2. Biomolecules
• Atom-smallest unit of matter (carbon, hydrogen, oxygen,
nitrogen and phosphorus are the atoms that make up most
biomolecules)
• Molecule-group of atom bonded together
• Polymer-molecules of many repeating units
• Biomolecules-molecules needed for life
-Carbohydrate (sugar)
-Proteins
-Lipids (fats)
-Nucleic acid (DNA and RNA)
4. Carbon is the central element
• All biomolecules contain a Carbon chain or ring
• Carbon (atomic number 6) has 4 outer shell
electrons (valence = 4)
• Therefore it’s bonding capacity is great
• It forms covalent bonds –hence, has strong bonds
• Once bound to other elements (or to other
Carbons), it is very stable
5. Carbon linkages
• Single chains
• Rings
Propane
The 4 types of biomolecules often
consist of large carbon chains
= C3H8
CH4 =
6. Carbon binds to more than just
hydrogen!!
• To OH groups in sugars
• To NH2 groups in amino
acids
• To H2PO4 groups of
nucleotides of DNA,
RNA, and ATP
Amino acid
OH, NH2, PO4 are called ‘functional groups’!
9. Carbohydrates (Sugars)
Structure : Polymer –a repeating unit called
saccharide
Function:
• Used by all cells for energy and used by
plants for structure
• energy is stored in the bonds between
carbon, hydrogen and oxygen
12. Oligosaccharides
• 3 to 10 monosaccharide units by glycosidic
bond:
-maltotriose
-raffinose
-blood group substance
13. Polysaccharides
Three Types
• Glycogen – animal storage product that
accumulates in the liver
Glucose→Glycogen→glucose→bloodstream
• Starch – plant energy storage
- Easily digested by animals through hydrolysis
• Cellulose- non digestable in human body
lacking of cellulase enzyme
14. Cellulose
• Polysaccharide found in plant cell walls
• For humans cellulose is indigestible and
forms dietary fiber
• Made up entirely of β glucoses
– Structure is constrained into straight
microfibrils
• Not an energy source for animals
• Chitin – insect exoskeletons
16. Monomers and polymers
• Monomers are made into polymers via dehydration reactions
• Polymers are broken down into monomers via hydrolysis
reactions
18. Fig. 3.5
Examples of sugar monomers*
*Remember how C’s are counted
within the ring structures (starting
from the right side and counting
clockwise)
19. Carbohydrates (sugars)
• Complex carbo’s
(polysaccharides)
– Starch
– Cellulose
– Glycogen
– Chitin
Glycogen to glucose
in animals
23. Proteins
• Mammal cell contains 10,000 proteins
• Control elements (enzymes)
– Organic catalysts
– Mediators of metabolism
– Direct development, maintenance, and growth
• Structural elements (cell membrane, muscles,
ligaments, hair, fingernails)
• Regulate what goes into/out of cells
24. Building Blocks of Proteins
Amino Acids
• Amino acids (monomers) are linked
together to form proteins (polymers)
– Each unique sequence of amino acids forms a
different protein
– All living things (even viruses) use the same 20
amino acids
• 20 different Amino Acids
– Amino end (NH2)
– Carboxyl end (COOH)
– Hydrogen
– R group – variable component
27. Proteins
• Composed of chains of
amino acids
• 20 amino acids exist
• Amino acids contain
– Central Carbon
– Amine group
– Carboxyl group
– R group
28. Fig. 3.20
The 20 Amino Acids
All differ with respect
to their R group
29. Peptide bonds
Peptide bonds occur between amino acids
• The COOH group of 1
amino acid binds to
the NH2 group of
another amino acid
• Forms a peptide bond
peptide bond!
