1. Cell Biology

2. What is a cell?
A cell is the smallest structural and functional unit of an organism

3. Cell Theory Microscopic lenses  discovery of cells Cell theory
All living things are composed of cells and their products
New cells arise from the division of older cells
Cells are the basic building blocks of life

4. Challenge time!
Can you think of something you would call “alive” that isn’t made of cells?

5. 1/9/12
Objective
Do Now
Do Later

6. Cells Two major classes of cells Eukaryotic Prokaryotic
Have many membrane bound compartments called organelles
Animals, plants, fungi
Prokaryotic
Have no membrane bound compartments
Bacteria

7. Evolution of Cells Tree of life can be divided into 3 domains
Bacteria/Archaea = prokaryotes
Eukarya = eukaryotes
Prokaryotic cells are older/more primitive

8. Organelles
Eukaryotic cells contain membrane bound compartments called organelles
Each organelle performs specific jobs to aid the overall function of the cell

9. Analogy time!
If a cell were a factory, what would its organelles be?

10. Nucleus Region of the cell that contains the DNA
Tightly coiled strands of DNA are called chromosomes
Nucleoplasm is fluid in the nucleus

11. Nucleus
Have you ever seen a nucleus before?
Sure you have!

12. Recall
The nucleus stores DNA, which contains your genetic code. What instructions are contained in this genetic code?
Why might you call the nucleus the brain of the cell?

13. Nuclear Envelope
The nucleus is surrounded by a double phospholipid bilayer
called the nuclear envelope
Proteins form channels through these membranes called nuclear pores

14. Recall The cell membrane is a single phospholipid bilayer
Why do you think the nuclear envelope is a double phospholipid bilayer?

15. Nucleolus Nucleolus = region of the nucleus Rich in RNA
Ribosomes are produced here
Then travel out to the cytoplasm

16. Ribosomes We’ve studied these already
What is the function of ribosomes?
Genes get transcribed into mRNA copies
Ribosomes translate mRNA into proteins
Where do ribosomes fit in this scheme?

17. Structure of Ribosomes
Ribosomes have 2 subunits, each containing protein and RNA

18. Nobel Prize time!
Enzymes are molecules that catalyze, or speed up the rate of a chemical reaction
Many proteins are enzymes
Ex: Digestive enzymes are proteins that speed up the rate of digestion of food molecules

19. Nobel Prize time!
1989 – Sid Altman wins Nobel Prize in chemistry for showing that RNA can catalyze reactions too
Discovered RNA component of ribosomes
When RNA was removed from ribosomes, they could no longer perform their job
 RNA is involved in the function of ribosomes

20. Application Question Enzymes catalyze, or speed up, reactions.
What reaction do ribosomes catalyze?

21. 1/10/12 Objective: Finish exploring organelles
Do Now: Take your matching quiz! (10 min-ish)
Do Later: Active reading of section 3.4

22. Cytoplasm The region outside the nucleus is called the cytoplasm
Contains many organelles

23. Quiz time!
Where is the cytoplasm in this egg?

24. Cytoskeleton How do cells maintain their shape?
Structural support from protein rods that are called the cytoskeleton
Microfilaments = actin polymers
Microtubules = tubulin polymers
Imaging microtubules with actin-Green Fluorescent Protein

25. Nobel Prize time!
2008 – Nobel Prize in Chemistry awarded for discovery of Green Fluorescent Protein
Naturally occurring in jellyfish
Gene for GFP can be spliced into gene for a protein of interest
Makes protein under study fluoresce.

26. Fluorescent Proteins
Extremely useful lab technique

27. Endoplasmic Reticulum
The Endoplasmic Reticulum (ER) is a series of flattened sacs connected to the nucleus
Involved in:
Transport throughout the cell
Protein synthesis
Lipid synthesis

28. Endoplasmic Reticulum
Two kinds of ER
Rough ER: phospholipid membrane is studded with ribosomes
Smooth ER: membrane contains no ribosomes

29. Extension Question The ER participates in
Transport throughout the cell
Protein synthesis
Lipid synthesis
What part of the ER do you think is involved with protein synthesis?

30. Golgi Apparatus Has a cool name Also a series of flattened sacs
Also involved in
transport throughout cell
processing of proteins

31. Mitochondria
Mitochondria break down sugar to produce energy (ATP) for the cell
Have a double phospholipid bilayer
Like nucleus
Inner and outer membranes
Matrix = interior space
Cristae = exterior space

32. Lysosomes “Garbage disposal of the cell”
Contain powerful enzymes to break down
Nutrients
Foreign objects
Worn out parts of the cell

33. Centrosomes 2 in each cell Microtubules grow out from the centrosomes
Participate in cell division
Centrosomes
Centrosomes organize the “Mitotic spindle apparatus”

34. Cilia and Flagella Cilia are shorter, more frequent
Flagella are longer
Usually 1 per cell
Whip-like projections
Structurally supported by microtubules

35. Vesicles Vesicles are the storage containers of the cell
Can hold a great variety of molecules
Form by endocytosis
Endocytosis = cellular intake of outside materials