Cell theory and prokaryotic cells

• cell theory: The scientific theory that all living organisms are made of cells as the smallest functional unit.
• The cell theory includes three main ideas:

  All living things are made of cells.

  A cell is the smallest unit of life.

  All new cells arise from existing cells.
• • Organisims that are made up of a single cell are said to be unicellular, some examples are bacteria, amoeba and paramecium.​
  • While cells that are made up of many cells are multicellular, some examples are plant , animal and fungi.​
• • Some cells are prokaryotic, which means their genetic material e.g DNA, lies freely in the cytoplasm and they do not have membrane bound organelles such as nucleus mitochondria or chloroplast.​
  • Some cells are Eukaryotic, which means their genetic material e.g DNA, is surounded by a Nuclear membrane​ and they have membrane bound organelles. Most eukaryotic cells are multicellular.
• label the bacteria

  A) genetic material-large loop of DNA

  B) pili

  C) ribosomes

  D) food granule

  E) prokaryotic flagellum

  F) plasmid DNA

  G) cytoplasm

  H) plasma membrane

  I) cell wall

  J) capsule or smile layer

  
• Prokaryotes :​

  • lack complex membrane bound organelles such as mitochondria, chloroplast and ER.​
  • Have ribosomes (70 s), but these are smaller than in eukaryotes.​
  • Ribosomes are always free in the cytoplasm rather than attached to membranes.​
• • Cell wall is made up of peptidoglycan (murein) ​
  • It is a large molecule that Contains amino acids and sugars ​
  • Capsule- protection against immune system ​Secreted slime ​
• plasmid

  • Small loops of DNA​
  • Separate from main DNA​
  • Contains genes for antibiotic resistance ​
  • Some have many plasmids