Millions of complex chemical reactions are going on in the human body at any given time. The balance of the endocrine system, which controls hormone levels, is one example; how the brain processes information from nerves and how signals are relayed from place to place is another. By studying and understanding these highly complex reactions, medical biochemists have found ways to better fight infection and disease on the molecular level. Much of the field is dedicated to research. The time experts spend studying samples and creating reactions has led to a number of breakthroughs in heath care and disease management, and it seems likely that this field will be very much “in demand” for years to come.
2. What is Biochemistry and why?
Biochemistry deals with the function and the
structure of the body at the molecular level
So, you can link the health and the disease
state to the normal and altered body
chemistry
3. We are made of molecules, atoms, and ions
We function by interaction of these
components
An alteration of these
components and- or disturbance
of their interaction leads to
disturbed function ( disease)
4. The major component is
Other components(organic or
inorganic) are dissolved or mixed
with water
WATER
5. Water constitutes the major part of body weight
Water is a covalent compound showing polarity
DIPOLE
11. Energy Balance
•Energy balance is the difference
between energy intake and energy
expenditure.
•Energy intake differs according
to age ,sex and physical activity
15. Adequate diet
* It is the diet which is essential for
normal growth, maintenance of life
and reproduction.
* It must supply essential nutrients
as vitamins, essential amino acids
and essential fatty acids.
• * It must contain :-
• 1- Carbohydrates 4- Vitamins
• 2- Lipids 5- minerals
• 3- Proteins 6- water
16. • Energy content of different food
sources:
Carbohydrates------ 4.1 Kcal/gm
Lipid ------------ 9.3 Kcal/gm
Proteins---------- 4.1 Kcal/gm
17. Introduction to metabolism
Metabolic pathways
1-Catabolic pathways ......that
generate energy
2-Anabolic pathways....... that
use energy to synthesize
important molecules
3-Amphibolic pathways ......that
are both anabolic and catabolic
19. • A -Pentoses
*( penta =5) sugars that contain 5
carbons . They are present in fruits
and can be formed in the body .
• Ribose is present in structure of RNA
(ribonucleic acid) and ATP ( energy
currency of the cell)
* Deoxyribose is present in structure
of DNA (deoxyribonucleic acid )
1-Monosacharides
20. • B –Hexoses
• ( hexa = 6) sugars that contain 6
carbons.
• Glucose (dextrose) is the major sugar
in blood , it is present in fruits and
honey
• Fructose is very sweet , and present
in fruits
• Galactose is present in milk ,
glycolipids and glycoproteins
21. 2-Disaccharides
• 1- Maltose
• * It is called malt sugar , it is
found in malt الشعير.
• * It is formed of two glucose
units.
• * It is formed by hydrolysis of
starch by amylase enzyme.
• * It is a fermentable للتخمر قابل
sugar.
22. • 2- Sucrose
• * It is called cane sugar (table
sugar) القصب سكر.
• * It is formed of glucose and
fructose.
• *It is fermentable
23. 3- lactose
• It is the milk sugar *
• It is formed of galactose and glucose . *
• It is synthesized by mammary gland during
lactation.*
• * Lactose is considered the best food for infant
due to :-
• 1- It is the least sweet, so the infant can take
large amounts of it.
• 2- It is non fermentable , so it does not cause
abdominal distention or colic.
• 3-It is laxative ,so it prevents the incidence of
constipation
25. • 1- Starch
• * It is the storage form of carbohydrates in plants
(never present in animals).
• * It is a branched chain formed of glucose units
linked by α 1— 4 glucosidic bond
• while at the branch point , it forms α 1— 6 glucosidic
bond .
• * Starch gives blue color with iodine .
• * Starch can be hydrolyzed by salivary amylase into
dextrins ( glucose units linked together ).
•
27. 2- Glycogen
•It is the animal equivalent of starch in plants
•Main storage polysaccharide in human liver and
muscles.
•Formed of glucose units liked by α 1— 4 glucosidic
bonds in the main chain and α 1— 6 at the branching
points.
• It is more extensively branched than starch.
•In muscles , it serves as energy reserve for muscle
contraction
• liver glycogen supplies glucose to other tissues
through blood.
* Glycogen gives a pink color with iodine.
28. • 3- Dextrins
• They are group of glucose units
linked together resulting from
partial hydrolysis of starch .
• They have different chain
lengths and degree of branching
• They are found in some food
products as corn syrup.
29. 4- Dextrans
•They are highly branched glucosan with
its units linked together by α 1-6 in the
main chain and α1—2 , α 1—3 or α 1—4
bonds at branch points.
•
* Dextrans are synthetic compounds used
in medicine as :
1- Plasma substituents in cases of
hemorrhage
2- Dextran –iron complex is used in
treatment of anemia
3-Dextran –sulphate is used as
anticoagulant.
30. 5- Cellulose
*It is the main structural molecules in cell walls of
plants .*
*It a glucosan formed of β 1— 4 glucosidic bonds.
*It is a straight chain , not branched so it is fibrous ,
tough and insoluble in water.
*Can not be digested by gastrointestinal enzymes of
human and carnivorous animals as the β1— 4
bonds are not hydrolyzed by amylase
• Digested in herbivorous animals.
* Called Dietary fibers
31. • Dietary fibers have a very important role in diet :
• 1- They add bulk to stool, stimulate intestinal
wall and prevent constipation.
• 2- Absorb 5-10 times as their own weight water ,
increasing bowel movement .
• 3- They bind to toxic compounds present in diet
decreasing their absorption, so they protect
against colon cancer.
• Average need of dietary fibers is
• 25-35 gm /day and are present in cereals, bread ,
fruits and vegetables.
