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Bacteria e. coli function

M1 (Microbiology)

The function of E. coli is to suppress the growth of harmful bacterial species and to synthesize numerous amounts of vitamins. It also causes human illness through different mechanisms.

Cell wall- the function of a cell wall is to act like a pressure vessel and to anticipate over-expansion when water enters in the cell. Also it protects the cell and gives it structural support and it defines the shape of the cell.

Nucleolus- the function of a nucleolus is to control what goes in the cell and to also synthesize RNA and to make ribosomes. The nucleolus is in the centre of the cell.

Ribosome-the function of ribosome is to make proteins and assemble them according to the genetic instructions. Also to serve as a site of mRNA translation.

Yeast cell (Saccharomyces cerevisiae)

The function of a yeast cell is to supply carbon dioxide; this inflates the dough whilst proof and the early stages of baking.

Mitochondria- the function of mitochondria also known as the powerhouse of a cell is to provide energy for the cell in the form of adenosine triphosphate (ATP). This helps the cell use the energy from the mitochondria to perform specific work such as functions and cell survival.

Nucleus- the function of a nucleus is to regulate all the cell activity by regulating the genetic expression. The nucleus also contains the genetic material of a cell. Therefore the nucleus is the master organelle of a cell.

Lysosome/vesicle- the function of a lysosome is the digestive system of a cell, they digest foreign bacteria getting rid of them and help repair the plasma membrane, they also destroy warn out or damaged organelles and protect the cell from foreign intruder.

Cell (plasma) membrane-the function of a plasma membrane is to control the movement of certain substances to enter or to leave the cell, both actively and passively. It also allows cell identification.

Cell wall- the function of a cell wall is to define the shape of the cell and to protect it by covering the cell membrane through its thick layer.

Cytoplasm- the function of a cytoplasm is to make sure metabolism reaction take place and to support the cell and to store chemical substances. It helps maintain the cells shape, to be consistent and to provide suspension to the organelles.

Endoplasmic reticulum- the function of endoplasmic reticulum is to transport synthesized proteins in air sacs called cisternae, to control protein synthesis; this function is for the rough endoplasmic reticulum whereas the smooth endoplasmic reticulum removes toxins from the system.

Vacuole- the function of a vacuole is to store ingested food, removes wastes, to maintain fluids and cellular structure.

Human immunodeficiency virus

The function of HIV is to target and destroy helper T cells. To also invade the brain and to multiply.

Nucleic acid (RNA) -the function of nucleic acid is to store and transfer genetic information and to direct the synthesis of the new protein. RNA is a copy of DNA and transfers all the genetic information from DNA.

Capsid (protein) -the function of capsid is to shield delicate genetic material from attack and alteration. Also to protect the viral and to help locate the virus so that it can infect the moderator.

Lipid (envelope) -the function of a lipid is tostore and transfers genetic energy.

Glycoprotein- the function of a glycoprotein is to act as a receptor on cell surfaces this helps bring other protein and cells together making the matrix strong and supportable.

P4 Microbiology

Characteristics for groups of bacteria


Proteobacteria are gram-negatives and has come from an ancestral purple photosynthetic bacterium. In the group the alpha subdivision, agrobacterium spp, beta subdivision, bordetella spp, delta subdivision etc. It has an outer membrane which is constructed by lipopolysaccharides, this moves about using flagella but some depend on the bacteria gliding. Another includes myxobacteria. This is a unique group of bacteria that can accumulate to form multicellular fruiting bodies. This includes the wide range of metabolism which most members are either obligately, chemoautotrophs, anaerobic, heterotrophic and facultatively. A diversity of genera converts energy from light through photosynthesis. This is called the purple bacteria also known for its reddish pigmentation.

Gram positive bacteria

Gram positives are the colour dark blue or violet by gram straining. They are characterized by having their cell wall structure peptidoglycan; they are cross- linked through short peptides. They have a cytoplasmic membrane; a gram positive also contains capsule polysaccharides this is found in some species. Lipoids and teichoic acids are also present, they form the acid lipoteichoic this acts as a chelating agent. The flagellum is also found in some species and when found it has two rings for support.


Cyanobacteria is also a gram negative, it has a gram negative type cell wall, and usually uses its gas vessels to move in water and they contain phycocynain pigment. This bacteria is greatly shaped and is a true prokaryotes. The photosynthetic system resembles the eukaryotes because it contains photo system and chlorophyll. It reserves food and this is called glycogen. The range n diameter is from about 1 to 10 micron.