Download Biochemistry and Enzymes - St. John the Baptist Diocesan High

 Biochemistry
is the study of
the chemical reactions that
occur within living things
 Our bodies are made up of
different types of chemicals
and molecules that all react
with each other in unique
ways
 These reactions are the fuel
for all of our life processes!

All organic molecules MUST
contain the following three
elements:

Carbon, Hydrogen, and Oxygen
The key element of life is
CARBON
 Carbon can form many bond
with itself (single, double,
triple, and rings)
 We identify FOUR types of
organic molecules:





Carbohydrates
Lipids
Proteins
Nucleic Acids
Does not contain carbon,
hydrogen, and oxygen all
at the same time
 Has some of these
elements, but not all
 Examples:

Water- makes up 60-98% of
living things
 Salts- helps maintain water
balance
 Acids and Bases- pH scale,
important for enzyme
function

 Carbohydrates
are sugars and complex
carbohydrates (called starches)
 Contain only carbon, hydrogen and oxygen
 In all carbohydrates, hydrogen is in a 2:1
ratio to oxygen

Example: Glucose = C6H12O6

Hydrogen = 12, oxygen = 6
 Most

carbohydrates end with the prefix: OSE
Example: Glucose, Maltose, Lactose, Sucrose
 Considered
a simple sugar
 They all have the formula: C6H12O6
 They all have a single ring structure
 Examples: Glucose, Fructose, Galactose
 Considered
a double sugar
 They all have the formula: C12H22O11
 Have a double ring structure
 Examples: Sucrose (table sugar), Lactose,
Maltose
 Made
up of three or more simple sugars
 Three examples:



Starch: How plants store excess glucose, used as
an energy source for humans
Glycogen: Animal starch, stored in liver and
muscles
Cellulose: Indigestible in humans, forms cell wall
in plants
 Dehydration



Synthesis:
Dehydrate = to LOSE water
Synthesize = to make
So dehydration synthesis means combining simple
molecules to form a more complex one with the
REMOVAL of water
 Example:

Hydrolysis:
Hydro = Water
 Lysis = To Cut
 So, hydrolysis means
breaking down larger
molecules into smaller one,
with the ADDITION of water

Also called: Chemical
Digestion
 Examples: Disaccharide +
Water  Monosaccharide
+ Monosaccharide

ANIMATION
 They
are opposite reactions to each other!
 Lipids
are also called fats
 Contain the elements: carbon, hydrogen, and
oxygen
 Hydrogen and oxygen are NOT in a fixed
ratio: that is specific to carbohydrates
 Three



functions of lipids
Energy Storage
Protection (your brain is covered in fat)
Insulation (keeps you warm)
 Lipids
tend to be the largest of the organic
molecules. They carry more energy than
carbohydrates, but they are not utilized to
make ATP during respiration because they are
too difficult and too large to break down
 Lipids also make up cell membranes!
 Lipids
are composed of one glycerol molecule
and three fatty acids
 Dehydration
synthesis adds each fatty acid to
the glycerol molecule
 Hydrolysis is used to break them down
Saturated fats are solids at
room temperature
 They typically come from
animals
 They are solids because all
of the bonds between
carbon atoms in the fatty
acid tails are SINGLE bonds,
so each lipid molecule is
able to pack together very
tightly
 Examples: butter, cheese,
Crisco

 Liquids
at room temperature
 Typically come from plants
 They are liquids because at least one of the
bonds between the carbon atoms in the
fatty acid tail is a DOUBLE bond. This
causes a kink in the chain, so lipid molecules
cannot pack together as tightly.
 Examples: vegetable oil, olive oil
Contain the elements: carbon, hydrogen,
oxygen, and nitrogen
 Made in the ribosomes
 Composed of small subunits call amino acids



Contain an amino group (NH3) and a carboxyl group
(COOH)
Main functions of proteins are growth, repair,
and energy
A
molecule composed of three or more amino
acids is called a polypeptide
 The chemical bond between two amino acids
is called a peptide bond
 Dehydration
synthesis joins two amino acids
together to form a DIPEPTIDE
There are 20 different amino acids
 These 20 amino acids can be joined together in
countless different combinations and sizes (like
the 26 letters of the alphabet)
 This accounts for the large number of different
types of proteins that exist!

