BIOCHEMISTRY
Basic Chemistry and the
Chemical Compounds of Life
Regents Biology
OBJECTIVES
Upon completion of this unit students will be able to:
1. Define biochemistry.
2. Differentiate empirical, molecular and structural formulas.
3. List the 4 most common elements found in living things.
4. Explain the differences between inorganic and organic compounds.
5. Understand that water is the most important inorganic compound for organisms.
6. State the functions of carbohydrates.
7. Understand that monosaccharides (i.e., glucose) is the building block for all carbohydrates.
8. Recognize the chemical formula for carbohydrates and chemical structure of glucose.
9. List several examples of carbohydrates.
10. Recognize that most carbohydrates end in –ose.
11. Explain the difference between a ribose sugar and a deoxyribose sugar.
12. Differentiate between a monosaccharide, disaccharide, and polysaccharide.
13. List three examples of polysaccharides and state their functions.
14. State the functions of lipids in the body.
15. Understand that a lipid molecule is made up of 3 fatty acids and 1 glycerol molecule.
16. List several examples of lipids.
17. Identify the two types of nucleic acids.
18. Differentiate DNA and RNA by structure and function.
19. Understand that amino acids are the building blocks of proteins.
20. Recognize the chemical formula and structure of an amino acid.
21. State that the chemical bond that links one amino acid to another is called a peptide bond and
that two amino acids combined is called a dipeptide.
22. Explain what is meant by a dipeptide and a polypeptide and explain how they are formed.
23. List five examples of polypeptides.
24. Explain in a sentence or two why there are so many possible kinds of proteins.
25. Recognize that a protein structure determines its function.
26. Understand the structure and function of an enzyme and that they usually end in –ase.
KEY WORDS
1. active site
2. amino acid
3. amino group
4. carbohydrates
5. catalyst
6. dehydration
synthesis
7. dipeptide
8. disaccharide
9.
10.
11.
12.
13.
14.
15.
16.
DNA
enzyme
hydrolysis
lipid
monosaccharides
nucleic acid
nucleotide
organic compound
17.
18.
19.
20.
21.
22.
23.
24.
peptide bond
polymer
polypeptide
polysaccharide
protein
RNA
starch
substrate
INTRODUCTION
• The processes of life (metabolism, excretion, etc.)
are, for the most part, CHEMICAL, and obey the same
laws of chemistry that nonliving things do.
• There are only about 100 different ATOMS AND
ELEMENTS, which is what matter is made up of.
Examples of these are CARBON, HYDROGEN, etc.
• Biochemistry is THE STUDY OF ATOMS AND
MOLECULES THAT ARE IMPORTANT FOR LIFE
• The CHEMICAL basis of many biological
processes is now understood,for example:
1. How the cell synthesizes proteins under the
direction of DNA:
• DNA  RNA  Proteins
2. The 3-D structure of proteins dictates their
function.
3. The double helix structure of DNA.
• Advances in BIOCHEMISTRY will allow scientists
of tomorrow to find the answers to some of the more
challenging questions in biology and medicine today,
for example:
1. What is the cure for cancer and AIDS?
2. How do we map the human genome?
3. How do we map the human brain in order to fully
CHEMICAL ELEMENTS and FORMULAS
• Remember that CELLS are the basic unit of life? Well, cells as well
as everything nonliving in this world, are made up of ATOMS of
elements.
• There are 3 different ways to express the amount or ratios of atoms
present in a molecule:
o Empirical formula – formula showing SIMPLEST proportions of
atoms in a compound
Ex.: CH
o Molecular formula – formula showing the EXACT COMPOSITION
of a compound
Ex.: C2H2
o Structural formula – Shows number and kind of atoms AND how
they are BONDED TO EACH OTHER
Ex.: H-C=C-H
INORGANIC vs. ORGANIC COMPOUNDS
• ALL organisms are made up of both ORGANIC and INORGANIC
compounds. So what’s the difference?
A. Inorganic Compounds
• The MOST important inorganic compound for living things is H2O
because we need it to live. Many of the biological processes that are
necessary for life take place in water. In fact, we are made up of over
65 percent water and can really only survive for a few days without
water!!!
• Inorganic molecules DO NOT CONTAIN CARBON
• So you say “So what, Mrs. Woytowich?” and I say “SO WHAT?!?!?!
Have you gone mad?
YOU,
GONE
MAD
B. Organic Compounds
• Of all of the atoms found on earth, there are four main ones that
are present in living things. The four main elements that are present
in organic compounds are:
ELEMENT
SYMBOL
CARBON
C
HYDROGEN
H
OXYGEN
O
NITROGEN
N
The element that is FAMOUS for being found
in organic compounds is CARBON because it
can bond to 4 things which makes it possible
for there to be so many organic compounds.
