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)

• Double sugars (disaccharides)

• Two 6-C chains or rings bonded together

Lactose

Carbohydrates (sugars)

• Complex carbo’s (polysaccharides)– Starch –energy storage

– Cellulose – structural support

– Glycogen – energy storage

– Chitin – structural

Glycogen to glucose in animals

Up to 10,000 glucose units!!

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

• 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

1º 2º

3° 4°

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 – single-stranded 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 lipids1- glycerides

• Make up 90% of lipid in food

• Differ with respect to ‘saturated’ or ‘unsaturated’ fatty acid chains

Types of lipids2- 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