Answer:
Explanation:bye have a great day
Answer:
Why doesn't Dr. Logan feel the bed bug feeding on him? The bed bug injects an anesthetic as it feeds. Bed bugs prefer humans over other hosts. Many blood-feeding parasites carry diseases but bed bugs do not.
Explanation:
Answer:
Explanation:
A. False - A symporter system requires that one of the molecules to be transported using passive transport.
B. True - The Na+ will move down the established concentration gradient releasing energy to facilitate movement of sucrose against its concentration gradient. This is known as secondary active transport.
C. False - sucrose moves through ion channels not by diffusion to better control its movement across the membrane.
D. True - Movement of molecules against their concentration gradient thus requiring energy input is known as active transport.
E. False - One of the molecules needs to be moving against its concentration gradient.
F. False - A Uniporter system allows the binding and transport of a single molecule at a time. A symporter allows simultaneous binding and transport of Na+ and sucrose molecules.
Answer:
lungs:
The blood first enters the right atrium.
The blood then flows through the tricuspid valve into the right ventricle.
When the heart beats, the ventricle pushes blood through the pulmonic valve into the pulmonary artery.
The pulmonary artery carries blood to the lungs where it “picks up” oxygen.
It then leaves the lungs to return to the heart through the pulmonary vein.
The blood enters the left atrium.
It drops through the mitral valve into the left ventricle.
The left ventricle then pumps blood through the aortic valve and into the aorta. The aorta is the artery that feeds the rest of the body through a system of blood vessels.
Blood returns to the heart from the body via two large blood vessels called the superior vena cava and the inferior vena cava. This blood carries little oxygen, as it is returning from the body where oxygen was used.
The vena cavas pump blood into the right atrium and the cycle begins all over again.
<span>Cells control cell division in order to maintain normal cell function. If something happens to the control of the cell division, the healthy cells will divide uncontrollably. These new cells are cancer cells. </span>
The mutations in three genes are responsible for development of cancers:
1. Mutation in proto-oncogenes. Proto-oncogenes normally signal cells to grow and differentiate. Proto-oncogenes can become oncogenes due to mutations which result in the uncontrollable division of the cells.
2. Mutation in tumor suppressor genes. In normal cells, tumor suppressor genes suppress genes essential for cell cycle and that way they prevent uncontrollable cell division. However, after a mutation in these genes, suppression is lost and the cell may progress to cancer.
3. Mutation in stability genes. In normal cells, they have no role either in cell death or growth, but they control mutation rate. Mutation in stability genes results in situation where all genes, including proto-oncogenes and tumor suppression genes, are more frequently mutated.
