prokaryotic and eukaryotic cells

• what are extremophiles?

  prokaryotic cells that first appeared 3.5 billion years ago when the surface of the earth was very hostile. These early cells were adapted to living in extremes of salinity, pH and temperature
• where are extremophiles found today?

  hydrothermal vents and salt lakes
• what demain are extromphiles usually?

  archeaa
• what are prokaryotic organisms always?

  uni cellular with a relatively simple structure. their DNA is not contained in a nucleus and they have few organelles which are not membrane bound.
• how is dna packaged in prokaryotes?

  generally only have 1 molecule of DNA ( a chromosome) which is supercoiled to make it compact. The genes on the chromosome are often grouped into operons, meaning a number of genes are switched on or off at the same time.
• what are the ribosomes like in prokaryotes?

  smaller than in eukaryotes. their relative size is determined by the rate at which they settle, or form a sediment, in a solution. Prokaryotic ribosomes are around 70s (eukaryotic 80s) Both are necessary for protein synthesis, but 80s ribosomes are involved in the formation of more complex proteins.
• what are prokaryotic cell walls made of?

  peptidoglycan, also known as murein. A complex polymer formed from amino acids and sugars
• what arrangement do prokaryotic flagella have?

  they do not have the 9 + 2 arrangement. The energy to rotate the filament that forms the flagellum is supplied from the process of chemiosmosis not from ATP.