Cell Respiration Flashcards
What is aerobic respiration?
It is a form of catabolic pathway (release energy, break down molecules) and the most efficient one. Oxygen and organic molecules are broken down to form carbon dioxide, water and ATP. Type of cellular respiration.
What is the chemical recycling process?
- Light energy is inputted by the sun in chloroplasts, 2. Photosynthesis occurs in chloroplasts, turning light, CO2 and water into organic molecules and oxygen, 3. cellular respiration occurs in the mitochondira, using og molecules and O2 to make CO2, H2O and ATP, 4. Cycle repeats
What is substrate level phosphorylization?
It is the direct formation of ATP by transferring a phosphate group from a substrate to ADP without the use of oxygen (anaerobic).
What is the ultimate goal of catabolic pathways?
To produce ATP to do work in the cell via electron transport during chemical (redox) reactions.
What are redox reactions?
Redox reactions are reduction-oxidation reactions.
What is the reduction portion of a redox reaction?
Reduction is the ADDITION of e- to another substance, REDUCING the amount of POSITIVE charge (ADDING NEGATIVE).
What is the oxidation portion of a redox reaction?
Oxidation is the LOSS of e- from a substance (ADDING POSITIVE charge)
Show the basic redox reaction formula.
X- + Y -> X + Y-, where X is being oxidized and Y is being reduced.
What is OIL RIG?
Oxidation Is Loss of e- and Reduction Is Gain of e-.
What is NADH and is it a redox reaction? Why/why not?
NADH is a form of stored energy, formed from NAD+ & H+. It is a redox reaction because NAD+ gains e- (reduction - loss of positive charge) and NADH to NAD+ is an oxidation process where NADH loses negative charge and gains positive charge.
What is the difference between the reaction of H2, O2 to form H2O in an uncontrolled reaction and cellular respiration?
In the normal reaction to form H2O, it is an uncontrolled, explosive reaction that releases heat and light energy since the electrons and protons are transferred in a single step. However, during cellular respiration, the electron transport chain allows for the controlled release of energy for the synthesis of ATP instead.
Describe the basic steps of aerobic respiration.
Glycolysis (glucose) makes pyruvate –> pyruvate oxidation makes acetyl CoA –> citric acid cycle/krebs cycle makes NADH and FADH –> oxidative phosphorylation with e- transport chain and chemiosmosis makes 30-32 ATP.
What is the function of glycolysis?
Glycolysis turns glucose into 2 pyruvate for pyruvate oxidation and the citric acid cycle.
Most of cellular respiration/aerobic respiration occurs within the mitochondria. What is the only step that occurs on the outside?
Glycolysis
What are the end products of glycolysis?
2 pyruvate & 2 H2O, 2 ATP, 2 NADH & 2 H+
Describe the energy investment phase of glycolysis (Steps 1 - 5)
1) ATP is used and turned into ADP and phosphate to become more reactive (phosphorylation). 2) Isomerization occurs (glucose to fructose). 3) Phosphorylation occurs (uses ATP). 4) Aldolase (enzyme) used to cleave fructose into 2 molecules. 5) Isomerization occurs once more.
Describe the energy payoff phase of glycolysis (Steps 6 - 10).
6) Redox reaction to made 2x NADH and phosphorylation occurs without the use of ATP. 7) Substrate level phosphorylation occurs (2x ATP is made). 8) Phosphate is relocated. 9) Dehydration rxn: H2O is lost as double bond is formed. 10) Substrate lvl phosphorylation occurs, forming 2x ATP and 2x Pyruvate.
How is pyruvate formed?
Via glycolysis.
Describe the oxidation of pyruvate. (Pyruvate oxidation).
1) The pyruvate formed by glycolysis is transported from the cytosol into the mitochondria via transport proteins. 2) De-carboxylation occurs (release of CO2). 3) Redox reaction/oxidation (NAD+ –> NADH + H+) 4) Coenzyme A attached, forming Acetyl CoA.
What is the end goal of pyruvate oxidation?
To turn the 2x pyruvate from glycolysis into 2x acetyl CoA.
Describe the citric acid/krebs cycle step by step.
1) Acetyl CoA enters the cycle, attaching to the present oxaloacetate. Citrate is formed and CoA-SH is released. 2) Dehydration rxn: H2O is lost as isomerization occurs, forming isocitrate. 3 & 4) Decarboxylation (redox) rxn. 2x NADH & H+ is released and 2x CO2 is released. 5) CoA-SH is added back, forming Succinyl CoA which is a high energy bond which allows for substrate level phosphorylation to occur in many animals. CoA-SH is released again. 6) Redox reaction: FAD –> FADH2. 7) Hydrolysis: H2O added, double bond broken. 8) Redox reaction, oxaloacetate is formed.
What is the main goal of the second half of the citric acid cycle? (Steps 5 - 8).
To recycle the CO2 receptor so Acetyl CoA can be accepted again.
After glycolysis, pyruvate oxidation and the citric acid cycle, what molecules are formed from ONE PYRUVATE molecule?
3x CO2, 1x ATP, 1x 4 NADH, 1x FADH2
After glycolysis, pyruvate oxidation and the citric acid cycle, what molecules are formed from ONE GLUCOSE molecule?
One glucose = 2 pyruvate, so 6x CO2, 2x ATP, 2x 4 NADH, 2x FADH.
