Biological Molecules Flashcards
What does ATP stand for and what is it?
Adenosine Tri Phosphate. It is the energy currency of a cell
what is ATP made up from?
Adenine
Ribose (sugar)
Phosphate
where is ATP made?
in photosynthesis and in respiration
Why is ATP not a long term energy store?
ATP is broken almost as soon as it is made as the bonds are unstable, so therefore it has a low activation energy
Formula for ATP formation
ADP + Pi + ATP synthase –> ATP +Water
Formula for hydrolysis of ATP
ATP + Water —> ADP + Pi + Energy
examples of energy from the hydrolysis of ATP
muscle contraction
cell division
active transport
what is phosphorylation?
adding a phosphate to a molecule
What happens to a molecule if it has undergone phosphorylation?
The molecule is more reactive as adding a phosphate has lowered the molecules activation energy
what are amino acids and what do they form?
they are monomers. lots of them form polypeptides
how does a peptide bond form?
when a condensation reaction occurs between 2 amino acids. between the amine and the carboxylic acid
how to test for proteins?
add biuret A/B
positive result = purple/lilac colour
negative test = pale blue colour
describe the primary structure of proteins and what bonds are present?
give examples
the sequence of amino acids in a polypeptide.
BONDS: peptide
EXAMPLES: all proteins
describe the secondary structure of a protein and what bonds are present?
give examples
the coiling of a polypeptide chain to form a helix
BONDS: hydrogen - holds the helix together
peptide
EXAMPLES: protein found in
fingernails
describe the tertiary structure of a protein and what bonds are present?
give examples
the folding and twisting of a polypeptide chain to form a specific 3D shape
BONDS: hydrogen
ionic
disulphide
peptide
EXAMPLES: enzymes
hormones
describe the quaternary structure of a protein and what bonds are present?
give examples
two or more polypeptides linked together
BONDS: hydrogen
ionic
disulphide
peptide
EXAMPLES: haemoglobin
insulin
antibodies
What are enzymes?
they are biological catalysts with a tertiary structure
they are proteins
describe the Induced Fit Hypothesis?
The active site is not complementary to the substrate
The active changes shape to fit the substrate (flexible)
describe and explain what enzymes do to activation energy?
Enzymes lower activation energy
when active site changes to form an E-S complex, the enzyme distorts the bonds in the substrate by placing it under tension
what are the properties of an enzyme?
proteins with a tertiary structure
flexible active site
globular
not used up in a reaction
lowers activation energy
how does temperature affect enzymes?
enzyme and substrate have more kinetic energy, so increased E-S complexes. faster ROR
how does substrate concentration affect enzymes?
more substrates = more E-S complexes. faster ROR
what is pH?
A measure of hydrogen ion concentration
how does pH affect enzymes?
changes in pH affects the charges on the amino acids that make up the active site.
This affects the ionic bonding in the tertiary structure
so active site can no longer shape to fit the substrate. No E-S complexes.
