Carbohydrates, lipids, proteins, and nucleic acids are the four major macromolecules that make up living things. Carbohydrates include sugars and starches and are used for energy storage. Lipids are composed of fatty acids and glycerol and function in energy storage, protection, and insulation. Proteins contain amino acids and perform a variety of functions including growth, energy production, and pH buffering. Nucleic acids like DNA and RNA contain nucleotides and store and transmit genetic information that directs cellular functions. These macromolecules are formed through dehydration synthesis and broken down through hydrolysis.

3. INTRODUCTIONOF BIOCHEMISTRY
BY
PROF DR MUHAMMAD
MUSTANSAR

15. CARBOHYDRATES
• Living things use carbohydrates as a key source
of ENERGY!
• Plants use carbohydrates for structure
(CELLULOSE)
– include sugars and complex carbohydrates
(starches)
– contain the elements carbon, hydrogen, and oxygen
(the hydrogen is in a 2:1 ratio to oxygen)

16. Monosaccharides (simple sugars)
• all have the formula C6 H12 O6
• all have a single ring structure
– (glucose is an example)

17. Disaccharides (double sugars)
• all have the formula C12 H22 O11
• sucrose (table sugar) is an example

18. Polysaccharides
• Formed of three or more simple sugar units
• Glycogen - animal starch stored in liver & muscles
• Cellulose - indigestible in humans - forms cell walls
• Starches - used as energy storage

19. How are complex
carbohydrates formed
and broken down?

20. Dehydration Synthesis
• Combining simple molecules to form a more
complex one with the removal of water
– ex. monosaccharide + monosaccharide ---->
disaccharide + water
– (C6H12O6 + C6H12O6 ----> C12H22O11 + H2O
• Polysaccharides are formed from repeated
dehydration syntheses of water
– They are the stored extra sugars known as starch

22. Hydrolysis
• Addition of WATER to a compound to
SPLIT it into smaller subunits
– (also called chemical digestion)
– ex. disaccharide + H2O --->
monosaccharide + monosaccharide
C12 H22 O11 + H2 O ---> C6 H12 O6 + C6 H12 O6

24. Lipids (Fats)
• Fats, oils, waxes, steroids
• Chiefly function in energy storage, protection,
and insulation
• Contain carbon, hydrogen, and oxygen but the
H:O is not in a 2:1 ratio
• Tend to be large molecules -- an example of a
neutral lipid is below

25. • Neutral lipids are formed from the union of one
glycerol molecule and 3 fatty acids
• 3 fatty acids + glycerol ----> neutral fat (lipid)
• Fats -- found chiefly in animals
• Oils and waxes -- found chiefly in plants
• Oils are liquid at room temperature, waxes are
solids
• Lipids along with proteins are key components of
cell membranes

26. PROTEINS
• contain the elements carbon, hydrogen, oxygen,
and nitrogen
• composed of MANY amino acid subunits
• It is the arrangement of the amino acid that
forms the primary structure of proteins.
• The basic amino acid form has a carboxyl
group on one end, a methyl group that only
has one hydrogen in the middle, and a amino

27. AN R GROUP IS ANY GROUP
OF ATOMS – THIS CHANGES
THE PROPERTIES OF THE
PROTEIN!

28. FUNCTIONAL GROUPS
• There are certain groups of atoms that are
frequently attached to the organic molecules we
will be studying, and these are called functional
groups.
• These are things like hydroxyl groups which
form alcohols, carbonyl groups which form
aldehydes or ketones, carboxyl groups which
form carboxylic acids, and amino groups

30. Major Protein Functions
•
•
•
Growth and repair
Energy
Buffer -- helps keep body pH constant

31. Dipeptide
• formed from two amino acid subunits
• Formed by the process of Dehydration Synthesis
• amino acid + amino acid ----- dipeptide + water

32. Hydrolysis of a dipeptide
• Breaking down of a dipeptide into amino acids
• dipeptide + H2O ---> aminoacid + amino acid

33. Polypeptide (protein)
• composed of three or more amino acids linked
by synthesis reactions
• Examples of proteins include insulin,
hemoglobin, and enzymes.
• ** There are an extremely large number of
different proteins.
• The bases for variability include differences in
the number, kinds and sequences of amino

34. NUCLEIC ACIDS
• in all cells
• composed of NUCLEOTIDES
• store & transmit heredity/genetic information
• Nucleotides consist of 3 parts:
•
•
•
1. 5-Carbon Sugar
2. Phosphate Group
3. Nitrogenous Base

36. DNA (deoxyribonucleic acid)
• contains the genetic code of instructions that direct a
cell's behavior through the synthesis of proteins
• found in the chromosomes of the nucleus (and a few
other organelles)

37. RNA (ribonucleic acid)
• directs cellular protein synthesis
• found in ribosomes & nucleoli

38. SUMMARY