The starting molecule is ATP
Answer:
C. NAD⁺
Step-by-step explanation:
NADH is oxidized to NAD⁺ in Complex I of the Electron Transport Chain.
NADH ⟶ NAD⁺ + H⁺ + 2e⁻
The electrons continue through the Electron Transport Chain, and the NAD⁺ is used in three places during the Krebs Cycle.
(a) Isocitrate to oxalosuccinate
Isocitrate + NAD⁺ ⟶ oxalosuccinate + NADH + H⁺
(b) α-Ketoglutarate to succinyl-CoA
α-ketoglutarate + NAD+ + CoA → succinyl CoA + CO₂ + NADH
(c) Malate to oxaloacetate
Malate + NAD⁺ ⟶ oxaloacetate + NADH + H⁺
The NADH produced by these three reactions can then be used by Complex I in the Electron Transport Chain.
Organisms that survive a new environment are said to have adapted to their surroundings.
