Biochemistry MCQs- August 11

Question 1

Question

IF WE WERE ABLE TO DETERMINE THE REACTIONS OF THE KREBS’ (TRICARBOXYLIC ACID) CYCLE FROM A WOOLLY MAMMOTH, WOULD YOU EXPECT THEM TO BE:

Answer

Totally different from the ones found in humans, but similar to those in elephants
Essentially the same as the ones found in both humans and elephants
Totally different to the ones found in humans and elephants
Similar to those in other extinct mammals, but very different from anything alive today

Question 2

Question

AN END-PRODUCT CAN ACT TO INHIBIT AN ENZYME BY BINDING AT THE:

Answer

Transitional site
Active site
Activation site
Allosteric site

Question 3

Question

THE SINGLE BIGGEST SIDE-EFFECT OF INSULIN THERAPY IS:

Answer

A fear of needles
Hyperactivity
Hypoglycaemia
Hyperglycaemia

Question 4

Question

WHICH OF THE FOLLOWING IS A COMMON PHYSIOLOGICAL METHOD OF LOWERING BODY TEMPERATURE?

Answer

Stimulation of the mitochondria in brown fat cells
Rhythmic Stimulation of skeletal muscle
Increased thyroid gland activity
Accelerated respiration

Question 5

Question

WHICH OF THE FOLLOWING STATEMENTS CONCERNING ENZYME CASCADES IS FALSE?

Answer

They amplify and diversify signals of hormones such as cyclic AMP
They are usually found in the extracellular space
They often involve second messengers
Multiple enzymes undergo conformational change and become activated

Question 6

Question

WHICH OF THE FOLLOWING STATEMENTS CONCERNING STEROID HORMONES IS TRUE?

Answer

They bind to cytoplasmic and/or nuclear proteins to form a hormone receptor complex
They are transcription factors
They bind and activate membrane-bound receptors
They are hydrophilic compounds

Question 7

Question

THE ENZYME-SUBSTRATE COMPLEX:

Answer

Is a key concept that helps to explain how enzymes reduce activation energy for chemical reactions.
Is a key concept that helps to explain how enzymes can reduce the Gibb’s free energy for a chemical reaction.
Is a key concept that helps to explain how enzymes can exhibit diverse substrate specificity.
Is a key concept that helps to explain how enzymes may exhibit Michaelis-Menton kinetics.

Question 8

Question

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:

Answer

One third of Vmax
Three times Vmax
Three quarters of Vmax
Six times Vmax

Question 9

Question

AN OXYANION HOLE IS:

Answer

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.

Question 10

Question

THE ENTHALPY CHANGE ASSOCIATED WITH A BIOCHEMICAL REACTION:

Answer

Is a term used to describe the amount of randomness or disorder that results as the reaction proceeds
Is a term used to describe the amount of ‘free energy’ change that results as the reaction proceeds
Is a term used to describe the amount of heat that is produced or consumed as the reaction proceeds
Is always determined at room temperature (25oC)

Question 11

Question

ENZYMES USUALLY UTILISE ONE OR MORE TRANSITION METAL ATOMS AT THE ACTIVE SITE TO:

Answer

Facilitate substrate binding
Facilitate transition state formation
Facilitate stabilisation of the tertiary structure
Facilitate conformational changes in the protein during the catalytic cycle

Question 12

Question

ENZYMES:

Answer

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

Question 13

Question

THE TRANSITION STATE IN AN ENZYME-CATALYSED REACTION:

Answer

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.

Question 14

Question

SERINE PROTEASES:

Answer

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

Question 15

Question

THE UBIQUITIN PROTEIN:

Answer

Is only found in eukaryotic cells
Is only found in bacterial cells
Is a key component of the Urea cycle
Is a key component of the Ubiquitin cycle

Question 16

Question

THE ALANINE CYCLE:

Answer

Is completely located in the mitochondrial matrix.
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.
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.
Is completely located in the cytoplasm of the cell – preventing the exposure of free ammonium to other components of eukaryote tissues.

Question 17

Question

THE MOST COMMON FORM OF FRUCTOSE IN SOLUTION IS:

Answer

A pyranose (six-membered) ring form
A furanose (five-membered) ring form
A straight chain, ketone form
A straight chain, aldehyde form

Question 18

Question

FATTY ACIDS:

Answer

Have a hydrophobic aliphatic carbon chain and a hydrophilic carboxylic acid group
Have a hydrophilic aliphatic carbon chain and a hydrophobic carboxylic acid group
Have a hydrophobic aliphatic carbon chain and a hydrophobic carboxylic acid group
Have a hydrophilic aliphatic carbon chain and a hydrophilic carboxylic acid group

Question 19

Question

TESTOSTERONE IS:

Answer

A sterol
A ketose monosaccharide
A fatty acid
A cofactor

Question 20

Question

WHICH IF THESE MOLECULES IS COMMONLY INVOLVED IN CELL SIGNALLING AND RIBOSOMAL TRANSLOCATION?

Answer

Question 21

Question

THE PRECURSORS FOR THE BIOSYNTHESIS OF SUCROSE ARE:

Answer

UDP-glucose and fructose 6-phosphate
UDP-fructose and glucose 6-phosphate
UDP-glucose and fructose
UDP-fructose and glucose

Question 22

Question

TO DETERMINE THE IDENTITIES OF THE COMPOUNDS IN THE CALVIN CYCLE, MELVIN CALVIN USED:

Answer

Nuclear magnetic resonance spectroscopy and chemical analysis
Paper chromatography and mass spectrometry
Paper chromatography and chemical analysis
Chemical analysis and mass spectrometry

Question 23

Question

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?

