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
• There are only about 100 different ATOMS AND
ELEMENTS, which is what matter is made up of.
Examples CARBON, HYDROGEN, etc.
• Biochemistry is THE STUDY OF ATOMS AND
MOLECULES THAT ARE IMPORTANT FOR LIFE
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:
• Empirical formula – formula showing SIMPLEST proportions of
atoms in a compound
– Ex.: CH
• Molecular formula – formula showing the EXACT
COMPOSITION of a compound
Ex.: C2H2
• 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
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
• it can bond to 4 things which makes it
possible for there to be so many organic
compounds.

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.
– Ex. Glucose C6H12O6
• The chemical names of carbohydrates usually
end in –OSE (i.e., glucose, sucrose, etc.)
• MONOSACCHARIDES are the simple sugars
 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:
A. CARBOHYDRATES
II. Dehydration Synthesis
• Sugar molecules can be bonded together by a process
called DEHYDRATION SYNTHESIS
• Synthesis means “PUTTING TOGETHER” and
dehydration means “REMOVING WATER”.
• 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:
A. CARBOHYDRATES
Polysaccharides
• Polysaccharides are LONG CHAINS OF REPEATING SUGAR
UNITS
• can be formed by DEHYDRATION SYNTHESIS
• Organisms store excess sugar in the form of polysaccharides:
1. PLANTS – STARCH
2. HUMANS – GLYCOGEN (IN LIVER AND MUSCLES)
• Polysaccharides can also be used to form tough, structural parts of
organisms:
1. PLANTS - CELLULOSE
2. INSECTS - CHITIN
CARBOHYDRATES
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
– AS A RESULT FATS YIELD MORE ENERGY
• A molecule of fat is formed from the combination
of FATTY ACIDS AND GLYCEROL
• Lipids functions
– BEING A RESERVE ENERGY SUPPLY
– 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
B. LIPIDS
II. Saturated vs. Unsaturated Fats
• Saturated fat: ALL CARBON-TO-CARBON BONDS ARE
SINGLE BONDS
C-C-C-C-C-C-C-C-C-C-C-C-C
• Unsaturated fat: ONE OR MORE PAIRS OF CARBON
ATOMS ARE JOINED BY A DOUBLE OR TRIPLE BOND
• Unsaturated fats are liquid at room temperature and are healthier
for you than saturated fats which are solid at room temperature
C. PROTEINS
I. Structure & Function
• Proteins are compounds that CONTAIN
CARBON, HYDROGEN, OXYGEN AND
NITROGEN
• 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
C. PROTEINS
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.
C. PROTEINS
III. The Peptide Bond
• Two amino acids may be bonded together by DEHYDRATION
SYNTHESIS TO MAKE A DIPEPTIDE
• The bond that forms is called a PEPTIDE BOND
• It 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 CATALYSTS, WHICH MEANS THEY
ARE NOT CHANGED DURING A REACTION,
– THEY ARE USED AGAIN AND AGAIN (RECYCLED)
• The substance that an enzyme acts on is called its
SUBSTRATE
• Enzymes usually end with the suffix -ASE.
– Examples: maltase, amylase, lactase and protease
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 ENZYMESUBSTRATE COMPLEX
• ENZYME-SUBSTRATE COMPLEX
– the enzyme may cause the substrate to separate into two
molecules
– 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
LOCK AND KEY MODEL
• THE SHAPE OF THE ACTIVE SITE OF THE ENZYME ONLY
FITS THE SHAPE OF CERTAIN SUBSTANCES
• EACH ENZYME CAN ONLY CATALYZE CERTAIN
SUBSTRATES
D. 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.
D. NUCLEIC ACIDS
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
– 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
•THYMINE IS
REPLACED WITH
URACIL