Fructose can enter and be converted to F6P to generate 2-glyc-aldeh.
Glycerol is a storage sugar
Can be converted to gly-3-phosp
Just be aware of other molecules
Polysaccharides have to undergo
Glycogen undergoes phosphorolytic cleavage, a breakage of alpha 1,4 bond to release glucose unit.
Glycolysis can be reversed
It requires ATP to generate glucose
Used when muscles undergo stress
If cells are deprived of nutrients or food
Slide 17 – The Krebs Cycle
Pyruvate enters and mito. Matrix, it moves through facilitated diffusion due to charge.
Convert pyruvate to acetyl coa
Acetyl coa is oxidized in krebs cycle and used to make CO2
NADH contributes to ETC
Coenzyme a is acetylated to generate acetyl CoA
Pyruvate to acetyl CoA enzyme
Acetyl CoA generates krebs cyele
For each pyruvate you get 3 NADH and FADH2 and 2CO2
We also generate a GTP for each pyruvate
Total: 6NADH 2FADH2 4CO2 2GTP
Sister molecule to ATP, it can transfer a Pi group to ADP as well
E- transport carriers tranport e- to ETC
When pyruvate moves into mito, converted to acetyl CoA, krebs cycle, generates CO2 NADH, FADH2, and the e- carriers will donate e- to specific and concentrated protein in inner mito matrix
Inner mit. Matr. Has a high ratio of proteins to lipids in membrane. 90% protein
Citric Acid Cycle
Tranfers protons to NAD+
Protons come from H20, which is used to provide extra protons
ETC, molecular O2 is used to make H20 at end of chain.
Inner membrane has cristae which increase surface are for ETC. more cristae = more ETCs/more energy made
Matrix: enzymes to power krebs cycle, DNA, ribosomes for mito proteins
Involve movement of H from inner matrix to intermembrane space.
Pyruvate dehydrogenase drives reaction of reaction and it is a complex of 3 enyzmes that converts pyruvate to acetyl CoA
Transfers Acetyl group from pyruvate to CoA and bind the two to make acetyl CoA
Acetyl CoA can now enter Krebs cycle!
Step 1 of Krebs cycle
Association of 3 carbon acetyl coa sugar with 4 carbon oxaloacetate
The reaction that bring these two together generates citric acid (citrate), using H from water.
Citrate converted to isocitrate
Iso is alpha-keto
Generated one NADH
Another NADH is produced
Succinyl CoA to succinate
GDP becomes GTP
Coenzyme A is produced
Used again at conversion reaction to make acetyl CoA
Succinate will continue to produce oxaloacetate
2 turns of the citric acid cycle produces 6NADH 2FADH2 2GTP
NADH is a reduced b-vitamin
FADH2 is a riboflavin, reduced flavin adenine dinucleotide, which arises from b vitamin riboflavin
1 glucose yield 6CO2 2ATP 2GTP 10NADH 2FADH2
12 high energy e- carrie molecules to inner matrix of mito
Niacin reduced to make NADH
FADH2 also made from riboflavin
Loses H readily in inner mitochondrial matrix
Guanine instead of adenine (ATP)
Regulatory Steps of Krebs Cycle
Pyruvate dehydrogenase is activated by low levels of ATP and vice versa
Hexokinase converts glucose to G6P
In citric acids cycle - 3 steps
Conversion of isocitrate to alpha-ketogluterate is regulated by the enzyme isocitrate dehydrogenase which produces the first NADH
INHIBITED BY HIGH LEVELS OF NADH AND ACTIVATED BY HIGH LEVELS OF ADP
Converstion of alpha-keto to succinyl coa
Alphaketo dehydrogenase puts H of NAD+ and regulated by high levels of NADH or high levels of succinyl CoA, if high, will shut don enzyme
Malate to oxaloacetate
When NADH is high, maltate dehydrogenase is inhibited, which converts maltate to oxaloacetate.
ETC generates a proton motive force used to power ATp synthase to make ATP
High energy e- transfer from FADH2 to O2
At the end of the ET water will be produced and ~34 ATP are produced due to ETC
For a singe NADH, 1/2 O2 and H removes H from NADH to make water
The last structure of ETC can hold O2 until the O2 obtains both e- to make H20, same for FADH2, instead of releasing a reactive ion.
Electron Chemical Gradient
Makes Chemiosmotic Coupled system
The unequal distribution of Hydrogen ions and charge across the membrane in which ATP synthase sits
NADH and FADH2 are in the inner mitochondrial membrane and they’re donating the electron hot potatoe hydrogens and the e-s that go along with them.
As e-s are donated, the proteins and complexes pump out H into the intermembrane space from membrane space across inner membrane
More positive charge is out of matrix and moved to inter membrane space
E-s transported provide mechanism of energy to move H and create a chemisomotic gradient w/ negative charge on inside.
The driving force that goes through the ATP synthase is so large that it doesn’t require energy to make ATP.
Uses protons to rotate and that rotation sucks in ADP
Concentration gradient is less
pH differential across membrane
more acidic in intermembrane space than in matrix space
There are 4 protein complexes that accept high energy e-s
They are complexes, not individual proteins
Complex I and II refer to the NADH dehydrogenase complex
Ubiquinone is an intermediate e- transfer protein is aka coenzyme Q
Tranfers 2 hydrogens from intermembrane space
For transfer of 2 e- from NADH 4 protons across the membrane
Cytochrome b-c1 is the complex III
Cytochrome c is another intermediate
Does not transport H
2 H move
Cytochrome oxidase complex IV
Makes water and holds oxygen until all H and e-s are transferred
2 H move
10 total H moved across membrane
we have dehydrogenated NADH
as we remove from NADH, you convert into a H+ proton, 2 e- and the 2- are transported along the complexes, and at each stage H are pumped, and eventually allow the transfer of molecular H2 to make water.
Reduction Potentials (slide 29)
NADH dehydrogenase has the largest reduction
The energy left is used by cytochrome oxidase complex to make H20
Coenzyme Q and cytochrome c
Cytochrome c is embedded in the membrane
Does not transport H across, simply accepts e-s
Has an iron heme that hold e-s that is linked to a copper ion that allows that O2 to be held until enough H has moved through complex 4 to make water stable
Complex 4 is important to make sure cell isn’t damaged by the oxidative phosphorylation