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Overview of Cells

Overview of Cells. Prokaryotes vs Eukaryotes The Cell Organelles The Endosymbiotic Theory. Prokaryotic Cells. Archaea Bacteria. Come in many different shapes and sizes .5 µm – 2 µm, up to 60 µm long

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Overview of Cells

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  1. Overview of Cells • Prokaryotes vs Eukaryotes • The Cell Organelles • The Endosymbiotic Theory

  2. Prokaryotic Cells • Archaea • Bacteria • Come in many different shapes and sizes • .5 µm – 2 µm, up to 60 µm long • Have large surface to volume ration – nutrients from outside can easily reach all parts of the cell

  3. Eukaryotic Cells • Protists • Fungi • Animal Cells • Plant Cells • Like prokaryotic cells, eukaryotic cells come in many different shapes and sizes, but have the same basic set of organelles • Multicellular organisms (fungi, plants and animals) have specialized eukaryotic cells that each perform a particular job and all work together for the benefit of the organism

  4. Eukaryotic Cells Common Organelles • Plasma membrane • Nucleus • Chromatin (DNA) • Nucleolus • Nuclear Envelope • Ribosomes • Rough Endoplasmic Reticulum (rough ER) • Smooth Endoplasmic Reticulum (smooth ER) • Golgi Apparatus • Centrioles • Mitochondria • Cytoskeleton • Vesicles, Peroxisomes, Lysosomes, Small Vacuoles

  5. Eukaryotic Cells Organelles only found in Plants • All those in animal cells except Centrioles • plus • Cell Wall • Chloroplasts • Large Vacuoles • The cell wall and vacuoles help plant cells maintain a rigidshape (keep plant fromdrooping)

  6. Organelles • Organelles are the parts within a cell that have specific functions • Prokaryotic cells (e.g. bacteria) are smaller and less complex (fewer organelles) than eukaryotic cells. Eukaryotic Cells • Plasma Membrane • Cytoplasm • Nucleus • Chromatin (DNA) • Nucleolus • Nuclear Envelope • Ribosomes • Vesicles, Peroxisomes, Lysosomes • Rough Endoplasmic Reticulum • Smooth Endoplasmic Reticulum • Golgi Apparatus • Centrioles • Mitochondria • Cytoskeleton Prokaryotic Cells • Plasma Membrane • Cytoplasm • Cell Wall • DNA (no nucleus) • Ribosomes Plant Cells (eukaryotic) • Cell Wall • Chloroplasts • Vacuole

  7. Polysaccharides Organelles Organelles are made of: • Proteins – made of amino acids • Lipids – made of fatty acids • Carbohydrates - polysaccharides made of sacharides (sugars) • Nucleic Acids (DNA and RNA) – made of nucleotides Nucleic Acids Proteins (Polypeptides) Lipids

  8. Components found in all cells Plasma Membrane • Made of a Phospholipid Bilayer • Various proteins, lipids, and sugars float in membrane • Semipermeable • Small hydrophobic molecules pass easily through • Contains pores that enable water and very small ions to pass through • large molecules must pass through channel proteins

  9. Components found in all cells Plasma Membrane • Eukaryotic cells also membrane-bound internal organelles composed of lipid bilayer membranes • Nuclear Envelope • Golgi Apparatus • Endoplasmic Reticulum (rough and smooth) • Mitochondria • Chloroplasts (in plants) • Vesicles, Lysosomes, Peroxisomes & Vacuoles

  10. Components found in all cells Cytoplasm • The fluid that fills cells and surrounds the organelles • Consists of: • Water (mostly) • Proteins (e.g. hormones and enzymes) • Small Molecules (e.g. ions)

  11. Components found in all cells DNA • Prokaryotic Cells • May be linear or circular • Contained in the nuclear region (nucleoid) • May also include short, circular plasmids • Eukaryotic Cells • Longer (approx. 9 feet per cell in humans), coiled around histone proteins to help pack it into the cell • Always linear • Contained in the nucleus • Known as chromatin when relaxed and chromosomes when condensed (supercoiled)

  12. Components found in all cells Ribosomes • Float freely in the cytoplasm of prokaryotic and eukaryotic cells • Also coat the rough ER of eukaryotic cells

  13. Components found in all cells Ribosomes • Build proteins using instructions encoded in DNA

  14. Components found in all cells Ribosomes • Build proteins using instructions encoded in DNA • Complex of protein and rRNA forming two subunits Purple = Proteins Blue = rRNA of small subunit Grey = rRNA of large subunit

  15. Components found only in Eukaryotic Cells Nucleus • Nuclear Envelope • double membrane • nuclear pores allow RNA to exit • Chromatin – “relaxed” DNA • Nucleolus – where ribosomes are assembled

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