1. The living cell
Is a miniature factory where thousands of reactions occur
Converts energy in many ways
Figure 8.1
Bioluminescence

3. Metabolism Is the totality of an organism’s chemical reactions
Arises from interactions between molecules
An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics

4. Molecular Factory
Factories are highly ordered systems which have an input of materials, energy requirements and an expected output
There is a design to factories- you don’t get automobiles from a Barbie factory…

5. Cells as factories Cell has three main functions
Make a product through a series of highly ordered steps and guided via an enzymatic and biofeedback process
Maintain balance
Reproduce
All parts of the cell play a role in maintaining the cellular factory.

7. Size range of cells

8. The Nucleus and Ribosomes
- enclosed by nuclear envelope
- contains most of the genes that
control the entire cell
+ DNA organized with
proteins into chromatin
- nucleolus
Nuclear lamina – protein filaments
that give structure to the inner
nuclear membrane

9. The Nucleus and Ribosomes (con’t)
- build proteins
- RNA/protein
complexes
- free/bound

10. The Endomembrane System
Includes:
nuclear envelope
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Plasma membrane*

11. Mitochondria and Chloroplasts
energy transformers of cells
+ double membranes
+ contain ribosomes/DNA
Mitochondrial DNA is only passed on
by mom

14. The Cytoskeleton Cytoskeleton provides structural support
for motility and regulation
+ network of fibers
- microtubules
- microfilaments
- intermediate filaments

16. Membrane Structure and Function
Collagen
proteoglycan
Fibronectin

17. Hydrophilic vs Hydrophobic

18. Membrane Structure and Function (con’t)
Fluid Mosaic Model
The Fluid Quality of Membranes
+ held together by hydrophobic interactions
- lipids/proteins drift about laterally
+ unsaturated hydrocarbon tails
- maintain fluidity at low temperatures
+ cholesterol
- stabilizes the membrane
restrains movement at high temp.
hinders close packing at low temp.

19. Membrane Structure and Function (con’t)
Fluid Mosaic Model
Membranes as Mosaics
+ membrane is collage of proteins
- integral proteins
transmembrane
- peripheral proteins
appendages

20. Membrane Structure and Function (con’t)
Functions of Membrane Proteins
Transport
Enzymatic Activity
Signal Transduction
Intercellular joining
Cell-cell recognition
Attachment to the cytoskeleton and ECM

21. Signal Transduction with G proteins

22. Voltage Gated Ion Channels

24. Diffusion
A.K.A. simple diffusion
Movement of small molecules across a selectively permeable membrane from an area of HIGH concentration to an area of LOW concentration w/o the use of energy (DOWN the concentration gradient)
e.g. O2, CO2, urea, & alcohol

25. Traffic Across Membranes (con’t)
Passive Transport
Osmosis
+ the diffusion of water
- hypotonic,hypertonic, isotonic
Tonicity – the ability of a solution to cause a cell to gain or lose water
Osmoregulation – the control of water balance e.g. contractile vacuole in paramecium

26. Osmosis The diffusion of WATER across a selectively permeable membrane
OSMOTIC PRESSURE
The pressure exerted on plasma membranes in solution
Isotonic solution
Hypertonic solution
Hypotonic solution

27. Water Potential
The physical property predicting the direction in which water will flow, controlled by the solute concentration

28. Water potential (ψ) = pressure potential (ψp ) + solute potential (ψs )

29. Plasmolysis
A phenomenon in plant cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment.

30. Osmotic Potential
The tendency of water to move across a selectively permeable membrane into a solution
Determined by measuring the pressure required to stop the osmotic movement of water into the solution.

32. Traffic Across Membranes (con’t)
Passive Transport
Facilitated Diffusion
+ diffusion with the help
of transport proteins
- gated channels

33. Facilitated Diffusion Protein Channel or Pore

34. Facilitated Diffusion Protein Carrier

36. Traffic Across Membranes (con’t)
Active Transport
energy-requiring process
+ ATP
pumps molecules against
concentration gradient
+ Na+/K+ pump

37. Active Transport
Requires cell energy (ATP) to move molecules AGAINST the concentration gradient; from an area of LOW concentration to an area of HIGH concentration
Sodium–Potassium pump (Exchange 3 sodium ions for 2 potassium ions)
Hydrogen ion, or proton pump (Pump hydrogen ion against the concentration gradient)

38. Phosphorylation
The addition of a phosphate (PO4) group (From ATP) to a protein or a small molecule
This changes the protein shape

40. Active Transport (Uniport)

41. Active Transport Na-K Pump

42. Na-K Pump Antiport

44. Traffic Across Membranes (con’t)
Membrane Potential
electrogenic pump
+ proton pumps (H+)
electrochemical gradient
+ cotransport

46. Traffic Across Membranes (con’t)

47. Bulk Media Transport
Endocytosis – Vesicle is created from the invagination of the plasma membrane, which pinches off, bringing large molecules into the cell
Pinocytosis – Cell drinking (endocytosis)
Phagocytosis – Cell eating (endocytosis)
Receptor Mediated Endocytosis – Substrate binds to receptor found on the plasma membrane to be brought into the cell
Exocytosis – Vesicle binds to the plasma membrane releasing the contents outside of the cell

48. Traffic Across Membranes (con’t)
Transport of Large Molecules
Exocytosis
+ the cell exports macromolecules
using vesicles from Golgi apparatus
Endocytosis
+ the cell takes in macromolecules
by forming new vesicles from membrane
- phagocytosis (“cellular eating”)
- pinocytosis (“cellular drinking”)
- receptor-mediated endocytosis
+ ligands