SUCROSE IS SYNTHESISED BY WHICH OF THESE GROUPS OF ORGANISMS?
Mammals
Birds
Bees
Trees
WHICH OF THE FOLLOWING LISTS CONTAINS ONLY ALDOSE, HEXOSE MONOSACCHARIDES?
Glucose, Fructose, Mannose
Sucrose, Fructose, Ribose
Mannose, Galactose, Glucose
Sucrose, Mannose, Glucose
WHICH IF THESE MOLECULES OR IONS WILL PASS MOST EASILY THROUGH A PHOSPHOLIPID BILAYER?
A sodium ion
Urea
A chloride ion
ATP
WHICH OF THE FOLLOWING CARBOHYDRATES IS COMMONLY USED AS THE ACTIVE INGREDIENT IN “FAKE TAN”?
Glyceraldehyde
Galactose
Ribose
Dihydroxyacetone
GLYCOGEN IS SYNTHESISED FROM WHICH PRECURSOR?
Glucose
UDP-glucose
Sucrose
Glucose 6-phosphate
IN THE FIRST REACTION OF THE LELOIR PATHWAY, GALACTOSE REACTS WITH ATP TO MAKE:
Galactose 1-phosphate
Galactose 2-phosphate
Galactose 4-phosphate
Galactose 6-phosphate
CONSIDER GLYCOLYSIS STARTING FROM GLUCOSE AND ENDING WITH PYRUVATE. WHAT IS THE NET GAIN OF ATP PER MOLECULE OF GLUCOSE?
No molecules
Two molecules
Four molecules
Six molecules
IN HUMANS, UNDER ANAEROBIC CONDITIONS, NADH PRODUCED IN GLYCOLYSIS IS REGENERATED BY THE REDUCTION OF WHICH COMPOUND TO LACTATE?
Acetyl Coenzyme A (AcCoA)
Pyruvate
Phosphoenolpyruvate
Ethanol
TO REPLENISH THE KREBS‟ (TRICARBOXYLIC ACID) CYCLE INTERMEDIATES, PHOSPHOENOLPYRUVATE (A THREE CARBON COMPOUND) IS CONVERTED TO OXALOACETATE (A FOUR CARBON MOLECULE). WHAT IS THE SOURCE OF THE ADDITIONAL CARBON ATOM?
Acetyl CoA
Carbon dioxide (CO2)
AMYLOPECTIN, A COMPONENT OF STARCH CONTAINS GLUCOSE UNITS BONDED TOGETHER BY(1→4) GLYCOSIDIC LINKS AND WHAT OTHER LINKAGE?
α(1→2) glycosidic links
α(1→6) glycosidic links
β(1→2) glycosidic links
β(1→6) glycosidic links
MALONATE IS TOXIC BECAUSE:
It competitively inhibits succinate dehydrogenase
It blocks the oxygen binding site in cytochrome c oxidase
It reacts with ATP
It prevents cell membranes from forming
IN CALVIN‟S “LOLLIPOP” EXPERIMENT TO INVESTIGATE THE INTERMEDIATES IN THE CALVIN CYCLE, THE FUNCTION OF THE BOILING ETHANOL WAS:
To provide a source of energy for the cells
To shield the cells from heat from the lights
To kill the cells so that the reaction was stopped
To separate the products on paper chromatography
THE CALVIN CYCLE USES WHICH REDOX COFACTOR?
NADP+
NADPH
NAD+
NADH
FATTY ACIDS ARE CARRIED IN THE BLOOD LARGELY:
In aqueous solution, not in complex with any other molecules
In complex with carbohydrates
In complex with cholesterol
In complex with proteins
CHOLESTEROL:
Has no effect on the fluidity of cell membranes
Can only increase the fluidity of cell membranes
Can only decrease the fluidity of cell membranes
Can increase or decrease the fluidity of cell membranes
ENZYMES:
Reduce the entropy associated with chemical reactions
Reduce the enthalpy associated with chemical reactions
Reduce the Gibb‟s free energy associated with chemical reactions
Reduce the activation energy associated with chemical reactions
KOSHLAND‟S INDUCED FIT MODEL FOR ENZYME-SUBSTRATE COMPLEX FORMATION:
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
CONSIDER AN ENZYME THAT SHOWS MICHAELIS-MENTEN ENZYME KINETICS, WHERE: Vo = Vmax . [S] / Km + [S] If a substrate, S, is present at a concentration of 2 mM, and Km is 1 mM, the rate of reaction (Vo) measured will be:
Half of Vmax
Two thirds of Vmax
Double Vmax
Three times Vmax
THE ENZYME-SUBSTRATE COMPLEX:
Is easily observed through Michaelis-Menten kinetic experiments
Is sometimes present in Michaelis-Menten kinetic experiments
Is a concept used to explain the results of Michaelis-Menten kinetic experiments
Is completely irrelevant to Michaelis-Menten kinetic experiments
IN ACID-BASE CATALYSIS:
An acidic- or basic- amino acid in the active site of an enzyme facilitates transition state formation by hydrogen abstraction from an appropriate substrate.
