More of Chapter 7

Cellular Respiration

A process by which living cells obtain energy from organic molecules and release waste products.

Know formula for cellular respiration

C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP and heat) Waste = CO2 and H2O

• Know the steps of Glycolysis, the three phases, isomerase, the names of the intermediates, and when ATP/NADH is required and produced.

Glucose--> 2 ATP invested Fuctose 1,6 Bisphosphat--> enzyme that cleaves called Isomerase 2 G3P release 2NADH and 4ATP end 2 Pyruvate

oxidation

Loss of electrons a process that involves the removal of electrons; occurs during the breakdown of small organic molecules.

• Define oxidation and reduction.

OIL RIG OXIDATION IS LOSS REDUCTION IS GAIN LEO says GER LOSS ELECTRON OXIDATION GAIN ELECTRON REDUCTION REDUCTION IS ADD ELECTRONS THINK ADD NEG CHARGE REDUCES THE OVERALL CHARGE OXIDATION IS REMOVE E-

• Describe how pyruvate is oxidized to acetyl CoA

Pyruvate oxidation occurs in the inner membrane of the mitochondria. This process is a source of acetyl-CoA molecules for the citric acid cycle. Pyruvate oxidation occurs in three easy steps. First, the pyruvate is oxidized (it goes from 3C to 2C acetyl. CO2 is released as a result). Secondly, NAD+ is reduced to NADH Finally, the pyruvate dehydrogenase complex attaches CoA to acetyl. The total energy yield for this process is 2NADH's.

Aerobic Respiration

Respiration that requires oxygen a type of cellular respiration in which O2 is consumed and CO2 is released.

Metabolism

The sum total of all chemical reactions that occur within an organism. Also, a specific set of chemical reactions occurring at the cellular level.

• Explain why ATP is required for the preparatory steps of glycolysis

Two ATP molecules are needed to phosphorylate the glucose resulting in Fructose-1,6-bisphosphate which can now be easily split into 2 x 3 carbon compounds and proceed to form 2 x pyruvates. http://glycolysis.co.uk/

Substrate level phosphorylation

a method of synthesizing ATP that occurs when an enzyme directly transfers a phosphate from an organic molecule to ADP , The breaking of the bonds yields energy that is used to phosphorylate (ADDING a phosphate group to ADP) ADP to ATP

reduction

add e- reduce atom charge a process that involves the addition of electrons to an atom or molecule

• Understand the chemical relationship between the glucose molecules used by cells as fuel and the carbon dioxide generated by the same cells as waste.

after the krebs cycle, all of the carbon atoms form the original glucose molecule are released as CO2

• Know where the Citric Acid Cycle occurs and what products are made.

in the mitochondrial matrix 4CO2 6NADH 2FADH2 2ATP

• Summarize the net ATP yield from the oxidation of a glucose molecule.

one molecule of glucose oxidized by aerobic respiration in prokaryotes yields the following: Glycolysis 2 net ATP from substrate-level phosphorylation 2 NADH yields 6 ATP (assuming 3 ATP per NADH) by oxidative phosphorylation Transition Reaction 2 NADH yields 6 ATP (assuming 3 ATP per NADH) by oxidative phosphorylation Citric Acid Cycle 2 ATP from substrate-level phosphorylation 6 NADH yields 18 ATP (assuming 3 ATP per NADH) by oxidative phosphorylation 2 FADH2 yields 4 ATP (assuming 2 ATP per FADH2) by oxidative phosphorylation Total Theoretical Maximum Number of ATP Generated per Glucose in Prokaryotes 38 ATP: 4 from substrate-level phosphorylation; 34 from oxidative phosphorylation. In eukaryotic cells, the theoretical maximum yield of ATP generated per glucose is 36 to 38, depending on how the 2 NADH generated in the cytoplasm during glycolysis enter the mitochondria and whether the resulting yield is 2 or 3 ATP per NADH

o Label the structures of a mitochondria.

