Warming Up

When The Doctor was preparing a drug that would be injected to the patient, suddenly, the patient who was lying in bed screaming out. The Doctor was surprised, so he asked to the patient:  The Doctor : Well...why are you screaming out ? What is the fear of injections ?  Patients : No...Sir,...

Cytosol

 At one time, it was believed that the cytoplasm intervening between the discrete organelles and deposits was unstructured. This belief was reinforced by the use of homogenization and centrifugation of the homogenates to yield fractions consisting of recognizable membrane-bound organelles. The...

Cytoplasmic Deposits

Cytoplasmic deposits are usually transitory components of the cytoplasm, composed mainly of accumulated metabolites or other substances. The accumulated molecules occur in several forms, one of them being lipid droplets in adipose tissue, adrenal cortex cells, and liver cells (Figure 2–38). Carbohydrate...

Intermediate Filaments

Ultrastructural and immunocytochemical investigations reveal that a third major filamentous structure is present in eukaryotic cells. In addition to the thin (actin) and thick (myosin) filaments, cells contain a class of intermediate-sized filaments with an average diameter of 10–12 nm (Figure 2–37...

Actin Filaments

Contractile activity in muscle cells results primarily from an interaction between two proteins: actin and myosin. Actin is present in muscle as a thin (5–7 nm in diameter) filament composed of globular subunits organized into a double-stranded helix (Figure 2–36). Structural and biochemical studies...