1. Cell Organelles

2. How small are cells? How much is a micrometer?
1 micrometer (µm) = 1/1,000,000 m
Typical cell size = 5 to 50 µm in diameter
In a dice that is 1 cm3
We could fit 1,000,000 cells

3. How small are cells?

4. Cell Organelles: Cytoplasm Nucleus Nucleolus Nuclear Envelope Vacuole
Lysosome
Cytoskeleton
Centrioles
Ribosomes
Endoplasmic Reticulum
Golgi Apparatus
Chloroplast
Mitochondria
Cell Wall
Cell membrane
Cilia & Flagella

5. Cytoplasm: Contains the various organelles
Area between the cell membrane and nucleus
“Jelly-like” material

6. Nucleus: Stores hereditary information (DNA)
Prokaryotic cells lack a nucleus, but they do contain DNA
Control center of the cell

7. Chromatin and Chromosomes:
Inside the nucleus are fine strands of chromatin (a complex of DNA bound to protein) that coil up and become densely packed, forming chromosomes
Chromosomes are visible under a microscope when a cell divides

8. Nucleolus and Nuclear Envelope:
Nucleolus – small dense region within the nucleus where ribosomes are synthesized
Nuclear Envelope – double membrane (lipid bilayer) that surrounds the nucleus

9. Vacuole:
Fluid-filled organelles that store water, salts, proteins, and carbohydrates
In many plant cells, there is a single large central vacuole filled with fluid - can occupy up to 90% of the cell’s volume
Animal
Animal
Plant

10. Paramecium’s Contractile Vacuole
Contracts rhythmically to pump excess water out of the cell – controls the water content of the organism

11. Lysosomes: Filled with enzymes
Breaks down carbohydrates, lipids, and protein that can be used by the rest of the cell
Breaks down organelles that have outlived their usefulness
Removes “junk” that would clutter the cell
Known as the “Clean Up Crew” or
“Suicide Sac” of the cell
Found in animal cells and specialized
plant cells
Some humans have diseases that
result from lysosomes that fail to
function properly.

12. Cytoskeleton:
Gives cells structure; helps to maintain shape & size; involved in cell movement
Helps to transport materials between different parts of the cell
Network of protein strands (scaffold)
Made up of microfilaments and microtubules

13. Microfilaments: Thin threads made of actin (structural protein)
Supports the cell
Contribute to cell movement

14. Microtubules: Larger strands; hollow tubes made of tubulin (proteins)
Maintain cell shape
Important in cell division – forms the mitotic spindle which helps to separate chromosomes
Form centrioles in animal cells
Help build cilia and flagella

15. Centrioles: Found near the nucleus
Used to organize cell division (mitosis)
Made of microtubules
arranged in 9 groups of 3
Found only in animal cells 9 8 1 7 2 6 3 5 4

18. Cilia: Short hairs present in large numbers
Propel unicellular organisms
Line cells of respiratory tract

19. Flagella: Longer hairs that are less numerous Found on sperm cells
Whip back and forth

21. Ribosomes:
Produce PROTEINS by following coded instructions that come from DNA
Most numerous organelle – found throughout the cytoplasm in all cells
Not surrounded by a membrane
Made of RNA and protein in the nucleolus & transported to the cytoplasm

23. Endoplasmic Reticulum (ER):
Moves molecules from one part of the cell to another
Intracellular Highway
System of membranous
tubules & sacs

24. Rough ER: Dotted with ribosomes Involved in the synthesis of proteins
Abundant in cells that make large amounts of protein

25. Smooth ER: Does not have ribosomes attached
Contains collections of enzymes that perform specialized tasks (i.e. detoxifying - liver)

26. Golgi Apparatus:
Modifies, sorts and packages proteins and other materials for storage or release
Processing, packaging, and secreting organelle
Works with the ER
Modifies proteins for export

29. Mitochondria:
Convert chemical energy stored in food into compounds that the cell can use - powerhouse
Transfer energy to ATP (main energy currency)
Surrounded by two membranes and contain DNA
Most numerous in cells with
high energy requirements
(liver & muscle)

30. Chloroplast: Capture solar energy & convert it to chemical energy
Surrounded by two membranes and contain DNA
Contains the green pigment chlorophyll
Found only in plant cells

31. Cell Wall: Supports and protects the cell
Rigid structure outside the cell membrane
Made of cellulose
Found only in plant cells

32. Cell Membrane: Controls what materials pass into and out of the cell
Selectively permeable
Made primarily of lipids and proteins

33. Fluid Mosaic Model:

34. Components of Cell Membrane:
Phospholipids – polar head & nonpolar tails
Integral Proteins – imbedded in lipid bilayer; usually have carbohydrates attached to them
Peripheral Proteins – surface only

35. Animal Cell:

36. Plant Cell:

37. Animal Cell - Label

38. Plant Cell - Label

39. Great websites to check out!
Interactive Cell Models – Cells Alive
Inside a Cell – Learn.Genetics (University of Utah)
Video – BBC Secret Universe: The Hidden Life of the Cell
Video – Inside the Cell