1. Fig. 1.11

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

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

4. Nuclear laminaNuclear 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
inner
membrane
DNA
matrix
cristae
ribosomes ATP synthase

8. Inner Membrane and matrix
electron
transport
system
ADP3-
ATP4-
pyruvate
Krebs
cycle
NADH
ATP
synthaseFADH2
hi [H+
]
Antiporter
P04
-2 H+
symporter

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
Phagocytosis
Autophagy
lysosomes

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

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

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
Cis Medial Trans

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

20. Glycosylation
Karp, Fig. 8.20

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

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
H2O
Cut open
liposome

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)
OUT
IN
Extracellular
domain (ECD)
Intracellular
domain (ICD)
Transmembrane
domain
Oligosaccharides
- always face out

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