METABOLISM AND ENZYMES Flashcards
What is metabolism?
The sum of all the chemical reactions in organisms.
Enzyme reactions can be? 2 words
Catabolic
Anabolic
Do catabolic reactions result in breakdown or production?
Breakdown
AB —-> A + B e.g. respiration
Do anabolic reactions result in breakdown or production?
Production
A + B —-> AB e.g. photosynthesis
Energy and catabolic reactions
Catabolic reactions release energy
Energy and anabolic reactions
Anabolic reactions require energy
How do living organisms obtain their energy?
The sun or food (solar energy or chemical energy)
What are enzymes?
They are biological catalysts, proteins in nature, that alter the rate of a reaction without being used up in the reaction.
What do biological catalysts do other than speed up the rate of reaction?
They lower the activation energy of the reaction.
What are proteins produced by and where?
By ribosomes in living cells.
What does specific mean in relation to enzymes?
Each enzyme is specific for a particular substrate—one enzyme per reaction.
In what direction do enzymes work?
They work in both directions-they are reversible.
What does the activity of the catalyst vary in?
pH, temperature, enzyme concentration, substrate concentration, and product concentration.
What do some enzymes require?
Cofactors e.g. minerals, vitamins, and sometimes other enzymes.
What are inhibitors?
Chemicals that attach to an enzyme and destroy its shape e.g.
antibiotics or heavy metals (bacteria and mercury)
Amylase is a ______ enzyme and breaks down _____ into _____
catabolic, starch, maltose
Can you describe the mechanism of enzyme action?
Substrate combines with the ACTIVE SITE of an enzyme.
INDUCED FIT THEORY: When the substrate joins the enzyme, it changes the shape of the active site slightly to make a better fit for the substrate.
A temporary ENZYME-SUBSTRATE COMPLEX is produced.
The bonds in the substrate are altered so that the substrate changes into the product(s).
Products leave the site. The active site returns to its original shape and can now accept a new substrate.
LOCK THEORY.
What is reaction rate?
The amount of product formed per unit or the amount of substrate used up per unit time.
Factors affecting the rate of enzyme action are…
Temperature
pH
Substrate concentration
Enzyme concentration
Denaturation
How does temp. affect the rate of enzyme action?
The activity of a catalyst varies with temperature. At low temperature, the molecules move slowly and collide infrequently so a low rate of reaction.
At higher temperatures there are more frequent collisions causing a high rate of reaction.
If the temperature is above a optimum temp. the active site is changed ans the enzyme becames denatured.
How does pH affect the rate of enzyme action?
Enzymes work best at their optimum pH e.g. pepsin = 2 and most human enzymes = 7.
When heated above what temperature do most enzymes lose their 3D shape?
60 degrees Celsius.
What is a denatured enzyme?
A denatured enzyme has lost its shape permanently and can no longer carry out it’s function.
What is biotechnology?
The use of organisms or their enzymes to produce commercial products.
