Macromolecules

BAHS 201
CELL BIOLOGY
Wilhelmina Annie Mensah
Dept. Of Med. Bchem.
UGMS , Ghana

What is biochemistry
• Biochemistry studies the chemical reactions that
occurs in living organisms
• In general it deals with body substance like
enzymes, hormones, carbohydrates, amino acids,
fats, proteins, DNA, RNA etc.
• Biochemists study their origin, formation,
functions and deficiency diseases.

Importance of biochemistry in
PHARMACY and NURSING
Biochemistry will help you to better understand
Drug Constitution
The half life of drugs
Drug storage
Drug metabolism
Biochemical tests

A molecule/ Monomer?
•A group of two or more atoms
held together by covalent bonds.
E.g. H2O, Glucose,
A macromolecule/Polymer?
A long molecule made of
monomers bonded
together to form a polymer
Molecule vrs Macromolecules

Formed from Condensation reactions called
dehydration synthesis (removal of water)
Forming Macromolecules

• Hydrolysis reaction
– Hydro = water;
– lysis = break
– Water is added and the lysis of the polymer occurs.
Forming Monomers

Monomer/ molecule -----
Polymer/ macromolecule----
Polymers are formed from—
Monomers are formed form---
The four types main types macromolecules are ........
Atoms joined by covalent
bonds
Long unit made of monomer
units
Condensation / dehydration
Hydrolysis or rehydration
Memory Check

Four main Macromolecules
 Carbohydrates
 Lipids
 Proteins
 Nucleic acids

CARBOHYDRATES
Carbohydrates are the most
abundant organic molecules
in nature.
Carbohydrates are present in
humans, animal tissues, plants and
in micro-organisms.
Carbohydrates are also present in
tissue fluids, blood, milk,
secretions and excretions of
animals

CARBOHYDRATES
The term carbohydrate
means a hydrate of carbon
 Its general formular is
Cn(H2O)n
Carbohydrates are defined as
organic substances containing
C, H, O
 Where H and O are in the ratio 2:1 as
found in H2O

CARBOHYDRATES
MONOSACCHARIDES OLIGOSACCHARIDES POLYSACCHARIDES
Classification Of Carbohydrate
Cannot be hydrolysed
into smaller unit
Two or more monomer units
On hydrolysis yield
monosaccharides or
oligosaccharides
a. Classified based on
the no. of C-atoms
a.Disaccharides
b.Trisachharides
c.Tetrasachharides
Basic units of
carbohydrates
They can be further
hydrolysed to smaller units
b.Classified based on the
type of functional group
a.Homo-polysaccharides
b.Hetro-polysaccharides

Based on the no of C-atoms Based on the functional group
- Trioses (C3H6O3)
- Tetroses (C4H8O4)
- Pentoses (C5H10O5)
- Hexoses (C6H12O6)
- Heptoses (C7H14O7)
- Aldoses :
- Aldehyde –CHO
e.g. Glyceraldehyde
Glucose
- Ketoses :
- ketone ( C = O)
e.g.Dihydroxyacetone
,
Classification Of Monosaccharides
MonosaccharidesMonosaccharides

Structure of Common Monosaccharides

• In aqueous solutions many monosaccharides form rings:
Structure of Common Monosaccharides

Uses of Monosaccharides
• Glucose ( 50%) is hypertonic and
provides a source of calories in a
minimal volume of water.
• Glucose 50% is frequently used to
restore blood glucose concentrations
in the treatment of hypoglycaemia
resulting from insulin excess or from
other causes.

• Fructose: as an
intravenous energy source
for patients with:
• Hepatic disease,
• Uncontrolled diabetes
mellitus
• Postoperative state.

• Dextrose is the name of a simple sugar chemically
identical to glucose (blood sugar) that is made
from corn.
• Dextrose is dissolved in solutions that are given
intravenously used to increase a person’s blood
sugar, which can be combined with other drugs, or
.
• Dextrose is also available as an oral gel or tablet.
Because dextrose is a “simple” sugar, the body can
quickly use it for energy.

Monosaccharide's of Biomedical Importance
24

OLIGOSACCHARIDES
They are formed by condensation of 2-9 monosaccharides
they are
a.Disaccharides (sucrose, lactose)
b.Trisaccharides (raffinose)
c.Tetrasaccharides (stachyose)
The smallest and the commonest oligosaccharides are
Disaccharides

Disaccharides
A disaccharide consists of 2 monosaccharide units (similar or
dissimilar)held together by a glycosidic bond( links a sugar to
another group)
They are crysatalline, water soluble and sweet to taste.

