enzymes Flashcards
metabolism and enzymes
what is metabolism?
metabolism is the total number of chemical reactions occurring within a living organim, and can be divided into two catergories; anabolic and catabolic.
each step of a metabolic pathway in cells is catalysed by enzymes. maintenance of a constant temperarature and chemical balance is so important to ensure efficient metabolism.
what are anabolic reactions?
anabolic reactions are metabolic pathways that construct molecules from smaller units. these processes require energy input to build complex molecules.
Anabolism is involved in growth, repairm and maintenance of tissues and cells. it helps synthesize importnat biomolecules like proteins, nucleic acids, carbohydrates, and lipids.
they consume energy, often from ATP or other high-energy molecules.
what are examples of anabolic reactions?
protein synthesis
DNA replication
photosynthesis
what are catabolic reactions?
they’re metabolic pathways that breakd down larger, complex molecules into smaller units. these processes release energy as chemical bonds are broken.
what are examples of catabolic reactions?
cellular respiration
digestion
fat breakdown
what are enzymes?
enzymes are large, globular protein molecules and their shape is essential to the way they function.
the molecule that an enzyme acts on is called a substrate.
the enzyme fist together with the substrate at a precise place on the enzyme’s surface called the active site.
the shape of the active site can’t be altered, or it won’t function effectively.
what are cofactors(or coenzymes)?
cofactors are non-protein groups on some enzymes that bind with the protein to help form the active site.
e.g. vitamins (riboflavin=B2), metal ions (zinc, copper).
some poisons work by disabling cofactors, therefore inhibiting functioning.
what is the role of enzymes?
they can speed up a reaction without a change in temperature, lowers activation energy needed to start a reaction, and many other things
what is the effect of temperature on enzymes?
enzymes are sensitive to temperature due to their protein nature.
enzymes within cells function best at body temperature.
above 40 degrees celsius their rate of reaction decreases and above 60 they bceome denatured and stop functioning.
what happens when enzymes are heated past their optimum temperature?
once they’re heated past their optiumum temperature they stop working, becoming denatured, which means it’s shape will no longer fit the substrate.
this permanently damages it.
what happens when enzymes are cooled down?
when they’re cooled down, they slow their activity and will eventually stop working.
if they’re reheated until optimum temperature they will start working again.
how does pH affect enzymes?
enzymes are sensitive to pH change, each enzyme has its own range of pH within it functions effectively.
if it goes out of the optimum pH range, the shape of the enzyme’s active site will change and it will denature.
at what pH level do enzymes function at?
enzymes in cells function in a neutral pH.
Pepsin and rennin, found in stomach acid function best at a low pH.
Amylase in saliva functions best at a weak alkaline pH.
