topic 1 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
Fibrils
Long, straight chains of β-glucose glucose
held together by many hydrogen bonds
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
Peptide bond
Covalent bond joining amino acids together in proteins
C–N link between two amino acid molecules
formed by a condensation reaction
What is the effect of temperature on enzyme-
controlled reaction
At low temperatures, there is not enough kinetic energy for successful collisions between the enzyme and substrate.
At too high a temperature, enzymes denature, the active site changes shape and enzyme- substrate complexes cannot form.
What is the effect of pH on enzyme-controlled
reaction
Too high or too low a pH will interfere with the charges in the amino acids in the active site.
This breaks the ionic and hydrogen bonds holding the tertiary structure in place
therefore the active site changes shape and the enzyme denatures Different enzymes have a different optimal pH
What is the effect of substrate concentration on enzyme-controlled
reaction
At low substrate concentrations, there will be fewer collisions between the enzyme and substrate. At high substrate concentrations, the rate plateaus
because all the enzyme active sites are saturated
What is the effect of enzyme concentration on enzyme-controlled
reaction
At low enzyme concentrations, there will be fewer collisions between the enzyme and substrate. At high enzyme concentrations, the rate plateaus
because there are more enzymes than the substrate, so many empty active sites.
Ester bond
–COO– chemical bond
formed between glycerol and fatty acids
Hydrophilic
The ability to mix, interact or
attract water
Hydrophobic
The tendency to repel and not mix with water
Glucose
Monosaccharide that exists as two isomers
β glucose and α glucose
Galactose
An example of a monosaccharide that forms lactose
Fructose
An example of a monosaccharide that forms sucrose
Isomer
Molecules with the same molecular formula
but the atoms are arranged differently
Maltose
Disaccharide
formed by the condensation of two glucose molecules
Lactose
Disaccharide
formed by the condensation of a glucose molecule and a galactose molecule
Sucrose
Disaccharide
formed by the condensation of a glucose molecule and a fructose molecule
Polypeptide
Polymer chain of a protein
made up of amino acids
bonded together by peptide bonds following condensation reactions
Amino acid
The monomer of a protein formed from C,H,O,N
contains a carboxyl group, amine group and an R group