Sickle-cell disease and hemoglobin c disease are both caused by point mutations, resulting in glutamic acid at position 6 in the β-globin being replaced by and respectively.
a) lysine; arginine
b) serine; cysteine
c) serine; a stop codon
d) valine; lysine
e) valine; glycine

Nephrons, the functional unit of kidneys, are responsible for formation of urine. the sentences describe situations that are the result of problems in the urine formation process. for the nephron shown below, match each situation to the step in the urine formation process where the problem lies.