Biochemistry
the study of the molecules
that make up living things
Organic Compounds

Molecules that contain both Carbon
and Hydrogen
such as…… CH4 or C6H5OH
Other Examples:
 Carbohydrates
 Lipids
 Proteins
 Nucleic acids (DNA, RNA)
Inorganic Compounds

Do not contain both carbon and
hydrogen
Examples:
 Carbon dioxide (CO2)
 Oxygen (O2)
 Water (H2O)
I. Carbohydrates
A. Functions
 major
source of energy for cells
 also used to construct cell structures
Dietary Sources of
Carbohydrates
Carbohydrates should make up
approximately 50% of daily calories
Dietary Sources of
Carbohydrates
Fiber
Starches
Sugar
B. Naming Carbohydrates

Most carbohydrate names end in “-ose”
C. Chemical Structure

All carbohydrates contain the elements
carbon (C), hydrogen (H) and oxygen (O)

The ratio of hydrogen to oxygen is 2:1

Carbohydrates have a “ring-like”
structure
Carbohydrate
C6H12O6
Types of Carbohydrates
1. Monosaccharides
“one sugar”
AKA :
(simple sugars)
Glucose Song

Click here to play video and song
All monosaccharides have the same
molecular formula:
C6H12O6
Examples of Monosaccharides

Glucose
also known as blood sugar/simple sugar

Fructose
◦ sweetest sugar
◦ found in honey, fruits

Galactose
less sweet – precursor to breast milk
Monosaccharides
 isomers: have the same molecular
formula, but different structural formulas

glucose, fructose and galactose are
isomers
Same number of atoms of each
molecule, different structure
ALL are…….. C6H12O6
2. Disaccharides
“two sugars”
General formula =
C12H22011
CAN YOU SEE WHAT WAS
LOST?????
2. Disaccharides
“two sugars”
Two monosaccharides chemically joined
together by a chemical reaction called
dehydration synthesis
Dehydration Synthesis

Dehydration:
to lose water

Synthesis:
to make
Dehydration Synthesis
Formation of a Disaccharide
Glucose
Fructose
H2O
Formation of a Disaccharide
Sucrose Glycosidic
Bond
Dehydration Synthesis

Animation of Dehydration Synthesis
Examples of Disaccharides
Sucrose - table sugar (sugar cane)
( Glucose and Fructose )

Examples of Disaccharides
Lactose -sugar present in milk
( Galactose and Glucose )

“Lactose Intolerance”
Individuals lack an enzyme (lactase) that
breaks down lactose
Examples of Disaccharides

Maltose : part of a larger carbohydrate
( Glucose and Glucose )
Breaks down with heat
Bread tastes sweeter after toasting
Flavoring for beer

How do we break down (digest) a
disaccharide?
ADD WATER
Hydrolysis

Opposite process of dehydration
synthesis

“Lyse” = to break

“Hydro” = water

Large molecules are digested by the
addition of water to break chemical
bonds
Hydrolysis Reactions
Hydrolysis
Hydrolysis

Animation of Hydrolysis
3. Polysaccharides (Complex
Carbohydrates)
“many sugars”----------POLYMER
Hundreds or thousands of monosaccharides
chemically joined together by dehydration
synthesis
Examples of Polysaccharides
 Cellulose
 Starch
 Glycogen
 Chitin
Examples of Polysaccharides
 Cellulose
Gives plant cell walls a rigid
structure
Humans cannot digest it → fiber
Cows, goats have bacteria in their
gut that digest cellulose
Examples of Polysaccharides
 Starch
Stored form of sugar in plants
Examples of Polysaccharides
 Glycogen
Stored form of sugar in liver, muscle of
animals
Examples of Polysaccharides
 Chitin
Makes up exoskeleton of insects,
crustaceans
II. Lipids

Include fats, oils, waxes, steroids
II. Lipids

Video TED-ED Fats
A. Functions
1. Stored form of energy
(More then Carbohyrates)
2. Used to form cell membranes
3. Transport fat-soluble vitamins
(A, D, E, K)
Functions
4. Provide essential fatty acids for the
synthesis of hormones
5. Cushions vital organs (heart, kidneys,
liver)
6. Insulation for body to conserve heat
B. Chemical Structure of Fatty Acid
and Lipids
1.
Contain the elements carbon, hydrogen
and oxygen in a linear structure, and
are long
1.
Ratio of H:O is greater than 2:1
2.
Have a carboxyl group( COOH ) at
an end of chain.
B. Chemical Structure of Fatty Acid
and Lipids
B. Chemical Structure of Fatty Acids
and Lipids
Triglycerides are a type of lipid
formed by dehydration synthesis of one
molecule of glycerol and three fatty
acids
Glycerol
A simple sugar alcohol compound, that is
the backbone to triglycerides
 Used to make triglycerides in human liver
and adipose (Fat Cells)

Triglyceride
Dehydration Synthesis of a
Lipid/Triglyceride
Dehydration Synthesis of a Lipid

Animation of formation of Triglyceride
How many H2O molecules are formed
during this process?
Why?
Triglyceride
During digestion, glycerol is split from fatty acids and may
recombine with them to form stored fat
Chemical Structure of Lipids
4. Phospholipids make up cell membranes
and are produced by dehydration
synthesis of one glycerol with 2 fatty
acids and one phosphate group
Phospholipids
Saturated Fats
•
Usually from animal sources
•
Solid at room temperature
•
Include butter, bacon, cheese, egg yolk
•
Diets high in saturated fats increase the
risk for cardiovascular disease
Unsaturated Fats



from plant sources
liquid at room temperature
consumption can decrease the risk of
cardiovascular disease

Describe the difference between these
two fats?
Types of Unsaturated Fats
a.

