Chapter 8 Metabolism Enzymes Notes

Chapter 8
An Introduction to Metabolism
• Metabolism is the sum of all chemical reactions in
your body.
• If a reactions breaks things down, it is catabolic
• If a reaction builds things up, it is anabolic
• Energy is the capacity to cause change.
• Energy of motion is kinetic energy
• Energy that is stored is potential energy
• Potential energy that is released during a chemical
reaction is chemical energy
Energy is released or
• In an exergonic reaction energy is
• When you break things down, you
release energy
• All catabolic reactions are exergonic
• Cellular respiration is exergonic.
• These are spontaneous reactions
• Delta G (a measure of free energy)
is negative
Energy is released or
• In an endergonic reaction energy is
• When you build things, you need
• All anabolic reactions are endergonic
• Photosynthesis is endergonic
• These are non-spontaneous reactions
• Delta G is positive
Making and breaking bonds
• Making bonds is called dehydration synthesis. You
take away water to make a new bond.
• Breaking bonds is called hydrolysis. You add water
to break a bond.
Introducing ATP
• ATP is adenosine triphosphate
• It is composed of a nitrogenous
base called adenine, a ribose
sugar, and a chain of 3
phosphate groups
• Energy is stored in the bonds
between the phosphate groups.
• When a bond is broken between
the Ps, it releases energy
• To get the energy,
hydrolysis occurs to
break off 1 P, turning
ATP into ADP
• During cellular
respiration, energy
from food is used to
add the P back on to
ADP to make more
• Enzymes are proteins. They are catalysts that speed
up chemical reactions by lowering the amount of
energy needed for those reactions to start (activation
Enzyme terms
• The thing an enzyme binds
to and acts on is called the
• The place where the enzyme
binds is the active site.
• Enzymes are specific and
only fit to their own substrate
like a key into a lock
• Enzymes are reusable and
are used over and over
Factors affecting enzymes
• 1. Temperature
• 2. pH
• 3. Salinity
Factors affecting enzymes
• Some enzymes need helpers:
• Cofactors are INORGANIC and bind to the
enzymes to make them work (zinc, iron, copper,
• Coenzymes are ORGANIC and bind to the enzyme
to make them work (vitamins)
Factors affecting enzymes
• Inhibitors block enzyme action
• Competitive inhibitors bind to
the active site of the substrate so
that the enzyme can’t get in
• Non-competitive inhibitors bind
somewhere on the substrate,
changing the shape of the active
site, so enzymes no longer fit
Related flashcards
Protein kinases

20 Cards

Enzyme inhibitors

36 Cards

EC 3.1

12 Cards


14 Cards

Create flashcards