The main oxygen-carrying protein in red blood cells is _________________________
ID: 42508 • Letter: T
Question
The main oxygen-carrying protein in red blood cells is ___________________________ .
The hemoglobin tetramer has two ___-globin and two ___-globin proteins.
Individuals with a mutant allele for the ?-globin gene sequence can have sickle-shaped red blood cells.
Those with one mutant allele for the ?-globin gene sequence have sickle cell________________, while those with two mutant alleles for the same gene sequence have sickle cell ______________.
Fill in the blanks below and make sure to indicate the polarity of each sequence.
Normal allele:
coding template
mRNA tRNA
protein seq
5
Explanation / Answer
Part-I:
1) The main oxygen-carrying protein in red blood cells is Hemoglobin.
2) The hemoglobin tetramer has two alpha () globin’s and two () globin’s.
3) Individuals with a mutant allele for the -globin gene sequence can have sickle-shaped red blood cells.
Those with one mutant allele for -globin gene sequence have sickle cell HBA HBs condition.
Those with two mutant alleles for the same gene sequence have sickle cell HBs HBs condition.
Part-2:
Based on the given data,
I:
Coding: 5’-ATG-GTG-CAC-CTC-ACT-CCT-GAG-GAG-AAG-3’
Template: 3’-TAC-CAC-GTG-GAG-TGA-GGA-CTC-CTC-TTC-5’
mRNA: 5’-AUG-GUG-CAC-CUC-ACU-CCU-GAG-GAG-AAG-3’
tRNA: 3’-UAC-CAC-GUG-GAG-UGA-GGA-CUC-CUC-UUC-5’
protein: +3HN-Met-Val-His-Leu-Thr-Pro-Glu-Glu-Lys-COO-
II:
Coding: 5’-ATG-GTG-CAC-CTC-ACT-CCT-GTG-GAG-AAG-3’
Template: 3’-TAC-CAC-GTG-GAG-TGA-GGA-CAC-CTC-TTC-5’
mRNA: 5’-AUG-GUG-CAC-CUC-ACU-CCU-GUG-GAG-AAG-3’
tRNA: 3’-UAC-CAC-GUG-GAG-UGA-GGA-CTC-CUC-UUC-5’
protein: +3HN-Met-Val-His-Leu-Thr-Pro-Val-Glu-Lys-COO-
The type of mutation is: Point Mutation
Sickle cell anemia is a blood disorder witnessed by improper folding of hemoglobin when hemoglobin levels are low and affects the oxygen carrying capacity of an individual. It is caused by alteration (mutation) in the protein hemoglobin. The point alteration is caused in -globin chain of hemoglobin.
Based on the molecular analysis of in gene that codes for -globin chain of hemoglobin, the GAG at 6th position codes for glutamic acid and the middle base “A” (adenine) is replaced with T (Thymine), which results change in the sequence GAG to GTG. Hence, the GTG codes for Valine. This mutation is called point mutation.
The glutamic acid is a hydrophilic amino acid it is replaced by a hydrophobic amino acid called valine. Thus, change in the amino acids results change in the hydro properties in the -globin chain of hemoglobin, and it leads to aggregation of the RBC, and form tetramers. These tetramers cannot bind to oxygen, thus due to deprivation oxygen makes the RBC to attain sickle cell shape.
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