The 10 Minute Review

1
The 10 Minute Review

• Chapter 6 A Tour of the Cell

Cells Alive Overview of Cell Parts
2
How do we study cells? Cytology

• Light microscopy resolving power measure of
  clarity
• Electron microscopy Fig. 6.4 TEM electron
  beam to study cell ultrastructure SEM
  electron beam to study cell surfaces
  
• Cell fractionation cell separation organelle
  study
• Ultracentrifuges cell fractionation 130,000 rpm

3
Cell Types Prokaryotic

• Nucleoid DNA concentration
• No organelles with membranes
• Ribosomes protein synthesis (not an organelle)
• Plasma membrane (all cells) semi-permeable
• Cytoplasm/cytosol (all cells)

4
How does Cell size affect the cell? Fig 6.8

• As cell size increases, the surface area to
  volume ratio decreases
• Rates of chemical exchange may then be inadequate
  for cell size
• Cell size, therefore, remains small

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What are the functions and characteristics of the
Nucleus?

• Genetic material... chromatin chromosomes nu
  cleolus rRNA ribosome synthesis
• Double membrane envelope with pores
• Protein synthesis (mRNA)

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What are the functions and characteristics of the
Ribosomes

• Protein manufacture
• Free cytosol protein function in cell
  cytosol
• Bound endoplasmic reticulum membranes,
  organelles, and export into a membrane

7
Endomembrane system What are the functions and
characteristics of the ER?

• Endoplasmic reticulum (ER)
• Continuous with nuclear envelope
• Smooth ER
• no ribosomes synthesis of lipids,
• metabolism of carbohydrates detoxification of
  drugs and poisons
• Rough ER
• with ribosomes
• synthesis of secretory proteins (glycoproteins),
  membrane production

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Endomembrane system What are the functions and
characteristics of the Golgi?

• Golgi apparatus ER products are modified,
  stored, and then shipped
• Cisternae flattened membranous sacs
• trans face (shipping) cis face (receiving)
• Transport vesicles

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Endomembrane system What are the functions and
characteristics of the Lysosome?

• sac of hydrolytic enzymes digestion of
  macromolecules
• Phagocytosis
• Autophagy recycle cells own organic material
• Tay-Sachs disease lipid-digestion disorder

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Endomembrane system What are the functions and
characteristics of the Vacuoles?

• membrane-bound sacs (larger than vesicles)
• Food (phagocytosis)
• Contractile (pump excess water)
• Central (storage in plants) tonoplast membrane

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A Tour of the Cell Part Deux

• http//learn.genetics.utah.edu/content/begin/cells
  /insideacell/
• http//learn.genetics.utah.edu/content/begin/cells
  /scale/

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What is the function and structure of the
Mitochondria?

• quantity in cell correlated with metabolic
  activity
• cellular respiration double membranous
  (phospholipid) cristae/matrix intermembrane
  space contain own DNA

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What is the function and structure of the
Chloroplast?

• type of plastid double
  membranous thylakoids (flattened disks)
  stroma
• grana (stacked thylakoids) own DNA

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What is the function and structure of the
Peroxisome?

• Single membrane
• Produce hydrogen peroxide in cells
• Metabolism of fatty acids detoxification of
  alcohol (liver)
• Hydrogen peroxide then converted to water

Dont Shoot!
Bombardier beetle
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What is the function and structure of the
Cytoskeleton?

• Fibrous network in cytoplasm
• Support, cell motility, biochemical regulation
• Microtubules thickest
  tubulin protein shape, support,
  transport, chromosome separation
• Microfilaments thinnest actin protein
  filaments motility, cell division,
  shape
• Intermediate filaments middle diameter
  keratin
  shape, nucleus anchorage

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What is the function and structure of the
Centrosomes/centrioles

• Centrosome region near nucleus
• Centrioles 9 sets of triplet microtubules in a
  ring used in cell replication only in animal
  cells

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What is the function and structure of the
Cilia/flagella?

• Locomotive appendages
• Ultrastructure 92 9 doublets of
  microtubules in a ring
  2 single microtubules in center
  connected by radial spokes anchored by basal
  body dynein protein

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Cell surfaces junctions

• Cell wall
• not in animal cells
• protection, shape, regulation
• Plant cell
• primary cell wall produced first
  middle lamella of pectin (polysaccharide)
  holds cells together
• some plants, a secondary cell wall strong
  durable matrix
• wood (between plasma membrane and primary
  wall)

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Extracellular matrix (ECM)

• Glycoproteins proteins
  covalently bonded to carbohydrate
• Collagen (50 of protein in human body)
• embedded in proteoglycan another
  glycoprotein-95 carbohydrate)
• Fibronectins bind to receptor proteins
  in plasma membrane called integrins (cell
  communication?)

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Intracellular junctions

• PLANTS
• Plasmodesmata cell wall perforations
  water and solute passage in plants
• ANIMALS
• Tight junctions fusion of neighboring cells
  prevents leakage between cells
• Desmosomes riveted, anchoring junction strong
  sheets of cells
• Gap junctions cytoplasmic channels allows
  passage of materials or current between cells