Biology 12 Enzymes
what does an enzyme do?
allows reactions to occur with lower activation energy
a reaction that combines simple molecules into complex molecules
anabolism
How does temperature affect enzymes
at 0 degrees there is no enzyme activity. adding heat speeds up activity but too much can cause the enzyme to denature.
the molecule that prevents an enzyme from working
nonsubstrate
describe a metabolic pathway
one product becomes the substrate for the next enzyme
the result of a chemical reaction
product
a molecule that composes all enzymes
protein
what are the differences between a reversible and non-reversible inhibitor
reversible = temporary attachment to the enzyme. Don't destroy it just slow it down nonreversible = permanent attachment. poisons
the chemical on which the enzyme acts
substrate
what is the optimum pH and the optimum temperature for enzymes in most locations of the human body?
temp = 38 degrees Celsius pH = 7
what are the four factors that affect enzymes
temp. pH, concentration, inhibitors
what is the saturation point in enzyme activity?
the point where the amount of substrates added do not matter because the enzyme is already working at max speed.
define activation energy
the quantity of energy needed to undergo a specific reaction
at what temperature do enzymes begin to denature?
45 degrees Celsius
name the two types of inhibitors and their affect on enzymes
Competitive= a molecule that plugs an enzyme, not allowing a substrate to lock with it. Noncompetitive= a molecule that changes the shape of an enzyme and attaches to it but not at the active site
define hyperthyroidism
too much thyroxin is produced. ADHD, underweight, insomnia, opthalmic goitre (bulging eyes)
what is a coenzyme and give examples
a helper molecule to make a good fit at the active site (organic) vitamins like A C D
what is a cofactor and give examples
a helper molecule to make a good fit at the active site. (inorganic) minerals like zinc, magnesium, potassium
a portion of an enzyme to which a substrate can attach
active site
the break down of complex molecules into simple molecules
catabolism
a molecule that speeds up chemical reactions
catalyst
a molecule that aids an enzyme in making the active site functional
coenzyme
how does pH affect enzymes
different enzymes have different optimum pH's. some react best at 2 while others at 8.
a chemical reaction that releases energy
exothermic
what is negative feedback
final products of a pathway often act as inhibitors of enzymes early in the pathway
how does concentration affect enzymes
increasing substrates increase enzyme activity until you get to the saturation point. more enzyme molecules = more reactions
what effects do end products have on enzymes?
it can become an inhibitor or slow down reaction
explain how an enzyme works
lock and key. each enzyme fits with a specific substrate at the active site and breaks it down.
name two specific places in the cell where enzymes are located
lysosomes, mitochondria
What is thyroxin
metabolism is regulated by thyroxin. produced in thyroid gland
define hypothyroidism
when too little thyroxin is produced. lethargy, weight gain, cretinism, enlarged thyroid gland (goitre)