Class Notes (1,100,000)
CA (620,000)
UofM (6,000)
BIOL (1,000)
BIOL 1020 (300)
Lecture 13

BIOL 1020 Lecture 13: October 3rd 2014.docx


Department
Biological Sciences
Course Code
BIOL 1020
Professor
J.Stacey
Lecture
13

This preview shows pages 1-2. to view the full 8 pages of the document.
October 3rd 2014
Lecture 12 Enzymes, Intro to cellular respiration
Did you get it?
A short Answer Question…
Describe the free energy changes involved in endergonic and exergonic
reactions. How do enzymes affect these reactions?
A chemical reaction that has a G of +3.5 kcal/mol. What does this
indicate?
A. The activation energy is 3.5 kcal/ mol.
B. It is an exergonic reaction.
C. The reactants have 3.5 kcal/mol energy.
D. The products have 3.5 kcal/mol energy.
E. The reaction requires a net input of 3.5 kcal/mol.
Some Enzymes work in forward and reverse directions
There are different Forms of Some Enzymes that assist different reactions
 Can only work in one way

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Regulation of enzyme activity
Activity: total amount of reactant converted to product (over time)
oNumber of enzyme molecules: genes
Activity of each enzyme molecule
opH, temp etc.
oconcentrations of substrates and products
oinhibitors and activators
Factors that affect enzyme activity:
A. cofactors – help enzymes
non-protein enzyme helpers
organic cofactor is called a coenzyme e.g. vitamins
inorganic (such as a metal in ionic form)
oEg magnesium needed for hexokinase
oForms complex with ATP
B. Inhibitors
Competitive inhibitors
oBind to the active site
oSubstrate cannot bind
Non- competitive inhibitors
oNot binding to active site
oBind to an allosteric site (not active site)
Cytosolic Version of enzyme
Mitochondrial version of
enzyme
You're Reading a Preview

Unlock to view full version

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

oCauses a change in the enzyme shape
oSubstrate cant bind to active site
Many drugs are enzyme inhibitors
Allosteric regulation of enzyme activity:
Activators
Increase the activity of enzyme
Allosteric activator binds to allosteric regulatory site
Regulation of enzyme activity
Substrate can activate the enzyme by stabilizing it
Regulation of metabolic pathways: feedback inhibition
Products of pathways are not always needed
End products of pathways can start to build up
End product of sometimes the intermediate of a pathway can inhibit an enzyme
in the pathway that produced it
oThis can prevent the waste of chemical resources
You're Reading a Preview

Unlock to view full version