BIOL 215 Exam 3 Learning Objectives
UPDATED Exam Questions and CORRECT
Answers
Explain the role(s) of electron carriers in the cell and describe their general structure. -
CORRECT ANSWER - -Electrons are stripped from organic molecules (glucose) &
carried by electron carriers to ETC
-Coenzymes (adenine dinucleotides) composed of C,H,N,O,P
Provide an overview of the process of aerobic respiration. Describe specifically where all of the
events are taking place (i.e. which subcellular location). - CORRECT ANSWER - -Fuel
molecules (organic) are oxidized to inorganic molecules to produce usable chemical energy
-C₆H12O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)
-Free energy released during electron transfer used to drive ATP synthesis
-Glycolysis: cytoplasm
-Citric Acid Cycle: mitochondrial matrix
-Oxidative Phosphorylation: inner mitochondrial membrane
Describe the glycolytic pathway, highlighting the driving forces behind the steps of the pathway.
Describe the pathway inputs and the pathway outputs. - CORRECT ANSWER - -Catabolic
& exergonic overall
-Net inputs: glucose + 2NAD⁺ + 2ADP + 2Pi
-Net outputs: 2 pyruvate + 2 NADH + 2 ATP + 2H⁺+ 2H₂O
-4 ATPs for every glucose
What is involved in the 'energy investment phase'? - CORRECT ANSWER - *Priming
intermediates - ATP input*
1.) Phosphorylation: Glucose → G6P (1 ATP consumed)
2.) G6P → F6P (has OH available for phosphorylation)
, 3.) Phosphorylation: F6P → F 1,6-bisphosphate (1 ATP consumed, higher free E bc more Ps
repelling)
*Cleavage*
4.) F 1,6 bisphosphate → DHA & G3P (reversible 3C sugars) via isomerase
-G3P is substrate for next step, driving reaction to right
What is involved in the 'energy payoff' phase? - CORRECT ANSWER - *Oxidation of
organic molecules*
1.) G3P → 1,3-Bisphosphoglycerate (NAD⁺→NADH)
*ATP production*
2.) 1,3-Bisphosphoglycerate → 3-phosphoglycerate (ADP → ATP)
3.) 3-phosphoglycerate → 2-phosphoglycerate → phosphoenolpyruvate (H₂O released)
*Pyruvate formation*
4.) Phosphoenolpyruvate → pyruvate (ADP → ATP)
Describe the fate of pyruvate in both aerobic and anaerobic environments. - CORRECT
ANSWER - -Anaerobic: reduced by NADH to reproduce NAD⁺ to continue glycolysis
(ethanol/lactate fermentation)
-Aerobic: CO₂ removed, NAD⁺ reduced → coenzyme A + acetyl → acetyl CoA (CA cycle)
Differentiate between organisms/cells based on their usage of oxygen (i.e. aerobic or anaerobic?;
obligate or facultative?). - CORRECT ANSWER - -Obligate aerobes require oxygen
-Obligate anaerobes cannot use O₂ (poison!)
-Facultative anaerobes/aerobes can use anaerobic or aerobic processes depending on availability
of O₂
Explain the driving force behind electron movement through the electron transport chain. What
drives the concomitant movement of protons across the IMM? - CORRECT ANSWER --
Electronegativity differences
-Electrons flow from complexes w/ lower EN to complexes w/ greater EN spontaneously
-The more EN molecule is reduced; energy is released
UPDATED Exam Questions and CORRECT
Answers
Explain the role(s) of electron carriers in the cell and describe their general structure. -
CORRECT ANSWER - -Electrons are stripped from organic molecules (glucose) &
carried by electron carriers to ETC
-Coenzymes (adenine dinucleotides) composed of C,H,N,O,P
Provide an overview of the process of aerobic respiration. Describe specifically where all of the
events are taking place (i.e. which subcellular location). - CORRECT ANSWER - -Fuel
molecules (organic) are oxidized to inorganic molecules to produce usable chemical energy
-C₆H12O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)
-Free energy released during electron transfer used to drive ATP synthesis
-Glycolysis: cytoplasm
-Citric Acid Cycle: mitochondrial matrix
-Oxidative Phosphorylation: inner mitochondrial membrane
Describe the glycolytic pathway, highlighting the driving forces behind the steps of the pathway.
Describe the pathway inputs and the pathway outputs. - CORRECT ANSWER - -Catabolic
& exergonic overall
-Net inputs: glucose + 2NAD⁺ + 2ADP + 2Pi
-Net outputs: 2 pyruvate + 2 NADH + 2 ATP + 2H⁺+ 2H₂O
-4 ATPs for every glucose
What is involved in the 'energy investment phase'? - CORRECT ANSWER - *Priming
intermediates - ATP input*
1.) Phosphorylation: Glucose → G6P (1 ATP consumed)
2.) G6P → F6P (has OH available for phosphorylation)
, 3.) Phosphorylation: F6P → F 1,6-bisphosphate (1 ATP consumed, higher free E bc more Ps
repelling)
*Cleavage*
4.) F 1,6 bisphosphate → DHA & G3P (reversible 3C sugars) via isomerase
-G3P is substrate for next step, driving reaction to right
What is involved in the 'energy payoff' phase? - CORRECT ANSWER - *Oxidation of
organic molecules*
1.) G3P → 1,3-Bisphosphoglycerate (NAD⁺→NADH)
*ATP production*
2.) 1,3-Bisphosphoglycerate → 3-phosphoglycerate (ADP → ATP)
3.) 3-phosphoglycerate → 2-phosphoglycerate → phosphoenolpyruvate (H₂O released)
*Pyruvate formation*
4.) Phosphoenolpyruvate → pyruvate (ADP → ATP)
Describe the fate of pyruvate in both aerobic and anaerobic environments. - CORRECT
ANSWER - -Anaerobic: reduced by NADH to reproduce NAD⁺ to continue glycolysis
(ethanol/lactate fermentation)
-Aerobic: CO₂ removed, NAD⁺ reduced → coenzyme A + acetyl → acetyl CoA (CA cycle)
Differentiate between organisms/cells based on their usage of oxygen (i.e. aerobic or anaerobic?;
obligate or facultative?). - CORRECT ANSWER - -Obligate aerobes require oxygen
-Obligate anaerobes cannot use O₂ (poison!)
-Facultative anaerobes/aerobes can use anaerobic or aerobic processes depending on availability
of O₂
Explain the driving force behind electron movement through the electron transport chain. What
drives the concomitant movement of protons across the IMM? - CORRECT ANSWER --
Electronegativity differences
-Electrons flow from complexes w/ lower EN to complexes w/ greater EN spontaneously
-The more EN molecule is reduced; energy is released
