Cytology, more commonly known as cell biology, studies cell structure, cell composition, and the interaction of cells with other cells and the larger environment in which they exist.Microscopic examination can help identify different types of cells. In a simple test like a complete blood count, a laboratory can look at white blood cells and identify the presence of an infection, or it may examine a low level of certain types of red blood cells and diagnose anemia.
The biochemical basis of cell differentiation is the synthesis by the cell of a particular set of proteins, carbohydrates, and lipids.The first cells presumably resembled prokaryotic cells in lacking nuclei and functional internal compartments, or organelles. These early cells were also anaerobic (not requiring oxygen), deriving their energy from the fermentation of organic molecules that had previously accumulated on the Earth over long periods of time.
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.
The structure and location of chromosomes is one of the chief differences between the two basic types of cells—prokaryotic cells and eukaryotic cells. Among organisms with prokaryotic cells (i.e., bacteria and blue-green algae), chromosomes consist entirely of deoxyribonucleic acid (DNA). The single chromosome of a prokaryotic cell is not enclosed within a nuclear membrane. Among all other organisms (i.e., the eukaryotes), the chromosomes are contained in a membrane-bound cell nucleus. The chromosomes of a eukaryotic cell consist primarily of DNA attached to a protein core. They also contain ribonucleic acid (RNA). Among both prokaryotes and eukaryotes, the arrangement of components in the DNA molecules determines the genetic information.
Every species has a characteristic number of chromosomes (chromosome number). In species that reproduce asexually, the chromosome number is the same in all the cells of the organism. Among sexually reproducing organisms, the number of chromosomes in the body (somatic) cells is diploid (2n; a pair of each chromosome), twice the haploid (1n) number found in the sex cells, or gametes. The haploid number is produced during meiosis. During fertilization, two gametes combine to produce a zygote, a single cell with a diploid set of chromosomes.
Chromatography is a physical method of separation in which the components to be separated are distributed between two phases, one of which is stationary (stationary phase) while the other (the mobile phase) moves in a definite direction.Affinity chromatography often utilizes a biomolecule's affinity for a metal. It is often used in biochemistry in the purification of proteins bound to tags.
Ion exchange chromatography uses ion exchange mechanism to separate analytes.Ion exchange chromatography uses a charged stationary phase to separate charged compounds including amino acids,peptides, and proteins.
"DNA makes RNA, RNA makes protein, and proteins make us." Francis Crick