Answer:
1. The difference between the normal hemoglobin protein DNA sequence and the sickle cell hemoglobin DNA sequence is a base to base shift, in this case adenine (GAG) to thymine (GTG).
2. The difference affects the amino acid sequence of the protein by replacing glutamic acid (Glu) with valine (Val).
Explanation:
In sickle cell anemia, a change in the DNA nucleotide sequence is observed, where adenine is substituted by thymine, whose expression is the change in the amino acid sequence of globine β, incorporating valine instead of glutamic acid. This represents a molecular mutation - point mutation - by subtitution, which corresponds to missense mutation.
<u>Normal hemoglobin protein in a RBC</u>
DNA CTG ACT CCT GAG GAG AAG TCT
Amino acids Leu Thr Pro Glu Glu Lys Ser
<u>Sickle cell hemoglobin protein in a RBC</u>
DNA CTG ACT CCT <em>GTG</em> GAG AAG TCT
Amino acids Leu Thr Pro <em>Val</em> Glu Lys Ser
When GAG is transcribed to mRNA, the CUC codon is obtained, which codes for glutamic acid. Thymine substitution causes the DNA sequence to change to GTG, which is transcribed as CAC, the codon that encodes the amino acid valine. The <u>change from glutamic acid to valine in β-globin causes an altered hemoglobin, giving the abnormal erythrocytes observed in sickle cell disease</u>.
Common mistakes and misconceptions
Natural selection is a mechanism, or cause, of evolution. Adaptations are physical or behavioral traits that make an organism better suited to its environment. Heritable variation comes from random mutations. Random mutations are the initial cause of new heritable traits.
Answer:
The movement of sucrose and other substances like amino acids around a plant is called translocation . In general, this happens between where these substances are made (the sources) and where they are used or stored (the sinks): from sources in the root to sinks in the leaves in early spring time.
Explanation:
Answer: the total amount of
Organic matter from plants and animals in a habitat.
Explanation:
There are choices for this question namely:
A. A second more extensive rise in glucose.
B. An overwhelmed insulin-adjusting mechanism.
C. A distention of the duodenum from an excessive amount of chyme.
<span>D. An overproduction of insulin that occurs in response to the rise in blood glucose
Dumping syndrome is an unsynchronized mechanism wherein there is a higher than normal rise of insulin levels causing transient but severe hypoglycemia. This typically presents within 1 and a half hour after eating wherein there is a physiological transient hypoglycemia but then overwhelmed by the non-synchrony of insulin effects causing severe hyperglycemia. Therefore the correct answer is "a</span>n overwhelmed insulin-adjusting mechanism." The choice "an overproduction of insulin that occurs in response to the rise in blood glucose" is wrong because an overproduction of insulin will result to lower blood glucose.
