Chapter 4 Flashcards
HOW DO BIOLOGICAL CATALYSTS WORK?
WHY DO WE REQUIRE THE USE OF BIOLOGICAL CATALYSTS?
WHY ARE THEY VERY SPECIFIC?
HOW ARE THEY MADE?
Enzymes are biological catalysts because they speed up metabolic reaction by creating a reaction pathway with a lower activation energy.
Enzymes are more specific than catalysts therefore, there is less chance off unwanted, potentially harmful, products being created.
Enzyme structure determines function. Instructions for making enzyme is coded in genes by chain of amino acids.
Enzymes allow metabolic reactions in the body to occur at average body temperature and pH. Reactions would usually need very high temperatures and pH’s but the use of catalysts allows reactions to occur in the body without you dying.
WHAT IS THE ACTIVE SITE?
This is where the substrate will bind during reaction. Each active site is highly specific so will catalyse only one specific reaction.
WHAT IS A CATABOLIC REACTION?
When metabolites are broken down
WHAT IS AN ANABOLIC?
When larger products are synthesised from metabolites
EXPLAIN THE FUNCTION OF THE ENZYME CATALASE?WHERE IS IT FOUND?
Found in organisms exposed to oxygen. They break down hydrogen peroxide which is toxic and can be very harmful.
It is found in peroxisomes in white blood cells and used to break down pathogens.
EXPLAIN THE FUNCTION OF THE ENZYME AMYLASE IN THE SALIVARY GLANDS?
Produced in the salivary glands.
Digest starch into maltose.
EXPLAIN THE FUNCTION OF THE ENZYME TRYPSIN?
Made in the pancreas, digest proteins in the small intestine. Break proteins into polypeptides by hydrolysing peptide bonds.
WHAT ARE COFACTORS?
Some enzymes work better with separate cofactors. The enzyme will form an enzyme-substrate complex in the presence of the cofactor.
Some can be co-substrates so they and the substrate bind together into the active site to fit perfectly. Some change the charge distribution on the surface to allow the enzyme to form temporary bonds with the substrate.
WHAT ARE PROSTHETIC GROUPS?
Permanantly bound cofactors.
WHAT ARE CO-ENZYMES?
An organic non-protein cofactor which binds to the active site just before or at the time of reaction. They are mainly gained from water soluble minerals.
DESCRIBE THE LOCK AND KEY HYPOTHESIS
Enzyme fits right in to the
DESCRIBE THE INDUCED FIT HYPOTHESIS?
Basically the active site changes slightly to alter its shape making it fit perfectly to the substrate by becoming exactly complimentary. `
EXPLAIN THE EFFECT OF TEMPERATURE ON ENZYME ACTION.
HOW DO YOU CALCULATE Q10?
All molecules have kinetic energy so are in continuous movement. As temperature increases, the particles have more kinetic energy. More particles also have energy equal to or greater than activation energy. So there are more successful collisions occurring. Therefore, more ESC’s are formed increasing rate of reaction.
As temperature increases even higher, the weaker bonds in the enzyme site start to break. This affects the tertiary structure of the enzyme rendering it useless. The enzyme is said to be denatured.
Optimum temperature is the temperature that the enzyme works best at.
To calculate the temperature co-efficient Q10
- This refers to the increase in the rate of a process when the temperature is increased by 10c - Q10 = (rate of reaction at (T+10)c)/(2rate of reaction at Tc)
EXPLAIN THE EFFECT OF EFFECT OF pH ON ENZYME ACTION.
A buffer resists changes in pH by donating or accepting electrons.
In enzymes changes in pH interfere with the bonds because of excess H+ ions. If pH is too high or too low the rate of reaction is affected. Eventually the enzyme will denature because the changes in H+ concentration affect the tertiary structure.
EXPLAIN THE EFFECT OF EFFECT OF SUBSTRATE CONCENTRATION ON ENZYME ACTION.
As substrate is added, rate of reaction increases. This is because more ESC’s can form so more reactions catalysed to higher rate. Substrate concentration becomes the limiting factor when all substrate molecules are in the active sites and some enzymes are still free.
