, oxygen and a proton motive force
NADH, oxygen and an electromotive force
THE “DARK” REACTIONS OF PHOTOSYNTHESIS IN GREEN PLANTS REQUIRE:
NADPH, ATP and carbon dioxide
NAD+, ATP and carbon dioxide
NADPH, ADP and oxygen
NADPH, ATP and oxygen
TWO METHODOLOGIES USED BY MELVIN CALVIN TO ELUCIDATE THE “DARK” REACTIONS OF PHOTOSYNTHESIS WERE:
Paper chromatography and synthetic organic chemistry
X-ray crystallography and titrations
Gene sequencing and fluorescence resonance energy transfer
Tissue culture and NMR spectroscopy
WHICH OF THESE COFACTORS IS NEEDED FOR THE SYNTHESIS OF MALONYL COENZYME A FROM ACETYL COENZYME A AND CARBON DIOXIDE?
Niacin
NAD+
Thiamine
Biotin
IN WATER, FATTY ACIDS CAN SPONTANEOUSLY ASSEMBLE INTO WHAT STRUCTURES?v
Micelles
Mitochondria
Mitotic spindles
Myosin
MALONATE INHIBITS AN ENZYME IN WHICH METABOLIC PATHWAY?
Tricarboxylic acid cycle
Leloir pathway
Glycogen biosynthesis
THE MICHAELIS CONSTANT, Km:
Has units of concentration
For a given enzyme is independent of the substrate used
Is a measure of the rate of acceleration carried out by the enzyme
Gives an idea of the enzyme’s catalytic efficiency
WHEN CONSIDERING ENZYME CATALYTIC MECHANISMS, ACID-BASE CATALYSIS:
Is usually dependant upon hydrogen bonding with at least one amino acid side chain at the active site to facilitate formation of the transition state
Is usually dependant upon hydrogen bonding between the carbonyl and amide groups of peptide bonds to facilitate formation of the transition state
Is usually dependant upon hydrogen bonding between a water molecule and the substrate to facilitate formation of the transition state
Is usually dependant upon hydrogen bonding with an oxidised metal ion prosthetic group in the active site to facilitate formation of the transition state
IN ENZYME CATALYSIS THE TERM “APPROXIMATION” REFERS TO:
A catalytic strategy that facilitates transition state stabilisation through formation of covalent bonds between a substrate and amino acid groups in the active site
A catalytic strategy that facilitates transition state stabilisation through formation of hydrogen bonds and electrostatic interactions between a substrate and amino acid groups in the active site
A catalytic strategy that facilitates transition state stabilisation through interaction with metal ions in the active site
A catalytic strategy that facilitates transition state stabilisation through direct transfer of a proton to the substrate from an acidic amino acid group in the active site
AN OXYANION HOLE IS:
A region of the enzyme active site that facilitates binding of positively charged substrates through their association with oxygen-containing amino-acid side chains in the enzyme
A region of the enzyme active site that facilitates binding of negatively charged substrates through their association with oxygen-containing amino-acid side chains in the enzyme
A region of the active site that facilitates binding of positively charged oxygen-containing groups present in a substrate
A region of the active site that facilitates binding of negatively charged oxygen-containing groups present in a substrate
THE PROTEIN UBIQUITIN:
Can be covalently linked to proteins via the N-terminal glycine residue
Is a polypeptide
Is an essential component of eukaryote respiratory chains
Can be covalently linked to proteins via isopeptide bond formation
PROTEOSOME-MEDIATED PROTEOLYSIS:
Is controlled by serine protease enzymes.
Is a key part of the control mechanism in the eukarote cell cycle
Is a key part of the control mechanism in the prokarote cell cycle
Is controlled by ubiquinone activating enzymes.
