sickle cell anemia

Examples of sickle cell anemia in the following topics:

• Transport of Oxygen in the Blood

  • Diseases such as sickle cell anemia and thalassemia decrease the blood's ability to deliver oxygen to tissues and its oxygen-carrying capacity.
  • In sickle cell anemia, the shape of the red blood cell is crescent-shaped, elongated, and stiffened, reducing its ability to deliver oxygen .
  • Patients with thalassemia produce a high number of red blood cells, but these cells have lower-than-normal levels of hemoglobin.
  • The protein inside red blood cells (a) that carries oxygen to cells and carbon dioxide to the lungs is hemoglobin (b).
  • Individuals with sickle cell anemia have crescent-shaped red blood cells.

• Types and Functions of Proteins

  • Small changes in the amino acid sequence of a protein can cause devastating genetic diseases such as Huntington's disease or sickle cell anemia.
  • Enzymes are essential for digestion: the process of breaking larger food molecules down into subunits small enough to diffuse through a cell membrane and to be used by the cell.
  • Enzymes are also essential for biosynthesis: the process of making new, complex molecules from the smaller subunits that are provided to or generated by the cell.
  • These proteins are secreted by endocrine cells that act to control or regulate specific physiological processes, which include growth, development, metabolism, and reproduction.
  • The proteins actin and tubulin form cellular structures , while keratin forms the structural support for the dead cells that become fingernails and hair.

• Protein Structure

  • In sickle cell anemia, a single amino substitution in the hemoglobin β chain causes a change the structure of the entire protein.
  • These dysfunctional hemoglobin proteins, under low-oxygen conditions, start associating with one another, forming long fibers made from millions of aggregated hemoglobins that distort the red blood cells into crescent or "sickle" shapes, which clog arteries .

• Protists as Human Pathogens

  • In vertebrates, the parasite develops in liver cells and goes on to infect red blood cells, bursting from and destroying the blood cells with each asexual replication cycle .
  • During the course of malaria, P. falciparum can infect and destroy more than one-half of a human's circulating blood cells, leading to severe anemia.
  • In response to waste products released as the parasites burst from infected blood cells, the host immune system mounts a massive inflammatory response with episodes of delirium-inducing fever as parasites lyse red blood cells, spilling parasitic waste into the bloodstream.
  • Without treatment, T. brucei attacks red blood cells, causing the patient to lapse into a coma and eventually die.
  • Red blood cells are shown to be infected with P. falciparum, the causative agent of malaria.