Cells Cells All living things are made of cells Some have only 1 cell, most are multicellular Most are very tiny Two general types PProkaryotes: no true nucleus EEukaryotes: true nucleus Prokaryotes and Eukaryotes Simple, single celled bacteria & cyanobacteria No true nucleus with a membrane. Chromosome simple ring of DNA not bound to proteins. May also have plasmids. No membrane bound organelles. All other cells e.g. plants & animals Nucleus has a nuclear membrane. 2 or more chromosomes of DNA wound around proteins & highly folded Membrane bound organelles present e.g. mitochondria Prokaryote = before nucleus Eukaryote = good nucleus Prokaryote cells (bacteria) Inside a prokaryote General characteristics of Cells cytoplasm membraneCells consist of jelly-like cytoplasm surrounded by a membrane. nucleusA nucleus sits in the cell organellesmembrane systemsVarious organelles and membrane systems are also present Size and shape Huge variety Related to function Plant cell Animal Cell Cell membrane Nucleus Ribosomes Golgi body What Golgi bodies do Lysosomes Mitochondrion Chloroplast (Plants only) Centriole (Animals only) Cytoskeleton Cytoplasmic streaming Microtubules Centrioles help form the spindle for cell division Cillia and Flagella Cell Wall of plants