cell structure

• what is a cell

  a cell is the smallest unit of life that can live on its own. cells make up all living organisms and their tissues
• what are the differences between eukaryotic and prokaryotic cells

  • eukaryotic cells are much larger than prokaryotic cells
  • eukaryotic cells contain membrane-bound organelles while prokaryotic cells do not
  • eukaryotic cells keep their DNA in the form of chromosomes within a nucleus whilst prokaryotic cells have their DNA loose in the cell
• 5 sub-cellular structures (organelles) that are found in both animal and plant cells

  • cell membrane
  • ribosomes
  • nucleus
  • mitochondria
  • cytoplasm
• what is the cell membrane and what is it's role

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

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

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

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

  they are the site of protein synthesis (where the proteins are made)
• 3 sub-cellular structures (organelles) 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 cell wall

  it provides strength and structure 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

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

  chloroplasts are the site of photosynthesis, so make glucose for the cell
• what is chlorophyll

  a green pigment within chloroplasts that absorbs sunlight for photosynthesis. it is chlorophyll that makes plants green
• 7 sub-cellular structures (organelles) that are found in bacterial cells

  • cell wall
  • cell membrane
  • cytoplasm
  • circular strand of DNA (nucleoid)
  • plasmid
  • ribosome
  • flagellum
• what are plasmids and what are their role

  plasmids are small, circular loops of DNA that are sperate to the main

  DNA. they contain 'extra genes' that are sometimes useful to the bacteria such as antibiotic resistance
• what is the prokaryotic cell wall composed of

  peptidoglycan