H H II II
threonine - proline -N-C-0
lys
CH2 o
1
CH2 - C OH
glutamic acid
Normal
hemoglobin
Amino acid
substitution
H н но
II II
threonine-proline —N-C-0-lys
H3C - CH - CH3
valine
Sickle cell
hemoglobin
1. What is the difference between the normal hemoglobin and sickle cell hemoglobin?
2. What portion of the normal hemoglobin is identical to the sickle cell hemoglobin?
3. Write down two questions that you have about each of the hemoglobin based on your observations.

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?