Give it up for CARBON!!!!!!!!!!
We LOVE carbon!!!!!!!!!!!!!

TYPES OF ORGANIC COMPOUNDS
· There are 4 types of organic compounds. They are:
ORGANIC
COMPOUNDS
CARBOHYDRATES
LIPIDS
NUCLEIC ACIDS
PROTEINS
COMPOSITION
FUNCTION(S)
C, H, O
SOURCE OF
ENERGY
C, H, O
CUSHIONING,
INSULATION,
ENERGY
C, H, O, N, P
DIRECT AND
CONTROL
ACTIVITIES
C, H, O, N
STRUCTURE AND
FUNCTION
A. CARBOHYDRATES
I. Structure & Function
• Carbohydrates are comprised of CARBON,
HYDROGEN, AND OXYGEN in a ratio of
1:2:1.
• The chemical names of carbohydrates usually
end in –OSE (i.e., glucose, sucrose, etc.)
• MONOSACCHARIDES are the simple sugars
and all carbs are made up of GLUCOSE.
• Monosaccharides have the EMPIRICAL
formula of CH2O and the most common have
the MOLECULAR formula of C6H12O6
 Sugars are biologically important because they CONTAIN LARGE
AMOUNTS OF ENERGY; nearly all organisms use glucose as a source
of energy.
NAME
FORMULA
TYPE
FUNCTIONS
Glucose
C6H12O6
MONOSACCHARIDE
ENERGY
Maltose
C11H22O11
DISACCHARIDE
““
Lactose
C11H22O11
Disaccharide
““
Sucrose
C11H22O11
Disaccharide
““
Cellulose
POLYMER
POLYSACCHARIDE
TOUGH OUTER
STRUCTURE
Glycogen
POLYMER
Polysaccharide
STORES EXCESS
SUGAR IN
HUMANS
Starch
POLYMER
Polysaccharide
STORES EXCESS
SUGAR IN
PLANTS
Some up-close-and-personal looks at some Carbohydrates:
GLUCOSE
SUCROSE
II. Dehydration Synthesis
• Sugar molecules can be bonded together by
a process called DEHYDRATION SYNTHESIS
• Synthesis means “PUTTING TOGETHER”
and dehydration means “REMOVING
WATER”.
• In living cells, ENZYMES bring about
dehydration synthesis.
• Dehydration synthesis makes ORGANIC
COMPOUNDS that the organism needs,
such as GLYCOGEN & PROTEINS.
We use it for ALL complex organic
compounds.
•By joining two simple sugars, a DISACCHARIDE is formed:
III. Polysaccharides
• Polysaccharides are LONG CHAINS OF
REPEATING SUGAR UNITS and can be
formed by DEHYDRATION SYNTHESIS
• Organisms store excess sugar in the form of
polysaccharides:
1. PLANTS – STARCH
2. HUMANS – GLYCOGEN
• Polysaccharides can also be used to form
tough, structural parts of organisms:
1. PLANTS - CELLULOSE
2. INSECTS - CHITIN
III. Hydrolysis
• Just as sugar molecules can be joined
together, they can be broken apart.
• Hydrolysis: WATER BEING ADDED TO SPLIT
UP A COMPLEX MOLECULE THAT WAS
FORMED FROM DEHYDRATION SYNTHESIS
B. LIPIDS
I. Structure & Function
• Lipids are commonly called FATS, OILS AND
WAXES
• Lipids are comprised of CARBON,
HYDROGEN, AND OXYGEN, as carbohydrates
are. The only difference is that THE RATIOS
ARE DIFFERENT AND AS A RESULT FATS
YIELD MORE ENERGY
• A molecule of fat is formed from the
combination of FATTY ACIDS AND
GLYCEROL
• Lipids function in BEING A RESERVE
ENERGY SUPPLY and PART OF THE
CELL MEMBRANE
• Lipids contain TWICE as much energy
as the same amount of carbohydrate!
• Mammals also use lipids for
CUSHIONING AND INSULATION
II. Saturated vs. Unsaturated Fats
• Saturated fat: ALL CARBON-TO-CARBON BONDS
ARE SINGLE BONDS
• Unsaturated fat: ONE OR MORE PAIRS OF CARBON
ATOMS ARE JOINED BY A DOUBLE OR TRIPLE BOND
• Unsaturated fats can be changed to saturated fats
by HYDROGENATION; ADDING HYDROGEN TO
THEM
C. NUCLEIC ACIDS
•Nucleic acids contain the elements CARBON, HYDROGEN,
OXYGEN, NITROGEN and PHOSPHORUS.
