Dr Johnson - Done Flashcards
What is the meaning of anabolism?
the non-spontaneous production of a molecule
What is the meaning of catabolism?
the spontaneous break down of a molecule
what is the meaning of the term redox?
the simultaneous oxidation and reduction
What enzyme catalyses the production of Glucose-6-Phosphate?
hexokinase
What substrate is added with glucose in step 1 of glycolysis?
ATP
what product is formed in step 2 of glycolysis?
fructose-6-phosphate
what enzyme catalyses the production of fructose-6-phosphate?
phosphoglucose isomerase
what is produced in step 3 of glycolysis?
fructose-1,6-bisphosphate
what substrate is added in step 3 of glycolysis?
ATP
what enzyme catalyses the production of fructose-1,6-bisphosphate?
phosphofructokinase
what is produced from fructose-1,6-bisphosphate in step 4 of glycolysis?
GADP and DHAP
What catalyses the splitting of fructose-1,6-bisphosphate?
aldolase
What is produced from the GADP produced in steps 4/5 of glycolysis?
1,3-biphosphoglycerate
What is the first energy yielding reaction in glycolysis and how is the energy stored?
Step 6, production of 1,3-biphosphoglycerate, NADH/H+
Why is a phosphate added to GADP to form 1,3-biphosphoglycerate?
To increase the phosphoryl transfer potential
What is catalysed the production of 3-phosphoglcyerate?
phosphoglycerate kinase
How is ATP produced in step 6 of glycolysis?
substrate level phosphorylation
what is produced from 1,3-biphosphoglycerate in glycolysis?
3-phosphoglcyerate and ATP
What is produced from 3-phosphoglycerate in step 8 of glycolysis?
2-phosphoglcyerate
What enzyme catalyses the production of 2-phosphoglycerate
phosphoglycerate mutase
Why is 3-phosphoglycerate converted to 2-phosphoglycerate?
Increases phosphoryl transfer potential
What is 2-phosphoglycerate broken down into in glycolysis?
Phosphophenolpyruvate and water
What catalyses the production of phosphophenolpyrulvte?
enolase
why is phosphophenolpyruvate produced in step 9 of glycolysis?
Increases phosphoryl transfer potential
What is the final step of glycolysis?
Production of Pyrucate and ATP from Phosphophenolpyruvate
What enzyme catalyses the final step of glycolysis?
Pyruvate kinase
Why do cancer cells acidify the surrounding environment?
damages cells around it resulting in tumour invasion
why do cancer cells grow without oxygen?
the blood vessels develop slower meaning their growth is not restricted?
How can the Warburg Effect be used to visualise cancer cells?
FDG is a glucose analogue so is brought to highly respiring cells
What is the end product of fermentation in the muscle cells?
2 lactate molecules per glucose
What is the end product of fermentation in yeast cells?
ethanol and CO2
when does fermentation take place?
when O2 is not available as the terminal electron acceptor
What is the main advantage of complexing a group of enzymes?
prevents side reactions
minimises distance
increase substrate channeling
What is does pyruvate react with in step one of the link reaction?
TTP to form hydroxyethyl TTP and CO2
What does hydroxyethyl TTP bind to in the second step of the link reaction?
Lipoamide to form Acetyl-dihydrolipoamide
In step 2 what is formed from Acetyl-dihydrolipoamide?
forms reduced lipoamide and acetyl CoA
what electron carrier is directly reduced by the reduced lipoamide molecule?
FADH to FADH2
What is the final electron acceptor for the link reaction?
NAD+ to NADH/H+
Why does fatty acid oxidation result in more energy/more ATP being produced?
Fatty acids are more reduced and therefore can be oxidised more
What are the products made in Fatty acid oxidation?
CoA, FADH2, NADH/H+
What type substrates join in step 1 if the CAC?
Oxaloacetate and Acetyl CoA
What catalyses the formation of citrate in the CAC?
Citrate synthase
What is produced in step 2 of the CAC?
isocitrate
What catalyses the production of isocitarte from citrate?
Aconitase
What occurs in the reaction to form isocitarate
Water is removed and then added back again
What is made after isocitrate in the CAC?
alpha-ketoglutarate
What molecules are produced along with alpha-ketoglutarate?
NADH/H+ and CO2
What enzyme catalyses the production of alpha-ketoglutarate?
Isocitrate dehydrogenase
What compound is added to alpha ketoglutarate to form succinyl CoA?
CoA
What compounds are made along with succinyl CoA?
NADH/H+ and CO2
What enzyme catalyses the production of succinyl CoA?
oxoglutarate dehydrogenase
Why is the production of succinyl CoA favourable?
It is an oxidation reaction
What does Succinyl CoA react with to form Succinate?
ADP, H2O and Pi
What by products are made by Succinate is formed?
ATP and CoA
What enzyme catalyses the production of succinate?
Succinyl CoA synthase
succinate combines with what molecules to produce fumurate and a by-product?
FAD
what enzyme catalyses the production of fumurate from succinate?
succinate dehydrogenase
Why is FADH2 produced when fumurate is made form succinate and not NADH/H+?
The energy released is not enough to couple the reduction of NAD
what is added to fumurate to form malate?
H2O
what enzyme catalyses the production of malate?
fumurase
what is the final step in the CAC?