OOHOH
C C
C
C O
C
H
OH
OHOH
OH
H
H
CH2OH
H
H
CHCH22OHOH
C C
C
C O
C
H
OH
OHOH
OH
H
H
CH2OH
H
H
C C
C
C O
C
H
OH
OH
OH
H
H
CH2OH
H
H
C C
C
C O
C
H
OH
OH
OH
H
H
CH2OH
H
H
O
H H
Glycosidic Bond
This is a CONDENSATION reaction, where a water molecule is lost.
Glucose
Maltose
Are joined by a
glycosidic linkage
(Dehydration/ condensation reaction)
Forming Disaccharides

Common Disaccharides
Monosaccharide Monosaccharide Disaccharide
Glucose Glucose Maltose
Glucose Fructose Sucrose
Glucose Galactose Lactose
Maltose Sucrose Galactose

Uses of Disaccharides
• Maltose can be converted from icodextrin
which is used in dialysis solutions.
• Sucrose : It is often used in medications
to impart a more pleasant taste to often
unpalatable chemicals
• Iron Sucrose : is a medicine which is used
in iron deficiency.

- Made up of repeating units of monsaccharides held by
glycosidic bonds
Polysaccharides (Glycans)
- During its formation a water molecule is released at each
condensation
-Unlike sugars they are not sweet.

- HOMOGLYCANS
- -Made up of only 1 type of
monosaccharide monomers
- Starch
- Glycogen
- Dextran
HETEROGLYCANS
-Made up condensation of2 or
more types of monosaccharides
• agar,
• Chitin,
• peptidoglycans etc
- They are ideal as STORAGE AND AS STRUCTURAL
COMPONENTS
- They are of 2 types Homoglycans and Heteroglycans.

• DextranDextran :: complex branched
glucan
• Polysaccharide made of
many glucose
• It is used medicinally as anIt is used medicinally as an
antithrombotic, to reduceantithrombotic, to reduce
blood viscosityblood viscosity

 Glycogen:
 Storage of excess
sugar in animals;
 stored in liver and
muscles
 It is the animal
short-term storage
form of energy

• Chitin:Chitin: Used as a structural material in
 Arthropod exoskeleton
 Fungal cell walls and
 Surgical thread

 Starch or amylum: consists
of a large number of
glucose units joined by
glycosidic bonds.
 This polysaccharide is
produced by most green
plants as an energy store

Cellulose : component of plant cell wall

InulinInulin
 Polymer of fructose i.e. fructosan
 Found in bulbs, garlic, onion etc
 Inulin is not readily metabolised in the
human body and is readily filtered
through the kidney. Hence used for
testing kidney function

 STORAGE form of energy (starch and glycogen).
 Main SOURCE of energy in the body( glycogen).
 Excess carbohydrate is converted to fat.
General Functions carbohydrates

 Structural basis of many organisms
1.Cellulose of plants
2. Exoskeleton of insects
3. Cell wall of microorganisms

 Components of several animal structure and
plant structures
1.cartilage
2.tendons,

 Carbohydrates are components of blood group
substances.

 Ascorbic acid, a derivative of carbohydrate
is a water-soluble vitamin

 Derivatives of carbohydrates are components of
antibiotics like erythromycin
used in the treatment of infections caused by Gram-
positive bacteria. It is similar in its effects to penicillin.

dr.aarif
With the water, I say, Touch me not,
To the tongue, I am tasteful,
Within limits, I am dutiful,
In excess, I am dangerous
LIPIDS

dr.aarif
Lipids are the chief concentrated storage form of energy forming
about 3.5% of the cell content.
Lipids are organic substances relatively
insoluble in water
soluble in organic solvents (alcohol, ether)
Lipids

Lipids consistLipids consist mostly of hydrocarbons (C , H, and O)(C , H, and O)
Lipids
Hydrophilic Head (“hydro”=water; “philic” = loving,
Hydrophobic Tails ( Phobic- fearing)
Polar Head
(hydrophilic)Glycerol
Fattyacid
Fattyacid
Non-Polar Tail
(Hydrophobic)

LIPIDS
Phospholipids
Glycolipids
Lipoproteins
Simple
Steroids
Terpenes
Esters of fatty acids
Esters of fatty
acid and glycerol
Esters of long
chain fatty acid
and long chain
alcohols
Esters of fatty
acids and
alcohol and
other groups
Esters of
hydrocarbon
rings and long
hydrocarbon
side chains
Derived

SIMPLE LIPIDS
They are esters of fatty acids with alcohol. They are of 2 types :
1. Neutral or true fats : Esters of fatty acids with glycerol
2. Waxes : Esters of fatty acids with alcohol other than glycerol.
Neutral / True fats/Triacylglycerol
True fats are made up of C, H, & O but O is less
A fat molecule is made up of 2 components :
a)GLYCEROL
b) FATTY ACIDS (1-3 mol, of same or diff long chained)