Answer

It is not possible to know this from the information provided
Dihydroxyacetone phosphate
The equilibrium is approximately equally balanced
Glyceraldehyde 3-phosphate

Question 24

Question

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?

Answer

Reaction 1
Reaction 2
They both occur at much the same rate
It is not possible to know this from the data provided

Question 25

Question

IN GLYCOLYSIS, THE CONVERSION OF PHOSPHOENOLPYRUVATE TO PYRUVATE IS COUPLED TO:

Answer

The phosphorylation of ADP to make ATP
The phosphorylation of GDP to make GTP
The reduction of NAD+ to make NADH
The oxidation of NADPH to make NADP+

Question 26

Question

IN YEAST UNDER ANAEROBIC CONDITIONS, ETHANOL IS PRODUCED AT THE END OF THE GLYCOLYTIC PATHWAY. WHY IS THIS ADVANTAGEOUS TO THE YEAST?

Answer

It enables the regeneration of NAD+
It enables it to produce more NADH
A molecule of ATP can be produced from the reaction
It helps the brewing industry

Question 27

Question

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?

Answer

Question 28

Question

LACTOSE IS A DISACCHARIDE OF:

Answer

Glucose and mannose
Mannose and fructose
Galactose and fructose
Glucose and galactose

Question 29

Question

THE COFACTOR FAD (FLAVIN ADENINE DINUCLEOTIDE) IS COMPOSED OF WHICH SUBUNITS?

Answer

Flavin, ribose, adenine and three phosphates
Flavin, two riboses, two adenines and a phosphate
Flavin, two riboses, two adenines and two phosphates
Flavin, ribose, adenine and two phosphates

Question 30

Question

NADPH IS USED IN THE CALVIN CYCLE TO:

Answer

Oxidise 1,3-bisphosphoglycerate
Reduce 1,3-bisphosphoglycerate
Oxidise ribulose 1,5-bisphosphate
Reduce ribulose 1,5-bisphosphate

Question 31

Question

IN GLUCONEOGENESIS, THE CORRECT SEQUENCE OF COMPOUNDS IN THE CONVERSION OF PYRUVATE TO PHOSPHOENOLPYRUVATE IS:

Answer

Pyruvate → Oxaloacetate → Phosphoenolpyruvate
Pyruvate → Lactate → Phosphoenolpyruvate
Pyruvate → Succinate → Phosphoenolpyruvate
Pyruvate → 1,3-bisphosphoglycerate → Phosphoenolpyruvate

Question 32

Question

THE INCREASE IN ATP LEVELS THAT ACCOMPANIES THE "PASTEUR EFFECT" CAUSES:

Answer

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

Question 33

Question

GLYCOGEN PHOSPHORYLASE IS:

Answer

inhibited by phosphorylation
activated by phosphorylation
activated by glucose
inhibited by AMP

Question 34

Question

PROTEIN KINASE A:

Answer

is an allosteric enzyme
phosphorylates phosphorylase kinase
phosphorylates glycogen phosphorylase
is activated by ADP

Question 35

Question

ADRENALINE:

Answer

induces glycogen synthesis in the liver
induces gluconeogenesis in the liver
accelerates glyconeogenesis in the heart
inhibits glycolysis in the heart

Question 36

Question

GLYCOGEN PHOSPHORYLASE KINASE

Answer

is activated by cAMP
is activated by dephosphorylation
is activated by autophosphorylation
is activated by protein kinase A

Question 37

Question

WHAT IS THE SOURCE OF ENERGY FOR ATP SYNTHESIS IN MITOCHONDRIA?

Answer

ADP and inorganic phosphate
Gradient of NADH across the inner mitochondrial membrane
Matrix aconitase
None of the above

Question 38

Question

WHAT IS THE OVERALL EQUATION FOR PHOTOSYNTHESIS?

Answer

18 CO2+ 2 NADPH + 3 ATP + light → 2 NADPH + 3 Glucose-1-phosphate + 3 ADP + 18 O2
2 H2O + 2 NADP+ + 3 ADP + 3 Pi + light → 2 NADPH + 2 H+ + 3 ATP + O2
2 H2O + 2 NAD+ 2 Pi → 2 NADPH + 2 H+ + O2 + light
CO2 + light + H2O → Glucose + O2

Question 39

Question

WHICH OF THE FOLLOWING IS NOT A REDOX CENTRE FOR RESPIRATORY CHAIN?

Answer

NADH
Cytochrome c
Oxygen
FADH2

Question 40

Question

THE OXYGEN MOLECULES RELEASED INTO THE AIR AS A PRODUCT OF PHOTOSYNTHESIS COMES FROM:

Answer

Light quanta
Cytochome c oxidase
Water
Carbon dioxide

	Created by MatthewEllis96 almost 6 years ago

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Biochemistry MCQs- August 11

Description

Resource summary

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18

Question 19

Question 20

Question 21

Question 22

Question 23

Question 24

Question 25

Question 26

Question 27

Question 28

Question 29

Question 30

Question 31

Question 32

Question 33

Question 34

Question 35

Question 36

Question 37

Question 38

Question 39

Question 40

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