Malate +NAD+ -> oxaloacetate +NADH/H+
what enzyme catalyses the production of oxaloacetate?
malate dehydrogenase
What was the main indicator that the CAC was in fact a cycle?
Many of the substrates are poisons
What is the role of KOH in the Warburg manometer?
absorbs CO2
What happens to the pressure in the flask of the Warburg Manometer as respiration takes place?
It increases
Which molecule is oxidised first in the G3P shuttle?
NADH/H+
What is the final electron acceptor in the G3P shuttle?
Ubiquinone
What is the aim of the G3P shuttle?
allows high rate of oxidative phosphorylation as cytoplasmic NAD+ is made
What is the aim of the Malate-Asparatate shuttle?
Produce NADH/H+ in the mitochondrial matrix
How could you describe the protein channels used in the Malate-Aspartate shuttle?
Antiports
What does malate move into the matrix in return for?
alpha-ketoglutarate
What does aspirate move into the cytosol in exchange for?
glutamate
What is the name of the inner most region of the mitochondria?
matrix
What is the name of the infolding membrane structures in the mitochondria?
cristae
What gradient is formed across the mitochondrial inner membrane?
Proton gradient
Why is the proton gradient produced in the mitochondria?
to allow the production of ATP
What is the best way to describe the electron transport chain?
downhill flow of electrons in energetically favourable redox reactions
If an electron potential is more negative, what does this mean about the substance?
it is more likely to donate electrons
if an electron potential is more positive. what does this mean about the substance?
It is more likely to accept electrons
What concentration should the compounds be in when measuring redox potentials?
Equimolar, equal parts of reduced and oxidised
For a standard redox potential, what are the conditions in the Hydrogen half cell?
1 atm H2, 1M H+
Why do we sometimes change the concentration in the hydrogen half cell when measuring redox potentials? What are the conditions changed to?
10^-7 M H+, physiological pH of the cell (pH=7)
What is the function of the salt bridge when measuring redox potentials?
To allow ions to flow neutralising difference in charge
What is the equation for free energy in terms of redox potential?
ΔG ̊= -nFΔE0
In the equation for free energy in terms of redox potential, what does n stand for?
number of electrons
In the equation free energy in terms of redox potential, what does F stand for?
Faraday constant
Why is aerobic respiration only 54% efficient?
energy is lost through heat
What classifies a protein as a flavoprotein?
uses FAD/FADH2 as a cofactor
Do flavoproteins allow more or less H+ to be pumped into the inner membrane space?
fewer
What complex do flavoprotein bypass?
Complex I
What molecule is reduced by Flavoproteins?
Ubiquinone
Which complex uses Flavin mononcleotide as a cofactor?
Complex I
Where does Complex I gain the 2 electrons from in the ETC?
oxidation of NADH/H+ to NAD+
How many protons are removed from the matrix by Complex I in the ETC
4 are directly pumped
2 are taken up to reduce UQ
What molecules are used internally in complex I of the ETC to transport electrons?
FMN
Iron-sulfur complexes
Which complex reoxidises the UQH2 produced by Complex I in the ETC?
Complex III
How many protons are moved by Complex III of the ETC?
0 are directly pumped
4 are moved due to oxidation of 2 UQH2 molecules
What molecules are reduced by the electrons produced by Complex III?
2 Cytochrome C molecules
1 Ubiquinone molecule
How many protons are removed from the matrix by Complex III, and what are they used for?
2, they reduce UQ
What complexes are used to channel electrons internally in Complex III?
Iron sulfur complexes
Haem groups
What is the enzymatic name of complex II in the ETC?
succinate dehydrogenase
What is produced when fumurate is formed from succinate by Complex II in the ETC?
2 FADH2
What complexes are used to transport electrons in Complex II of the ETC?
Iron sulfur complexes and Haem groups
What molecule does Complex IV of the ETC oxidise?
cytochrome c
What groups transfer electron in Complex IV of the ETC?
Haem
What is the fate of the electrons from the oxidised Cytochrome C in Complex IV of the ETC?
join with 2H+ from matrix and 1/2 O2 to form water
Where does the energy come from in Complex IV of the ETC to allow direct pumping of 2H+?
Formation of water
Who developed the chemiosomotic theory?
Mitchell
What was the original hypothesis for the production of ATP before chemiosomsis?
A high energy intermediate
What proton pump molecule was used to show chemiosomotic theory?
Bacteriorhodopsin
How did Mitchell show that the proton gradient was needed for ATP production?
He put an uncoupler in to allow H+ movement and prevent the gradient from building up
How does ATP synthase provide energy from the proton gradient present across the membrane?
protons with potential energy bind to the rotating ring structure allowing the transfer to mechanical/kinetic energy
Why does the F1 head of ATP synthase change conformation?
The stalk is connected to the head and spins changing the confirmation of the Beta domains
What is the O conformation of the Beta domain of ATP synthase?
change over between ATP release and ADP+Pi binding
What is the L conformation of the Beta domain of ATP synthase?
production of ATP
What is the T conformation of the Beta domain of ATP synthase?
ATP remains bound
What is the equation for calculating the free energy using the membrane potential and PMF?
Δp = Δψ - 2.3 RT/F ΔpH ΔG = -nFΔp
