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IF WE WERE ABLE TO DETERMINE THE REACTIONS OF THE KREBS’ (TRICARBOXYLIC ACID) CYCLE FROM A WOOLLY MAMMOTH, WOULD YOU EXPECT THEM TO BE:
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Totally different from the ones found in humans, but similar to those in elephants
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Essentially the same as the ones found in both humans and elephants
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Totally different to the ones found in humans and elephants
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Similar to those in other extinct mammals, but very different from anything alive today
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AN END-PRODUCT CAN ACT TO INHIBIT AN ENZYME BY BINDING AT THE:
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Transitional site
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Active site
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Activation site
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Allosteric site
Frage 3
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THE SINGLE BIGGEST SIDE-EFFECT OF INSULIN THERAPY IS:
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A fear of needles
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Hyperactivity
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Hypoglycaemia
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Hyperglycaemia
Frage 4
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WHICH OF THE FOLLOWING IS A COMMON PHYSIOLOGICAL METHOD OF LOWERING BODY TEMPERATURE?
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Stimulation of the mitochondria in brown fat cells
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Rhythmic Stimulation of skeletal muscle
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Increased thyroid gland activity
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Accelerated respiration
Frage 5
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WHICH OF THE FOLLOWING STATEMENTS CONCERNING ENZYME CASCADES IS FALSE?
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They amplify and diversify signals of hormones such as cyclic AMP
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They are usually found in the extracellular space
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They often involve second messengers
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Multiple enzymes undergo conformational change and become activated
Frage 6
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WHICH OF THE FOLLOWING STATEMENTS CONCERNING STEROID HORMONES IS TRUE?
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They bind to cytoplasmic and/or nuclear proteins to form a hormone receptor complex
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They are transcription factors
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They bind and activate membrane-bound receptors
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They are hydrophilic compounds
Frage 7
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THE ENZYME-SUBSTRATE COMPLEX:
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Is a key concept that helps to explain how enzymes reduce activation energy for chemical reactions.
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Is a key concept that helps to explain how enzymes can reduce the Gibb’s free energy for a chemical reaction.
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Is a key concept that helps to explain how enzymes can exhibit diverse substrate specificity.
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Is a key concept that helps to explain how enzymes may exhibit Michaelis-Menton kinetics.
Frage 8
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CONSIDER AN ENZYME THAT SHOWS MICHAELIS-MENTON ENZYME KINETICS, WHERE:
Vo = Vmax . [S] / Km + [S]
If a substrate, S, is present at a concentration of 6 mM, and Km is 2 mM, the rate of reaction (Vo) measured will be:
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One third of Vmax
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Three times Vmax
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Three quarters of Vmax
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Six times Vmax
Frage 9
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AN OXYANION HOLE IS:
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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.
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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.
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A region of the active site that facilitates binding of positively charged oxygen-containing groups present in a substrate.
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A region of the active site that facilitates binding of negatively charged oxygen-containing groups present in a substrate.
Frage 10
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THE ENTHALPY CHANGE ASSOCIATED WITH A BIOCHEMICAL REACTION:
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Is a term used to describe the amount of randomness or disorder that results as the reaction proceeds
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Is a term used to describe the amount of ‘free energy’ change that results as the reaction proceeds
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Is a term used to describe the amount of heat that is produced or consumed as the reaction proceeds
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Is always determined at room temperature (25oC)
Frage 11
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ENZYMES USUALLY UTILISE ONE OR MORE TRANSITION METAL ATOMS AT THE ACTIVE SITE TO:
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Facilitate substrate binding
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Facilitate transition state formation
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Facilitate stabilisation of the tertiary structure
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Facilitate conformational changes in the protein during the catalytic cycle
Frage 12
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Reduce the entropy associated with chemical reactions
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Reduce the enthalpy associated with chemical reactions
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Reduce the Gibb’s free energy associated with chemical reactions
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Reduce the activation energy associated with chemical reactions
Frage 13
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THE TRANSITION STATE IN AN ENZYME-CATALYSED REACTION:
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Is always covalently associated to the enzyme.
