1.1 biological molecules

Carbohydrates

living organisms need carbohydrates - to act as a source of energy e.g. sugars, starch, glycogen - to play a structural role in plant cell walls e.g. cellulose

Glucose

isomers are molecules with the same molecular formula as each other, but with the atoms connected in a different way

β glucose image

α glucose image

large chain of monomers is called a polysaccharide

plants form starch

aniamls form glycogen

valuable storage molecules that can be broken down into monosaccharides when energy is required

pair of monomers is called a disaccharide

glucose + galactose --> lactose

glucose + fructose --> sucrose

Glucose + glucose --> maltose

When combined in pairs, monosaccharides form disaccharides, forming a Glycosidic bond image

single is called a monosaccharide

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part of nucleotides

source of energy in respiration

building blocks for polysaccharides

formula image e.g. glucose image

soluble substances

monomer is a saccharide

protein

protein structure

quaternary

two or more polypeptide chains in tertiary form combined to form complexes joined by bonds similar to those in tertiary structure

Tertiary

the folding on the alpha helix to form very specific 3D shapes, maintained by bonds

secondary: beta pleated sheet

less common. formed by hydrogen bonding between the peptide bonds in the polypeptide chain

secondary: alpha helix

most common secondary form, formed by hydrogen bonding between the peptide bonds in the polypeptide chain

primary

the type, number and sequence of amino acids in a polypeptide chain, linked by peptide bonds only

polymerization through condensation to form peptide bonds

20 different amino acids -- usually R group varies

chain of amino acids is a polypeptide (simplest form of protein)

made of amino acid monomers

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Proteins are made of C, H and O in addition to Nitrogen.
Some can also contain sulphur and phosphorus, but always look out for the nitrogen.

nucleic acids

RNA - ribonucleic acid

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URACIL

ADENINE

GUANINE

CYTOSINE

DNA - deoxyribonucleic acid

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double strands

GUANINE + CYTOSINE - triple bond

ADENINE + THYMINE - double bond

made of nucleotide monomers

1 nucleotide is made from -

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1 phosphate - up the side

1 base - up the side

1 pentose sugar - in the middle

polymers are DNA and RNA

lipids

phospholipid

'head' is the hydrophilic phosphate group

the 'tail' is the hydrophobic fatty acids

formed when 2 fatty acids and a phosphate group join to a glycerol

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monomer is called a glycerol -- when condensation reaction occurs, ester bonds are formed to form glycerides e.g. triglycerides (3 fatty acids and 1 glycerol)

used for water proofing, insulation and protection

source of energy

contribute to the flexibility of cell membranes

made of carbon, hydrogen and oxygen plus phosphorus as phosphate in phospholipids (not in set ratio(