Overview of Cells Prokaryotes vs Eukaryotes The Cell Organelles The Endosymbiotic Theory

Archaea Bacteria Prokaryotic Cells 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

Protists Fungi Animal Cells Plant Cells Eukaryotic 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

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

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 rigid shape (keep plant from drooping)

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. Prokaryotic Cells – Plasma Membrane – Cytoplasm – Cell Wall – DNA (no nucleus) – Ribosomes 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 Plant Cells (eukaryotic) – Cell Wall – Chloroplasts – Vacuole

Polysaccharides 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 Lipids Proteins (Polypeptides) Organelles

Components found in all cells 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 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 Components found in all cells Plasma Membrane

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

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) Components found in all cells DNA

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

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 Components found in all cells Ribosomes

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