Cells

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Cells
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Types of Cells

• Prokaryotic
• No membrane bound organelles
• Bacteria
• Nuclear Area

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Cellular Evolution

• Current evidence indicates that eukaryotes
  evolved from prokaryotes between 1 and 1.5
  billion years ago.
• Two theories
• 1. Infolding theory
• 2. Endosymbiotic theory

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1. Infolding Theory

• The infolding of the prokaryotic plasma membrane
  gave rise to eukaryotic organelles.

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2. Endosymbiotic theory

• Endosymbiosis refers to one species living within
  another - the host.
• Theory - the movement of smaller photosynthetic
  (chloroplast) and heterotrophic (mitochondria)
  prokaryotes into larger prokaryotic host cells.

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Eukaryotic Animal Cell
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Eukaryotic - Plant Cell
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Eukaryotic

• Cytoplasm
• Contents of cell, besides the nucleus
• Cytosol
• Gel-like fluid that fills all spaces

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Nucleus

• Manages Cell Functions
• Contains DNA and Nucleolus

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Nucleus

• Surrounded by double membrane, which is supported
  by nuclear lamina (network of fibers)

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Chromosomes

• DNA and all associated RNA and proteins in
  distinct units

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Chromatin

• Unwound chromosomes

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Nucleolus

• Knot of chromatin
• Produces Ribosomes

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Nucleolus
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Nuclear Membrane

• Double membrane
• Four layers
• Porous but Selective

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Ribosomes

• Site of Protein Synthesis.
• Half RNA, Half Protein
• Millions!

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Endoplasmic Reticulum (ER)

• Folded network of membranes that extend from the
  nucleus to the cell membrane.
• Delivery System of the cell.
• Two types- Smooth ER and Rough ER

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ER

• Lumen
• Inside the ER

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Smooth ER

• No Ribosomes.
• Lipid synthesis

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Rough ER

• Dotted with Ribosomes

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Vesicles

• Carry things
• Bud off of ER or Golgi

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Golgi Apparatus

• Receives new proteins and lipids, repackages
  them, and sends them back out

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Lysosome

• Contain digestive enzymes.

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Vacuole

• The storage compartment of the cell.

• Plants have 1 large vacuole, animals have many
  smaller

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Mitochondria

• Site of cell respiration
• Double Membrane

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Mitochondria

• Has its own DNA
• Was once Prokaryotic??

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Plastids

• Double Membrane
• Contain DNA, RNA, ribosomes
• Reproduce independently
• Only in plants

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Chromoplast

• Make and store yellow, orange, red pigments
• Chromo color

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Leucoplast

• Storage (of starch)

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Chloroplast

• Photosynthesis

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Peroxisomes

• Oxidation reactions
• Detoxify
• Glyoxysomes- specialized
• Converts fatty acids to carbohydrates

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Cytoskeleton

• Shape and Movement
• Flexible
• Made of proteins
• Three parts

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Cytoskeleton

• Microtubules
• Thickest
• Hollow
• Cables for structures to move along

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Cytoskeleton

• Microtubules make up
• Centrioles
• Cilia
• Flagella

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Cytoskeleton

• Intermediate Filaments
• Maintain cell shape

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Cytoskeleton

• Microfilaments
• Thinnest
• Movement

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Extracellular matrix

• Network of glycoproteins outside of and within
  cell membrane (i.e. collagen)
• Helps coordinate cell activities and behaviors
  from cell to cell

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Cell to Cell Junctions

• In plants
• Plasmodesmata
• Holes in the cell wall to allow cytosol to be
  shared between neighboring cells

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Cell to Cell Junctions

• In Animals
• Tight Junctions
• Prevent leaking
• stitches
• Desmosomes
• Fasten cells together
• screws
• Gap Junctions
• Channels to allow passage of materials from cell
  to cell

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GAP JUNCTIONS
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