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>.
When chiasmata can first be seen in cells using a microscope, the following processes has most likely occurred in prophase I.
<h3>When chiasmata can first be seen in cells using a microscope?</h3>
Recombination can occur at any two chromatids within this tetrad structure.
Crossovers between homologous chromatids can be visualized in structures known as chiasmata, which appear late in prophase I.
Thus, option "C" is correct, Prophase I.
To learn more about prophase I click here:
brainly.com/question/4137695
#SPJ1
<h2>Second law of thermodynamics</h2>
Explanation:
- Living organisms are highly organizational and therefore it seems that it feeds from “negative entropy” or, by other words, maintaining and getting to a stationary condition where the entropy level is low.
- Nevertheless it is necessary to understand that the proper definition of the second law of thermodynamics says that the entropy of an adiabatically isolated system never decreases.
- In this context a living cell or organism is not an isolated system, since it gets the nutrients from the exterior, that is, there is an exchange of heat or matter with the environment, and by doing so, we have to consider the system as an open one, together with its environment, restoring the balance to the universe in an increase of entropy, or by other words, increase of disorder.
<u>Answer:</u>
Nature consists of both the organism and the environment. The relationship between them are intertwined. Organisms are mainly divided into three
a) The producers
b) The consumers
c) Decomposers
These three organisms are interlinked with each other. Without them there is no existence of the environment. The producers produce the food, the consumers consume them and the decomposers decompose and release it in the form of energy. In each cycle energy is released and absorbed. The balance in the environment is maintained by the food pyramid.
