Bio II - Cell Respiration

whats the overall chemical equation for cell respiration

C6H12O6 + 6O2 —> 6CO2 + 6H2O delta G= -685

is cell respiration a exergonic or endergonic reaction

a energonic reaction that releases a lot of energy

Does cell respiration release this energy fast or slow

it releases it slowly in order to couple other reactions with the breakdown of glucose such as ATP synthesis

how does the breakdown of glucose enable the synthesis of ATP

the breakdown of glucose releases energy that can be used to synthesis ATP. Glucose hold this energy in the form of chemical potential energy in its bonds and atoms. 

What is the order of components of cell respiration

• Glycolysis

  • energy investment phase

  • cleavage phase

  • energy liberation phase

• breakdown of pyruvate

• citric acid cycle

• oxidative phosphorylation

what occurs in glycolysis (reactant, products, energy used/created)

glucose is broken down to 2 pryuvate molecules, 4 molecules of ATP are created in total but 2 are used in the process which results in net production of 2 ATP. 2 NADH molecules are created as well. 

what happens in the energy investment phase 

the 2 ATP molecules are hydolysized into ADP and phosphates. The phosphates are attached to the glucose molecule making 1,6-biphosphate 

What happens in the cleavage phase

the 1,6-biphosphate is broken down into two molecules of glyceraldehyde-3-phosphate which is a 3 carbon molecule 

what happens in the energy liberation phase

glyceraldehyde-3-phosphate is made into two molecules of pyruvate. The phosphates on these molecules are removed to make 4 ATP and 2 NADH 

What happens in the breakdown of pyruvate

the two molecules of pyruvate are modified to make acetyl CoA, two molecules of NADH are made.

What is the process of the breakdown of pyruvate

the pyruvate is taken to the mitchondria where it is oxidized and broken down by pryuvate dehydrogenase. CO2 is removed and the acetyl group leftover is attached to coenzyme a to make acetyl CoA. Electrons are removed as well which are take to NAD+ to make 2 NADH

what happens in the citric acid cycle (reagents, products, energy?)

citrate is formed from the acetyl group from acetyl CoA. 2CO2, 3NADH, 1FADH2, and 1 gtp (1ATP) is formed 

What us the process of the citric acid cycle 

an acetyl group is removed from acetyl CoA and is attached to oxaloacetate to form citrate. 2 CO2 molecules release and 3 NADH, 1 FADH2, and 1 GTP is made 

what. happens in oxidative phosphorylation  (reagents products, energy)

uses the electron transport chain and its established H+ gradient ot supply the energy needed for ATP synthesis. A lot of ATP is made via chemiosmosis 

What happens in the ETC leading up to oxidative phosphorylation

electrons from NADH are first transfered to NADH dehydrogenase (I), then to ubiquinone and to cytochrome b-c. From there the electrons travel to cytochrome c and cytochrome oxidase. The final receptor is O2. When the O2 accepts the electrons, it becomes H2O and a H+ gradient is established by the movement of electrons 

What happens in oxidative phosphorylation

ATP synthase uses the electrochemical gradient to synthesize ATP in its three compartments. ATP synthase harnesses some of the energy released from the movement of the ion.

How does ATP synthase spin

the part of ATP synthase that is embedded in the membrane spins by the movement of H ions passing through. When it rotates, the y subunit comes into contact with a new B subunit which has three different conformations it switches through to make ATP. 

substrate-level phospharylation

enzyme directly moves a phosphate from an organic molecules to ADP, making ATP

What are high energy intermediates

molecules that store a lot of energy within their bonds (like ATP, NADH, or FADH2)

fermentation

way to make ATP without O2 being present that avoids the buildup of NADH and the shortage of NAD+, usually makes like 2 molecules of ATP

Why cant the cell just go through cell respiration without oxygen

oxygen is the final electron acceptor in oxidative phosphorylation. Glucose can only be made in glycolysis only but oxygen usually oxidizes NADH to NAD+ in glycolysis so even that process has an issue. Fermentation fixes this problem. 

How are the components of cell respiration regulated

by feedback inhibition and availability of substrate/enzyme

How does the breakdown of alcohol work

ethanol goes through enzyme Alcohol dehydrogenase and turns into a toxic intermediate called acetaldehyde, another enzyme then breaks that down to acetate which is safe 

anaerobic conditions

without oxygen present

fermentation in muscle cells

When muscles work really hard there is not oxygen. The pyruvate created by glycolysis is reduced to make lactate. An oxygen is needed for this to happen so the cell takes them from NADH which turns it into NAD+. This also serves the purpose of oxidizing the NADH to prevent buildup. Lactate is secreted out of the cell and when oxygen is available lactate is taken back in and is converted back to pyruvate. 5

fermentation of yeast

when oxygen is absent, yeast metabolizes sugar and pryuvate is made and broken down to CO2 and acetaldehyde. Acdetaldehyde is reduced by NADH to make ethanol and makes NAD+ which solves the inital issue.