outer inter inner matrix http://www.docstoc.com/docs/103658505/CELLULAR-RESPIRATION-review-worksheet-answers

• Trace the path of high-energy electrons from glucose to water in aerobic respiration.

pg 144 nadh (when converting back to NAD+) release two e- that travel across 3 complex pumping H+ into the intermembrane space. O2 greedy grabs e- binds with 2H+ and makes water. without O2 the whole path would stop because O2 could not grab the e-

• Understand the relationship between glycolysis and cancer.

pg149 Glycolytic enzymes are overexxpressed... The 3 enzymes of glycolysis whose overexpression is most commonly associated with cancer are G3P (glyceraldehyde-3-phosphate Dehydrogenase, enolase, and pyruvate kinase... in many cancers, all 10 glycolytic enzymes are overexpressed! G3P dehydrogenase Enolase Pyruvate kinase All 10 enzymes in glycolysis can be upregulated in cancer cells.

• Distinguish between substrate-level phosphorylation and oxidative phosphorylation.

substrate level phosphorylation = occurs in the glycolysis, and krebs cycle. NAD and FAD gets reduced. A net production of 4 ATP are produced. Glucose gets broken down. oxidative phosphorylation= occurs in Elecrton Transfer Chain. NADH+ and FADH+ get oxidised and regenerated. 34 ATP are produced. Substrate level phosphorylation is the production of ATP by direct transfer of a phosphate group to an ADP from a reactive intermediate. This occurs during glycolysis. Substrate-level phosphorylation is a fast source of ATP in the muscle during times of oxygen debt. It also occurs in cells without mitochondria such a red blood cells. Oxidative phosphorylation also creates ATP, but by a different route. It uses the electrochemical gradient of protons across the inner mitochondrial membrane to generate ATP from ADP. This gradient is set up by the oxidation of nutrients. Oxidation and phosphorylation are linked in this method of ATP production. Most ATP is generated through this process.

• Describe the role of NADH and FADH2 in cellular respiration.

to carry electrons from glucose molecule to the ETC http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html to provide energy that pumps H+ (Protons) across the inner membrane of a mitochondrion

• What is the value of Citric Acid Cycle? Where do the electron carriers go?

to the etc

ATP

...

ATP synthase

...

Acetyl CoA

...

Aerobic Respiration vs. Anearobic Respiration

...

Chemiosmosis

...

Citrate

...

Citric acid cycle

...

Electron Transport Chain (ETC)

...

FAD/FADH2

...

Glycolysis

...

H+ electrochemical gradient

...

Intermembrane space

...

Metabolic cycle

...

Mitochondrial matrix

...

NAD+/NADH

...

Oxaloacetate

...

Oxidative phosphorylation

...

pyruvate

...

phosphorylation

..., The transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by phosphorylation., -Adding a Phostphate group to any molecule

• Describe the distinct metabolic pathways used by cells to harvest the energy stored in glucose under aerobic conditions. (Fig 7.1)

1) Glycolysis glucose(6carbon) -->2 Pyruvate(3carbon each) Net: 2 NADH 2 ATP via substrate-level phosphorylation 2) Breakdown of Pyruvate 2 pyruvate ---> 2 CO2 + 2 acetyl (2carbons) Net: 2 CO2 2 NADH 3) citric acid cyle 2 acetyl---->4 CO2 Net: 4CO2 6 NADH 2 FADH2 2 ATP via substrate-level phosphorylation 4) Oxidative Phosphorylation: The oxidation of NADH and FADH2 via the ETC provides energy to make more ATP via ATP syntase O2 is consumed 32 ATP via chemiosmosis

o Name the four stages of cellular respiration and state the region of the eukaryotic cell where each stage occurs.

1) Gycolysis in the cytosol 2)Breakdown of Pyruvate to an acetyl group in the mitochondrial matrix 3)Citric acid cycle in the mitochondrial matrix 4)Oxidative phosphorylation occurs along the cristae, which are invaginations of the inner mitochondrial membrane