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)