Chapter Nine: Cellular Respiration: Harvesting Chemical Energy

Q1: where does cellular respiration take place?

A1: in mitochrondia, prokaryotic cell in cytoplasm.
Q2: why is cellular respiration important?
A2: Living cells require transfusions of energy from outside sources to perfirm their many tasks. and cellular respiration is the process that living things can change sources to energy.
Q3: what's the defference between fermentation and anaerobic?
A3: fermentation only get through glycolysis, only produce a few ATP. anaerobic respiration takes place in centain prokaryotic organisms do not use oxygen as a final electron accepetor.



Five Facts:
1. glycolysis harvests chemical energy by oxidizing glucose to pyruvate
2. the citric acid cycle completes the energy yielding oxidating of organic molecules
3. during oxidative phosphorylation. chemiosmosis couples electron transport to ATP synthesis
4. fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen
5. catabolic pathways yield energy by oxidizing organic fuels



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Substrate-level phosphorylation is a type of chemical reaction that results in the formation and creation of adenosine triphosphate (ATP) by the direct transfer and donation of a phosphoryl (PO3) group to adenosine diphosphate (ADP) from a reactive intermediate. While technically the transfer is PO3, or a phosphoryl group, convention in biological sciences is to refer to this as the transfer of a phosphate group. In cells, it occurs primarily and firstly in the cytoplasm (in glycolysis) under both aerobic and anaerobic conditions.

Summary:
Oxidation-reduxtion reaction, or redox reaction is the electron transfers. Redox reaction loss elelctrons from one substance called oxidation, and addition of electrons to another substance reduction. NAD+ is electron carrier coenzyme. Electron transport chain breakdown electrons in many steps in order to control the release of energy. C6H12O6 (aq) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) is the whole process of cellualr respiration which require oxygen. Anaerobic respiration and fermentation don't need oxygen. fermentation only get through glycolysis, only produce a few ATP. anaerobic respiration takes place in centain prokaryotic organisms do not use oxygen as a final electron accepetor.Cellular respiration can be diveded into three processes:glycolysis, citric acid cycle, and oxidative phosphorylation.
Glycolysis breakdown glucose into two three-carbon pyruvates. It occures in cytosol. Its reactants are glucose, 2ATP, NAD+; products are 2pyruvate, 2H2O, 4ATP, and 2NADH. It has energy investment and energy payoff. By the end of energy investment, glucose breakdown to Glyceraldehyde-3-phosphate. Citric acid cycle complete breakdown and take place in mitochrondia matrix. It needs pyruvate, coe A, 4NAD+, 1ATP, and 1FAD and produces 3CO2, 1ATP, 4NADH, and 1FADH2. Oxidative phosphorylation is in mitochrondia cristae. It requires NADH, FADH2, ATP, and oxygen, and produces NAD+, FAD, ATP, and water. It has electron transport chain and chemiosmosis. Hydrogen ions from NADH and FADH2 go out then flow back by ATP synthase. The whole energy sequence is: glucose-NADH-electorn transport chain-proton motive force-ATP.

Key Term:

1. acetyl CoA-Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme.
2. alcohol fermentation-Glycolysis followed by the conversion of pyruvate to carbon dioxide and ethyl alcohol.
3. chemiosmosis-An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cells occurs by chemiosmosis.
4. facultative anaerobe- An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present.
5. obligate anaerobe-An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.
6. oxidizing agent-The electron acceptor in a redox reaction.
7. ATP synthase-A complex of several membrane proteins that provide a port through which protons diffuse. This complex functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membrane of eukaryotic cells and in the plasma membrane of prokaryotes.
8. lactic acid fermentation-Glycolysis followed by the conversion of pyruvate to lactate, with no release of carbon dioxide.
9. substrate-level phosphorylation-The formation of ATP by an enzyme directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.
10. cytochrome-An iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells.

Video:

http://www.youtube.com/watch?v=_hGW6NjCUSs