biology essay on cells

It can also be sub-divided into nerve cells, muscle cells, etc. The function of golgi bodies is to process materials manufactured by the cell. Microscope Investigations on the similarity of structure and growth in animals and plants. The germ cell is useful in reproducing new species. Zygote is also an undifferentiated cell. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope. A prokaryotic cell store specialised compounds in the form of granules or droplets. It is found in large quantities in the cytoplasmic particles of the cell. Intermodal cells of Char a are 110 cm in length.

Essay on Cell - Biology Discussion

Cells are not only the building blocks of the organisms, they are also the functional units of life. Schwann (1838) discovered that animal cells lacked cell wall. (b) Differentiated or Post-mitotic Cells: The cells are specialized to perform specific functions. They are now- a-days placed in a super kingdom called Prokaryote. The mitochondria are the minute, semi-solid body enclosed in a membrane with a complex internal structure. Nucleus: Carrier of hereditary information, control of cell metabolism, cell differentiation, synthesis of DNA and RNA, formation of ribosomes, control of reproduction. Cell An Open System: An open system is the one which is separated from its surroundings by a boundary that allows transfer of materials and energy across. Many biology essay on cells such awards in the fields of chemistry, physiology, and medicine have been made for contributions that bear directly on cell biology (see Table 1-1). In his later years, Malpighi turned to investigations of plant tissues and suggested that they were composed of structural units that he called utricles (later to be called cells). In accordance with their nature and function. Leeuwenhoek was the first to describe sperm cells (of humans, dogs, rabbits, frogs, fish, and insects) and observe the movement of blood cells in the web capillaries of the frogs foot and the rabbits ear. The newly made proteins are taken into the tubes of the rough ER so that they cannot escape into the cytoplasm, and are threaded through pores in the membrane to accumulate in the cisternal space where they can fold into their normal three-dimensional shape. The protoplasm is the combination of cytoplasm and nucleus.

Essay on Cell Biology - Biology Discussion

Duplication of work is avoided. Advertisements: Here a single cell is: (i) Capable of independent existence and biology essay on cells (ii) Able to perform all the essential functions of life. The cell membrane separates a watery cytoplasm from a watery external environment also referred to as the extracellular fluid. Cell Theory: The theory was jointly put forward by Schleiden and Schwann (1839) in their paper. The organisms having prokaryotic cells are called prokaryotes. In his description, Hooke wrote that he found the sections to be all perforated and porous, much like a honeycomb and referred to the boxlike structures as cells. Cells can be split into two types, prokaryotic (see figure 1) and eukaryotic (See figure 2). The cell division is not a simple process; complicated changes have been noted in the substances of the nucleus.

A prokaryotic cell is smaller and simpler; it requires far fewer genes to operate than the eukaryotic cell. In some cases, the nucleolus also contains large quantities of RNA. Intracellular biology essay on cells Compartmentalization: Membrane lined cell organelles act as intracellular compartments. The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. Robert Hooke named the compartments as cellulae (singular- cellula) now known as cells (Latin cella hollow spaces or compartments). New cells arise from pre-existing cells through division. (Roberts, 2009) C: Nucleus The nucleus is usually spherical and about 10m across, it has two main functions. Robert Brown (1831) discovered the presence of nucleus in the cells of orchid root.

612 words free sample essay on Cell biology

Therefore, he concluded that cells constitute the ultimate units of all plant tissues. Other organisms (having eukaryotic cells) are included in super kingdom Eukaryote. Microvilli are one of such developments. The cell surface membrane is the boundary between the cell and its environment; it has very little mechanical strength but plays a vital role in controlling which materials pass into and out of the cell. The cytoplasm is semi-fluid, jelly-like, hyaline substance; its outer surface is much more thick to form the boundary of the cell. He was the first to describe the existence of the capillaries, thereby completing the work on the circulation of the blood started by the great English physiologist William Harvey. Cytoplasm: (a) Endoplasmic Reticulum Cytoskeleton, channelization, synthesis of fats, steroids, proteins, formation of vacuoles and vesicles, advertisements: (b) Ribosomes Protein synthesis, (c) Mitochondria Krebs cycle, amino acid synthesis, fatty acid synthesis, (d) Chloroplasts Photosynthesis, (e) Amyloplasts Storage of starch, (f) Golgi. Objections: (i) Viruses are acellular and do not have a cellular machinery. All known living things are made up of cells. There are altogether 23 pairs of chromosome; 22 pairs act as autosomes and the other pair is known as sex-determining chromosome or sex chromosome.