Topic 1 - Biological Molecules And Nucleic Acid Flashcards
Monomer
The smaller units from which larger molecules are made
Polymer
Molecules made from a large number of monomers joined together
Monosaccharide
The monomers from which larger carbohydrates are made
e.g. glucose, fructose, galactose
Disaccharide
Formed by the condensation of two monosaccharides
held together by a glycosidic bond
e.g. maltose, sucrose, lactose
Polysaccharide
Formed by the condensation of many glucose units
held by glycosidic bonds
e.g. starch, glycogen, cellulose
Cellulose
Polysaccharide in plant cell walls formed by the condensation of
β-glucose
Glycogen
Polysaccharide in animals
formed by the condensation of
α-glucose
Starch
Polysaccharide in plants
formed by the condensation of α-glucose
contains two polymers - amylose and amylopectin
Glycosidic bond
C–O–C link
between two sugar molecules formed by a condensation reaction
it is a covalent bond
Amylose
Polysaccharide in starch made of α-glucose
joined by 1,4-glycosidic bonds
coils to form a helix
Amylopectin
Polysaccharide in starch
made of α-glucose
joined by 1,4 and 1,6-glycosidic bonds
branched structure
Condensation reaction
A reaction that joins two molecules together
with the formation of a chemical bond
involves the elimination of a molecule of water
Hydrolysis reaction
A reaction that breaks a chemical bond
between two molecules
involves the use of a water molecule
Microfibrils
Long, straight chains of β-glucose running parallel to one another
Cross linked by hydrogen bonds
These molecules joined to form microfibrils which in turn are grouped to form fibres
Triglyceride
Formed by the condensation of one molecule of glycerol and three molecules of fatty acids
forming 3 ester bonds
Phospholipid
Formed by the condensation of one molecule of glycerol and two molecules of fatty acid
held by two ester bonds
a phosphate group is attached to the glycerol
Induced-fit model
The enzyme active site is not initially complementary to the substrate
the active site moulds around the substrate
this puts tension on bonds lowers the activation energy
Competitive inhibitor
A molecule that is the same/similar shape as the substrate
binds to the active site
prevents enzyme-substrate complexes from forming
Non-competitive inhibitor
A molecule that binds to an enzyme at the allosteric site
causing the active site to change shape
preventing enzyme-substrate complexes from forming
Primary structure
The sequence of amino acids on a polypeptide chain
Secondary structure
The folding or coiling
to create a β pleated sheet or an
α helix
held in place by hydrogen bonds
Tertiary structure
The further folding to create a unique 3D shape
held in place by hydrogen, ionic and sometimes disulfide bonds
Quaternary structure
More than one polypeptide chain in a protein
Can also have prosthetic group
Peptide bond
Covalent bond joining amino acids together in proteins
C–N link between two amino acid molecules
formed by a condensation reaction