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Is never covalently associated to the enzyme.
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Can never be observed experimentally.
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Can often be similar in structure to potent enzyme inhibitors.
Frage 14
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Are proteases that hydrolyse polypeptides with serine in the F1 position
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Are proteases that are found in the cytoplasm of all cells
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Utilise a serine residue at the active site to facilitate substrate binding
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Utilise a serine residue at the active site to facilitate cleavage of peptide bonds
Frage 15
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THE UBIQUITIN PROTEIN:
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Is only found in eukaryotic cells
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Is only found in bacterial cells
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Is a key component of the Urea cycle
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Is a key component of the Ubiquitin cycle
Frage 16
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Is completely located in the mitochondrial matrix.
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Facilitates 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.
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Facilitates 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.
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Is completely located in the cytoplasm of the cell – preventing the exposure of free ammonium to other components of eukaryote tissues.
Frage 17
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THE MOST COMMON FORM OF FRUCTOSE IN SOLUTION IS:
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A pyranose (six-membered) ring form
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A furanose (five-membered) ring form
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A straight chain, ketone form
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A straight chain, aldehyde form
Frage 18
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Have a hydrophobic aliphatic carbon chain and a hydrophilic carboxylic acid group
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Have a hydrophilic aliphatic carbon chain and a hydrophobic carboxylic acid group
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Have a hydrophobic aliphatic carbon chain and a hydrophobic carboxylic acid group
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Have a hydrophilic aliphatic carbon chain and a hydrophilic carboxylic acid group
Frage 19
Antworten
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A sterol
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A ketose monosaccharide
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A fatty acid
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A cofactor
Frage 20
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WHICH IF THESE MOLECULES IS COMMONLY INVOLVED IN CELL SIGNALLING AND RIBOSOMAL TRANSLOCATION?
Frage 21
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THE PRECURSORS FOR THE BIOSYNTHESIS OF SUCROSE ARE:
Frage 22
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TO DETERMINE THE IDENTITIES OF THE COMPOUNDS IN THE CALVIN CYCLE, MELVIN CALVIN USED:
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Nuclear magnetic resonance spectroscopy and chemical analysis
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Paper chromatography and mass spectrometry
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Paper chromatography and chemical analysis
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Chemical analysis and mass spectrometry
Frage 23
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TRIOSE PHOSPHATE ISOMERASE CATALYSES THE ATTAINMENT OF EQUILIBRIUM BETWEEN THE GLYCOLYTIC INTERMEDIATES GLYCERALDEHYDE 3-PHOSPHATE AND DIHYDROXYACETONE PHOSPHATE. UNDER THE CONDITIONS PREVAILING IN A HUMAN CELL, ON WHICH SIDE DOES THE EQUILIBRIUM LIE?
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It is not possible to know this from the information provided
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Dihydroxyacetone phosphate
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The equilibrium is approximately equally balanced
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Glyceraldehyde 3-phosphate
Frage 24
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CONSIDER TWO REACTIONS. REACTION 1 HAS A ΔG°′ VALUE OF -20 kJ.mol-1 AND REACTION 2 HAS A ΔG°′ VALUE OF -50 kJ.mol-1. WHICH REACTION PROCEEDS AT THE FASTEST RATE AT ROOM TEMPERATURE AND PRESSURE AND pH 7?
Frage 25
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IN GLYCOLYSIS, THE CONVERSION OF PHOSPHOENOLPYRUVATE TO PYRUVATE IS COUPLED TO:
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The phosphorylation of ADP to make ATP
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The phosphorylation of GDP to make GTP
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The reduction of NAD+ to make NADH
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The oxidation of NADPH to make NADP+
Frage 26
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IN YEAST UNDER ANAEROBIC CONDITIONS, ETHANOL IS PRODUCED AT THE END OF THE GLYCOLYTIC PATHWAY. WHY IS THIS ADVANTAGEOUS TO THE YEAST?
