Answer:
B. Human activities and natural events can damage the environment.,
Explanation:
Human activities are those activities carried out by a human being. The environment is being degraded daily as a result of the activities of man as well as natural occurrences e.g earthquake, tsunami, wild fire etc.
Human activities also called anthropogenic activities that damage the environment include sewage pollution, burning of fossil fuels, oil spillage etc. Hence, according to this question, human activities and natural events can damage the environment.
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>.
Answer:
DNA replication
Explanation:
DNA replication is the process whereby the genetic material (DNA) duplicates itself into two identical copies. This process must occur prior to any cellular division (meiosis or mitosis) in order to ascertain that each daughter cell gets an even and correct amount of DNA.
The process of DNA replication begins with the unwinding of the double stranded DNA molecule into two single strands of DNA. One strand called leading strand runs from 3'-5' while the other strand runs from 5'-3'. However, DNA replication proceeds in the 5'-3' direction.
Theories are educated guests that are tested by experiments
