cell structure

• what is a cell

  The smallest unit of life that can live on its own.

  Cells make up all living organisms and their tissues
• the differences between eukaryotic and prokaryotic cells

  1. E cells are larger that P cells
  2. E cells contain membrane-bound organelles while P cells don't
  3. E cells keep their DNA in the form of chromosomes within a nucleus while P cells have their DNA loose in the cell in plasmids
• example of prokaryotic cell

  bacterial cell
• examples of eukaryotic cells

  animal and plant cells
• 5 sub-cellular structures (organelles) that are found in both animal and plant cells

  1. cell membrane
  2. ribosomes
  3. nucleus
  4. mitochondria
  5. cytoplasm
• what is cell membrane and its role

  • the protective barrier around the outside of the cell
  • it controls which substances can pass in and out of the cell
• what is the cytoplasm and its role

  • a jelly-like liquid that fills the cell
  • allows substances to dissolve and chemical reactions to take place
• role of the nucleus

  contains the genetic material (DNA) of the cell, and so controls what the cells does
• role of the mitochondria

  carry out aerobic respiration so provide energy (in the form of ATP) for the cell to use in chemical reactions
• role of ribosomes

  site of protein synthesis (where proteins are made)
• 3 sub-cellular structures that are found in plant cells but NOT animal cells

  • cell wall
  • permanent vacuole
  • chloroplast
• in plants what is the cell wall made of

  cellulose
• what is the role of the plant cell wall

  provides strength to the plant cell preventing it from bursting or shrinking when water enters/leaves the cell via osmosis
• what does the permanent vacuole contain

  cell sap (a solution of sugars , salts and amino acids)
• what is the role of the permanent vacuole

  supports the cell, maintaining it's turgidity (shape)
• role of chloroplasts

  site of photosynthesis, so make glucose for the cell
• chlorophyll

  a green pigment within chloroplasts that absorbs sunlight for photosynthesis

  makes plants green
• 7 sub-cellular structures that are found in bacterial cells

  1. cell wall
  2. cell membrane
  3. cytoplasm
  4. circular strand of DNA (nucleoid)
  5. plasmid
  6. ribosome
  7. flagellum
• what are plasmids and what is their role

  • small circular loops of DNA that are separate to the main DNA
  • contain 'extra genes' that are sometimes useful to the bacteria such as antibiotic resistance
• what is the prokaryotic cell wall composed of

  peptidoglycan