Glycerol: A glycerol mol has 3 carbons
each bearing a –OH group
A fatty acid mol is an unbranched
chain of C-atoms.
It has a –COOH group at one end and a
H bonded to almost all the C-atoms
Fatty acids may be saturated or
unsaturated
SIMPLE LIPIDS
1.Neutral / True fats

When a fatty acid attaches to glycerol
it becomes a fat
Fats have a structure that looks like a E
Unsaturated fatty acid in a fat makes it
an unsaturated fat
Saturated fatty acid in a fat makes it a
saturated fat
SIMPLE LIPIDS
1.Neutral / True fats/Triacylglycerol

Unsaturated fats :
– one or more double bonds in the
fatty acids allows for “kinks” in the
tails
– liquid at room temp
– most plant fats
(a) Saturated fat and fatty acid
Stearic acid
(b) Unsaturated fat and fatty acid
cis double bond
causes bending
Oleic acid
Saturated fats:
No double bonds in fatty
acid tails
solid at room temp
most animal fats
SIMPLE LIPIDS

Functions Simple Lipids
1. Storage form of energy
(triacylglycerol) in adipose
tissues
• Adipose tissue is the major
storage site for fat in the
form of triglycerides in the
skin
• Fat under skin serve as
thermal insulator against
cold.

Functions Simple Lipids
1. Fat around kidney and
heart serve as padding
against injury.
2. Act as electric insulators
in neurons as myelin
sheath
3. Help in absorption of fat
soluble vitamins (A, D, E
and K)

2. WAXES
Lipids which are long chain saturated fatty acids and a long chain
Saturated alcohol of high mol wt other than glycerol
Example :
1.Bees wax : secretion of abdominal glands of worker honey bees
2.Shellac wax - from the lac insect kerria lacca
3.Lanolin or wool fat : Secretion of cutaneous glands and obtained
from the wool of sheep
3. Sebum : secretion of sebaceous glands of skin
4. Cerumen : soft and brownish waxy secretion of the glands in the
SIMPLE LIPIDS

Bee wax
WAXES
Sebum in skin
Lanolin
Ear wax in ear
SIMPLE LIPIDS

Uses Waxes
SIMPLE LIPIDS
Lanolin is frequently used in
protective baby skin treatment and
as a treatment for sore nipples in
breastfeeding mothers.[13]
Shellac wax is used in dental
technology, in (partial) denture
production.

COMPLEX LIPIDS
They are derivatives of simple lipids having
additional group like
 phosphate,
 N2-base,
Protein etc.
They are further divided into
Phospholipids,
Glycolipids,
Lipoproteins.
Polar Head
(hydrophilic)
Phosphate
Protein
Glycerol
Fattyacid
Fattyacid
N-Base
Non-Polar Tail
(Hydrophobic)

1. Phospholipid
Polar Head
(hydrophilic)
Phosphate
x
Glycerol
Fattyacid
Fattyacid
Alcohol
Non-Polar Tail
(Hydrophobic)
They consists of
Two fatty acids tails(long
chains of hydrogen and
carbon molecules)
Glycerol 'head.‘
 The glycerol molecule is
also attached to a phosphate
group,
The phosphate can be
attached to an alcohol and
another group
COMPLEX LIPIDS

Function Phospholipids
COMPLEX LIPIDS
Structural component of cell
membrane. Often occur with other
molecules (e.g., proteins, glycolipids,
sterols) in a bilayer.

2. Glycolipid
CEREBROSIDE are the
most simplest form of
glycolipids
They are lipids with a
carbohydrate
attached.
COMPLEX LIPIDS

COMPLEX LIPIDS
Functions of Glycolipids
Glycolipids are Structural components of
plasma membrane

COMPLEX LIPIDS
Glycolipids are components of
blood group substances.

COMPLEX LIPIDS
Glycoprotein serve as cell surface receptors.

3. Lipoprotein
5 types of lipoproteins :
1. chylomicrons
2. VLDL (Very Low density Lipoprotein)
3. LDL (Low density Lipoprotein)
4. HDL (High density Lipoprotein)
5. Free fatty acid albumin complex
COMPLEX LIPIDS
They contain lipids and proteins in their molecules.
They are main constituent of membranes.
They are found in milk and Egg yolk.