 Organic
molecule that
carries genetic
information

Examples: DNA, RNA
 Contains
the elements:
carbon, hydrogen,
oxygen, nitrogen, and
phosphorus
 Composed of small
subunits called
nucleotides
 Each



nucleotide is composed of:
A Sugar
A Phosphate Group
A Nitrogen Base
1.
What is the difference between an organic
and an inorganic molecule?
Organic = Must contain elements
carbon, hydrogen, and oxygen
Inorganic = Contains two of the
three elements, but not all three
at the same time
2.
What organic molecule is composed of
hydrogen and oxygen in a 2:1 ratio?
Carbohydrate
1.
What is the difference between
dehydration synthesis and hydrolysis?
Dehydration Synthesis creates larger
molecules from smaller ones with the
REMOVAL of water
Hydrolysis breaks down larger molecules
into smaller ones with the ADDITION of
water
 Is
the following molecule a monosaccharide,
disaccharide, or a polysaccharide?
Disaccharide
 What
type of organic molecule is shown
below?
Lipid
Is this lipid saturated or un saturated?
Saturated
A
catalyst is a substance that speeds up the
rate of a chemical reaction, without entering
the reaction itself
 Catalysts can be


Inorganic- heat
Organic- enzymes
 Most
catalysts are organic!
 An
enzyme is an organic catalyst made of
proteins
 Most enzymes end in –ase
 Enzymes work by lowering the activation
energy of chemical reactions. This means it
lowers the amount of energy needed to start
a chemical reaction, so it occurs faster!
 Example: lipases breaks down lipids,
proteases break down proteins
Enzymes act on molecules
called substrates
 Enzymes fit into their
substrates like a lock fits into
a key- it is VERY SPECIFIC
 This is called the lock and
key model
 The active site is the pocket
within an enzyme where the
substrate fits
 Typically, enzymes are larger
than their substrates

Animated Introduction
to Enzymes
 1.
Enzyme joins with substrate
 2. Enzyme and substrate fit together like a
lock and key, forming an enzyme-substrate
complex
 3. Enzyme action takes place
 4. Enzyme and products separate. The
enzyme is unchanged and can be reused!
 Enzymes
can be very picky! They only work
under very specific conditions.
 The following factors all affect the rate
(speed) in which an enzyme will work:



pH
Temperature
Concentration of enzymes and substrates
 The
pH scale measures how acidic and basic
a solution is
 A pH value less than 7 is considered acidic
 A pH value greater than 7 is considered basic
 Water is considered neutral, with a pH of 7
 Different
enzymes work
at different pH’s
 Pepsin, an enzyme that
breaks down proteins,
works best at a pH of 2.
Why?
 Amylase, an enzyme that
breaks down
carbohydrates, works
best at a pH of 6.8. Why?
 Typically,
as temperature
increases, enzyme action
also increases
 All enzymes have an
optimum temperature, or
a temperature at which the
enzyme is most effective
 Optimum temperature for
humans is 98.6⁰F
 Optimum temperature for
dogs is 101-102⁰F
 When
temperatures are too high, enzymes
begin to change shape
 When an enzyme changes shape it is called a
denatured enzyme
 If an enzyme changes shape, it can no longer
fit with its substrate, so it cannot function
 As
concentration of both the enzyme and the
substrate increases, the rate of enzyme
action increases to a certain point, and then
it will level off
 If
the concentration of the enzyme increases,
reaction rate will initially increase.
However, as all of the substrate is broken
down, the excess enzymes have nothing to
combine with, so reaction rate levels off.
 If the concentration of the substrate
increases, reaction rate will initially
increase. However, as all of the enzyme is
used up, the excess substrates then have
nothing to combine with, so reaction rate
levels off.
 What
is an enzyme?
An organic catalyst that speeds up
the rate of a chemical reaction.
 How
does it work?
It works by lowering the activation
energy of a chemical reaction.
 What
is the lock and key model of enzyme
action?
All enzymes fit into their substrates
in a very specific manner. They fit
like a lock and key.
 What
are three factors that affect the rate
of enzyme action?
Temperature, pH, concentration