1. Organization of the Cell

2. Cell Theory
Cells are the basic living units of organization and function
All cells come from other cells
Work of Schleiden, Schwann, and Virchow contributed to this theory
Each cell is a microcosm of life

3. Biological Size and Cell Diversity

4. Cell surface area-to-volume ratio
Plasma membrane must be large enough relative to cell volume to regulate passage of materials
Volume increases faster than surface area so cells must divide
Cell size and shape related to function

5. Cell Surface Area-to-Volume Ratio

6. Microscopes
Light microscope, referred to as compound microscope, used by most students
Two features determine how clearly an object is viewed
Magnification
Resolution
Light microscope has 500 times more resolution than human eye

7. Electron microscope Developed in the 1950s
Allows study of the ultrastructure of cells
10,000 times more resolution than human eye

8. Types of electron microscope
Transmission electron microscope TEM
Used to view internal cell structures
Scanning electron microscope SEM
Produces 3-D picture of cell surface
Can’t be used to view living cells

9. Comparing light and electron microscopy

10. Cell fractionation
Used to determine isolate & tell function of organelles
Cells broken apart and the resulting cell extract spun in a centrifuge
Centrifugal force separates extract
Pellet – heavier cell organelles
Supernatant – liquid poured off

11. Cell fractionation

12. Prokaryotic
Bacteria and Archaea (ancient bacteria)
DNA not enclosed in a nucleus
Eukaryotic
All other known organisms
Highly organized membrane-enclosed organelles
Cytoplasm
Nucleoplasm

13. Functions of cell or plasma membranes
Divide cell into compartments, allowing for specialized activities
Interacting membranes form endomembrane system
Vesicles transport materials between compartments (ER  Golgi, Golgi  plasma membrane…)

14. Diagram of a plant cell

15. Diagram of an animal cell

16. The cell nucleus
Contains DNA
Bounded by
Nuclear envelope
Double membrane perforated with nuclear pores
DNA forms chromatin, which is organized into chromosomes
Nucleolus
RNA synthesis and ribosome assembly

17. The cell nucleus

18. Endoplasmic reticulum (ER)
Network of folded internal membranes in the cytosol
Connected to Nuclear envelope
Smooth ER
Site of lipid synthesis
Site of detoxifying enzymes
Detoxifies drugs & alcohol
Stores Ca++ in muscle cells
Rough ER
Ribosomes on surface manufacture secretory proteins
Proteins may be moved into the ER lumen (interior)

19. Endoplasmic reticulum (ER)

21. Golgi complex Glycoproteins
Cisternae that process, sort, and modify proteins
In animal cells, Golgi complex also manufactures lysosomes
Glycoproteins
Transported to the cis face (receiving side)
Golgi modifies carbohydrates and lipids and packages into vesicles that pinch off the trans face (shipping side)

22. Golgi complex

23. Lysosomes break down worn-out cell structures, bacteria, and other substances
Responsible for cell death & recycling
Peroxisomes
Involved in lipid metabolism and detoxification
Contain enzymes (catalase) that produce and degrade hydrogen peroxide H2O2  H2O + O2

24. Lysosomes

25. Mitochondria Sites of aerobic respiration
Organelles enclosed by a double membrane
Has its own genome
Place important role in apoptosis
Cristae (internal folds) and matrix (innermost space) contain enzymes for aerobic respiration
Nutrients broken down and energy packaged in ATP
Carbon dioxide and water by-products

26. Mitochondria

27. Chloroplasts
Plastids that carry out photosynthesis
Inner membrane of chloroplast encloses the stroma gel-like liquid)
Contains stacks of interconnected sacs called thylakoids
Stack of thylakoids called grana
During photosynthesis, chlorophyll traps light energy (sunlight)
Energy converted to chemical energy in ATP

28. Chloroplast

29. Cellular respiration and photosynthesis

30. Cytoskeleton Internal framework made of Microtubules - tubulin
Microfilaments - actin
Intermediate filaments - keratin
Provides structural support
Involved with transport of materials in the cell
Make up cilia, flagella, and centrioles

31. The Cytoskeleton

32. Cilia and flagella
Thin, movable structures that project from cell surface
Function in movement
Microtubles anchored in cell by basal body

33. Structure of cilia

34. Many animal cells also surrounded by an extracellular matrix (ECM)
Glycocalyx
Cell coat formed by polysaccarides extending from plasma membrane
Many animal cells also surrounded by an extracellular matrix (ECM)
Most bacteria, fungi, and plant cell walls made of carbohydrates

35. Extracellular matrix

36. Plant cell walls