miércoles, 25 de febrero de 2009

Preguntes de Tasques Ciències Naturals

What Prokaryotic and Eukaryotic Cells Have in Common
http://www.phschool.com/science/biology_place/biocoach/cells/common.html
  • Both have DNA as their genetic material (it’s DNA that tells cells what kind of cells they should be).
  • Both are covered by a cell membrane.
  • Both contain RNA.
  • Both are made from the same basic chemicals: carbohydrates, proteins, nucleic acid, minerals, fats and vitamins.
  • Both have ribosomes (the structures on which proteins are made).
  • Both regulate the flow of the nutrients and wastes that enter and leave them.
  • Both have similar basic metabolism (life processes) like photosynthesis and reproduction.
  • Both require a supply of energy.
  • Both are highly regulated by elaborate sensing systems ("chemical noses”) that make them aware of the reactions within them and the environment around them.