The cis and trans GroEL rings undergo conformational changes in a reciprocating fashion, with events in one ring influencing events in the other ring. The entire GroEL/ES chaperonin complex functions as follows;

a) One GroEL ring that has bound 7 ATP also binds an improperly folded substrate protein, which associates with hydrophobic patches that line the inner wall of the GroEL chamber

b) The GroES cap then binds to the GroEL ring like a lid on a pot, inducing a conformational change in the resulting cis ring

c) Within ~10 s the cis ring catalyzes the hydrolysis of its 7 bound ATPs and releases the resulting Pi , which weakens the interactions binding GroES to GroEL

d) A second molecule of improperly folded substrate protein binds to the cis ring, followed by 7 ATP

e) The binding of substrate protein and ATP to the cis ring conformationally induces the trans ring to release its bound GroES, 7 ADP, and the presumably now better-folded substrate protein

Which of the following is incorrect functions of GroEL/ES chaperonin complex?

#Question id: 638

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the following class of enzymes with them

#Question id: 637

#Unit 1. Molecules and their Interaction Relevant to Biology

Effect of temperature on enzymatic catalysis is analysed by the rate v of a chemical reaction varies with temperature according to the Arrhenius Equation which explains the sensitivity of enzyme reactions to temperature. A plot to determination of the activation energy Ea involves

#Question id: 636

#Unit 1. Molecules and their Interaction Relevant to Biology

DNA polymerase contains a lysine residue that is important for binding to DNA. Mutations were found that converted this lysine to either glutamate, glycine, valine, or arginine. Which mutations would be predicted to be the most and least harmful to the ability of the enzyme to bind DNA?

#Question id: 635

#Unit 1. Molecules and their Interaction Relevant to Biology

The enymatic rate constant (kcat/Km) of orotidine 5ʹ-phosphate decarboxylase is 6 x 10⁷ M^-1s^-1 and the nonenzymatic rate constant (kn) is 3 x 10^-16 s^-1.  What is the value of the enzymeʹs catalytic proficiency?

#Question id: 634

#Unit 1. Molecules and their Interaction Relevant to Biology

An enzyme has a Vmax of 50 micromol product formed (minute x mg protein)-1 and a Km of 10 microM for the substrate. When a reaction mixture contains the enzyme and 5 microM substrate, which of the following percentages of the maximum velocity will be closest to the initial reaction rate?

#Question id: 633

#Unit 1. Molecules and their Interaction Relevant to Biology

An amino acid transporter protein is responsible for the transport of a specific amino acid across a membrane. The KI values of several competitive inhibitors of the amino acid transporter are shown above. Based on these data, which of the following is most likely the amino acid transported by this protein?