Duchaine Flashcards
the last step of the
biosynthesis of Cholesterol occurs by
reduction by
NADPH
Acetyl CoA
Commonly
used to add 2 carbons to
biomolecules (e.g. A.A.s)
Condensation vs Hydrolysis
Condensation produces H2O and is energetically unfavourable
Hydrolysis requires H2O and is energetically favourable
Examples of condensation reactions
polysaccharides, nucleic acids, proteins
Examples of hydrolysis reactions
ATP to AMP
Stepwise oxidation of sugar in cells
What happens to energy
small activation energies overcome at body temperature owing to the presence of enzymes
activated carrier molecules store energy
direct burning of sugar
What happens to energy
large activation energy overcome by the heat from a fire
all free energy is released as heat; none is stored
glycolysis molecules
- one molecule of glucose
- fructose 1,6-biphosphate
- two molecules of glyceraldehyde 3-phosphate
- two molecules of pyruvate
One molecule of glucose
two molecules of pyruvate
Fructose 1,6-biphosphatase
reverses the activation of
Fructose 6-phosphate, hence creating an apparently ‘futile cycle’
Glycolysis net products,
2 molecules of NADH and 2 of ATP and 2 pyruvate
hexokinase
The phosphorylation of glucose at position 6 in glycolysis
glucose + ATP to glucose 6-phosphate +ADP
phosphoglocose
isomerase
the isomerization of glucose-6-phosphate to fructose-6-phospate
phosphofructokinase
the phosphorylation of fructose-6-phosphate
aldolase
the cleavage of fructose-1,6-bisphosphate by aldolase. This yields two different
products, dihydroxyacetone phosphate and glyceraldehyde-3-phosphate
triose phosphate isomerase
the isomerization of dihydroxyacetone phosphate to another molecule of
glyceraldehyde phosphate
glyceraldehyde-3-phosphate dehydrogenase
the dehydrogenation and phosphorylation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
phosphoglycerate kinase
the transfer of the 1-phosphate group from 1,3-bis-phosphoglycerate to ADP to yield ATP, which yields 3-phosphoglycerate
phosphoglycerate
mutase
the isomerization of 3-phosphoglycerate to 2-phosphoglycerate
enolase
the dehydration of 2-phosphoglycerate to phosphoenolpyruvate
pyruvate kinase
the transfer of the phosphate group from phosphoenolpyruvate to ADP, to yield another ATP
From the pyruvate and NADH produced what can be excreted
fermentation leading to lactate by NAD+ regeneration
fermentation leading to excretion of alcohol (ethanol) and CO2
Hydrolysis of stored fat results in
fatty acids, glycerol
fatty acids being oxidized results in
ATP and CO2
Fatty acids and sugars are all converted into
acetyl CoA
One turn of the Krebs cycle (Citric acid cycle) produces
three NADH, One GTP, and one FADH2, two molecules of CO2
Fad to FADH2
2H and 2e-
Mitochondria vs chloroplast
mitochondria –> outer, inner, membrane, intermembrane space, matrix space
chloroplast –> outer, inner, membrane, intermembrane space, stoma, thylakoid membrane, thylakoid space
How is hydrogen moved across the membrane
high enegy electron to a low energy electron and the hydrogen is moved
What follows glycolysis?
kreb cycle
Where does the Krebs (Citric acid) cycle occur?
matrix of the mitochondria
How does the Krebs (Citric acid) cycle start?
Starts by the coupling of two carbons carried by AcetylCoa, generating Citric acid (6 carbons) from
Oxaloacetate (4 carbons).
Carbons in Citric acid
6 carbons
Carbons in Oxaloacetate
4 carbons
What happens to citric acid? why?
Citric acid is progressively oxidized to yield high-energy
activated carriers, and regenerate Oxaloacetate.
Each citric acid cycle yeilds
Each cycle produces 3 NADH, 1 FADH2, 1GTP, and 2
CO2 (waste).
Does the citric acid cycle require oxygen?
Requires Oxygen
Density gradient centrifugation on mitochondria
seperates the layers, inner membrane, outer membrane, and matrix
Where is the cardiolipins
rich in Inner membrane
Combustion
H2+1/2O2 = H2O
Oxidative phosphorylation
ADP to ATP while NADH to NAD+
Electron transport
drive pump that pymps protons across membrane
Where does electrons from through?
HNADH dehydrogenase complex, cytochrome b-c1 complex, cytochromo oxidase complax
The electron transport carriers
Composed of more than 15 electron carriers
(>60proteins) embedded within the inner membrane
What does the electron transport allow for
Sequential changes in conformation permit the
translocation of protons across the membrane
What does the electron transport utilize
Utilize Heme groups, Ubiquinone, Iron-Sulfur centres,
and copper atoms to ‘handle’ the electrons.
How do electrons move in electron tranport chain
The electrons move from one carrier to another, going
from an high energy state, to the lowest energy state
(towards greater redox potential)
End point of electron tranport chain
• The end point is the reduction of Oxygen into H20
Confomation A, B, and C, affinity for hydorgens
A - high affinity for H+
B - high affinity as H is bound
C- low infinity as H+ is released
In normal conditions what happens to the a,b,c,d units to produce O2
partially oxidized
In anaerobic conditions what happens to the a,b,c,d units to produce O2
fully reduced
An electrochemical proton
gradient
High positive and hydrogen concentration in intermembrane space
low hydorgen and high negative charge in matrix
What does the voltage gradient in inner membrane drive?
