Describe the characteristics of respiration
*oxidatative phosphorylation captures the energy of high energy electrons to synthesize ATP
* The flow of electrons from NADH and FADH2 to O2 occurs in the electron transport chain or respiratory chain
*the exergonic set of oxidation-reduction reactions g
The citric acidy cycle and oxidative phosphorylation are called
cellular respiration
O2 required, Acetyl-CoA, Complete oxidation to Co2, , High electron carriers FADH2 and NADH, redox reactions
Aerobic Metabolism
The electron transport chain is a series of coupled-oxidation reduction reactions name the high energy carriers
NAD+/NADH, FAD/FADH2
How many rounds of the calvin cycle are required for the production of hexose 6C
6 rounds
What complex does not require proton pumps
complex II
How is succinate dehydrogenase unique when compared to other enzymes in the citric acid cycle
it is the only enzyme embedded in the mitochondrial membrane, it is directly associated with the electron transport chain
Intermediates of the citric acid cycle have been arranged alphabetically below. What is the correct arrangement based on sequential appearance as intermediates in the citric acid cycle?
citrate, isocitrate, a -ketoglurarate, succinyl CoA, succinate, fumareate
Although tth atp/adp ratio and the availability of substrates and cycle intermediates are very important factors affecting the rate of the citric acid cycle, the NADH/NAD+ ratio of paramount importance. Why?
the oxidized cofactors NAD+ and FAD are absolutely required as electron acceptos in the multiple dehydrogenase reactions of the Citric acid cycle. When these oxidized cofactors are not available, the citric acid stops ( reoxidation stops in the absence of
of the enzymes of the citric acid cycle, which is not a freely soluble enzyme
succinate dehydrogenase
in the reaction catalyzed by succinyl-CoA synthetase, a sucinylphosphate transfers its phosphate to a ___
histidine residue
In going from acetyl-CoA to succinate, two carbons have enetered the cycle and two have been released as Co2. Why is the cycle not considered as complete at this point?
the oxaloacetate used to initiate the cyle must be regenerated
Which enzyme of the citric acid cycle most closely resembles the pyruvate dehydrogenase complex in terms of its structure, organization and the reaction it performs?
a-ketoglutarate dehydrogenease
What is the correct statement concerning the enzymatic mechanism of citrate synthase
after citryl coA is fromed additional structural changes occur in the enzyme
Assuming the acetyl coA was labeled with radioactive 14C as depicted below, where would the radiolabel appear after one turn of the citric acid cycle?
equally divieded between the carboyzyl groups of oxaloacetate
Which are the energy capture sites in the Citric acid cycle
steps 3,4,5,6,8
why is citric acid cycle considered to be part of aerobic metabolism even though O2 does not explicity appear in any reaction?
because it produces reduced electron carriers which are re-oxidized by transferring their electrons ultimately to oxygen, . Citric acid cycle depends on a steady supply of NAD+ generated from NADH by readion of NADH with oxygen , if there is no exygen to
How do nonphotophosynthetic cells and organisms generate NADPH
the pentose phosphate pathway
what is the rate limiting step of the pentose phosphate pathway
the first reaction of the pentose phosphate pathway
In the pentose phosphate pathway no ____is produced
ATP
The most important regulatory factor in the pentose phosphate patheway is
concentration of NADP+
Pentose phosphate pathway can operate in four distinct modes , name these
1. Ribose 5-phosphate needs exceed the needs for NADPH
2. NADH and ribose 5-phosphate needs are balanced
3. More NADPH is needed than ribose 5-phosphate
4. NADPH and ATP are both required
NADPH generated by the pentose phosphate pathway is required to maintain adequate levels of
reduced glutathoine
_____ can cause the red blood cells to lyse
Heinz bodies
The pentose phosphate pathway is compsed of two distinct phases what are these and what are their roles?
Oxidative phase (generates NADPH is irreversible)
Nonoxidative phase ( allows for the interconversion of phosphorylated sugars
Glucose is normally completely oxized to ____ in the mitochondria
CO2
Under what what circumstance can glucose be completely oxidized to CO2 in the cytoplasm
When NADPH is required
the oxidative phase of the pentose phosphate pathway is followed by the nonxoidative phase, the resulting fructose 6 phosphate and glyceraldehyde 3-phosphate are used to generate glucose 6-phosphate through gluconeogenesis, the cycl
How can ribose be used as a fuel
mode 4
explain why the calvin cycle and the pentose phosphate are almost mirror images of each other?
NADPH in the synthesis of glucose, the PPP begins with oxidation of a glucoase- derived carbon atom to CO2 and generates NADPH. The regeneration phase of the CA cycle converts C6 and C3 molecues back into the starting material -the C5 molecule
Phosphate into C6 and C3 are _______ of the glycolytic pathway
intermediates
phosphorylation has opposite effects on glycogen synthase and
glycogen phosphorylase
why is the fact that phosphorylation has opposite effects on glycogen synthesis and breakdown advantageous?
it prevents synthesis and breakdown from taking place simultaneously which would lead to a useless expenditure of energy
phosphorylation of glycogen synthase happens by
protein kinase A and glycogen synthase kinase ( GSK)
_____ plays a key role in regulating glycogen metabolism
protein phosphate 1
largest stores of glycogen are in the
liver ( 10 % total weight) and muscle ( 2% of total weight)
enzymatic breakdown of glycogen happens by
glycogen phosphrylase and glycogen debranching enzyme
regulation of glycogen phosphorylase happens by _____ and regulation of phosphorylase kinse happens by ____
phosphorylase kinse, hormones
In the glycogen structure the R group attached is called the reducing end ( free hemiacetal) which can interact with
oxidizing agents
glycogen phosphorylase reaction cleaves
a( 1,4) bonds
In glycogen phosphorylase what are the allosteric interactions: hormone regulators?
insulin, epinephrine, glucagon
what is the difference between phosphorylation and phosphorlase
Lation is a transfer of a phosphate group from ATP to the enzyme. Lase catalyzes a completely different reaction by the insertion of a phosphate group into a glycoside bond
What is insulin and glucagon's role in glycogen phosphorylase?
insulin is the signal of the fed state, leads to the dephosphorylation of glycogen phosorylase a to the b form
glycagon signals low blood sugar, leads to phosorylation of glycogen phosphorylase b to the a form
____converts phosphorylase b to phosrylase a and also controls rate of glucose release from glycogen?
phosohorylase kinase
In fasting glucagon ______ and _______. In exercise epinephrine enhances glycogen breakdown in muscle and the liver and provides fuel for _____
stimulates glycogen breakdown in the liver when blood glucose is low, muscle contraction