Cellular Respiration Flashcards
Define potential energy
The energy stored in an object due to its position or arrangement
Define free energy
The energy available to do work in a thermodynamic system
What are anabolic reactions?
Reactions that build larger molecules from smaller units
What are catabolic reactions?
Reactions that break down larger molecules into smaller units
Define endergonic reactions
Reactions that require energy input to proceed
Define exergonic reactions
Reactions that release energy as they proceed
What are the Laws of Thermodynamics?
Principles that describe the relationship between heat, energy, and work
Define entropy
A measure of disorder or randomness in a system
What is activation energy?
The minimum energy required to initiate a chemical reaction
What is required to drive endergonic reactions in cells?
Coupling with exergonic reactions or input of energy
Why is controlled oxidation of glucose necessary compared to rapid combustion?
It allows for gradual energy release and prevents damage to cells
What type of reaction involves phosphorylation?
Transfer of a phosphate group to a molecule
Enzyme: kinase
What type of reaction involves isomerization?
Conversion of one isomer to another
Enzyme: isomerase
What type of reaction involves cleavage?
Breaking of chemical bonds in a molecule
Enzyme: lyase
What type of reaction involves redox (oxidation-reduction)?
Transfer of electrons between molecules
Enzyme: oxidoreductase
What type of reaction involves substrate-level phosphorylation?
Direct transfer of phosphate to ADP to form ATP
Enzyme: kinase
What type of reaction involves decarboxylation?
Removal of a carboxyl group from a molecule
Enzyme: decarboxylase
What type of reaction involves synthesis?
Combination of smaller molecules to form a larger one
Enzyme: synthase
What are the important products formed in glycolysis?
- 2 ATP
- 2 NADH
- 2 pyruvate
What is the purpose of glycolysis?
To convert glucose into pyruvate and produce energy carriers
Where does glycolysis occur? Is O2 required?
In the cytoplasm; O2 is not required
Why must glucose be phosphorylated before further reactions in glycolysis?
To trap glucose in the cell and destabilize it for further breakdown
What is the importance of the reduction of NAD+ to NADH?
It allows for the transfer of electrons and energy storage
Where does pyruvate oxidation and Krebs Cycle occur? Is O2 required?
In the mitochondria; O2 is required indirectly
Why is acetyl-CoA such an important substance in metabolic processes?
It serves as a key substrate for the Krebs Cycle and energy production
What is the substrate that starts the Krebs Cycle?
Acetyl-CoA
What is the role of NAD+ and FAD in cellular respiration?
They act as electron carriers that facilitate redox reactions
Why are there two different electron acceptors involved in the Krebs Cycle?
To maximize energy extraction from the substrate
What happens to NADH and FADH2 at the inner mitochondrial membrane?
They donate electrons to the electron transport chain
How does electronegativity change as electrons pass through the electron transport chain?
It increases, facilitating the flow of electrons and energy release
What is the role of oxygen in oxidative phosphorylation?
It acts as the final electron acceptor, forming water
Why must there be a difference in [H+] across the membrane?
To create a proton gradient that drives ATP synthesis via chemiosmosis
How does ATP synthase use chemiosmosis to form ATP?
It uses the proton gradient to drive the conversion of ADP to ATP
Why can 3 ATP be produced from the oxidation of NADH while only 2 ATP from FADH2?
NADH donates electrons at an earlier point in the chain, yielding more energy
What is the difference between oxidative phosphorylation and substrate-level phosphorylation?
Oxidative phosphorylation uses an electron transport chain, while substrate-level phosphorylation involves direct transfer of phosphate
How does the efficiency of aerobic respiration compare with anaerobic respiration?
Aerobic respiration is more efficient, producing more ATP per glucose
Why is cellular respiration not 100% efficient?
Some energy is lost as heat and not all energy is captured as ATP
