BIBC 102 Exam 1A KEY

BIBC 102 Exam 1A KEY - Metabolic Biochemistry Summer Session 2010 Midterm Exam(360 points EXAM A Section 1DO THIS PART OF THE EXAM FIRST 1(12 pts

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Metabolic Biochemistry KEY Summer Session 2010 Midterm Exam (360 points) EXAM A Section 1—DO THIS PART OF THE EXAM FIRST 1) (12 pts.) Answer the following questions regarding this amino acid: a. What class of amino acids, based on its R-group, does this amino acid belong to: Polar , uncharged b. Circle the alpha-carboxyl group in this amino acid. 2) (6 pts.) For the chemical reaction: A B k 2 k 1 Define the forward velocity of the reaction in terms of the rate constant (assume the reverse velocity is negligible). V = k 1 [A] 3) (6 pts.) For the chemical reaction: A + B C + D Define the equilibrium constant in terms of equilibrium concentrations of reactant and product. k 1 k 2 K eq = [C][D] [A][B] 4) (12 pts.) Enzymes affect which of the following for the reactions they catalyze (check all that apply: (3 pts. each checked or unchecked) a. the rate constant X b. the equilibrium constant ___ c. the standard free energy of activation ( ) X d. the standard free energy change ( G’°) ____ 5) (15 pts.) G’° for a chemical reaction is large and positive. For each item below, indicate whether they are true (T) or false (F) for this reaction. (3 pts. each) a. The reaction is exergonic F b. The reaction is endergonic T c. K eq < 1 T d. K eq = 1 F e. The reaction is favorable F
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6) (6 pts. each) Tell whether each statement below regarding enzyme reaction mechanisms is true (T) for false (F). a. Electrons must be transferred between the substrate and amino acid side chains of the enzyme active site for a reaction to be catalyzed ( i.e. , a redox reactions are an inherent part of any catalytic mechanism). F b. Amino acid substitutions that disrupt the reaction mechanism of an enzyme will decrease . F c. The stable, longer-lived intermediate that occurs during the reaction mechanism of chymotrypsin is referred to as the acyl-enzyme intermediate. T d. The substrate or intermediates never actually become covalently bonded to the active site of the enzyme during a catalytic reaction mechanism. F e. When cleavage of ATP is used to power an endergonic reaction, hydrolysis takes place in the enzyme active site to remove the -phosphate, and the energy released is transferred to the substrate. F 7) (12 pts.) It is common for amino acids that form the active site of an enzyme to have side chains that participate in the reaction mechanism. List one amino acid whose R-group commonly participates in reaction mechanisms and draw the structure of the R-group only. (6 pts. each for amino acid and R-structure) Most common: serine --CH 2 OH Other good answers cysteine –CH 2 SH histidine, glutamic acid, aspartic acid (see text for structure) Not acceptable any hydrophobic, non-polar amino acid 8) (25 pts.) Which of the following describe a competitive inhibitor? Check all that apply. (5 pts. each checked or unchecked)
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/19/2010 for the course BIBC BIBC 102 taught by Professor Price during the Summer '08 term at UCSD.

Page1 / 9

BIBC 102 Exam 1A KEY - Metabolic Biochemistry Summer Session 2010 Midterm Exam(360 points EXAM A Section 1DO THIS PART OF THE EXAM FIRST 1(12 pts

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online