Topic 2: Metabolisms and Enzymes Flashcards
Define cell metabolism
Cells acquire energy by breaking down biological macromolecules in catabolic reactions
Define catabolic reaction
energy releasing; break down molecules
What happens to energy in catabolic reactions?
Energy is lost as heat and not available to do work; the rest of the energy is harvested by the cell and transferred to other processes in the cell that need it
Define anabolic metabolism
smaller products put together to build larger, more complex products that have higher energy
____ moves energy from catabolism to anabolism and becomes ADP and vice versa
ATP
Plants using photsynthesis use anabolic reactions to produce glucose from absorbing photons. The ______ _____ is transferred to ____ which is used to do work.
light absorbed; ATP
Which is a catabolic reaction? Why?
a. transcription
b. translation
c. DNA replication
d. Hydrolysis
Hydrolysis - reaction breaks down polymers into smaller monomers
What is an enzyme?
a molecule that catalyzes biochemical reactions
How does a catalyst work?
Increases the rate of a chemical reaction without itself being consumed in the reaction by lowering the activation energy of the reaction
Enzymes bind to the ____ molecules and hold them in such a way to make chemical bond-breaking and forming processes take place more _____.
reactant; easily
True or False: Because enzymes do not change and are not used by the reaction, they can be reused as many times as possible so long as the enzyme remains active.
True
True or False: Enzymes change the free energy of the reaction.
False
Endothermic reactions have what kind of metabolism?
Anabolic
Exothermic reactions have what kind of metabolism?
Catabolic
Define Active Site
the location within the enzyme where the substrate binds
Define the functional domains of the active site
Binding Site - where the substrate is loosely held in place by the enzyme
Catalytic Site - where the enzyme is able to influence the bond stability of the substrate
Increasing the environmental temperature increases the rate of the reaction to a certain point. When the temperature goes beyond the optimal range, what is likely to occur?
Denaturation
What is the induced-fit model?
When the enzyme and substrate come together, their interaction causes a mild shift in the enzymes structure that forms an ideal binding arrangement between enzyme and substrate.
What is significant about the enzyme-substrate complex?
Lowers the activation energy and promotes rapid progression
How does the enzyme-substrate complex effect anabolic reactions?
the enzymes promote chemical reactions that involve more than one substrate by bringing the substrates together in an optimal orientation for a reaction which increases the speed because the substrates are held at angles that are more likely to cause a reaction
Because the enzyme is not used in a reaction, the concentration of enzymes are very _____.
small
Define competitive inhibitor
something that binds to the active site and blocks the regular substrate from getting to the active site
How can competitive inhibitors bind to the active site?
They are very similar to the actual enzyme
Define noncompetitive inhibition
An inhibitor molecule binds to the enzyme in a location other than the active site (allosteric site) but still manages to block the substrate from binding to the active site
Define allosteric site
A regulatory site that can turn on or off the enzyme
Define allosteric inhibition
Inhibitor molecules bind to enzymes in a location where their binding induces a conformational change that reduces the affinity of the enzymes for its substrate
Define feedback inhibition
Involves the use of a reaction product to regulate its own further production
What happens when there is a high concentration of the end product? Why?
The end product will go back and inhibit the first enzyme and shut down the pathway
