Transcript PowerPoint 14 – Enzymes

Why is it important to eat protein?
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Your body needs 20 different amino acids
to make all the necessary proteins
Your body is only able to produce 12 of
these amino acids on its own
The other 8 amino acids come from foods
you eat that contain protein (meat, nuts,
dairy products, beans, etc.) – These are
called essential amino acids because you
cannot survive without eating them
The bottom line about DNA…
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No DNA = No Protein = No Cells = No Life
Reproduction is all about passing DNA
from one cell to another and from one
generation of organisms to the next
Note Sheet 14 - Enzymes
What is an enzyme?
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Enzyme – a type of protein that helps chemical
reactions in a living thing start and happen
quickly
Catalyst – something that makes things happen
and/or speeds things up
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Enzymes are catalysts, they catalyze chemical
reactions (they make reactions happen)
Enzyme Facts
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Almost all processes in a cell need enzymes to
occur at significant rates
Most enzyme reaction rates are millions of times
faster than those of comparable un-catalyzed
reactions
Enzymes are known to catalyze about 4,000
biochemical reactions
Many drugs and poisons are enzyme inhibitors
Reactions happen faster with
enzymes
Pepsin
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Ex. Pepsin is an
enzyme in your
stomach that helps you
break down proteins
into amino acids
Lactase
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Ex. Lactase is an
enzyme that breaks
down the sugar
lactose into more
easily digestible
substances
Helicase
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Ex. Helicase is
an enzyme that
“unzips” DNA
by breaking
the hydrogen
bonds in
between the
base pairs
What is an enzyme?
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Since enzymes are proteins, the
instructions to build all enzymes are in an
organism’s DNA
Organisms could not survive without
enzymes – they make things happen
How does an enzyme work?
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Each enzyme is specially built to either bring
specific substances together making a new
substance, or to break substances apart
How does an enzyme work?

Each enzyme is specially built to either bring
specific substances together making a new
substance, or to break substances apart
How does an enzyme work?

Each enzyme is specially built to either bring
specific substances together making a new
substance, or to break substances apart
How does an enzyme work?

Each enzyme is specially built to either bring
specific substances together making a new
substance, or to break substances apart
Lysozyme splitting a large molecule into
smaller molecules
The Importance of Enzymes
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Since the tight control of enzyme activity is
essential for maintaining a balanced
environment inside cells, any malfunction
(mutation, overproduction, underproduction or
deletion) of a single critical enzyme can lead to a
genetic disease
The importance of enzymes is shown by the fact
that a lethal illness can be caused by the
malfunction of just one type of enzyme out of
the thousands of types present in our bodies
Enzyme Inhibiting Poison
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Alpha-amanitin, which is
found in relatives of the
death cap mushroom, is a
potent enzyme inhibitor
It prevents the RNA
polymerase II enzyme
from transcribing DNA
which brings about cell
death
Enzyme Inhibiting Poison
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Individuals who have ingested mushrooms with
alpha-amanitin may not be aware for some time
that they have eaten a poison mushroom
because symptoms may not appear until 6 to 12
hours, or even as late as 48 hours
First symptoms include sharp abdominal pain,
nausea, vomiting and watery diarrhea or bloody
stools. There is usually great thirst.
By the 3rd or 4th day, jaundice, renal shutdown,
convulsions, and coma occur. Symptoms such as
dilated pupils, stiffness of neck, and twitching of
facial muscles precede convulsions and death