•There are two kinds of nucleic acids which were originally
found in the part of the cell called the nucleus:
•DNA – DEOXYRIBONUCLEIC ACID
•RNA – RIBONUCLEIC ACID
•DNA is the hereditary material passed from one generation
to the next during reproduction.
•RNA works with DNA to direct and control the development
and activities of all cells of an organism.
•The building blocks of nucleic acids are NUCLEOTIDES.
I. Structure of DNA and RNA
•The general structure of a nucleic acid molecule is
that of A LONG CHAIN OF REPEATING UNITS
•In DNA, there are 4 different bases that can be
attached to the chain: ADENINE (A), GUANINE (G),
CYTOSINE (C), THYMINE (T)
•The sequence of bases acts as a CODE OR
TEMPLATE that determines what proteins will be
made in the cell. The proteins then determine the
nature of the cell what activities the cell will
undertake.
•The entire DNA molecule is coiled into a DOUBLE
HELIX. By repeated coilings DNA is “packed” and is
able to fit into tiny structures within the cell.
•An RNA molecule is similar to a DNA molecule, but it has some
differences. The structure of an RNA molecule is different than the
structure than a DNA molecule by:
•RNA CONSISTS OF A SINGLE STRAND OF BASES
•THE SUGAR IN RNA IS RIBOSE, NOT DEOXYRIBOSE
•THE BASE THYMINE IS REPLACED WITH URACIL
D. PROTEINS
I. Structure & Function
• Proteins are compounds that CONTAIN
CARBON, NITROGEN, HYDROGEN, AND
OXYGEN
• The functions of proteins are:
• STRUCTURAL PARTS OF CELLS AND
BODY TISSUES (HAIR, NAILS,
CARTILAGE)
• PIGMENTS IN BLOOD, SKIN, EYES, AND
CHLOROPHYLL
• HORMONES (CHEMICAL MESSENGERS)
• ENZYMES
II. Amino Acids
•Amino acids are THE BUILDING BLOCKS OF
PROTEINS
•Each amino acid is called a MONOMER. The structure
of an amino acid is:
The R group is
variable or RANDOM
•There are 20 different amino acids that are found as
part of proteins.
•Amino acids can be linked together in any sequence
and in chains of varying length.
•These chains can fold and twist in space to make
STRUCTURES OF DIFFERENT SHAPES
III. The Peptide Bond
•Two amino acids may be bonded together by
DEHYDRATION SYNTHESIS TO MAKE A DIPEPTIDE
(FORMED BY A PEPTIDE BOND)
•The bond forms between THE AMINO GROUP OF
ONE AMINO ACID AND THE CARBOXYL GROUP OF
THE NEXT
•A chain of amino acids is called a POLYPEPTIDE. All
proteins are made up of POLYPEPTIDES (CHAINS OF
AMINO ACIDS).
ENZYMES ARE PROTEINS…………..
•Enzymes are PROTEIN SUBSTANCES THAT MAKE
CHEMICAL REACTIONS OF LIVING ORGANISMS
POSSIBLE
•Enzymes enter into a chemical reaction TEMPORARILY—
JUST LONG ENOUGH TO MAKE IT HAPPEN
•Enzymes are NOT CHANGED DURING A REACTION,
THEY ARE USED AGAIN AND AGAIN (RECYCLED)
•Catalyst: SUBSTANCE THAT AFFECTS A REACTION
WITHOUT BEING CHANGED ITSELF
•The substance that an enzyme acts on is called its
SUBSTRATE
•Enzymes usually end with the suffix -ASE. Examples:
maltase, amylase, and protease)
II. How Enzymes Work
• The ability of enzymes act as CATALYSTS depends
on their SHAPE
• There is a region on the surface of an enzyme called
the ACTIVE SITE
• The substrate molecules fit the shape of the active
site; when the substrate comes into contact with the
active site, it forms a TEMPORARY UNION CALLED
THE ENZYME-SUBSTRATE COMPLEX
• At the ENZYME-SUBSTRATE COMPLEX, the
enzyme may cause for the substrate to separate into
two molecules, and may also JOIN TWO
MOLECULES (USING TWO SUBSTRATES)
• The theory of enzyme action where the enzyme and
substrate fit together at an active site is called the
LOCK-AND-KEY MODEL
•Much like a lock and key, THE SHAPE OF THE
ACTIVE SITE OF THE ENZYME ONLY FITS THE
SHAPE OF CERTAIN SUBSTANCES; EACH
ENZYME CAN ONLY CATALYZE CERTAIN
SUBSTRATES