Download Biomolecules

Biomolecules
Carbohydrates
Proteins,
Lipids,
and Nucleic acids
Carbon is the central element
• All biomolecules contain a Carbon chain or ring
• Carbon 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
Carbon linkages
• Single chains
• Rings
Propane
Carbon binds to more than just
hydrogen
• To OH groups in sugars
• To NH2 groups in amino
acids
• To H2PO4 groups in
nucleotides of DNA, ATP
Amino acid
These are called ‘functional groups’!
Carbohydrates (or sugars)
• Simple sugars
(monosaccharides)
• Only one 6-C chain or
ring involved
• General formula
(CH2O)
Carbohydrates (sugars)
Lactose
• Double sugars
(disaccharides)
• Two 6-C chains or
rings bonded together
Carbohydrates (sugars)
Up to 10,000 glucose units!!
• Complex carbo’s
(polysaccharides)
–
–
–
–
Glycogen to glucose
in animals
Starch –energy storage
Cellulose – structural support
Glycogen – energy storage
Chitin – structural
Proteins
• Composed of chains
of amino acids
• 20 amino acids exist
• Amino acids contain
–
–
–
–
Central Carbon
Amine group
Carboxyl group
R group
There are four levels of protein
structure
1º
3°
2º
4°
• Primary = sequence of
aa’s
• Secondary = forms
pleated sheet, helix, or
coil
• Tertiary = entire length
of aa’s folded into a
shape
• Quaternary = several
aa sequences linked
together
Shape is critical to protein
function
Types of proteins
•
•
•
•
Enzymes
Hormones
Structural proteins
Receptor proteins
Nucleic acids: DNA and RNA
• DNA =
deoxyribonucleic acid
• DNA is a double
polymer (chain)
• Each chain is made of
nucleotides
• The 2 chains bond
together to form a
helix
DNA nucleotides – double
stranded polymer
• Each nucleotide in
DNA contains:
– 5-C sugar
(deoxyribose)
– Phosphate
– Nitrogen base
-adenine (A)
-guanine (G)
-cytosine (C)
-thymine (T)
RNA Nucleotides – singlestranded polymer
• Each nucleotide in
RNA contains:
– 5-Carbon sugar –
Ribose***
– Phosphate
– Nitrogen base
•
•
•
•
Adenine (A)
Guanine (G)
Cytosine ©
Uracil (U)***
Lipids
• Made of the same
elements as
carbohydrates, but
insoluble in water
• Do not form polymers!
• Major function:
– Energy storage
– Insulation
– Cell membranes
Types of lipids
1- glycerides
• Make up 90% of lipid
in food
• Differ with respect to
‘saturated’ or
‘unsaturated’ fatty acid
chains
Types of lipids
2- steroids
• Contain a central core
of 4 rings
• Difference in
functional groups
relates to steroid
function in the body
• 3 main forms of
steroids
– Cholesterol
– Estrogen
– testosterone
Lipids and Health
• Hierarchy of dietary
fats:
– Fats containing
Omega-3 fatty acids
– Mono- and poly
unsaturated fats
– Saturated fats
– Trans fats
Lipids:
3) Phospholipids
• Make up cell
membranes
• Produces a bi-layer
• Polar “head” region
point to outside and
inside of cell
• Non-polar “tails” only
to inside of membrane