27 terms

5 steps 5 chapter 7 Respiration

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Aerobic respiration
Energy producing reactions in animals that involve three stages: glycolysis, the Kreb's cycle, oxidative phosphorylation. Requires oxygen.
Anaerobic respiration
Energy producing reactions, known as fermentation, that do not involve oxygen. It begins with glycolysis and concludes with the formation of NAD+.
Glycolysis
Occurs in the cytoplasm of cells and is the beginning pathway for both aerobic and anerobic respiration. During glycolysis, a glucose molecule is broken through a series of reactions into two molecules of ATP, NADH and pyruvate.
PGAL (phosphoglyceraldehyde)
Molecule important to energy producing reactions photosynthesis and respiration.
Key, idea glycolysis
One glucose = 2 pyruvate, 2ATP, 2 NADH
It always produces 2 ATPs under aerobic and anaerobic conditions
Kreb's cycle
Energy-producing reaction that occurs in the matrix of the mitochondria, in which pyruvate is broken down completely in H2O and CO2 to produce 4 NADH, 1FADH2, and 1 ATP.
Mitochondria
Double membrane organelle That is the host for Kreb's cycle in the matrix and oxidative phosphorylation in the cristae.
Key idea kreb's cycle
Each glucose dropped into glycolysis the kreb's cycle occur twice. Each pyruvate dropped into the kreb's cycle produces 4NADH, 1FADH2, 1ATP, and 2 CO2. The pyruvate from original molecule produces: 8 NADH, 2FADH2 and 2 ATP.
glucose produces what kind of energy related compounds in the Krebs cycle
1 glucose= 10 NADH, 2 FADH2, 4 ATP
Oxidative phosphorylation
Aerobic process in which NADH and FADH2 send their electrons down the electron transport chain to produce 34 ATP.
Key idea glucose = how many ATP?
In total during aerobic respiration each molecule of glucose can produce 36 ATP.
Electron transport chain (ETC)
The chain of molecules, located in the mitochondria, that passes electrons along during the process of chemiosmosis to regenerate NAD+ to form ATP. Each time an electron passes to another member of the chain, the energy level of the system drops.
Remember anaerobic conditions in electron transport chain...
1/2 O2 is the final acceptor in the chain, and if no O2 is present (anaerobic conditions) the production of ATP from NADH and FADH2 is compromised.
How many ATP can be produced from NADH and FADH2?
Every NADH that goes through the electron transport chain can produce 3 molecules of ATP while each FADH2 can only produce 2.
what happens in the electron transport chain?
(Bucket of water being passed down to put out a fire)
Each time and electron passes to another member of the chain the energy level of the system drops. At the end the final electron acceptor 1/2 O2 accepts a pair of electrons and some hydrogen ions to produce water.
Chemiosmosis
The coupling of the movement of electrons down the electron transport chain with the formation of ATP using the driving force provided by a proton gradient. Seen in both photosynthesis and respiration.
Coupling reaction
It is a reaction that uses the product of 1 reaction as part of another reaction.
ATP synthase
Enzyme that uses the flow of hydrogens to drive the phosphorylation of an adenosine diphosphate molecule to produce adenosine triphosphate (ATP).
Key idea: Chemiosmosis
As molecules accept and pass on electrons they pump hydrogen ions in to the space between the inner and outer membrane of the mitochondria. This creates a proton gradient that drives the production of ATP.
Key idea: movement towards ATP synthase
The difference in hydrogen concentration on the two sides of the membrane cause protons to flow back into the matrix of the mitochondria through ATP synthase channels.
(Remember) where does chemiosmosis takes place?
Chemiosmosis takes place in the mitochondria BUT it also takes place in chloroplast during the ATP-creating steps of photosynthesis. BUT, there's a difference, the difference is that in photosynthesis light is driving the electrons along the ETC in plants.
Key Idea: Oxidative phosphorylation
1) Each NADH= 3 ATP.
2) Each FADH2= 2ATP
3) 1/2 O2 is the final acceptor of the transport chain and it will not function if oxygen is not present.
4) Oxidative phosphorylation serves the important function of regenerating NAD+ so that glycolysis and the Kreb's cycle can continue.
5) Chemiosmosis occurs in photosynthesis as well as respiration.
Key idea: why does fermentation occur?
If no oxygen is present the Electron transport chain can't work which causes a build up of NADH. This means that the NAD+ that is regenerated by oxidative phosphorylation isn't being produced which causes a NAD+ shortage. In order for glycolysis to proceed to the pyruvate stage it needs NAD+. this is why fermentation comes into play.
Fermentation
Anaerobic respiration pathway that occurs in absence of oxygen. Produces less ATP than aerobic respiration.
Alcohol fermentation
Occurs in fungi, yeast and bacteria. Pyruvate is converted in two steps to ethanol, regenerating two molecules of NAD+.
Lactic acid fermentation
Occurs in human muscle cells when oxygen is unavailable. Pyruvate is directly reduced to lactate by NADH to regenerate the NAD+ needed for the resumption of glycolysis.
Remember one thing of alcohol fermentation
Yeast, Fungi and bacteria produce ethanol.
Humans produce lactic acid. (only during O2 deficit.)
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