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bacterial cell.pptx

  1. Bsc nursing 1 year Microbiology Unit :- 2 ( microbes) BY :- PRAGYA TIWARI
  2. Microbes:- Microbes are tiny living things that are found all around us and are too small to be seen by the naked eye. They live in water, soil, and in the air. The human body is home to millions of these microbes too, also called microorganisms. Some microbes make us sick, others are important for our health. The most common types are bacteria, viruses and fungi. There are also microbes called protozoa. These are tiny living things that are responsible for diseases
  3. Classification of microbes :- Microorganisms are categorized into four major groups: 1.Bacteria:- These are microscopic, single- celled organisms that grow in diverse environments. These organisms can live in soil, the ocean, and also in the human gut. 2.Virus :- A virus is an infectious microbe consisting of a segment of nucleic acid (either DNA or RNA) surrounded by a protein coat. Viruses invade healthy cells and start to multiply from these cells. A virus can’t reproduce without these host cells.
  4. 3.Algae:- These are simple, non- flowering, and typically aquatic plants of a huge group that have seaweeds and many single-celled forms in them. Algae has chlorophyll in it lacks true stems, roots, leaves, and vascular tissue. Algology or is the study of algae 4.Fungi: These are a group of microorganisms that are eukaryotic in nature and these consist of microorganisms such as yeasts, moulds and mushrooms.
  5. 5.Protozoa: Protozoa (also protozoan, plural protozoans) is an informal term for single-celled eukaryotes, either free-living or parasitic, which feed organic matter such as other microorganisms or organic tissues and debris.
  6. Bacterial morphology :-  Morphology describes bacterial shape and size, arrangement and it’s structure.  There shape can we spherical (cocci), Rod shaped (bacilli) or in helical curve (spiral).  Some microbes are various shaped called pleomorphic. According to shape of bacteria :- 1.cocci :- it derived from kokkos means berry. They are spherical in shaped. 1. Staphylococcus :- cocci in cluster. 2. Streptococcus :- cocci in chain. 3. Diplococci :- cocci in pair. 4. Tetrad :- cocci in group of four. 5. Sarcina :- cocci in group of eight.
  7. 2.Bacilli :- it derived from word bacules means rod cylindrical and rod shaoed organisms a re called bacilli following are :- 1. Coccobacilli :- is some of organism length may approximately the width of the organism. These called coccobacilli. 2. Corynebacteria :- Chinese letter arrangement is seen in corynebacteria. 3. Vibrio :- these are comma shaped, curved rod and derived the name from there characteristics vibratory motality. 4. Spirochaetes :- it derived from word speria means coil , they are Relativility long, thin, flexible organism having several coils. 5. Actinomycetes :- it derived from word actis-ray mykes fungus. They ate branching filaments bacteria. 6. Mycoplasma :- there organism which lack cell wall and do not cause a stable morphology, they have round and oval body.
  8. According to size of bacteria :- 1. Higher bacteria :- they are branching bacteria like :- actinomycetes 2. Lower bacteria :- single small bacteria eg :- cocci, bacilli, vibro. According to oxygen requirement :- 1. Aerobic :- Required oxygen to grow. 2. Anarobic :- do not required oxygen to grow 3. Facultative :- they grow under both aerobic and anarobic conditions.
  9. Bacterial cell :- Like other living cells bacteria possess cytoplasmic members, cell wall, ribosomes etc. The special structure they may possess are capsule, flagella, Fimbriae and pili. Which are present outside the cell wall.
  10. 1.Cell wall :-  It is given shape to the bacilli.  It is touch and rigid structure surrounding the bacteria like a shell.  Cell wall possess bacterial antigen which are important an virulence and immunity.  It is elastic and pores. Function:- 1. Give shape to the cell. 2. Role in division of bacteria. 3. Provide attachment. 4. Protection of internal structure. 5. Offer resistance to harmful effects of environment. 6. Confers rigidity.
  11. 2.Cytoplasmic members :-  It is elastic semipermeable membrane and mainly Lipoprotein in nature and like beneath cell wall separating it from the cell Semiplasma.  It control the inflow and outflow of water , nutrients and waste products in or out.  It can be demonstrate by electron microscope only  Protoplasma =cytoplasm + nucleus + Other organelle. Function :- 1. Presence in the membrane of specific enzymes which used in possess through membrane selective nutrients. 2. It hepls in DNA replication. 3. It provide little Machnical strength to bacterial cell.
