Biochemistry

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Biochemistry
An Introduction to the Chemistry of
Life for Biology Students
Organic Chemistry
 Organic chemistry is the study of Carbon
compounds.
 Organic compounds are compounds
composed primarily of a Carbon
skeleton.
 All living things are composed of organic
compounds.
Organic Chemistry
 What makes Carbon Special? Why is
Carbon so different from all the other
elements on the periodic table?
 The answer derives from the ability of
Carbon atoms to bond together to form
long chains and rings.
Organic Chemistry
Carbon can form immensely
diverse compounds, from simple
to complex.
Methane with 1 Carbon
atom
DNA with tens of Billions of
Carbon atoms
Biochemistry
 Biochemistry is a special branch of
organic chemistry that deals with matter
inside the living cell called Protoplasm.
 Protoplasm is an enormously complex
mixture of organic compounds where
high levels of chemical activity occur.
Biochemistry
 How much
biochemistry do you
need to know for this
course?
 1. You need to know
the structure of
organic molecules
important to major
biological processes.
2. You will be
expected to learn
the basic
biochemical
processes of
major cell
functions, such as
photosynthesis,
respiration, and
protein synthesis.
Primary Organic
Compounds
You are expected to
learn the structure
and functions of
these organic
compounds:
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
Polymers ands Monomers
 Each of these types of molecules are
polymers that are assembled from single
units called monomers.
 Each type of macromolecule is an
assemblage of a different type of
monomer.
Monomers
Macromolecule
Carbohydrates
Monomer
Monosaccharide
Lipids
Proteins
Not always polymers;
Hydrocarbon chains
Amino acids
Nucleic acids
Nucleotides
How do monomers form
polymers?
 In condensation reactions (also called
dehydration synthesis), a molecule of
water is removed from two monomers as
they are connected together.
Hydrolysis
 In a reaction opposite to condensation, a
water molecule can be added (along with
the use of an enzyme) to split a polymer
in two.
Carbohydrates
 Carbohydrates are made of carbon,
hydrogen, and oxygen atoms, always in a
ratio of 1:2:1.
 Carbohydrates are the key source of
energy used by living things.
 The building blocks of carbohydrates are
sugars, such as glucose and fructose.
Carbohydrates
 What do the roots
mono-, di-, and poly
mean?
 Each of these roots
can be added to the
word saccharide to
describe the type of
carbohydrate you
have.

How do two monosaccharides
combine to make a
polysaccharide?

Polysaccharides
Lipids, also known as fats
 The structure of a fat is that of a threecarbon glycerol molecule with up to three
long chains of hydrogens and carbons
called, hydrocarbons. The fatty acid tails
are the long hydrocarbon chains. Lipids
are NONpolar and do not dissolve in
water.
What Are Fats?
 Fats are important for your body because they
insulate your nerve cells, balance your hormones,
protect you from cold, keep the skin and arteries
supple and also lubricate your joints. Fats contain
a little more that twice as much energy as
carbohydrates and proteins.
 Humans store fat just below the skin to help
insulate the body from cold weather and to store
energy in case of famine. Some scientists believe
that prehistoric humans often faced times of famine
and may have evolved to crave fat.
Pure fats are found in three broad areas:
vegetable oils (corn oil, peanut oil, olive
oil and nuts), meats (the white layer
which outlines the cut of meat), and dairy
products (butter, margarine, mild and
cheese).
The type of fatty acids within each
specific type of fat determines the
character of the fat including how healthy
it is. Carbon bonds determine the type of
fatty acid.
Saturated vs. Unsaturated
Fat
 Carbon atoms are able to make chemical bonds with up to
four other atoms. Each carbon in the fatty acid tail is bond to
two other carbons, one in front of it and one behind it in the
hydrocarbon chain. When a particular carbon is doublebonded to one of these carbons, it can only make one other
bond to a hydrogen. When the carbon is single-bonded to the
carbon on either side of it, it can make bonds with two
hydrogen atoms. Saturated fats are bonded to as many H as
possible, unsaturated fats have double carbon bonds so are
not saturated with hydrogen.
Unsaturated Fats
Unsaturated fats have double-bonded carbons, so
each carbon can only bond to one hydrogen.
These fats are “kinked” and cannot pack tightly.
Unsaturated fatty acids remain liquid at room
temperature. Unsaturated fats are considered
good fats because of the lower cholesterol
content. They usually come from plants sources,
like olive oil.
Saturated Fats, the Bad
Fats
 Saturated fats , which do not have carbon-carbon
bonds and so can pack tightly together, make a
solid structure at room temperature. Avoid fatty
meat because they are rich in saturated fat, which
stimulates the production of cholesterol and can
lead to clogged arteries (and a greater chance of
a heart attack).
Hydrogenated Fats
 If it needs to be solidified, it has to be
hydrogenated, or saturated with hydrogen
by breaking the carbon double bonds and
attaching hydrogen. Commercial food
manufacturers sometimes do this to retard
spoilage and solidify liquid oils. Some of
these manufactured fats are trans-fatty
acids, common in fast foods. These fats
are NOT healthy fats.
Saturated vs. Unsaturated
 By virtue of their tightly packed structure,
the saturated fatty acids increase
the levels of bad cholesterol (LDL) and
clog the arteries. On the other hand, the
unsaturated fatty acids increase
the levels of good cholesterol (HDL) by
taking the LDL to the liver to be broken
down and removed from the body.
Proteins
 Proteins are building blocks of structures
called amino acids. Proteins are what
your DNA codes to make. A peptide bond
forms between amino acids by
dehydration synthesis.
Levels of Protein
Structure

Protein Structure
Level
Primary
Secondary
Description
The amino acid
sequence
Helices and Sheets
Disulfide bridges
Tertiary
Quaternary
Multiple polypeptides
connect
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