1. Fig. 1.11

2. Nucleus: structure and function
Heterochromatin =
too compacted, transcriptionally inactive
nuclear envelope
Nucleolus
Nucleoplasm
Euchromatin = can be transcriptionally active

3. Nuclear envelope and lamina
cytoplasm
N. lamina
Nuclear
pore
heterochromatin

4. Nuclear lamina

5. Lamins are filamentous proteins in the intermediate filament family
Lamin phosphorylation in prophase disassembles the nuclear lamina & allows for nuc. envel. breakdown
Laminins are extracellular proteins, unrelated

6. Nuclear pore nuclear localization signals (nuclear import signals)
nuclear export signals
highly regulated

7. Mitochondria(on) outer membrane DNA inner membrane matrix cristae
ribosomes
ATP synthase

8. Inner Membrane and matrix
hi [H+]
electron
transport
system
ATP
synthase
FADH2
NADH
Krebs
cycle
ATP4-
Antiporter
ADP3-
symporter
pyruvate
P04-2 H+

9. Endosymbiotic theory: Mitochondria are similar to prokaryotes
Own circular, naked DNA
Own ribosomes - similar to prokaryotic
e.g. sensitive to same inhibitors
Divide by fission
Double membrane suggests endocytosis

10. Lysosomes: membranous organelles filled with digestive enzymes
Breakdown endocytosed materials
Thru’ phagocytosis or receptor mediated endocytosis
Breakdown old organelles (residual body)
Acidic pH

11. Phagocytosis vs. Autophagy
lysosomes
Autophagy

12. Membrane trafficking RER to cis Golgi
Modified in Golgi (glycosylation, phosphorylation)
Sorted at trans Golgi network into
Lysosomal
Regulated
constitutive

13. Rough endoplasmic reticulum
Ribosomes
Synthesis of secreted and membrane proteins

14. Rough Endoplasmic reticulum

15. Signal hypothesis: signal peptide, SRP, SRP-receptor, translocon
SRP = signal recognition particle

16. Smooth ER, lipid synthesis, detox, Ca2+ sequestration

17. Golgi

18. Transport thru’ Golgi cisternae is vectorial
Medial
Trans

19. Protein modifications occur in steps in the Golgi
Protein modifications occur in steps in the Golgi. The extent of changes varies.
CIS &
CGN
RER retrieval, PO4 on mannose,
mannose removal
mannose removal
N-acetylglucosamine addition
MEDIAL
fucose and glucose addition
TRANS
sialic acid addition, sorting
TGN

20. Glycosylation
Karp, Fig. 8.20

21. Sorting at the TGN constitutive secretion lysosomal pathway regulated
trans Golgi network

22. Receptor Mediated endocytosis

23. Plasma membrane & Fluid mosaic model

24. Phospholipids are most common in membranes
Polar
Head
Fatty
acid
tails

25. phospholipids, glycolipids, and cholesterol

26. Thermodynamics drives membranes to form sealed compartments
Cut open liposome
H2O

27. Fluidity means that lipids (& proteins) can “float” in the membrane via diffusion
Time

28. Three classes of membrane proteins: Transmembrane proteins (a type of IMP)
Oligosaccharides - always face out
Extracellular
domain (ECD)
OUT
Transmembrane
domain
Intracellular
domain (ICD) IN

29. Three classes of membrane proteins: Lipid-anchored membrane proteins (IMPs)
Covalently linked to a glycophospholipid.
E.G.: Normal cellular scrapie protein
& alkaline phosphatase
OUT
Covalently linked to fatty acid IN
E.G.: ras

30. Three classes of membrane proteins: Peripheral membrane proteins (PMPs)
OUT IN
Or, PMPs could bind to specific lipid heads.
Specific interaction between IMP & PMP

31. IMPs as -helix or -barrel

32. Selective permeability

33. Osmosis causing cell lysis.

34. Four mechanisms by which solute molecules move ACROSS membranes
Simple diffusion
across bilayer
Simple diffusion
thru channel
Facilitated
Diffusion thru’ passive transporters
Active
transport

35. Membrane Potential Affects Molecular Movement
A. neutral
No effect on inward transport
No effect on outward transport
B. cation
Favors inward transport
Opposes outward transport
C. anion
Opposes inward transport
Favors outward transport

36. Passive transport by channel proteins: don’t bind solute & can be ligand-, voltage-, or stress-gated

37. Passive Transport by Facilitated diffusion
Solute binds transporter protein
So, transport is saturable

38. Kinetics of carrier-mediated transport

39. Active transport by the Na/K pump or ATPase