How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene?

It can lead to a mute, missense or nonsense mutation

Explanation:

Single base substitutions are known as point mutations and there are two types:

1) Transversion: when a purine is substituted by a pyrimidine or viceversa

2)Transition: when a purine or pyrimidine is substituted by a base of the same nature, in simpler words purine - purine or pyrimidine-pyrimidine.

The three posible scenarios with this kind of mutations are:

1. Mute mutation: no effects overall because the substitutes base codifies for the same amino acid

2. Missense mutation: the base substituted codifies for a different amino acid

3. Nonsense mutation: the base substituted forms an stop codon

I hope you find this information useful and interesting! Good luck!

its like this, "if i give a plant an unlimited amount of sunlight,then the plant will grow to its largest possible size."

hope it let me know if it does or doesn't =^-^=