Chapter 8 an Introduction to Metabolism Flashcards
what is a catabolic pathway?
A metabolic pathway which releases energy by breaking down complex molecules to simpler compounds.
ex. cellular respiration
What are anabolic pathways?
pathways that consume energy to build polymers from monomers
ex. synthesis of amino acids
What is kinetic energy?
energy associated with the relative motion of objects
What is thermal energy?
a type of kinetic energy associated with the random movement of atoms or molecules
What is potential energy?
energy matter posseses because of its location or structure.
What is chemical energy?
term used by biologists to refer to potential energy available for release in a chemical reaction
Complex molecules are high in ___ energy
chemical/potential
A glucose molecule tends to be ___ unstable than the smaller molecules it can become, meaning it has a ___ delta G
more
higher
When is metabolism at equilibrum?
When the cell is dead. If it were at equilibrium it would not be able to do work.
Describe the process by which the phosphate bonds in ATP can be broken. What type of reaction is this?
hydrolytic, exergonic rxn
terminal phosphate is broken by H2O
inorganic phosphate leaves the ATP and it becomes ADP
Why is the delta G in ATP hydrolysis greater than the delta G of ATP hydrolysis in standard conditions
the conditions in the cell are different, reactant and pdt concentrations differ from 1M
Why is the description of ATP phosphate bonds as “high-energy” misleading?
the reactants (ATP and water) have high energy relative to the energy of the products (ADP and phosphate)
the release of energy during ATP hydrolysis comes from the change of the system rather than the phosphate bonds themselves
Why does ATP hydrolysis release so much energy?
the three phosphate groups in ATP are negatively charged and repulse each other. Think of them as a compressed sprign
What is phosphorylation? When is it performed by the cell?
transfer of a phosphate group from ATP to some other molecule called a phosphorylated intermediate
couples exergonic and endergonic reactions
As temperature increases, enzymatic reactions ___ to a certain point
increase
What is feedback inhibition?
a metabolic pathway is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway
How do an activator and an inhibitor have different effects
on an allosterically regulated enzyme?
The activator binds in such a way that it stabilizes the active form of an
enzyme, whereas the inhibitor stabilizes the inactive form.
Choose the pair of terms that correctly completes this sentence:
Catabolism is to anabolism as ____________ is to ____________.
(A) exergonic; spontaneous
(B) exergonic; endergonic
(C) free energy; entropy
(D) work; energy
Q1. B
Most cells cannot harness heat to perform work because
(A) heat does not involve a transfer of energy.
(B) cells do not have much thermal energy; they are
relatively cool.
(C) temperature is usually uniform throughout a cell.
(D) heat can never be used to do work.
Q2 C
If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to
(A) add more of the enzyme.
(B) heat the solution to 90°C.
(C) add more substrate.
(D) add a noncompetitive inhibitor
Q4, A
