Question

Where does the mitochondria get the glucose from?


idk


Eating


The sun

Answer 1

Short answer: Eating (for animals). More completely: mitochondria use the products of cellular metabolism — primarily pyruvate from glucose — to make ATP. Where that glucose comes from depends:

- In animals/humans: glucose comes from food (carbohydrates) or from stored glycogen or from gluconeogenesis in the liver. Digestion breaks carbs into glucose, it enters the bloodstream, cells take it up via GLUT transporters (insulin helps), and glycolysis in the cytoplasm converts glucose to pyruvate, which enters the mitochondria.
- In plants and many bacteria: glucose is made in chloroplasts by photosynthesis using sunlight, CO2 and water — so the Sun is the ultimate energy source for those organisms.
- Mitochondria can also burn other fuels (fatty acids, some amino acids) after those are processed into intermediates that enter the mitochondrion.

So “Eating” is the direct source for animals; “the Sun” is the ultimate source for most life because plants convert sunlight into the sugars animals eat.