30. Fig. 3.21
The chain (polymer) of amino acids forms a variety of
loops, coils, and folded sheets from an assortment of
bonds and attractions between amino acids within the
chain(s)
31. Classification of Protein
• Simple protein:(depends on size and solubility)
– Fibrous protein (Ligament, Cartilage, hair, nail)
– Globular protein
• Albumin
• Globulin
• Histone
• Gliadine
33. Classification depends on functions
• Structural protein (collagen, elastin)
• Catalytic protein (Enzyme)
• Transport protein (Alb, transferrine)
• Hormonal protein (regulation:insulin,glucagon)
• Gene regulatory (histone, protamin)
• Protective protein (prevent
infection:immunoglobulin-G)
• Receptor protein (LDL receptor)
• Contractile protein (muscle contraction: actine,
myocine)
34. There are at least 7 functions of proteins
• Enzyme catalysts – specific for 1 reaction
• Defense – antibody proteins, other proteins
• Transport- Hgb, Mgb, transferrins, etc
• Support – keratin, fibrin, collagen
• Motion – actin/myosin, cytoskeletal fibers
• Regulation- some hormones, regulatory proteins
on DNA, cell receptors
• Storage – Ca and Fe attached to storage proteins
36. • Nucleic Acid: Polymer of Nucleotides connected
by 3/
, 5/
- phosphodiester bond.
• Types of Nucleic Acid: There are 2 types of NA
-RNA (Ribonucleic acid)
-DNA (Deoxyribonucleic acid)
37. Monomer/Building blocks
• RNA: Monomeric unit of RNA is ribonucleotide
• DNA: Monomeric unit of DNA is deoxy
ribonucleotide
38. Structure of Nucleotides
• Nucleoside: Nitrogen base + Ribose sugar
• Nucleotide: It is monomer of nucleic acid
and it contains: Nucleoside+Phosphate
group
42. Nitrogen Bases
DNA and RNA contains the same
purines (nitrogen base) namely
• Adenine (A)
• Guanine (G)
• DNA and RNA contains the same
Pyrimidine (nitrogen base) namely
Cytocine (C)
However the nucleic acids differ with respect to the
second pyrimidine base-DNA contains Thymine
(T) where as RNA contains Uracil (U)
49. Nucleic Acids
• Polymers composed of monomer
units known as nucleotides
• Information storage
– DNA (deoxyribonucleic acid)
• Protein synthesis
– RNA (ribonucleic acid)
• Energy transfers
– ATP (adenosine tri-phosphate) and
NAD (nicotinamide adenine
dinucleotide)
50. Functions of Nucleic Acids
• DNA – Physical carrier of genetic
information
– Restricted to nucleus
• RNA – key component of protein
synthesis
– Messenger RNA (mRNA) – blueprint for
construction of a protein
– Ribosomal RNA (rRNA) – construction site
where the protein is made
– Transfer RNA (tRNA) – truck delivering the
proper AA to the site of construction
51. Biological Function:
i. Conveys genetic information
ii. Act as co-enzymes e.g. NAD+, FAD, FMN,
NADP
iii. Participate in energy metabolism and serve as
energy store.
iv. Act as intracellular 2nd
mrssenger e.g. cAMP,
and cGMP
v. Regulation of coronary blood flow, e.g.
adinosine.
55. Lipids
• Made of Carbon, Oxygen, Hydrogen.
• Lipids are not polymeric substances rather
they are mostly small molecules.
• Building blocks of most of the lipids are
fatty acid
• Some lipids such as cholesterol, lack fatty
acid.
56. Criteria of Lipids
• Insoluble in water but soluble in one or
more fat solvents.
• Common fat solvents (Non polar/ organic
solvent) are-
• Ether, Chloroform, Benzin, alcohol, acetone
and carbon tetra chloride.
• Heterogeneous substance
• Utilized by living organisms
57. Criteria of Lipids
• Saturated-Solid at room temperature. No
double bonds
• Unsaturated-liquid at room temperature.
Double bonds between carbons.
58. Classification of Lipids
• Simple:
-Esters of fatty acids with alcohol
-They do not contain any non lipid substance
-Basically composed of Fatty acid + alcohol
e.g. Neutral fat and wax
59. Classification of Lipids contd.
• Complex lipid or compound lipid-
-Esters of fatty acid with alcohol along with
other non lipid substances.
-Basically composed of fatty acid+ alcohol+
other non lipid substance.
