Biophotonics_Concepts_to_Applications

of the genes that control the cell. The entire region between the nucleus and the
surrounding membrane is called thecytoplasm. The cytoplasm contains a semifluid
medium in which are suspended various subcellular structures calledorganelles.
Table1.7gives a summary of the various key organelles and their functions in a
eukaryotic cell.

Golgi apparatus

Nucleus

(5 μm diameter)

Nucleolus

Nucleoplasm

Mitochondrion

Ribosome

Microtubules

Lysosome

Rough ER

Smooth ER

Cytoplasm Cell membrane

Cell size

10-100 μm

Peroxisome

Fig. 1.11 Major constituents of a eukaryotic cell

Table 1.7 Summary of the various key organelles and their functions in a eukaryotic cell

General function Organelle and its functions

Genetic control •Chromosomesin the nucleus: serve as the location for

inherited DNA, which program the synthesis of proteins

• Nucleolusin the nucleus: produce ribosomes
  Production of macromolecules •Ribosomes: responsible for synthesis of polypeptides


• Rough endoplasmic reticulum(ER): assist in protein
  synthesis and membrane production


• Smooth ER: synthesize lipids; store and release calcium
  ions in muscle cells; handle liver cell functions


• Golgi apparatus: handle chemical products of the cell
  Maintenance of the cell •Lysosomes: digest food and other materials


• Peroxisomes: metabolize lipids and carbohydrates;
  handle enzymatic disposal of hydrogen peroxide
  Energy processing •Mitochondria: responsible for cellular respiration and
  synthesis of adenosine triphosphate (ATP)
  Support, movement, and
  communication between cells


• Cytoskeleton: maintains cell shape, anchors organelles,
  moves cells and organelles within cells


• Glycocalyx: protects surfaces; binds cells in tissues


• Intercellular junctions: handle communication between
  cells; bind cells in tissues

18 1 Overview of Biophotonics