3.6 - Prokaryotic cells and viruses

• Which is smaller, a eukaryotic cell or a prokaryotic cell ?

  Prokaryotic
• Do prokaryotes have a nucleus ?

  No, they have a nucleotide region and no nuclear envelope
• What does a prokaryotes cytoplasm lack ?

  Membrane-bound organelles
• How are a prokaryotes ribosomes different to a eukaryotes?

  Are smaller, 70S
• What do prokaryotes have instead of a nucleus ?

  Have a single circular DNA molecule that’s free in the cytoplasm
• Do prokaryotes have a cell wall and if so describe it ?

  Yes, a cell wall made of murein (a glycoprotein)
• What surrounds a prokaryotic cell sometimes ?

  A capsule
• Is prokaryotic DNA associated with proteins ?


  No
• Do prokaryotes have a cell-surface membrane ?


  Yes
• What other DNA do prokaryotes have ?

  Plasmids
• What do plasmids do ?

  Can give the give the bacterium resistance to harmful chemicals
• A difference between eukaryotes and prokaryotes concerning introns ?

  Prokaryotic DNA has no introns so it’s all coding DNA
• Can prokaryotes contain chloroplasts ?

  No, only some have bacterial chlorophyll
• Give 8 differences between prokaryotic and eukaryotic cells ?


  .

  
• 5 difference between prokaryotic and eukaryotic DNA ?


  .

  
• The roles of the cell wall, capsule, cell-surface membrane, circular DNA and plasmids ?


  .

  
• The 3 steps of binary fission ?

  circular DNA doubles, plasmids double, cytoplasm divides in 2
• Equation to find the no. of bacteria in a population ?

  no. of bacteria to start x 2^n(the no. of divisions)
• Do prokaryotes have flagella and what do they do ?

  Yes, can have one or more, are used for movement
• What 5 features are always presents in a bacterium ?

  Murein cell wall, cell-surface membrane, cytoplasm, circular DNA in nucleoid region, 70S ribosomes
• What 5 features do bacterium sometimes have ?

  Flagellum, capsule, in folding cell membrane, plasmids, pili
• What do pili do ?

  Enable bacteria to attach to surfaces and involved in sexual reproduction
• What defines a virus ?

  Acellular and non-living
• Are viruses smaller than bacteria ?


  Yes
• What genetic material do viruses contain ?

  Nucleic acids (DNA or RNA )
• Where is the muckier acid found in a virus ?

  Enclosed within a protein coat called a capsid
• What other material do some viruses (such as HIV) have surrounding them ?

  A lipid envelope
• What proteins on the outside do viruses have ?

  Attachment proteins
• What do the attachment proteins allow the virus to do ?

  Identify and attach to host cells
• What enzyme is contained in the capsid of a virus?

  Reverse transcriptase
• What structure surrounds the virus ?

  Matrix
• What granules and droplets can bacteria have ?

  Glycogen granules and oil droplets
• How do infect cells and replicate ?

  Attachment proteins bind to receptors on host cells surface, Allows capsid containing nucleic acid to be injected into cell, Viral DNA inserted into host DNA and is transcribed with host DNA, Viral RNA is translated into viral proteins using host ribosomes, Virions assemble inside the cell, The cell bursts or visions bud from the surface