2. Chapter 3
Cell structure and function

3. Chapter 3 Cell structure and protein function
Structure determines function.
That which alters structure alters function.
Cells:
membranes─internal and external partitions
nucleus─genomic DNA
ribosomes─protein synthesis
endoplasmic reticulum ─synthesis and calcium dynamics
Golgi apparatus ─secreted proteins
mitochondria─ ATP synthesis
miscellaneous organelles

4. Chapter 3 Cell structure and protein function (cont.)
Central dogma: genes to proteins
transcription (DNA to RNA) 
splicing (RNA to mRNA) 
translation (mRNA code determines
amino acid sequence in protein synthesis)
ATP/chemical energy: substrate/oxidative phosphorylation
Enzymes and metabolic pathways

5. Figure 3-2
Cell Structure
Sizes, on a log scale.

6. Figure 3-3
Electron Micrograph of organelles in a hepatocyte (liver cell).

7. Organelles have their own membranes.
Figure 3-4
Human Cell
Organelles have their own membranes.

9. Membrane functions:

10. Membrance structure Figure 3-6
Electron micrograph and sketch of plasma membrane
surrounding a human red blood cell.

11. Arrangement of integral and peripheral proteins
Figure 3-7
Phospholipid bilayer

12. the linear sequence of the protein Circles represent amino acids in
Figure 3-8
The amino acids along
the membrane section
non-polar side chains
are likely to have
the linear sequence of the protein
Circles represent amino acids in
Schematic cartoon of a transmembrane protein.

13. Figure 3-9
Drawing of the fluid-mosaic model of membranes, showing the phospholipid bilayer and imbedded proteins.

14. Membrane junctions: Figure 3-10a
Desmosomes provide strong attachments.

15. Tight junctions prevent leaks.
Figure 3-10b

16. Connexons
Figure 3-10d
Gap junctions communicate and coordinate.

17. {site of ribosome assembly}
Nucleus and nucleolus
Figure 3-11
{site of ribosome assembly}
{genomic DNA}
Ribosomes

18. Endoplasmic reticulum:
Figure 3-12

19. Golgi apparatus:
Figure 3-13

20. Mitochondria:
Figure 3-14

21. Endosomes: membrane-bound vesicular and tubular structures,
Located between the plasma membrane and the golgi apparatus
Function as Golgi apparatus in sorting and modifying, and directiong
Vesicles
Lysosomes:
Are spherical or oval organelles
Highly acidic, and contains digestives enzymes,
To destroy bacteria
Peroxisomes:
Dense oval bodies
H2O2 is toxic to the cell

22. Figure 3-15
Protein filaments function in movement and support.

23. Thank you for your attention,,,

24. Figure 3-16
NUCLEUS
The DNA code is “transcribed” into mRNA.
RIBOSOMES
The mRNA is “translated” to give instructions for proteins synthesis.