The glycolytic pathway in dinosaurs
Was likely to be completely different to modern day animals, because every organism has different metabolic pathways
Was likely to be completely different to modern day organisms because they eat different types of food
Was likely to be similar or identical to modern day organisms, because metabolic pathways have been highly conserved through evolution
Is something we cannot make meaningful predictions about because we have no knowledge of how metabolism has evolved
In thin layer chromatography, ninhydrin can be used to stain which compounds?
Monosaccharides
Amino acids
Keto acids
All of the above
Which of the following lists contains the components of a phospholipid?
Choline, phosphate group, glycerol, fatty acids
Choline, phosphate group, glyceraldehyde, fatty acids
Carnitine, phosphate group, glycerol, amino acids
Carnitine, phosphate group, glyceraldehyde, amino acids
Testosterone belongs to which class of compounds?
Fats
Oils
Ketose monosaccharides
Sterols
Which of the following passes easily through phospholipid bilayers?
Chloride ions
ATP
Glucose 6-phosphate
Water
Peripheral membrane proteins
Pass through the cell membrane
Are non-covalently associated with integral membrane proteins
Are covalently linked to membrane lipids
Are always linked to sugars
Which of the following fatty acids is likely to have the highest melting temperature?
One with 14 carbon atoms and no double bonds
One with 14 carbon atoms and one double bond
One with 16 carbon atoms and no double bonds
One with 16 carbon atoms and one double bond
In the furanose ring form of β-D-fructose, how many of the carbon atoms are chiral?
0
2
4
6
Cellulose is a polymer of
α-D-glucose units only
β-D-glucose units only
α-D-glucose and β-D-fructose units
β-D-glucose and α-D-fructose units
In catabolic (degradative) reactions in humans, the most commonly used oxidising cofactors are
NAD+ and FAD
NADP+ and FAD
NADH and FADH2
NADPH and FADH2
Considering only the glycolytic pathway, what is the net gain in ATP molecules, per molecule of glucose processed?
1
Under anaerobic conditions, glycolysis in mammals can result in the compound lactose. Why?
To make ATP by substrate level phosphorylation
To regenerate NAD+
To make NADH for oxidative phosphorylation
To replenish Krebs’ (tricarboxylic acid) cycle intermediates
Which of the following statements about gluconeogenesis is TRUE?
Glucose is generated from the hydrolysis of phosphate from glucose 6-phosphate. No ATP is produced in this reaction.
Glucose is generated from the hydrolysis of phosphate from glucose 6-phosphate. One molecule of ATP is produced in this reaction.
In mammals, acetyl coenzyme A (AcCoA) can be a starting point.
The reactions are exactly the same as glycolysis, except in reverse.
Isomerisation of glucose 1-phosphate to glucose 6-phosphate occurs in
Glycolysis and gluconeogenesis
Glycogen synthesis and degradation
Glycolysis and the Leloir pathway
The Leloir pathway and glycogen degradation
In the Calvin cycle, carbon dioxide reacts with ribulose 1,5-bisphosphate. The first product(s) of this reaction is/are:
Two molecules of 3-phosphoglycerate
Two molecules of glyceraldehyde 3-phosphate
One molecule of glucose 6-phosphate
One molecule of fructose 6-phosphate
In Calvin’s experiments to identify the compounds in the Calvin cycle, the function of the hot ethanol was
To shield the algae from the heat of the lamps
To provide a source of carbon atoms for the algae
To kill the algae after a defined time point
To solublise the compounds in the algae
The main source of energy for sperm cells is
Glucose
Fatty acids
Glycerol
Fructose
The transition state in an enzyme-catalysed reaction:
Is always covalently associated to the enzyme.
Is never covalently associated to the enzyme.
Can never be observed experimentally.
Can often be similar in structure to potent enzyme inhibitors.
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.
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 de-amination 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 de-amination 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.
Serine proteases:
Are proteases that hydrolyse polypeptides with serine in the F1 position
Are proteases that are found in the cytoplasm of all cells
Utilise a serine residue at the active site to facilitate substrate binding
Utilise a serine residue at the active site to facilitate cleavage of peptide bonds
Consider an enzyme that shows Michaelis-Menton kinetics where: vo = Vmax . [S] / (Km + [S]) If a substrate, S, is present at a concentration of 4 mM, and Km is 2 mM, the rate of reaction (vo) measured will be:
Half of Vmax
Two thirds of Vmax
Double Vmax
Three times Vmax
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 site 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 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.
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.
If the ΔG°′ of the reaction Malate → Oxaloacetate is +30 kJ/mol, what will happen in the presence of malate dehydrogenase under standard conditions?
The reaction will proceed fast with the formation of the explosive products.
The reaction will not occur spontaneously.
The reaction will never reach equilibrium.
The reaction will proceed spontaneously from left to right.
Which of the following redox couple have the highest midpoint redox potential?
ubiquinol/ubiquinone
NADH/NAD+
H2O/½O2
ferrocytochrome c/ferricytochrome c
What is the source of energy for ATP synthesis in mitochondria?
AMP, ADP and inorganic phosphate
Gradient of Na+ across the inner mitochondrial membrane
Matrix fumarase and aconitase
None of the above
Which of the following cannot reduce mitochondrial respiratory chain in normal conditions?
NADH
Oxygen
FADH2
Ubiquinol
The oxygen molecules released into the air as a product of photosynthesis comes from:
Light quanta
Cytochome c oxidase
Carbon dioxide
Production of lactic acid in anaerobic muscle cells is:
Caused by breakdown of glycogen
Caused by a buildup of AMP
Coupled to the recycling of NAD+ to NADH by lactate dehydrogenase when it oxidises pyruvate
Due to pyruvate being reduced by lactate dehydrogenase while it recycles NADH to NAD+
Phosphofructokinase-1 activity is:
Inhibited by fructose 2,6-bisphosphate
Inhibited by AMP
Inhibited by citrate
Stimulated by citrate
The Warburg effect:
Is the inhibition of glycolysis that occurs in anaerobic cells when exposed to oxygen
Is the continued use of anaerobic fermentation by cancer cells even in the presence of oxygen
Is caused by an over-active glycerol phosphate shuttle in cancer
Is due to the inhibition of phosphofructokinase-1 by AMP
Glycogen synthase activity is:
Inhibited by ATP
Stimulated by glucose 6-phosphate
Stimulated by fructose 1,6-bisphosphate
Which of the following is NOT true of Aldosterone?
It is a mineralocorticoid
It is a peptide hormone
It is a steroid hormone
It is released in response to angiotensin II
Calcitonin is a hormone that is released from:
The pituitary gland
The thyroid gland
The hypothalamus
The parathyroid gland
Which of the following is NOT a feature of metabolic pathways?
Sequential feedback inhibition
Common intermediate metabolites
The presence of aquaporins
End product inhibition
Which of the following is NOT true of the anabolic hormone insulin?
It increases glycogen synthesis
It increases fatty acid synthesis
It increases esterification of fatty acids
It increases protein breakdown (proteinolysis)
Which of the following has NOT been a commercial method for the synthesis of artificial human insulin?
Separate A- and B-chain synthesis in E. coli
Phage display in E. coli
Pro-insulin synthesis in E. coli
Biosynthesis in brewer’s yeast (Saccharomyces cerevisiae)
