1. Chapter 7 Test: Friday Cell Project: 9/25/14
A Tour of the Cell
Chapter 7
Test: Friday
Cell Project: 9/25/14

2. Video Time
If you are curious,

3. How Do We Study Cells

4. Light Microscopes Definition: two important powers: Advantages:
magnification (magnifying power)
resolution (resolving power)
Advantages:
Disadvantages:

5. Electron Microscopes
Definition:
Advantages:
Disadvantages:

6. Cell Fractionation two steps: homogenization
differential centrifugation: tool-ultracentrifuge

7. All cells have: plasma membrane DNA (not necessarily in a nucleus)
cytoplasm

8. Limits on Cell Sizes
lower limits
upper limits: surface area-to-volume

9. Compartmentalization
Internal membranes allow eukaryotic cells to battle the surface area-to-volume ratio problem that limits cell size.
Eukaryotic cells can form “compartments” which segregate certain reactions that interfere with each other (local environments)
These internal membranes participate directly in the cells metabolism (enzymes)
Each membrane has a unique composistion (enzymes for cellular respiration - mitochondria)

10. Nucleus: Cell’s Genetic Library
contains most of the genes in a eukaryotic cell
nucleus is enclosed by the nuclear envelope
separates nuclear DNA from the cytoplasm
envelope is a double membrane, each is a lipid bilayer with associated proteins
envelope is perforated by nuclear pores, lined by a pore complex which regulates transport

11. Nuclear Organization DNA Proteins - histones Chromatin Chromosomes
Nucleolus

12. Ribosomes build a cell’s proteins
sites of protein synthesis = translation
cells with high rates of protein synthesis have …large numbers of ribosomes
free ribosomes - suspended in the cytosol; make proteins that work in the cytosol
bound ribosomes - attached to the outside of the membranes of the nuclear envelope and ER; make proteins that are (1) included in the membrane; (2) packaging within an organelle; (3) exported from the cell

13. Endoplasmic Reticulum
extensive membranes which may account for over half of the cell’s total membrane
Rough ER - ribosomes on surface
bound ribosomes make secretory proteins
cells that are specialized for secretion often have tremendous amounts of rough ER
also the membrane factory of the cell - synthesis of phospholipids

14. Smooth ER - lack ribosomes
different functions in different cells
phospholipid, steroid, and sex hormone synthesis
metabolism of carbohydrates
detoxification of drugs and poisons
(increased smooth ER production in liver cells is the basis for drug tolerances)
storage and release of calcium ions during muscle contraction

15. Golgi Apparatus
products are modified as they move from region to the next
products are sorted into vesicles, pinch off from the Golgi
surface molecules on the vesicle direct its movement through the cell

16. Lysosomes contains hydrolytic enzymes for digestion of macromolecules
lysosomes fuse with food vacuoles that are formed during phagocytosis
some cells recycle their own cell parts - autophagy
apoptosis - programmed cell death - sometimes uses lysosomes for destruction of the cell

17. Vacuoles
food vacuoles
contractile vacuoles
central vacuole

18. Mitochondria
site of cell respiration, catabolic processing of fuels to produce ATP
“Powerhouse of the Cell”
respiratory enzymes are found throughout the mitochondria
glucose + oxygen ----> carbon dioxide + water + ATP

19. Chloroplasts one of a group of organelles called plastids
Site of photosynthesis - organic molecules are created from carbon dioxide and solar energy

20. Cytoskeleton
Three parts (classified by size): Microtubules; Intermediate Filaments; Microfilaments
mechanical support
maintain or change cell shape
anchor and direct organelle movement
control movement of cellular appendages
muscle contraction

21. Prokaryotes vs. Eukaryotes
compare:
contrast:

22. Animal Cells vs. Plant Cells
compare:
contrast:

23. Summary