Lecture 9- Cellular Respiration Flashcards
What are the four main stages of cellular respiration in order?
Glycolysis → pyruvate oxidation → citric acid cycle → oxidative phosphorylation
What is the source of electrons for cellular respiration?
Glucose
What are the reactants and products of pyruvate oxidation?
Pyruvate → Acetyl-CoA
Where does glycolysis take place?
Cytosol
The initiation of the citric acid cycle is marked by the reaction between ______ and ______.
Oxaloacetate and Acetyl-CoA
Where does the citric acid cycle take place?
Mitochondrial matrix
Which substances undergo redox during cellular respiration?
Glucose is oxidized and oxygen is reduced
Where does oxidative phosphorylation take place?
Mitochondrial cristae
Is cellular respiration an endergonic or exergonic process? Is the change in Gibbs free energy negative or positive?
Exergonic process → negative change in Gibbs free energy
Oxidative phosphorylation is composed of two major stages. What are these stages?
Electron transport chain (ETC) & chemiosmosis
How does glucose enter mammalian cells?
Facilitated diffusion via GLUT1
True or false: Two ATP are generated during pyruvate oxidation
False; ATP is not used or made during pyruvate oxidation
True or false: For every one glucose molecule, there is one cycle of the citric acid cycle
False; there are two cycles of the citric acid cycle for every one glucose molecule
What are the two main stages of glycolysis?
Investment phase → payoff phase
How many ATP are produced via oxidative phosphorylation?
Approximately 28
The conversion of glucose to glucose-6-phosphate is catalyzed by _____.
Hexokinase
True or false: In the absence of oxygen, glucose will proceed to pyruvate oxidation indefinitely
False; pyruvate oxidation may be able to occur for a short period in the absence of oxygen, but not for extended periods of time
At the end of glycolysis, where are the electrons from the initial glucose?
Pyruvate and NADH
In which molecule is energy stored during the citric acid cycle?
NADH
What are the gross products of glycolysis?
4 ATP + 2 NADH + 2 Pyruvate
What are the net products of glycolysis?
2 ATP + 2 NADH + 2 Pyruvate
At the end of pyruvate oxidation, where are the electrons?
Acetyl-CoA and NADH
True or false: Glycolysis is an anaerobic process
TRUE
True or false: Upon entry to a cell, glucose will remain as glucose until it is needed by the organelles
False; glucose is split immediately after entering the cytosol
Which metabolic process will pyruvate undergo in the absence of oxygen?
Fermentation
What occurs during pyruvate oxidation?
Catalyzed by pyruvate dehydrogenase, a carboxyl group is removed from pyruvate, releasing carbon dioxide → NAD+ reduced to NADH
What is the first metabolite of glycolysis?
Glucose-6-phosphate
Why is the first phase of glycolysis considered an investment?
Two ATP are needed to facilitate conversion of glucose to glyceraldehyde-3-phosphate (G3P)
True or false: The investment phase of glycolysis is an exergonic process
False; the investment phase of glycolysis is an endergonic process