ADP-ATP exchange
What does the pH gradient in inner membrane drive?
pyruvate import
Voltaic membrane difference
180 to 190 mV
pH osmotic membrane difference
0.5 pH units
What does the work to pump protons across inner membrane of the mitco
Electrons in Chemio-Osmotic coupling
In Chemio-Osmotic coupling what donates the electrons
NADH and FADH2
The energy stored within this gradient is used to
ATP: Oxidative phosphorylation
by the FoF1 ATP synthetase complex
ATP per NADH
2.5
ATP per FADH2
1.5
FADH2 gives its electrons lower in the ETC, lower
yield
ATP per glucose
–Under normoxic conditions,
the TOTAL YIELD of ATP per glucose =30ATP
Oxidized form
Reduced form
NADP/NADPH
Oxidized form- NADP
Reduced form- NADPH
What is required in oplymerization reacrion?
one packet of energy is not sufficient for the polymerization reaction and therefore the chemistry that’s involved actually burns both bonds that are invested in phosphate
maximize the flow of energy by
stepwise oxidation with stored energy in activayted carriers
How is the PFK regulated by GDP
allostericallly
ATP and AMP levels on PFK and fructose 1,6, biphosphate
PFK inhibited by ATP
F16BP inhibited by AMP
What drives the entire reaction glycolysis
pyrvuvate kinase
transfer of one phosphate to ADP to form ATP
most others are in equilibrium
ATP in glycolysis
Invested
Produced
Net
2
4
+2
What forms a bond with glyceraldehyde-3-phosphate
covalent bond to SH group of a cysteine side chain of enzyme glyceraldehyde 3-phosphate dehydrogenase
also forms noncovalent to NAD+
What happens to thioester bond?
oxidation and phosphate displaces forming 1-3 bisphosphooglycerate
What happens in the final step of 7?
high energy bond to phosphate is transferred to ADP forming ATP and 3-phosphoglyerate
Summary of steps 6 and 7 in terms of molecular shapes
aldehyde to a carboxylic acid with NADH and ATP produced
- OXIDATION OF SINGLE BOND
IS STEP 6 AND 7 favoured
energetically favoured
creatine phosphate
restore ATP
Purpose of fermentation
quick ATP generation
How do animals generate ATP such as gold fish
use pyruvate and covert tp acetaldehyde producing NAD+ and CO2/ethanol
Convertion of pyruvate to acetyl coA
produces NADH
oxidation of fatty acids form
ATP and CO2
What comes out of a fatty acetyl CoA?
get rid of 2 carbons
produces NADH and FADH2 and one acetyl CoA
18C fatty acetyl Coa produces how many
Acetyl CoAs
Cycles
NADH
FADH2
9
8
24
8
what is better source of energy?
fatty acids but slower
What drives NADH to NAD and the electrons to ATP
O2
oxidative phosphorylation
Net products from one glucose molecule in mitochondria
2 pyruvate –> 8 NADH +2 FADH2 +2 GTO
Net products from one fatty acid molecule in mitochondria
8 acetyl Coa + 1 palmitoyl CoA –> 31 NADH +15 FADH2 + 8 GTP
The flow of electrons throgh ETC
NADH to NAD+ as the electrons move through NADH dehydrogenase complex as H+ is pumped into intermembrane space
Hydrogen is pumped into intermembrane space through cytochrome b-c1 complex and electrons move into cytochrome oxidase complex
in cytochrome oxidase complex the Hydrogen is pumped across and 2H combine with 2 e- and 1/2 O2 to form an H2O
Free energy in each of the complex
NADH dehydrogenase complex
cytochrome b-c1 complex
cytochrome oxidase complex
highest to lowest free energy per electron
Cytochrome c and ubiquinone purpose
handle electrons and hand them over
Where is hydrogen being pumped in the ETC
matrix to intermembrane space
Electron path
NADH dehydrogenase to ubiquinone to cytochrome b-c1 complex to cytochrome c to cytochrome oxidase complex
How many electrons are put into the ETC by NADH
2
Electron transport is coupled with
hydrogen transport to change charge back to normal
fully reduced ubiquinone
contains 2 e- and 2 H+
Heme purpose
they are reduced and oxidized in generally increasing reduction potentials to transfer four electrons ultimately to reduce O2
how many electrons at once entering from cytochrome c
4 which produce two h2Os
What are some electron handlers
heme groups, ubiquinone, iron-sulfur centers, and cooper atoms
What will increase in anaerobic conditions?
lactate and (CO2 and other things in gold fish)
How is hydrogen enter the matrix
Hydrogen gradient by ATP synthesis
by ATP synthase and converts ADP to ATP
How can H+ gradient be regenerated
by H+ pump using ATP to burn and produce gradient
ATP hydorlysis
Purpose of ETC in bacteria
flagellum to move around the Cecelia
Where do food molecules come from?
cytosol
Where does the citric acid cycle occur?
matrix
