Download Chemical Reactions and Enzymes Notes

2-4 Chemical Reactions and Enzymes
• Chemical Reaction – a process that
changes one set of chemicals into another.
• Products – elements & compounds that
are produced by a reaction
• Reactants – elements & compounds that
enter into a reaction.
Reactants
Products
Energy in Reactions
• Exergonic Reactions - some chemical
reactions release energy
– Happen spontaneously
– Ex: HCl + Zn
H + ZnCl
• Endergonic Reactions - some chemical
reactions absorb energy
– Will not occur without a source of energy
– H2 + O H2O
– Activation Energy: the energy needed to start a
chemical reaction.
Exergonic vs. Endergonic
• “Uphill” reaction
• Requires Energy
(Activation Energy)
• Absorbs Energy
• “Downhill” reaction
• Spontaneous
• Releases Energy
Enzymes
• Catalyst – a substance that speeds up a
chemical reaction by lowering the
activation energy.
• Enzymes – are proteins that act as a
biological catalyst.
Enzyme Action
Substrate
Active Site
Enzyme
Substrate – the reactants of an enzyme catalyzed
reaction
Active Site – where the substrate and enzyme join.
– Have complimentary shapes
– Can only bind with a specific molecule – “induced fit”
Animation
Regulation of Enzyme Activity
• Enzymes work best at certain pH levels
and temperatures.
– Most enzymes in humans work best at 37 C
• Denaturation – a change in the enzymes
Animation
shape.
– Enzyme becomes nonfunctional
– Heat and pH can cause denaturation
• Some enzymes can be turned on and off
– Lactose intolerance
Graphic Organizer Assignment
Use the large sheet of paper provided to create graphic
organizers as follows:
1. T-Chart – Use Functional groups and list structure vs.
what the group makes (e.g. alcohol, acid, ketone etc.)
2. Spider Map – Use “enzyme” for the center circle and
elaborate on information related to enzymes from
there.
3. Venn Diagram – Compare and contrast endergonic
and exergonic reactions, include a graph of each type
4. Vocabulary Word Map – Use “organic molecules” to
start, then list carbohydrates, lipids, proteins and
nucleic acids. Add vocab related to these four classes
of organic molecules. Draw at least one structure for
each of the four classes.
Y axis
B
A
C
D
X axis
1.
2.
3.
4.
5.
What letter represents the product?
What letter represents the reactant?
What letter represents the activation energy?
How should the x and y axis be labeled?
Is the reaction exergonic or endergonic?
Explain
Vocab for 2nd constructed response:
Enzyme – a protein that is a catalyst (speeds up a chemical reaction)
Reactants – compounds that enter a reaction
Products – compound produced by a reaction
Substrate – reactant(s) that join with enzyme
Active site – where enzyme and substrate join
Denatured – a change in the enzyme’s shape
Structure (shape) and function - enzymes must have the right shape
to work properly
Othe Factors that affect enzyme function:
Temperature
pH
Concentration of enzyme