1. Chapter 7 Notes:
Parts of the Cell

2. Cell Theory
A fundamental concept of biology is called the “cell theory”
It states that:
All living things are composed of cells
Cells are the basic units of structure and function in living things
New cells are produced from existing cells

3. Prokaryotes vs. Eukaryotes
All cells can be categorized two basic groups:
Prokaryotes: These cells are simple, usually small cells that do not have nuclei, but do have genetic material. All prokaryotes are bacteria.
Eukaryotes: These cells are larger, more complex, have nuclei and other membrane-bound organelles. All non-bacterial organisms are eukaryotes, and can be multicellular.

4. Humans have about 50 trillion cells in their bodies!
Blue whales have quadrillion cells in their bodies.
= 50,000,000,000,000
= 100,000,000,000,000,000!

5. How long do cells live?
White blood cells typically live only 7-8 hours. That’s a short life!
Red blood cells; a week

6. (Credit: Duane Froese, ScienceDaily Aug. 28, 2007)
How long do cells live?
Live bacteria have been found in Canada that are over 500,000 years old. That’s a long life!
Professor Eske Willerslev collecting soil samples in the permafrost in the Yukon, Canada. Researchers found half million year old bacteria in some of the samples collected.
(Credit: Duane Froese, ScienceDaily Aug. 28, 2007)

7. Parts on the Outside Cell membrane Cell Wall (not on animal cells)
Cilia
Flagella

8. CELL MEMBRANE Boundary between cell and its external environment
Analogous to factory doors/windows, etc.
Two layers = lipid bilayer

9. CELL MEMBRANE
Controls movement of materials (O2, H2O, CO2, nutrients, waste) in and out of cell

10. CELL WALL (plants) Surrounds the cell membrane
Adds strength and support to cell
Analogous to external support beams for factory walls

11. CILIA Short hairs on outside of the cell Provide movement
Analogous?? Move the factory
Lung Cilia
Image: Richard Superfine

12. FLAGELLA Long, whip-like tail on the outside of a cell
Moves the cell; Provides movement

13. Parts on the Inside Cytoplasm, which contains…
Nucleus (nuclear envelope, nucleolus, chromatin)
ER, Golgi Apparatus, Ribosomes
Vacuoles, Lysosomes
Chloroplasts, Mitochondria
Cytoskeleton

14. CYTOPLASM Portion of the cell outside of the nucleus
Jelly-like material suspends the other organelles
Analogous to factory air/open space

15. NUCLEUS Control center for eukaryotic cells Contains chromosomes
Analogous to factory manager/boss office?

16. Not all eukaryotic cells have one nucleus…
Red blood cells (erythrocytes) discard their nuclei at maturity, which makes them better at carrying oxygen to body tissues.

17. Not all eukaryotic cells have one nucleus…
Skeletal muscle cells and plasmodial slime molds have many nuclei within a single cell membrane.

18. Uncondensed Chromosome
CHROMATIN
DNA wrapped around proteins
Makes up chromosomes: instructions to run cell.
Analogous to factory operating manual
Condensed Chromosome
Uncondensed Chromosome

19. NUCLEAR ENVELOPE Boundary between nucleus and cytoplasm
Contains pores (holes) for materials to pass in/out
Analogous to factory managers office walls/door

21. RIBOSOMES Site where proteins are made (protein synthesis)
Outside nucleus in cytoplasm or on rough ER
Analogous to assembly line robots which build what the factory makes

22. NUCLEOLUS Produces the RNA that makes up ribosomes
Analogous to factory: instructions to build factory robots or assembly line tools
Photos by Mr. Stephens

23. ENDOPLASMIC RETICULUM (ER)
Folded membrane, which connects nucleus to cell membrane
Site for assembly and transport of proteins
Analogous to factory conveyor belts

24. ENDOPLASMIC RETICULUM (ER)
ROUGH ER; w/ ribosomes
SMOOTH ER; no ribosomes; produces lipids

25. GOLGI APPARATUS Packages and ships proteins outside or inside the cell
Shipping dept

26. LYSOSOMES Membrane-bound sac with digestive enzymes inside
Digests: worn-out organelles, food, bacteria/viruses;clean up messes/ recycle
Analogous: Clean up crew

27. VACUOLES Storage sac for: food, enzymes, water, wastes, etc…
Analogous to factory inventory room

28. MITOCHONDRIA Produces energy for the cell
Breaks sugars (glucose) down for energy (ATP)
Analogous to factory power plant

29. CHLOROPLASTS (plants)
Performs photosynthesis
Converts energy from light to create sugars and starches; food for plant.
Analogous to factory solar panels

30. CHLOROPLASTS (plants)
Green because of pigment called “chlorophyll”

31. Photosynthetic Sea slugs

32. Photosynthetic Sea slugs
Some sea slugs use algae chloroplasts as a photosynthetic food source. They’ve been observed to live for up to nine months without eating!

33. MICROTUBULES Cytoskeleton
Provides support for organelles and maintain cell shape; used in cell division
Analogous to factory internal support beams

34. MICROFILAMENTS Make up part of Cytoskeleton
Provides internal support for cell

35. CENTRIOLES Cytoskeleton (made of microtubules)
Coordinate cell division (absent in most plant cells)