How is dna read and made, from what end to what end?

Think of DNA as a code and think of your brain as a computer. Computers must have code to tell them what to do! Without DNA, we wouldn’t be able to function! People who are missing some “code” aka a strand of DNA may have some disabilities such as blindness. This is because their brain doesn’t known what to do with their eyes because they don’t have “code” to tell them what to do!

Hope that this helped.

The higher you go up the less oxygen there is 

light dependent reactions:

release oxygen during the photolysis of wateroccur in the granaproduce atp

light independent reactions:

fix carbon dioxide occur in the stromaproduce glucose

hope this !