An acid- or basic- substrate in the active sit of an enzyme facilitates transition state formation by hydrogen abstraction from a catalytic amino acid in the active site.
Both are correct.
Neither are correct.
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 TERM „APPROXIMATION‟ HAS A SPECIFIC MEANING IN ENZYME CATALYSIS. THIS IS BEST DESCRIBED AS:
A catalytic mechanism that facilitates transition state formation by covalent interactions.
A catalytic mechanism that facilitates substrate-enzyme complex formation by covalent interactions.
A catalytic mechanism that facilitates transition state formation by non-covalent interactions.
A catalytic mechanism that facilitates substrate-enzyme complex formation by non-covalent interactions.
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.
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.
THE PROTEIN UBIQUITIN:
Can be covalently linked to proteins via the N-terminus glycine residue.
Is a polypeptide.
Is an essential component of eukaryote respiratory chains.
Can be covalently linked to proteins via isopeptide bond formation.
IF THE /_\G'° OF THE REACTION C D IS –20 kJ/mol, WHAT WILL HAPPEN IN THE PRESENCE OF A SPECIFIC ENZYME C-CONVERTASE UNDER STANDARD CONDITIONS?
The reaction will stop
The reaction will proceed spontaneously from left to right.
The reaction will never reach equilibrium.
The reaction will not occur spontaneously.
WHICH OF THE FOLLOWING IS AN EXERGONIC PROCESS?
Biosynthesis of NADPH
Transport of protons by respiratory chain
Oxygen reduction by cytochromec oxidase
Brain activity due to the thinking about this question
WHICH OF THE FOLLOWING STATEMENTS ABOUT MIDPOINT REDOX POTENTIALS IS INCORRECT?
Redox potentials can be used to calculate free energy changes
The strongest oxidants have the most negative potential.
Redox potential is measured in millivolts.
Oxygen reduction has a very high potential.
WHICH OF THE FOLLOWING REDOX COUPLE HAVE THE HIGHEST MIDPOINT REDOX POTENTIAL?
ubiquinol/ubiquinone
NADPH/NADP+
ferrocytochrome c/ferricytochrome c
H2O/½O2
WHICH OF THE FOLLOWING STATEMENTS ABOUT MITOCHONDRIAL ELECTRON TRANSPORT IS INCORRECT?
The inner mitochondrial membrane is positively charged on the inside.
The enzyme ATP-synthase can synthesise ATP.
Electron transfer to O2 is highly exergonic.
The proton motive force can be used for active transport.
WITH RESPECT TO BIOCHEMICAL PATHWAYS „BRANCHING POINTS‟ ARE:
Catalysts of the individual steps in a metabolic pathway.
Compounds which are intermediates between reactants and end products
Point at which an intermediate may proceed down one of several alternative pathways
Substrates involved in the metabolic pathway
WHICH ONE OF THE FOLLOWING IS METABOLISM NOT REQUIRED FOR:
acquisition and utilisation of energy
synthesis of molecules needed for cell structure and function
growth and development
binding of a hormone to a receptor
WHICH ONE OF THE FOLLOWING STATEMENTS IS TRUE FOR THE SYMPATHETIC NERVOUS SYSTEM?
It prepares us for strenuous muscular activity
It prepares us for relaxing (non-strenuous) activity
It is one of 3 autonomic nervous systems
It is a part of the endocrine system
CALCITONIN IS A HORMONE WHICH IS RELEASED FROM THE:
Thyroid gland
Parathyroid gland
Pituitary gland
Pancreas
DIABETES INSIPIDUS IS CAUSED BY:
A lack of insulin
A lack of ADH
A lack of oxytocin
An excess of insulin
PHOSPHOFRUCTOKINASE-1 ACTIVITY IS:
stimulated by citrate
inhibited by AMP
inhibited by citrate
inhibited by fructose 2,6-bisphosphate
GLYCOGEN SYNTHASE ACTIVITY IS:
inhibited by ATP
stimulated by fructose 2,6-bisphosphate inhibited by AMP
stimulated by fructose 1,6-bisphosphate
THE RAISED LEVELS OF LACTIC ACID IN MUSCLES AFTER ANAEROBIC EXERCISE IS:
caused by an increase in ATP levels in the muscle cell
caused by an increase in AMP levels in the muscle cell
due to pyruvate being oxidised by lactate dehydrogenase to allow recycling of NAD+ to NADH
due to pyruvate being reduced by lactate dehydrogenase to allow recycling of NADH to NAD+
PROTEIN KINASE A:
is activated by 5'AMP
phosphorylates glycogen phosphorylase
is activated by cyclic AMP
phosphorylates fructose bisphosphatase-1
THE GLYCEROL PHOSPHATE SHUTTLE:
is responsible for transferring NADH from the cytosol to the mitochondrion matrix
is responsible for transferring ATP from the cytosol to the mitochondrion matrix
transfers reducing potential from cytosolic NADH to the mitochondrion
transfers reducing potential from cytosolic ATP to the mitochondrion