  12. 3.Cytoplasm :-  It is watery viscous solution of various organic and inorganic solutes containing DNA , ribosomes, Mesosomes, and Vacuoles.  It can be stain by basic dye. Function:- They are site of respiratory enzymes in bacteria co-ordinate Nuclear and cytoplasmic division during binary fission. Responsible for compartmenting DNA at sporulation.
  13. 4.Slime layer :-  Some bacteria secrete viscid substance, which may diffuse out into surrounding media remain outside cell wall.  This viscid carbohydrate material called slime layer Function:- 1. main function is to protect the bacteria from environmental dangerous such as antibiotics.
  14. 5.Capsule :-  It is gelatinous secretion of bacteria. Which get organized as a thick coat around cell wall, it is known as capsule. The capsule of most bacteria consists of a polysaccharides.  Development of capsule is depends on the existence of favorable environmental conditions, such as presence of high sugar concentration and blood serum. Function :- 1. Attachment to surface. 2. Protection against Phagocytosis Engulfment killing or digestion. 3. Reserve of nutrients and protection against dedication. ( complete drying) .
  15. 6.Nucleus :-  The nucleus contains the thin fibre of double standard DNA helix tightly coiled inside the cytoplasm.  It does not have Nucleolus. (Nucleoli are small bodies often seen within the nucleus.)  The nucleus is the site for the genetics transcription. (Transcription is the process of copying a segment of DNA into RNA.)
  16. Function :- 1. The main function is to govern gene expression, And facilitate DNA replication during cell cycle. 2. control of the protein and enzyme synthesis. 3. Control of cell division and cell growth. 4. Storage of DNA, RNA and ribosomes.
  17. 7.Plasmid :-  Some prokaryotes also carry smaller circles of DNA called plasmids.  Plasmids are the extra chromosomal structures in the cells of bacteria which have the ability to self replicate. Function :- 1. They are genetically modified and are used in the recombinant DNA technology.(Recombinant DNA technology comprises altering genetic material outside an organism to obtain enhanced and desired characteristics in living organisms or as their products).
  18. 8.Mesosomes :-  It is convoluted (complex) and Multilaminated structure produced by complex cover of the plasma membrane seen in maany but not all bacteria. And are present in the cytoplasm and remain attached with the cytoplasmic membrane (plsma membrane). Function :- 1. It is concerned with respiration, cell division and sporulation, DNA replication etc.
  19. 9.Ribosomes:-  There are two types of ribosomes, free and fixed.  Free ribosomes are located in the cytosol and are able to move throughout the cell, whereas fixed ribosomes are attached to the rER.  Eukaryotic ribosomes are called 80S ribosomes while prokaryotes such as bacteria have a smaller version called 70S ribosomes. Function :- 1. it is the site of protein synthesis in the cell. 2. The ribosome reads the messenger RNA (mRNA) sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to form proteins.
  20. 10.Flagella:-  These are Filamentous, cytoplasmic appendages (attachment) protruding through cell waal which act as a organ of locomotion (ability to move from one place to another.)  These are unbranched, long thread like structure composed of entirely of protein.  It is 0.02 micrometer thick, and it is several times in length of the bacterial cell.  The flagella are present in all motile bacteria, excepting spirochaetes.  Their no. Varies upto 10-20/cell depending on bacterial species.
  21. According to the arrangement and distribution of flagella are following types :- 1. Atrichous :- without flagella. 2. Monotrichous:- single polar flagella. 3. Amphitrichous:- single flagella attached to each ends. 4. Lophotrichous:- multiple flagella located at the same spot on the bacteria’s surfaces. 5. Peritrichous:- numerous flagella all over the bacterial cell.
  22. 11.Pili/fimbriae:-  These are Filamentous, short, thin, straight, hair like appendage 0.1to 1.5 u long and less than 4-8 nm thick.  They are also called pili.  Each bacteria may have 100-500 fimbriae Peritrichously all over teh body of thr bacteria.  They are made up of protein. Function :- 1. The primary function of pili are to attached a bacterial cell to specific surface to other cells 2. Pili can also attachment between bacterial cell.