BIOCH200 Lecture Notes - Lecture 2: Chemical Polarity, Activation Energy, Reaction Mechanism

58 views3 pages

skycaribou653

24 Nov 2017

School

University of Alberta

Department

Biochemistry

Course

BIOCH200

Professor

Jonathan Parrish

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

They take part through amino acids, co- factors, or both: stabilizing the transition state: binding to transition state aids to decrease the activation energy (g++). Parts of protein interact with transition state and enzyme active site binds to transition state better than they bind to the substrate: defi(cid:374)e the ter(cid:373) (cid:862)a(cid:272)ti(cid:448)e site. (cid:863) A small portion of the protein, where the substrate binds, and catalysis occurs. Determines the affinity, specificity and rate of enzyme activity: describe how substrates bind in the active site with specificity and relatively high affinity. Design of the active site allows it to bind with substrate. It is like a key fitting a lock. Like polar groups in the active side or groups that can participate in acid-base reactions: defi(cid:374)e the ter(cid:373) i(cid:374)du(cid:272)ed fit. Some enzymes change shape when substrate binds like closes off active side to exclude more water, and bring catalytic groups together: e(cid:454)plai(cid:374) (cid:449)hat is (cid:373)ea(cid:374)t (cid:271)(cid:455) the (cid:862)pro(cid:454)i(cid:373)it(cid:455) a(cid:374)d orie(cid:374)tatio(cid:374)(cid:863) effe(cid:272)t.

Related Questions

Can have multiple right answers, or none:

Enzymes

	a.	Alter the activation energy barrier for the reaction
	b.	Always form covalent bonds with their
	c.	Reduce the overall free energy change for the reaction
	d.	Can provide proton donors or acceptors to catalyze a reaction

Enzymes catalyze reactions by

	a.	Increasing the temperature and pressure within the micro-environment of the active site
	b.	Stabilizing the transition state of the reaction
	c.	Increasing the affinity for the reaction product(s)
	d.	Bringing multiple substrates into proximity with each other

QUESTION 6

Examples of chiral centers in biomolecules include:

	a.	The C alpha of leucine
	b.	The C alpha of glycine
	c.	The third C of the glycerol backbone of a phopholipid
	d.	The anomeric carbon of glucose in its cyclic form

33-To stabilize the transition state complex, which of the following must be lowered? A) Initial energy state B) Activation energy C) Net energy change D) The Vmax B) Final energy state 34- Which of the following statements about allosteric enzymes is CORRECT? A The binding of substrate to any active site affects the other active sites B The plot of initial velocity vs. substrate concentration is a straight line C The Keq of the reaction is increased when allosteric activator is bound D The enzymes contains only one polypeptide chain E Allosteric activators bind to all active sites equally 35. Which statement about the two different models proposed to explain enzyme specificity is CORRECT. a. The substrate changes shape when enzyme binds in the Lock and Key Model. b. The enzyme undergoes a covalent modification when bound to substrate in the Lock and Key Model. c. The active site of the enzyme alternates in conformation between opened and closed in the Induced Fit Model. d. The enzyme changes conformation after binding the substrate in the Induced Fit Model. eÂ·The product structure is altered after it has bound to the enzyme in the Induced Fit Model. 36. An enzymatic reaction proceeds with maximal velocity (Vmax) when A. the substrate concentration is equal to that of a competitive inhibitor. B. allosteric effectors are present. C. the enzyme substrate complex is maximal. D. the substrate concentration exceeds that of a noncompetitive inhibitor. E. all of the substrate is bound to the enzyme. 37. Which of the statements below are incorrect? A With all other factors that modify the rate of the enzyme catalyzed reaction remaining constant as we raise the temperature of an enzyme catalyzed reaction there is an initial increase of velocity with temperature. B. The rate of reaction increases with temperature because there is an increasing number of molecules with sufficient energy to pass over the energy barrier which we call the energy of activation C. Reaction rate increases with temperature until a maximum is reached, when the rate of the reaction will suddenly suddenly fall to zero because the enzyme will be denatured and therefore inactive. D. The reaction rate initially increases as temperature rises owing to increased kinetic energy of the reacting molecules E. Enzymes in crease reaction rates due to their ability to lower the energy barriers for reactions F. None of the above 38- Which of the following is true for the induced fit theory of enzyme action? A. The conformation of the substrate changes before binding to the enzyme. B. The active site changes shape during binding of the substrate C. The substrate fits into a preformed active site through a lock-and-key mechanism. D. Enzymes alternate between conformations where the active site is either open or closed. E. The substrate causes a cleft to form in the enzyme where it subsequently binds

BIOCH200 Lecture Notes - Lecture 2: Chemical Polarity, Activation Energy, Reaction Mechanism

Document Summary

Get access

Related Documents

BIOCH200 : BIOCH 200 studyGuide pt2.docx

BIOCH200 Lecture Notes - Lecture 17: Drug Design, Nucleophile, Heme

BIOCH200 Lecture Notes - Lecture 14: Oxyanion, Ion, Glyceraldehyde 3-Phosphate Dehydrogenase

Related Questions