Answer:
1. The average heterozygosity at this locus should be decreasing over time
3. Diploidy is helping to preserve the sickle-cell allele at this locus
Explanation:
Sickle cell anemia is caused by a mutation in the beta hemoglobin gene. The mutation substitutes amino acid valine for glutamic acid. The mutation makes the hemoglobin less soluble. The mutated hemoglobin forms crystal-like structures and affects the shape of RBCs. The RBCs carrying the mutated hemoglobin are sickle-shaped. The mutation is recessive in nature and the disease is expressed in homozygous recessive genotype. However, the heterozygous genotype exhibit resistance to malaria pathogen since the pathogen can not survive in altered RBCs. The presence of one normal allele prevents these heterozygous individuals to be affected by the disease.
Therefore, the heterozygous genotype for sickle cell anemia is preferred by natural selection in malaria-prone regions such as Africa. The individuals with African ancestry would have higher heterozygosity at the beta hemoglobin locus. In American populations, homozygous recessive genotypes have a higher frequency as the disease is not expressed in recessive conditions and malaria is not prevalent there. So, the U.S. populations of African-Americans would exhibit reduced heterozygosity at the locus over generations.
8-11 is -3. When subtracting a bigger number from a smaller number, the answer will always be negative.
Answer:
b. Enzymes always change their shape when they bind to a molecule.
d. An enzyme’s shape is related to the shape of the substrate it binds to.
Explanation:
Enzymes are proteins that are secreted by special cells in living organisms. They are the organic catalysts of biochemical reactions.
The role of the enzyme in the enzyme catalyzed reaction is to bring reactants together on its surface so as to have better interactions.
Enzymes have the capability to fit the substrate into an induced fit position.
The process by which enzymes change shape in a reaction is called the induced fit.
This way an enzyme holds the substrate tightly for the reactions to occur.
<u>Answer:</u>
<em>The diet that helps in preventing cancer is “a diet high in fiber and low in saturated fats.</em>
<u>Explanation:</u>
Though cancer cannot be fully prevented or cured by the <em>healthy diet </em>but the risk can be lowered. By having the diet that is rich in fiber like, broccoli, beans etc. helps in preventing the risk of esophageal cancer.
The intake of oranges, berries, peas etc. helps in reducing the stomach and esophageal cancer as they are low in<em> fats and high in fiber contents.</em>