Biochemistry 2

=multiplechoice1. Cellulose and starch are both polymers of

=multiplechoice2. In naturally occurring proteins

A) Amino acids are in the L form

B) Amino acids are in the D form

C) An equal mixture of L and D form amino acids occur

D) All amino acids are hydrophobic

E) All nucleotides are of the A type

=multiplechoice . Tryptophan, tyrosine and phenylalanine

A) Are all hydrophilic amino acids

B) Are the building blocks of DNA

C) Absorb light in the UV region of the spectrum

D) Have glycosidic linkages

E) Are carbohydrate compounds

=multiplechoicePeptide bonds

Link amino acids in protein and have free rotation

Are partial double bonds with free rotation

Link the building blocks of RNA

Link amino acids and have partial double bond character

Are the bond responsible for making glucose ring structures

=multiplechoiceThe predominant lipid responsible for formation of a lipid bilayer is

=multiplechoiceThe backbone of the strands in a DNA in the double helix are maintained at a fixed distance from each other because

A) The distance from C-1’ to C-1’ of the GC base pair is the same as the distance from C-1’ to C-1’ of the AT base pair

B) The distance from C-1’ to C-1’ of the AC base pair is the same as the distance from C-1’ to C-1’ of the GT base pair

C) The distance from C-1’ to C-1’ of the GC base pair is the same as the distance from C-1’ to C-1’ of the AU base pair

D) Of the presence of an extra hydroxyl group on the ribose sugar

E) Of the process of transcription

=multiplechoiceThe isoelectric point (pI) of a protein is the pH

A) At which the protein structure is optimal for its particular function

B) At which the molecule is negatively charged and dissolves in alkali

C) At which the molecule is uncharged and so loses solubility in water

D) At which the protein is hydrolysed into its component amino acids

E) At which all proteolytic enzyme activity is prevented

=multiplechoice A simple enzyme

A) Has only one substrate

B) Catalyses only lyase reactions

C) Contains only protein

D) Has a heme prosthetic group

E) Does not lower the energy of activation

=multiplechoice In terms of enzyme catalysis, an active site is

A) The bond in the substrate which the enzyme acts on

B) A pocket or region on the enzyme with which the substrate interacts

C) The chiral carbon of an amino acid

D) The C or N terminal end

E) The part of zymogen that is removed to release the active enzyme

=multiplechoice A competitive inhibitor of an enzyme

A) Forms an irreversible interaction with the enzyme

B) Binds to a different region of the enzyme from the substrate and changes the apparent Vmax

C) Binds to a different region of the enzyme from the substrate and changes the apparent KM

D) Binds to the same region of the enzyme as the substrate and changes the apparent Vmax

E) Binds to the same region of the enzyme as the substrate and changes the apparent KM

=multiplechoice The formation of a blot clot requires

=multiplechoice Active transport of Na+ across the biological membrane

A) Involves direct contact with the lipid core of the membrane

B) Requires energy

C) Can only happen down a gradient of Na+ ions

D) Generates ATP from creatine phosphate

E) Requires Troponin C

=multiplechoice Contraction of skeletal muscle happens when

A) Calcium is release from the sarcoplasmic reticulum

B) Tropomyosin covers the myosin binding sites on actin

C) The S1 heads of actin tilt and release repeatedly

D) Troponin C binds creatine phosphate

E) G-actin dissociates from F-actin

=multiplechoice The refractive zone in nerve stimulation is

A) Due to the action of a Na+/K+ ATPase

B) Sequestering of Ca2+ ions into the sarcoplasmic reticulum

C) A hyperpolarisation due to K+ export from the cell

D) Ligand-gated channel closing

E) Active transport of a substance into the cell

=multiplechoice Which of the following compounds is a common second messenger in hormone action?

=multiplechoice Which two cellular processes are simultaneously regulated by adrenalin?

A) Amino acid uptake and protein synthesis

B) Glycogen breakdown and glycogen synthesis

C) Fat synthesis and glucose breakdown

D) Gluconeogenesis and fat breakdown

E) Oxidation and reduction reactions

=multiplechoice Acetyl CoA is a substrate in

A) Glycolysis and ligand gated channels

B) The ribosomes

C) The Kreb’s cycle and fat synthesis

D) Conversion of glucose to glucose-6-phosphate

E) Synthesis of mRNA by RNA polymerase

=multiplechoiceTransport of electrons across the mitochondrial membrane by the respiratory redox chain

A) Occurs during anaerobic respiration

B) Is critical for gluconeogenesis

C) Only occurs in the sarcoplasmic reticulum

D) Is responsible for the relay of signal along an axon

E) Provides the energy for ATP synthesis by the F1F0-ATPase

Which of these electron transport and oxidative phosphorylation system components can pass directly to molecular oxygen?

=multiplechoiceThe activity of the respiratory redox chain

A) Results in the export of glucose from the mitochondria

B) Generates proton motive force

C) Stimulates production of cAMP

D) Occurs during the production of lactic acid

E) Stimulates phosphorylation of MAPK in the Ras signalling cascade

=multiplechoiceA hydrolase is a enzyme which

A) Transports water through the lipid bilayer

B) Transfers phosphate groups from one molecule to another

C) Transfers carboxyl groups onto pyruvate

D) Participates in oxidative reactions, for example alcohol dehydrogenase

E) Breaks covalent bonds using water, for example a protease

Biochemistry 2

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