-e.g.Phospholipid, glycolipid, lipoprotein,
sulfolipid.
60. Classification of Lipids contd.
• Derived lipid
-Derivative obtained by hydrolysis of simple
lipids and complex lipid which still possess
the general charecteristics of lipid, e.g. fatty
acid, alcohol, glycerol, steroid, fat soluble
vitamins, keton bodies etc.
61. Neutral fat and wax
• They are regarded as neutral because they
do not have any change at normal body pH.
• It is also known as oil or triglycerides
• Neutral fat of plant source have more
unsaturated FA and that of animal source
have more saturated FA
62. Triglycerides
• Fats and oils used for long term energy
storage
• 38 KJ of energy per gram (2x carbs)
• Slower to build up and break down than
carbohydrates
63. Waxes
• Composed of long hydrocarbon chains and
are strongly hydrophobic
• Highly saturated
• Solid at room temperature
• Form waterproof coatings
70. Phospholipids and cell membranes
• P-lipids make up the majority of cell
membranes including:
– The plasma membrane
– Nuclear envelope
– Endoplasmic reticulum (ER)
– Golgi apparatus
– Membrane-bound vesicles
71. Sterols
Have a backbone of 4 carbon rings
Different steroids created by attaching different functional
groups to the rings
Different structures create different function
73. Cholesterol
• Important component of animal cell
membranes
• Precursor to all other steroids
• Participates in all chemical reactions that
make other steroids
• High levels in blood may contribute to
cardiovascular disease
77. Classification of FA
A. Based on total number of carbon (chain
length)
1. Short chain FA (carbon number<10)
e.g. Acetic acid (2C), Caproic acid (6C)
2. Long chain FA (carbon number>10)
e.g. Palmitic acid (16C), Stearic acid (18 C)
78. B. Based on saturation of carbon:
1. Saturated Fatty acid:
• They do not contain any double bond in
their hydrocarbon chain
• They represent about 50% of body fatty
acid pool
• Common source:
Animal fat: butter, ghee
Vegetable oil: coconut oil, palm oil.
e.g.Palmitic acid, Stearic acid
79. • Unsaturated Fatty acid
• They contain one or more double bond in their
hydrocarbon chain
• With one double bond-Monounsaturated FA
(MUFA)
• e.g. Olive oil, canola oil (Oleic acid;18C)
• With 2 and more double bond-Polyunsaturated FA
(PUFA)
• e.g. Soybean oil, mustard oil, sunflower oil
(except palm and coconut)
• Also found in fish oil
80. • C. Nutritional classification
1. Non essential FA
• These are the fatty acids which body can
synthesize
• Palmitic acid, stearic acid, oleic acid etc.
81. 2. Essential Fatty Acid
• These are the PUFA which are not
produced in human body but must be
supplied with diet
e.g. Linoleic acid:18 C Omega 6 FA with 2
double bonds
82. Glycerol and fatty acid chains
What specific bonds form between glycerol and
each fatty acid chain?
Would you think this to be an hydrolysis or a
dehydration synthesis rxn?
83. Saturated and unsaturated fats
The difference resides in the number of H’s attached
to C’s in the fatty acid chains; the amount of
“saturation” on the C’s
84. Saturated vs unsaturated fats and diet
• Saturated fats
Saturated fats raise LDL-cholesterol levels in the
blood (animal fats, dairy, coconut oil, cocoa
butter)
• Polyunsaturated fats
Polyunsaturated fats leave LDL-cholesterol
unchanged; but lower HDL-cholesterol (safflower
and corn oil)
• Monounsaturated fats
Monounsaturated fats leave LDL and HDL levels
unchanged (olive oil, canola, peanut oil, avocados)
• One variety of polyunsaturated fat (Omega-3 fatty
Omega-3 fatty
acids
acids) guards against blood clot formation and
reduce fat levels in the blood (certain fish,
walnuts, almonds, and tofu)
85. Cell environment organizes P-lipid
bilayer to proper orientation
Hydrophilic (polar) “heads” of P-lipid oriented to the
exterior; hydrophobic (non-polar) “tails” oriented to
the interior