Monounsaturated Fats: olive oil
Have one double bond between
carbon atoms
Types of Unsaturated Fats
b.
Polyunsaturated Fats: soybean,
safflower oils; fish oils

Have two or more double bonds
between carbon atoms
3. Trans Fats (Hydrogenated Fats)
Food Manufacturers convert unsaturated
vegetable oils to saturated fats, making
them solid, by adding hydrogen
 Very unhealthy type of fat.
Protein Song
III. Protein
Tens of thousands of different proteins
make up the human body
 Each protein has a unique 3-dimensional
structure that corresponds to a specific
function
 Proteins perform most of the jobs the
body needs to function

A. Functions

Make up structures of the body and
individual cells (structural proteins)

Used to move substances throughout the
body and into and out of cells
(transport proteins)
A. Functions

Used to make Antibodies (chemical
defense)

To form Hormones

To form Enzymes ( needed for all
chemical reactions
B. Chemical Structure

Proteins are made up of the elements:
carbon (C)
hydrogen (H)
oxygen (O)
nitrogen (N)
Proteins are nitrogenous compounds:
they contain the element: nitrogen
Proteins are polymers

Proteins are made up of building blocks
(monomers) called amino acids
Amino acids each consist of a central
carbon atom with:
-COOH (carboxyl group)
-NH2 (amino group)
-H (hydrogen atom)
-R (functional group – different for each of
the 20 different amino acids)

Both lipids and amino acids have carboxyl
groups
There are 20 different amino acids in humans, each
differing in their functional group (R)

12 of the amino acids can be synthesized
by the human body (infants can make 11)
► nonessential amino acids

The other 8 amino acids must be obtained
from the diet
► essential amino acids
Dipeptide: 2 amino acids joined
together by dehydration synthesis
Animation

dehydration synthesis to form a dipeptide
Peptide Bond
Which arrow points to the peptide
bond???

A peptide bond forms when 2 amino
acids are chemically joined
100 or more amino acids joined
together = polypeptide
Amino Acids

Monomers (building blocks) that make up
proteins

Proteins are polymers
Are carbohydrates polymers???
 Are lipids polymers???

Protein Structure

The structure or shape of a protein is
important for its function. The
directions come from DNA
Protein Structure

Structure defines function and is very
specific!!!!
Primary Structure of a Protein
Is the linear sequence of amino acids
The Code (directions) for
making proteins comes from
DNA.
It is the (R) group of one amino acid
that interacts with another amino acid
that give a protein its shape
It might be a positive charge, a negative
charge, hydrophobic or hydrophilic

Primary
structure
5
1
15
10
30
35
20
25
45
– The specific
sequence of
amino acids in a
protein
40
50
55
65
60
70
85
80
75
95
90
100
110
105
115
120
125
129
Figure 3.21
Amino acid

A slight change in the primary structure of a
protein affects its ability to function
– The substitution of one amino acid for another in
hemoglobin causes sickle-cell disease
1
2
(b) Sickled red blood cell
6
7. . . 146
4
5
Normal hemoglobin
(a) Normal red blood cell
1
3
2
3
6
7. . . 146
4
5
Sickle-cell hemoglobin
Figure 3.22
Protein Shape

Proteins have four levels of structure
1. Primary Structure – Single Chain
1. Secondary Structure: Alpha Helix or Beta
Pleated Sheet – These are formed by
HYDROGEN BONDING
1. Tertiary Structure – Formed by other chemical
bonds of functional groups
1. Quaternary Structure – Two or more
polypeptides put together
Figure 3.23
Protein Shape

Proteins have four levels of structure
Hydrogen bond
Pleated sheet
Polypeptide
(single subunit)
Amino acid
(a) Primary structure
Complete
protein,
with four
polypeptide
subunits
Hydrogen bond
Alpha helix
(b) Secondary
structure
(c) Tertiary
structure
(d) Quaternary structure
Figure 3.23

Protein Video
What affects Protein Structure?

A protein’s shape is sensitive to the surrounding
environment
– Unfavorable temperature and pH changes can cause
a protein to unravel and lose its shape
– The protein is then said to have Denatured and it
does not function at all.
Temperature
reaction rate
human
enzymes/protein
37°
temperature
Each enzyme/protein works best within a narrow
pH range

DNA is a Polymer – made up of
thousands of repeating units called
nucleotides

Nucleotide:
1. Phosphate Group
2. Deoxyribose (5-carbon sugar) molecule
3. Nitrogenous Base
Important: The bases are held together
by Weak Hydrogen Bonds

Molecules Gone Wild