energy and metabolism pt.2 for quiz Flashcards
what is activation energy (Ea)?
the minimum energy required for a reaction
in what 4 ways can we control and affect enzymes?
- general environment - temperature and pH
- each enzyme has an optimal temp. which it can function
- each enzyme has an optimal pH which it can function
- chemicals influence the enzyme- the 2nd and 3rd structure
why is maintaining homeostasis so important?
because it could lead to breakdowns if not functioning right
2 main types if enzymes inhibitors, what are they ?
- competitive inhibitors
2. noncompetitive inhibitors
what do competitive inhibitors do?
they bind to the active sight of an enzyme, competing with the substrate
what do noncompetitive inhibitors do?
they bind to another part of an enzyme cause the enzyme to change shape or making the active sight less effective
why must a cell’s metabolic pathways be regulated?
because chemical chaos would result if they were not regulated
how does a cell tightly control the metabolic pathways?(2 ways)
- by switching on or off the genes that encode specific enzymes
- by regulating the activity of enzymes
what does allosteric regulation of enzymes do?
may either inhibit or stimulate on enzymes activity (turn it off or on and speed it up or down)
when does allosteric regulation occur? and which inhibition is it?
occurs when a regulatory molecule binds to a protein at once site and affects the protein’s function at another sight
this is noncompetitive inhibition
what are most allosterically regulated enzymes made from?
polypeptide subunits which is the quatinarty structure and has active and inactive forms
what stabilizes the active form of the enzyme?
the binding of an activator
what stabilizes the inactive form of the enzyme?
the binding of an inhibitor
what is feedback inhibition?
the end product of a metabolic pathway that shuts down the pathway
what does feedback inhibition prevent?
it prevents a cell from wasting chemical resources by synthesizing more product than is needed
what is the basic process of feedback inhibition?
end product can shut down the pathway- shuts down the process (so they don’t make too much)- once we run out we use the end product - opening up the pathway so- the process starts all over again.
what do structures within the cell do?
help bring order to metabolic pathways
what do some enzymes act as and what is an example?
they act as structural components of membranes
ex. in Eukaryotic cells some enzymes reside in specific organelles - enzymes for cellular respiration are located in the mitochondria
what are the three main kinds of work a cell does?
- chemical (manipulate matter)
- transport (once built transported through the cell to do its function)
- mechanical (things that mechanically move like cilia and flagella)
what is required of cells to do work?
cells manage energy resources by energy compiling, the use of an exergonic process to drive an endergonic one
what is most energy coupling in cells mediated by?
the structure and hydrolysis of ATP
what does ATP stand for and what does it do?
Adenosine triphosphate and it is the cell’s energy shuttle
what is ATP composed of? (3 things)
- a ribose (a sugar)
- adenine (a nitrogenous base)
- three phosphate groups
what can break the bonds between the phosphate groups of ATP’s tail ?
hydrolysis
what does energy do when the terminal phosphate bond is broken?
energy is released from ATP
Where does the release of energy from ATP come from?
comes from the chemical change to a state of lower free energy, not from the phosphate bonds themselves (free energy calculation)
what powers the 3 three types of cellular work?
the hydrolysis of ATP
what can be used to drive an endergonic reaction?
the energy from the exergonic reaction of ATP hydrolysis can be used to drive an endergonic reaction
ATP is a renewable resource, what is it regenerated by?
addition of a phosphate group to adenosine diphosphate (ADP)
where does the energy into a phosphorylate (ADP) come from?
comes from catabolic reactions in the cell- cellular respiration
ATP cycle is a revolving door, when does energy pass?
during its transfer from catabolic to anabolic pathways.
do we store ATP?
no, it is unstable and we make it when we need it
