1B: Enzymes

Why does the sickle cell $eta$-globin mutation cause red blood cells to sickle under low oxygen?

Valine creates a hydrophobic patch, promoting hemoglobin polymerization.

Sickle cell anemia mutation: $eta$-globin codon 6 changes from GAG to GTG. How should this mutation be classified?

Missense mutation; glutamate is replaced by valine.

Nonsense vs frameshift mutation

Nonsense creates a premature stop codon; frameshift shifts all downstream codons.

Silent vs missense mutation

Silent changes a codon without changing the amino acid; missense changes the amino acid.