Cellular Anatomy

1
Lecture 8

• Chapter 4
• Cellular Anatomy

2
Learning Objectives

• Discuss the many components of the endomembrane
  system
• Recall the function of the dynein arm
• Explain how plant cell wall, cell junctions, and
  plasmodesmata relate to eachother
• Recall and define the 3 types of cell junctions
  in animals
• Discuss whether viruses are alive

3
Endomembrane Review

• System produces molecules for use inside and
  outside of cell
• Many organells work together
• Nucleus
• Smooth
• Rough ER
• Golgi apparatus
• Lysozomes

4
Endomembrane System

• For review (ties together concepts of last
  lecture)

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Lysozomes

• Greek breakdown body
• Made by endomem. sys.
• Has digestive enzymes in a membrane sac
• Functions
• Engulf and digest worn-out organelles to recycle
• White blood cells use to destroy targets
• Food vacuoles can be broken down

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A Look at Lysozomes
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Lysozome Movie
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Storage Diseases Faulty Lysozomes

• Pompes disease lysosomes missing
  glycogen-digesting enzyme
• Excess glycogen accumulates in liver cells
• Tay-Sachs disease lysozomes missing
  lipid-digesting enzyme
• Excess lipids accumulate in brains nerve cells
• NTSAD Tay-Sachs website

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Vacuoles

• Membrane covered sacs
• Function as storage space for cells
• Plants have central storage vacuole
• For water, nutrients, etc.

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Energy-Converting Organelles

• Chloroplasts
• Mitochondria

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Chloroplasts

• Mostly in plants
• Have double membrane
• Photosynthesis

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Mitochondria

• Double membrane
• Sugars (like glucose) are used to make ATP
• ATP is energy storage molecule for cell processes

13
Cytoskeleton

• Involved with cellular movement
• Helps provide structure
• Three kinds of elements
• Microfilaments
• Intermediate filaments
• Microtubules

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Microfilaments

• The thinnest of the fibers
• Made of actin

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Intermediate Filaments

• Mid-sized
• Function in anchoring and reinforcing organelles

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Microtubules

• Straight, hollow tubes
• Easily assembled, reassembled
• Can act as guides for organelle movement (like
  railroad track)
• Ex Lysozome moving towards a food vacuole

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7th Inning Stretch
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Cilia and Flagella

• Microtubules bundled in plasma membrane
• Pattern 9 doublets 2 central microtubules
• At anchoring point, only 9 doublets, form a basal
  body

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Cilia Movie

• Watch the surface of the Paramecium
• Its cilia are moving

20
Dynein Arm

• Moves cilia and flagella
• Movement requires ATP
• Movie follows
• Contrast cilia vs. flagella

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Movement of Cilia Flagella
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Plant Cell Wall

• 10-100X thicker than cells plasma membrane
• Made of cellulose
• Fibrous (like fiberglass)
• Has plasmodesmata openings
• Allow for cellular junctions (connections between
  cells)

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Cytoplasmic Streaming in Plant Cells
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Cell Junctions Between Animal Cells
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Tight junctions

• Continuous, help form leak-proof seams
• Ex intestinal cells have these

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Anchoring junctions

• Not leak-proof, more like rivets or buttons

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Communicating Junctions

• Hollow, they allow cells to share water, molecules

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Q What Does All Life Have?
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What All Life Has

• Consists of cells
• Has DNA as genetic material
• Has metabolism

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Q Are Viruses Alive?
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Viruses Are Not Alive

• No cells
• No organelles (ie too simple to be alive)
• No endomembrane system
• No mitochondria
• Dont have metabolism of their own
• Yes, some have DNA, but some dont