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It enables the regeneration of NAD+
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It enables it to produce more NADH
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A molecule of ATP can be produced from the reaction
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It helps the brewing industry
Frage 27
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UNDER ANAEROBIC CONDITIONS IN HUMANS, HOW MANY MOLECULES OF CARBON DIOXIDE (CO2) ARE PRODUCED BY THE METABOLISM OF ONE MOLECULE OF GLUCOSE BY GLYCOLYSIS AND SUBSEQUENT PATHWAYS?
Frage 28
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LACTOSE IS A DISACCHARIDE OF:
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Glucose and mannose
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Mannose and fructose
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Galactose and fructose
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Glucose and galactose
Frage 29
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THE COFACTOR FAD (FLAVIN ADENINE DINUCLEOTIDE) IS COMPOSED OF WHICH SUBUNITS?
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Flavin, ribose, adenine and three phosphates
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Flavin, two riboses, two adenines and a phosphate
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Flavin, two riboses, two adenines and two phosphates
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Flavin, ribose, adenine and two phosphates
Frage 30
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NADPH IS USED IN THE CALVIN CYCLE TO:
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Oxidise 1,3-bisphosphoglycerate
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Reduce 1,3-bisphosphoglycerate
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Oxidise ribulose 1,5-bisphosphate
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Reduce ribulose 1,5-bisphosphate
Frage 31
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IN GLUCONEOGENESIS, THE CORRECT SEQUENCE OF COMPOUNDS IN THE CONVERSION OF PYRUVATE TO PHOSPHOENOLPYRUVATE IS:
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Pyruvate → Oxaloacetate → Phosphoenolpyruvate
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Pyruvate → Lactate → Phosphoenolpyruvate
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Pyruvate → Succinate → Phosphoenolpyruvate
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Pyruvate → 1,3-bisphosphoglycerate → Phosphoenolpyruvate
Frage 32
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THE INCREASE IN ATP LEVELS THAT ACCOMPANIES THE "PASTEUR EFFECT" CAUSES:
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decreased glycolytic flux by allosteric stimulation of lactate dehydrogenase
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allosteric inhibition of fructose 1,6-bisphosphatase
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allosteric inhibition of phosphofructokinase-1
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increased glycolytic flux by allosteric activation of phosphofructokinase-2
Frage 33
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GLYCOGEN PHOSPHORYLASE IS:
Frage 34
Frage 35
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induces glycogen synthesis in the liver
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induces gluconeogenesis in the liver
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accelerates glyconeogenesis in the heart
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inhibits glycolysis in the heart
Frage 36
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GLYCOGEN PHOSPHORYLASE KINASE
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is activated by cAMP
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is activated by dephosphorylation
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is activated by autophosphorylation
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is activated by protein kinase A
Frage 37
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WHAT IS THE SOURCE OF ENERGY FOR ATP SYNTHESIS IN MITOCHONDRIA?
Frage 38
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WHAT IS THE OVERALL EQUATION FOR PHOTOSYNTHESIS?
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18 CO2+ 2 NADPH + 3 ATP + light → 2 NADPH + 3 Glucose-1-phosphate + 3 ADP + 18 O2
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2 H2O + 2 NADP+ + 3 ADP + 3 Pi + light → 2 NADPH + 2 H+ + 3 ATP + O2
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2 H2O + 2 NAD+ 2 Pi → 2 NADPH + 2 H+ + O2 + light
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CO2 + light + H2O → Glucose + O2
Frage 39
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WHICH OF THE FOLLOWING IS NOT A REDOX CENTRE FOR RESPIRATORY CHAIN?
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NADH
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Cytochrome c
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Oxygen
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FADH2
Frage 40
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THE OXYGEN MOLECULES RELEASED INTO THE AIR AS A PRODUCT OF PHOTOSYNTHESIS COMES FROM:
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Light quanta
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Cytochome c oxidase
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Water
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Carbon dioxide