IN MICHAELIS-MENTON KINETICS, FORMATION OF THE ENZYME-SUBSTRATE COMPLEX:
Is always the rate limiting step in an enzyme catalysed reaction
Is never the rate limiting step in an enzyme catalysed reaction
Is always a necessary pre-requisite to formation of the transition state and therefore product turnover
Is never a necessary pre-requisite to formation of the transition state and therefore product turnover
THE TRANSITION STATE MODEL FOR ENZYME CATALYSIS:
May explain why enzymes have particular substrate specificity
May explain why enzymes are able to catalyse chemical reactions that cannot be facilitated in any other way
May explain why enzymes increase the rate of a reaction by reduction of the activation energy change for the reaction
May explain why enzymes can effectively reduce the loss of energy from a chemical reaction as heat
THE CATALYTIC EFFICIENCY OF AN ENZYME CATALYSED REACTION:
Can be described by the ratio: kcat/Km
Can be described by the ratio: Km/kcat
Can be described by the ratio: Vmax/kcat
Can be described by the ratio: kcat/Vmax
THE UREA CYCLE:
Is completely located in the mitochondrial matrix – preventing the exposure of free ammonium to other components of the eukaryote cell
Allows free ammonia obtained directly from deamination of glutamate to be converted to urea – preventing the exposure of free ammonium to other components of the eukaryote cell
Allows free ammonia obtained directly from deamination of tryptophan to be converted to urea – preventing the exposure of free ammonium to other components of the eukaryote cell
Is completely located in the cytoplasm of the cell – preventing the exposure of free ammonium to other components of the eukaryote cell
FRUCTOSE 2,6-BISPHOSPHATE IS:
A glycolytic intermediate
The precursor of glyceraldehyde 3-phosphate and dihydroxyacetone phosphate
Produced from fructose 2-phosphate
A second messenger
THE BUILD UP OF LACTIC ACID IN MUSCLES AFTER ANAEROBIC EXERCISE IS:
Caused by an excess of ATP in the cytoplasm
Due to its synthesis being coupled to ATP hydrolysis
Due to pyruvate being reduced by lactate dehydrogenase to allow recycling of NADH to NAD+
Due to pyruvate being oxidised by lactate dehydrogenase to allow recycling of NAD+ to NADH
THE INCREASE IN ATP LEVELS THAT ACCOMPANIES THE "PASTEUR EFFECT" CAUSES:
Decreased glycolytic flux by allosteric stimulation of lactate dehydrogenase
Allosteric inhibition of fructose 1,6-bisphosphatase
Allosteric inhibition of phosphofructokinase-1
Increased glycolytic flux by allosteric activation of phosphofructokinase-2
PROTEIN KINASE A IS ACTIVATED BY:
5'-AMP
cAMP
ADP
NADH
THE WARBURG EFFECT IS:
The term used to describe the inhibition of glycolysis in anaerobic cells that occurs when oxygen is supplied
Caused (in some cancers) by a defect in the glycerol phosphate shuttle
Caused by an over-active glycerol phosphate shuttle in cancer
Due to the inhibition of phosphofructokinase-1 by NADH
THE RENIN-ANGIOTENSIN SYSTEM HELPS REGULATE:
Body fluids
Blood pressure
Body temperature
Breathing
WHICH OF THE FOLLOWING IS TRUE OF ECTOTHERMS?
They generate most of their heat through internal processes
They get most of their heat from the environment
They generate most of their heat from external processes
They cannot regulate their body temperature
IN BIOCHEMICAL PATHWAYS THE COMMON INTERMEDIATES ARE:
Initial substrates which feed into metabolic pathways
Compounds which catalyse the individual steps in a metabolic pathway
Compounds which occur at cross-over or branching points in metabolic pathways
Metabolic hubs which allow the use and re-use of relatively small numbers of molecules
THE KREBS (OR TCA) CYCLE IS AN EXAMPLE OF WHICH TYPE OF PATHWAY?
Anabolic
Catabolic
Amphibolic
Hyperbolic
WHICH OF THESE SYSTEMS IS MOST COMMON IN BIOLOGICAL SYSTEMS?
Positive feedback
Formative feedback
Negative feedback
Neutral feedback
