3.1.4

Question 1

sickle cell anemia

Answer 1

common genetic disease in areas where malaria is endemic

Question 2

sense strand

Answer 2

the DNA strand that’s not transcribed

it has the same sequence of bases as mRNA molecule, but thymine replaced with uracil

Question 3

which base is replaced by which in sense strand?

Answer 3

thymine is replaced by uracil

Question 4

antisense strand

Answer 4

the transcribed strand—it’s complementary to the mRNA causes of sickle cell anemia

Question 5

glutamic acid

Answer 5

amino acid….it’s the normal hemoglobin formed

Question 6

valine

Answer 6

amino acid…it’s the mutant hemoglobin formed in sickle cell

Question 7

hemoglobin

Answer 7

a protein found in red blood cells (erythrocytes) that carries oxygen throughout body

Question 8

pleiotropy

Answer 8

when 1 gene has multiple effects

Question 9

causes of sickle cell anemia

Answer 9

1. base substitution mutation (GAG–> GTG in sense strand)
2. change to the base sequence of mRNA transcribed (GAG–> GUG)
3. corresponding change to sequence of polypeptide in hemoglobin
   (glutamic acid–>valine in the 6th position)

Question 10

what happens in sickle cell anemia (specific process)

Answer 10

1. The gene HBB codes for beta subunit of hemoglobin
2. standard Hb^A allele reads GAG on sense strand, and HB^s allele reads GTG in same location
3. When HBB locus is transcribed, the mRNA from Hb^a has GAG for 6th codon–> translates to glutamic acid
4. The mRNA copied from Hb^s has codon GUG–> codes for valine
5. After initial mutation–> creates new allele

Question 11

result of 1 specific base substitution in sickle cell anemia

Answer 11

the glutamic acid is substituted by valine as the 6th amino acid in the beta hemoglobin polypeptide