Biomolecules

1. BIOMOLECULE
S
The Chemistry Of
Life

2. BIOSYNTHESIS
–The process of
building organic
molecules by
living organisms
is called
biosynthesis.

3. Biomolecules
–Biomolecules (also
known as
macromolecules) are
organic compounds
that make up all living
organisms.
–four macromolecules
are carbohydrates,
lipids, nucleic acids,
and proteins.

5. CARBOHYDRATE
–A carbohydrate is a
biomolecule consisting of
carbon (C), hydrogen (H)
and oxygen (O) atoms,
usually with a hydrogen–
oxygen atom ratio of 1:2:1 (as
in water) and thus with the
empirical formula Cm(H2O)n
(where m may or may not be
different from n), which does
not mean the H has covalent
bonds with O (for example
with CH2O, H has a covalent
bond with C but not with O)

6. FUNCTIONS OF
CARBOHYDRATE
S
–one of the major functions of
carbohydrates is to provide
energy to organisms.
Monosaccharides, in particular,
are the main source of energy
for metabolism. When they are
not yet needed, they are
converted into energy-storing
polysaccharides, such as starch
in plants and glycogen in
animals.

8. THREE MAJOR CLASSES OF
CARBOHYDRATES
–Monosaccharides
–Disaccharides
–Polysaccharides

9. What are Monosaccharides?
–Monosaccharides are poly-
hydroxy-aldehydes or -
ketones, generally with an
unbranched C-chain. A
carbohydrate is an organic
compound with the formula
(CH2O), with n > 3.

10. Monosaccharides
–The monosaccharides (mono = one,
saccharide = sugar) are the basic subunits
of carbohydrates. They contain from 3 to 7
carbons and have the general formula of
(CH2O)n where n ranges from 3 to 7 (5 or 6
being the most common).

11. –Common monosaccharides include: glucose,
fructose, galactose, ribose, and deoxyribose.

14. What are
Aldehydes?
–In aldehydes,
the carbonyl
group has one
hydrogen atom
attached to
it together
with either a
2nd hydrogen
atom or a
hydrogen
group
–CHO

15. What are
Ketones?
–In ketones,
the carbonyl
group has 2
hydrocarbon
groups
attached to
it. Ketone
does not have
a hydrogen ato
m attached to
the carbonyl
group.

16. –The structure of
Ribose and
Deoxyribose is
almost identical,
with just one
difference. Ribose
sugar has a hydroxyl
(OH) group at
position 2, whereas
deoxyribose sugar
has a hydrogen (H)
atom at position 2.
Due to this,
deoxyribose sugar is

19. Disaccharides
–Disaccharides (di- = “two”) form when two
monosaccharides undergo a dehydration reaction
(also known as a condensation reaction or
dehydration synthesis). During this process, the
hydroxyl group of one monosaccharide combines
with the hydrogen of another monosaccharide,
releasing a molecule of water and forming a
covalent bond.

20. Disaccharides
–A disaccharide (also called a double
sugar ) is the sugar formed when two
monosaccharides (simple sugars) are
joined by glycosidic linkage.
–Three common examples are sucrose,
lactose, and maltose.
–The general molecular formula of a disaccharide
is C12H22O11

24. Polysaccharides
–polysaccharides are major
classes of biomolecules.
They are long chains of
carbohydrate molecules,
composed of several smaller
monosaccharides.

25. Glycogen
– polysaccharides of
glucose
–It is the main storage
carbohydrate in animals
and fungi.
–Glycogen is also known
as animal starch. It is
stored in the liver,
muscle and brain.
–(C₆H₁₀O₅)n

27. Starch
–Starch is the main
storage carbohydrate of
plants.
–Starch is the main
dietary energy source for
humans. It is present in
most cereals, roots,
tubers and also in some
vegetables.

28. –The chemical formula of
the starch molecule
is (C6H10O5)n
–Starch is made up of long
chains of sugar molecules
that are connected
together.
–The linear polymer
AMYLOSE is the most
basic form of starch, while
AMYLOPECTIN is the

30. Cellulose
–Cellulose is the
main structural
component of the
plant cell wall.
It is exclusively
present in plants.
–Cellulose is the
most abundant
organic compound
of the plant
kingdom

31. –Cellulose is an
organic compound
with the
formula (C6H10O5)n,
–a polysaccharide
consisting of a linear
chain of several
hundred to many
thousands of linked
D-glucose units.

32. –Cellulose is an important
dietary fiber in humans. It
helps in the digestion and
excretion of waste by
acting as a bulking agent
for feces.
–Humans cannot digest
cellulose fibers.
–Cellulose is a major form of
energy source for animals
like cow, horse, sheep etc.
who’s gut microbiota
secretes cellulase enzymes
to break down cellulose
into glucose for energy.

33. –Chitin (C8H13O5N)n is
a long-chain polymer
of N-
acetylglucosamine,
an amide derivative
of glucose
–Chitin is the second
most abundant
polysaccharide in
nature

34. Chitin
Chitin is a long-chain
polymer of a
derivative of glucose.
It is found in many
living things. For
example, it is a
component of the cell
walls of fungi, the
exoskeletons of
arthropods such as
crustaceans and
insects