system
Given the following post, respond as if you're commenting on Reddit:
human
What is going on in a banana when it becomes ripe?

I imagine that something is going on chemically to make the fruit sweeter. How does it do so on its own?
gpt
The fruit is starting to decompose as soon as it is disconnected from the plant. Enzymes and microorganisms in the fruit are no longer suppressed by the fruits own enzymatic defense, and start to break down the molecules. The sweet taste comes from long carbohydrate chains, fibre, which is not digestible by humans. From there it breaks into shorter chains of carbohydrates, sugars, that we can digest. The shorter the chain, the sweeter the taste. The same thing goes on with the other components, proteins and fats. The breaking down results in new flavors, as the chemical properties change with the molecules getting smaller. And also the consistency and color changes this way. 

Tl;dr, it's the decomposition process going on.