Chapter 9: Cellular Respiration Flashcards
Cellular Respiration and Four Processes
oxidation of organic compounds to extract energy in chemical bonds(OIL RIG); Glucose, oxygen, ADP, and a phosphate group create ATP; Overall, focus on what goes in and what comes out
Glycolysis, Pyruvate Oxidation, Krebs/citric acid cycle, and Electric Transport Chain
Glycolysis
- process of breaking apart glucose, Multiple enzymes and intermediates involved
What goes in: Glucose, 2 ATP invested(NEEDS push of energy to destabilize glucose and split glucose in half)
What comes out: 2 pyruvate, 2 NADH, 4 ATP(net gain of 2 overall!)
Remember this is about collecting those electrons, not just about ATP!
Summary: Two ATP are invested, a stable molecule of Glucose splits in half into pair of G3P(3 carbon molecules) by phosphates, Harvesting 2 NADH, creating 2 pyruvates for the next step, and has a gain 4 ATP(net gain 2)
1 glucose always equals 2 pyruvates, process doubled from beginning
Pyruvate Oxidation
happens in mito matrix, after sugar is coverted to pyruvate in glycolysis; electrons removed from molecule(oxidation is loss)
Connector between glycolysis in cellular cytoplasm and krebs cycle in mito matrix
Process: carbon is removed from pyruvate(3-carbon molecules) in the form of CO2; the chopped off portion of pyruvate has electrons being released that will be recaptured to help NAD+ become NADH; the pyruvate remaining after CO2 leaves will become attached to CoA to form Acetyl Coa
Pyruvate is ——– to Acetyl CoA: Oxidized! Pyruvate is breaking apart to provide electrons!
NAD+ is ——– to NADH: Reduced! Will collect the broken off electron(that is later dropped off at an electron transport chain!)
What goes in: 2 NAD+, 2 pyruvate, 2 CoA
What comes out: 2 CO_2, 2NADH
Citric Acid Cycle/Krebs Cycle
What goes in: Acetyl Co-A, 3 NAD+, FAD
What comes out: 3 NADH, FADH_2, 2 waste CO_2, ATP
Split into three Segments: A,B,C
All three segments are preparation for the Electron Transport Chain!
The point of these steps are to collect electrons in a more efficient way(avoid wasting energy) to have a big ATP payoff in Electron Transport Chain!
Segment A of Citric Acid Cycle/Krebs Cycle
A oxaloacetate(4-carbon) combines with Acetyl CoA(2-carbon) to form a 6-carbon citrate
After CoA gives up its two electrons here, it will be recycled to get more from pyruvate oxidation
Segment B
citrate loses two carbons(broken bond that generates CO2 and releases many electrons)
two carbons being lost from citrate will lead to Two NAD+ reduced to NADH(collects broken electrons twice; 5-carbon and then 4-carbon)
Segment C
the regeneration stage
the FAD is reduced to FADH2 when the 4-carbon group refunctions and collects more electrons
another NAD+ is reduced to NADH
Electron Transport Chain
What goes in: NADH, FADH2
What comes out: NAD+, FAD, ATP, H2O
In the inner mito membrane and intermembrane
Dropping electrons off in ETC from NADH and FADH2, Since they are transporter; Oxidation of NADH to NAD+ and FADH2 to FAD
Energy of electron is used number of times to pump protons out of mito matrix into the intermembrane space; High concentration of protons in intermembrane space from matrix will form a proton gradient
Hydrogen are pumped through here into the intermembrane space, with energy from some electrons; Harvesting many in order for hydrogen help form ATP
Electron giving energy here, but not just thrown away by itself after process; Becomes free radical, Will try bond with other things around it/possibly damage things; To avoid this, we make water in process(Hydrogen in intermembrane space and oxygen outside)
Oxygen is known as final electron acceptor in this process; If oxygen not available, process will back up
will lead to ATP synthase
ATP synthase
Protons all stored up, going down concentration gradient to link phosphate to adenosine diphosphate to create adenosine triphosphate
Chemiosmosis: Hydrogen flows down concentration gradient to help create ATP
Enzyme cofactors
nonorganic molecule that helps speed up chemical reaction)
Example: NAD+ and FAD
NAD+: Energy-rich molecule is oxidized, NAD+ is reduced to NADH; Two high energy electrons transferred to NAD+, H+ ions follow along to balance the charge
Can also be a two way street: From standpoint of NAD+, reduction left to right and oxidation right to left
FAD: reduces to FADH2 when collecting electrons from energy rich molecule, very similar to NAD+
Describe more about the final electron acceptor in cellular respiration
oxygen: collects final electron in ETC, from the outside of mitochondria and hydrogen in the intermembrane space
If not available, the process will get backed up(ATP not generated efficiently when this happens)
Helps move electrons down a chain to form ATP; Reduced to water to avoid free radical electron from disrupting anything
Lactic Acid Fermentation in Anaerobic respiration
When the final electron acceptor oxygen cannot flow, a temporary fix is allowing pyruvate to become a short term form of electron acceptor
(Reduced, OIL RIG, gaining electrons)
taking electron/hydrogen off of NADH to create lactic acid with 2 pyruvate; when hard points are over, 2 lactate will convert back to 2 pyruvate
Structures of mitochondria
outer membrane, intermembrane space, inner membrane, mitochondrial matrix
outer membrane
The outer membrane is a smooth, semi-permeable membrane that surrounds the mitochondrion. It contains large protein channels called porins that allow the passage of small molecules and ions.
Intermembrane space
The intermembrane space is the narrow region between the outer and inner membranes. It contains enzymes that are involved in cellular respiration, as well as proteins that help to transport molecules across the inner membrane.
hydrogens to form proton gradient for ATP from electron transport chain go here