Functions Lipoprotein
COMPLEX LIPIDS
 Transport of lipids
 Transport of fat soluble vitamins

DERIVED LIPIDS
They are derivatives obtained on the hydrolysis of the simple
and complex lipids.e.g. steroids, terpenes. etc
1. Steroid
The steroids do not contain
fatty acids but are included in
lipids as they have fat-like
properties.
They are made up of 4
fused carbon rings

DERIVED LIPIDS
Functions of Steroids
• Cholesterol
Hormone production. Cholesterol
plays a part in producing hormones
such as estrogen, testosterone,
progesterone, aldosterone and
cortisone
Vitamin D production. Vitamin D is
produced when the sun’s ultraviolet
rays reach the human skin surface.

DERIVED LIPIDS
Functions of Steroids
• Cholesterol
Cell membrane support.
Cholesterol plays a very
important part in both the
creation and maintenance of
human cell membrene

Functions of Terpenes
Terpenes are a major component of essential oils produced by
plants. They give fragrance and perform various therapeutic
functions
DERIVED LIPIDS

Diseases associated with abnormal chemistry or
metabolism of lipids-
71
Clinical significance of lipids
 Obesity
 Atherosclerosis
 Diabetes Mellitus
 Hyperlipoproteinemia
 Fatty liver
 Lipid storage diseases

72
1.Excessive fat deposits cause obesity. obesity is a risk factor for
heart attack.
2. Abnormality in cholesterol and lipoprotein metabolism leads to
atherosclerosis and cardiovascular diseases .
3. In diabetes mellitus, the metabolisms of fatty acids and
lipoproteins are deranged, leading to ketosis

73
4. Hyperlipidemia, hyperlipoproteinemia, or hyperlipidaemia
involves abnormally elevated levels of any or all lipids and/or
lipoproteins in the blood . It is the most common form of
dyslipedemia (which includes any abnormal lipid levels).
5. Some fat in your liver is normal. But if it makes up more than 5%-
10% of the organ's weight, you may have fatty liver disease.
6. Lipid storage diseases are a group of inherited metabolic
disorders in which harmful amounts of fatty materials (lipids)
accumulate in various tissues and cells in the body

Discussion Question
1. How will my knowledge about carbohydrate
and lipids structure and function enrich my
work as a health professional.(outline 5points)
2. What are the uses of carbohydrates and lipids
in medicine .(5 uses)

Proteins
• Proteins consist of
C, H, O and N (S & P)
• Polymers (polypeptides)
of amino acids joined by
peptide bonds

• Peptide bonds
connect amino acids
to form polypeptide
chains
• One or more
polypeptide chains
make up a protein
Proteins Structure

General Functions of Proteins
1. Transport of substances in the body . E.g. Haemoglobin
transports oxygen.
2. Enzymes which catalyze chemical reactions in the body
3. Defence function .e.g Immunoglobulins(antibodies)
4. Hormones are proteins. They control many biochemical
events. Example: Insulin.

5. Contraction of muscles. E.g Muscle proteins(actin and
myosin).
6. Gene expression. They control gene expression and
translation.E.g Histones.
7. Nutrient and storage .E.g albumen of egg, Casein of
milk , Ferritin that stores iron.
Functions of Protiens

8. Proteins act as buffers. E.g Plasma proteins.
9. Proteins function as anti-vitamins. E.g. Avidin
of egg.
10.Proteins are infective agents.e.g Prions
which cause mad cow disease are proteins.
Medical And Biological Functions

10. Some toxins are proteins E.g Enterotoxin of
cholera microorganism.
11. Some proteins provide structural strength and
elasticity to the organs and vascular system. E.g
Collagen and elastin of bone matrix and ligaments.
10. Some proteins are components of structures of
tissues. E.g α-keratin is present in hair and
epidermis
Medical And Biological Functions

Nucleic Acids structural Components

Building the nucleic acid polymer
Nucleotides are joined together by Phosphodiester bondsNucleotides are joined together by Phosphodiester bonds
ester bondester bond
ester bondester bond
Phosphodiester bondPhosphodiester bond

1. DNA (Deoxyribonucleic acid)
– double stranded (DNA helix)
– can self replicate
– makes up genes which code for proteins is
passed from one generation to another
1. RNA (Ribonucleic acid)
– single stranded
– functions in actual synthesis of proteins coded
for by DNA
– is made from the DNA template molecule
Nucleic Acids Types

1. They are involved in the storage, transfer and expression
of genetic information.
2. Some nucleic acids acts as enzymes and coenzymes.
E.g. RNA, act as catalyst and RNA is coenzyme for
telomerase which seals ends of chromosomes.
3. DNA exhibits structural polymorphism. It assumes
several forms depending on certain conditions. Several
DNA variants are known.
Functions of nucleic acid in the cell

Macromolecules

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