/
Bacteria REVIEW Bacteria are single-celled Bacteria REVIEW Bacteria are single-celled

Bacteria REVIEW Bacteria are single-celled - PowerPoint Presentation

giovanna-bartolotta
giovanna-bartolotta . @giovanna-bartolotta
Follow
346 views
Uploaded On 2020-01-28

Bacteria REVIEW Bacteria are single-celled - PPT Presentation

Bacteria REVIEW Bacteria are singlecelled organisms Are present in air water and on most solid materials Bacterial cells are very small and can only be seen with the aid of a microscope Bacteria ID: 774012

Share:

Link:

Embed:

Download Presentation from below link

Download Presentation The PPT/PDF document "Bacteria REVIEW Bacteria are single-cell..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.


Presentation Transcript

Bacteria REVIEW

Bacteria are single-celled organisms Are present in air, water and on most solid materials Bacterial cells are very small and can only be seen with the aid of a microscope. Bacteria

When observed under a microscope the cells can be seen to differ in shape and in conformation of groups of cells. Cells are either spherical or rod-shaped Spherical bacteria are called cocci Those that are rod shaped are called bacilli. This is the first basis for differentiating between bacterial cells. Bacterial Shapes

Bacteria are also classified according to cell cluster formation :Diplococci          * two cocci cells paired Staphylococci  * a number of cells clustered together Streptococci    * a number of cells arranged in a chain Rod-shaped & Spherical Bacteria

Some bacteria are capable of locomotion by means of flagellaelong, hair-like appendages growing out of the cell Some rod-shaped bacteria contain spores These are formed when the cells are faced with adverse conditions, such as high temperature once suitable conditions are reestablished the spores germinate to form new cells. Bacterial characteristics

Close examination of the simple cell reveals that it is composed of the following components : Cell wall -this gives the cell its shape and retains the constituentsCell membrane-used for filtering in food constituents and discharging waste products Nucleoid -where the genetic material of the cell is stored; Cytoplasm- a semiliquid proteinaceous substance which contains starch, fat and enzymes. Bacterial Components

The cell membrane is semipermeable and allows the cell to feed by osmosis i.e. the exchange of water between the cytoplasm of a living cell and the surrounding watery material. Only small molecules can pass in and out of the cell e.g. with a sugar solution on one side of a semipermeable membrane and water on the other, water will diffuse in, diluting the sugar solution. The sugar molecules cannot pass out so a hydrostatic pressure, known as osmotic pressure, develops . Bacteria can feed by selective intake of nutrients dissolved in water. They can also take in nutrients against the normal osmotic flow active transport.