Bioenergetics and ATP Production Quiz

A branched-chain polysaccharide composed of ⍺-D-glucose monomers.

Glycogen is synthesized from glucose 1-phosphate, which needs to be activated by UDP for incorporation into the glycogen chain.

Glycogen is broken down to release glucose 1-phosphate from the ends of the chains.

Skeletal muscle uses glycogen as an immediate energy source during physical activity.

The liver uses glycogen to regulate blood glucose levels by releasing glucose into the bloodstream.

A metabolic pathway responsible for the production of NADPH and the precursor for nucleotide synthesis, Ribose 5-phosphate.

Irreversible reactions in the pentose phosphate pathway that produce NADPH and CO2.

Reversible reactions in the pentose phosphate pathway that interconvert sugars and produce intermediates for other metabolic pathways.

The study of how energy is transferred and used in biological systems.

A measure of the energy difference between reactants and products in a reaction.

A reaction that releases energy, making it spontaneous (occurs without external energy).

A reaction that requires energy to occur, making it non-spontaneous (needs energy input).

The molecule that serves as the primary energy currency of cells.

The direct transfer of a phosphate group from a substrate to ADP to produce ATP.

The process of generating ATP using the energy from the electron transport chain, fueled by NADH and FADH2.

The breakdown of glucose into pyruvate, producing ATP and NADH.

The synthesis of glucose from non-carbohydrate sources like pyruvate, lactate, or glycerol. This is the reverse of glycolysis.

The breakdown of glycogen, the storage form of glucose, to release glucose.

The synthesis of glycogen from glucose, storing glucose for later use.

A series of metabolic reactions that oxidizes acetyl-CoA, producing ATP, NADH, and FADH2.

A series of protein complexes embedded in the mitochondrial membrane that use energy from electron transport to generate a proton gradient, powering ATP synthesis.

The final stage of cellular respiration, where oxygen is used to accept electrons from the ETC, generating ATP.

The synthesis of ATP using the energy stored in the proton gradient across the mitochondrial membrane, driven by the ETC.

The Electron Transport Chain (ETC) is a series of protein complexes embedded in the inner mitochondrial membrane. It plays a crucial role in cellular respiration by transferring electrons from electron carriers (NADH and FADH2) to oxygen, generating a proton gradient. This gradient is then used by ATP synthase to produce ATP, the energy currency of the cell.

NADH and FADH2 are electron carriers that donate electrons to the ETC. NADH is produced during glycolysis, pyruvate oxidation, and the citric acid cycle, while FADH2 is produced during the citric acid cycle.

The ETC consists of four major protein complexes (I-IV) and two mobile electron carriers (coenzyme Q and cytochrome c). These complexes work together to transfer electrons and pump protons from the mitochondrial matrix to the intermembrane space.

The ETC is a powerful energy generator, using the flow of electrons to pump protons across the inner mitochondrial membrane, creating a proton gradient. This gradient provides the energy for ATP synthesis by ATP synthase.

During the ETC, NADH produces approximately 2.5 ATP molecules per molecule, while FADH2 produces approximately 1.5 ATP molecules per molecule. The difference arises from the entry points of these electron carriers into the ETC.

Glycolysis, the citric acid cycle, and oxidative phosphorylation (including the ETC) contribute to the overall energy gain from glucose metabolism. This process yields a net total of 36 or 38 ATP molecules per glucose molecule.

The malate-aspartate shuttle is one mechanism that allows NADH generated in the cytoplasm to enter the mitochondria and participate in oxidative phosphorylation. It involves a series of reactions that ultimately result in the formation of NADH within the mitochondrial matrix.

The glycerol 3-phosphate shuttle is another mechanism that allows NADH from the cytoplasm to enter the mitochondria. However, this shuttle produces FADH2 within the mitochondrial matrix, which then contributes to ATP synthesis through the ETC.

Gluconeogenesis is the metabolic process that synthesizes glucose from non-carbohydrate precursors, such as pyruvate, lactate, and glycerol. It occurs primarily in the liver and kidneys and is crucial for maintaining blood glucose levels during periods of fasting or starvation.

Glycogen is a storage form of glucose found primarily in the liver and muscles. It serves as a readily available source of glucose for the body, particularly during periods of low blood glucose levels.