Exam 4 Flashcards
Why is the T state of glycogen phosphorylase less active?
the active site is partially blocked
What physiological conditions render phophorylase b less active?
high ATP and high G6P levels
In muscle, the first event in the breakdown of glycogen due to binding of a hormone is that
G protein is activated
Why is glycogen branching important?
branching increases the solubility of glycogen
Branching increases glycogen synthesis and degradation by increasing the potential sites of action
Delta E is a measure of a molecule’s
ability to donate or accept electrons
Complex I is a complex in the electron transport chain. This complex is most likely
amphilic
A transcription factor
binds to DNA
The SRP for NAD+/NADH redox =-0.32V thus, NADH is a
good electron donor
The standard electron potential is a comparison of
the electron donating capability of a molecule relative to the H2/H+ redox couple
When mitochondria are actively carrying out aerobic respiration, the pH of the matrix is
greater than the pH of the IMS
The final reduced species in the electron transport chain is
H2O
T/F
Cytochrome c only participates in one-electron transfers.
True
What are the two main tissues that store glycogen
muscle and liver
What does epinephrine do?
causes the phosphorylation of glycogen synthase a to make glycogen synthase b and causes the phosphorylation of glycogen phosphorylase b to make glycogen phoshphorylase a
In terms of glycogen phosphoylase, of which form does most of the allosteric regulation exist?
b
The purpose of glycogenin is
to prime for glycogen synthesis because glycogen synthase can only add UDPglucose to the glycogen chain if it contains more than 4 glucose molecules
How is energy used to make ATP “stored” by the electron transport chain?
protons are non-spontaneously pumped into the unfavorable region, the intermembrane space
The loss of the AMP-binding site in muscle glycogen phosphorylase could lead to
phosphorylase b will be inactive even when the AMP level is high. Hence, glycogen will not be degraded in the muscle unless glycogen phosphorylase is converted into the a form by a hormone induced pathway
What would happen to a human if there was a mutation of Ser 14 to Ala 14 in its liver glycogen phosphorylase?
b cannot be converted into the much more active a form. Hence, the mobilization of liver glycogen will be markedly impaired
CoQ is a mobile electron carrier in the ETC. It is most likely
hydrophobic
Why can’t G1P leave the cell?
there is no membrane transporter for G1P
The hemes on Complex IV are considered
prosthetic groups
In general, transaminase catalyzes
a group transfer
The glycerol 3 phosphate dehydrogenase shuttle provides
means to collect the electrons from NADH reduced in glycoslysis
T/F
A typical muscle cell during rest will have more glycogen phosphorylase b and more glycogen synthase a
True
What is the purpose of the Q cycle?
it allows for a mobile carrier of 2 electrons to donate them to an acceptor that only takes 1 electron
A synthase generally catalyzes
a covalent bond formation
When glucose levels are high ____ is released into the bloodstream, and when glucose levels are low ____ is released.
insulin, epinephrine
What does insulin do?
activates GLUT4 receptors by making them more sensitive to glucose on fat and muscle cells
The relative concentrations of ATP and ADP control the cellular rates of
transition reaction
ETC
glycolsysis
What is unique about the active site of glycogen phosphorylase?
the active site is wide enough for approximately 5 glucose molecules to fit in the region
What does insulin inhibit?
glycogen synthase kinase (GSK)
What two metabolites are predicted to increase in skeletal muscle when fat becomes the major substrate oxidized?
acetyl CoA, citrate
