Part and Functions of the Cell Flashcards
serves as cellular boundary separating one cell from the other. This portion is difficult to resolve in the light microscope because of its thin structure with 7 to 10 nm. It has a “fluid” nature in which protein molecules, enzymes, attachment points, and the permeability and reactive sites are present. This important structure determines and regulates the passage of materials in and out of the cell.
Plasma membrane or plasmalemma
The _____ is a dense body in the translucent cytoplasm. Most often, it appears lying in central portion of a typical animal cell bounded by a nuclear membrane or envelope. Dispersed throughout the nucleus, within the nucleoplasm, is the ________. This is the fundamental unit of the cell that carries hereditary code. “It is a vault of genetic information encoding the past history and future prospects of the cell.”
nucleus, deoxyribonucleic acid or DNA
This is the fundamental unit of the cell that carries hereditary code. “It is a vault of genetic information encoding the past history and future prospects of the cell.”
deoxyribonucleic acid or DNA
The ______ is the colloidal-liquid portion that constitutes much of the cell. It contains a number of organelles suspended in a matrix, which is termed the ______.
cytoplasm, cytosol
is a mesh of tubules and flattened sacs interconnected to each other. Ribosomes may cover the outer flattened surface of ER; this area is usually called rough or granular ER. In some ER, ribosomal granules are not present; these are the smooth ER. Rough ER participates in protein synthesis. Smooth ER, on the other hand, performs separate functions. It is much involved in cholesterol synthesis and in the production of steroid hormones. In some cells (e.r., liver cells), it is also involved in the metabolism of lipid and cholesterol.
Endoplasmic reticulum (ER)
In most cases, _______complex lies between the nucleus and the free surface border of the cell. In some cell types, it may be well distributed in the cytoplasm and mainly concentrated proximal to the nucleus. The GA complex consists of closely packed tubules with vacuoles and vesicles. The complex is involved in the concentration, packaging, and sorting of materials produced in ER.
Golgi apparatus or GA
are specialized vesicles, which are believed to be produced by another ER complex called GERL (Golgi-endoplasmic reticulum producing lysosomes). Lysosomal vesicles contain hydrolytic enzymes responsible for “intercellular digestion.”
Lysosomes
are rod-like, granular and filamentous bodies bounded with membranes. The inner membrane is thrown into folds called cristae that protrude inward. Inside the mitochondria, the area not occupied by the cristae, is filled with granular materials, the mitochondrial granules. Matrix granules may also be found. The mitochondrial matrix contains oxidative enzymes necessary for the production of the energy rich compound called ATP (adenosine triphosphate). ATP is required for a number of physiological processes, including protein synthesis, muscle contraction, and transport of various ions across cell membrane.
Mitochondria
are vesicles containing enzymes not found in the lysosomes, i.e.: urate oxidases, a – amino acid oxidases, and catalase. These peroxisomes have the ability to produced hydrogen peroxide.
Peroxisomes
include glycogen, lipids, and pigments (melanin). Centrosome is specialized region or zone of the cytoplasm that contains centriole. This zone is close to the nucleus and most distinct during cell division. The centrosome is associated with the process of mitosis, particularly in the organization of microtubules within the spindle fiber.
Cytoplasmic inclusions
or slender-like structures in the cytoplasm make up the cytoskeleton of the cells. Most microfilaments are contractile, enhancing cell shapes.
Filaments
are slender, cylindrical bodies with a rigid structure. Their protein components are called tubulin with amino acid sequence resembling that of actin. Microtubules are one of the important elements of the spindle apparatus in dividing cells.
Microtubules
site forphotosynthesis.
Chloroplast
Green pigment of plants.
Chlorophyll
helps maintain water balance.
Vacuole
allow the movement of molecules and substances between cells.
Plasmodesmata
