1. Anatomy & Physiology of Cells

2. Overview of the Cellular Basis of Life
A cell is the basic structural and functional unit of living organisms. When you define the properties of a cell, you are in fact defining the properties of life.
The activity of an organism is dependent on both the individual and collective activity of the cells.
According to the principle of complimentarity, the biochemical activities of cells are determined and made possible by the specific subcellular structures of cells.
The continuity of life has a cellular basis.

3. Properties of a Cell
Cells are chemically composed chiefly of carbon, hydrogen nitrogen, oxygen, and trace amounts of several other elements.

4. Size
Diameters range from about 2 micrometers (1/12,000 of an inch) in to 10cm or more in the largest cell. The typical human cell is about 10 micrometers. The largest, the fertilized egg, is nearly 100 micrometers in diameter.
Lengths range from a few micrometers to a meter or more. Some skeletal muscle cells are 30cm long, and the nerve cells that cause your foot muscles to contract run from the end of your spinal cord to your foot.

5. Shape
A cell’s shape reflects its function. Flat, tile-like epithelial cells that line your cheek fit closely together, forming a living barrier that protests underlying tissues from bacterial invasion.
Examples:
Spherical (fat cells)
Disk-shaped (red blood cells)
Branching (nerve cells)
Cube-like (kidney tubule cells)

7. 3 Major Parts Nucleus: Control center
Cytoplasm: packed with and supports the organelles
Plasma membrane: forms the external cell boundary

8. The Plasma Membrane
The plasma membrane is a thin, stable structure composed of a double layer, or bilayer, of phospholipids molecules with protein molecules dispersed in it. It is called the fluid mosaic model because the molecules are able to slowly float around the membrane.

9. The lipid bilayer forms the basic “fabric” of the membrane and is relatively impermeable to most water soluble molecules.

10. Membrane proteins imbedded in the lipid bilayer are responsible for most specialized functions of the plasma membrane.
Receptor Proteins: react to the presence of hormones or other regulatory chemicals and trigger metabolic changes in the cell
Marker Proteins: (glycoproteins) allows cells to recognize each other for immune or developmental purposes
Transport Proteins: either channel or transport needed chemicals through the membrane that can not otherwise pass through the lipid bilayer

11. There are 2 distinct protein populations:
Integral proteins: embedded into the membrane
Peripheral proteins: attach to integral membrane proteins, or penetrate the peripheral regions of the lipid bilayer
Branching sugar groups are attached to most of the proteins that abut the extracellular space. The term glycocalyx is used to describe these attachments.

12. Functions of glycocalyx
1. Determining the ABO and other blood groups. 2. Provide binding sites for other toxins. 3. Recognition of the egg by sperm. 4. Determining cellular life span. 5. Serving in the immune response. 6. Helping to guide and direct embryonic development.

13. Movement of Substances Through Cell Membranes
If a cell is to survive, it must be able to move substances to places where it is needed. Membrane transport processes can be classified as either passive, not requiring any energy expenditure, or active, requiring energy to pull substances across the membrane.

14. Passive Transport Processes
Simple Diffusion
molecules or ions spread spontaneously from regions of higher concentration to regions of lower concentration until equilibrium is reached
Dialysis – form of diffusion in which the selectively permeable membrane causes the separation of smaller solute particles from larger ones.

15. Passive Transport Processes
Osmosis – the diffusion of a solvent through a selectively permeable membrane. Occurs when there is a difference in solute concentration on the two sides of the membrane. Osmotic water flows are extremely important in determining the ditribution of water in the various fluid-containing compartments of the body (cells, interstitial fluid, blood, etc.)

16. Osmosis Hypertonic – movement of water out of an area
Isotonic - equal movement of water into and out of
Hypotonic – movement of water into an area

17. Passive Transport Processes
Facilitated Diffusion – molecules (ex. Sugar) combine with a carrier molecule at the surface of the membranes. This union changes the shape of the carrier, which moves glucose to the other side of the membrane. Only moves molecules from regions of higher to lower concentrations.

18. Active Transport Processes
Active Transport – movement of molecules from an area of lower concentration to an area of high concentration; requires energy to pump molecules against the concentration gradient

19. Active Transport Processes
Endocytosis – bringing in bulk molecules or substances through the plasma membrane by forming vacuole around it
Phagocytosis – solid particles; cellular eating
Pinocytosis – water with dissovled substances; celular drinking
Receptor-mediated – bringing in molecules attached to surface markers
Exocytosis – sending out bulk packages; usually things packages by the Golgi Apparatus and waste removal

20. Specializations of the Plasma Membrane
Membrane junctions help to bind cells closely to form tissues.
Tight junctions: protein molecules in adjacent plasma membranes fuse together tightly like a zipper, obliterating the intercellular space and forming an impermeable junction; ex. Epithelial cells of the digestive tract

21. Membrane junctions
Desmosomes: act as mechanical couplings or adhesion junctions that prevent separation of tissue layers – membranes do not actually touch

22. Membrane junctions
Gap junctions: provide for direct passage of chemical substances between adjacent cells – the cells are connected by hollow cylinders composed of transmembrane proteins, called connexons – embryonic cells prior to development of circulatory system and in adults in electrically excitable tissues such as heart and smooth muscle, and also between some nerve cells

23. Cell Metabolism
Metabolic pathways can either be catabolic or anabolic.
Catabolism – cellular respiration is an example
Anabolism – DNA replication and protein synthesis are examples

24. The Role of Enzymes
The activation energy needed to start a chemical reaction is too great for a number of chemicals to react by themselves. A catalyst is needed to reduce the amount of activation energy needed to start a chemical reaction.
Enzymes act as chemical catalyst in the cell. Enzymes are functional proteins.

25. Classification and Naming of Enzymes
Two systems used for naming enzymes: 1. The suffix –ase is used with the root name of the substance whose chemical reaction is catalyzed, or 2. with the word that describes the kind of chemical reaction catalyzed. Enzymes investigated before these methods of nomenclature were adopted are still called by older names, such as pepsin and trypsin.

26. Enzymes are classified into several groups according the chemical reactions catalyzed:
Oxidation-reduction enzymes – (oxidases, hydrogenases, dehydrogenases) Energy release from muscular contraction and all physiological work depends on these enzymes.
Hydrolyzing enzymes – (hydrolases) Digestive enzymes belong to this group. Named after the substrate they act on (lipase, sucrase, maltase).
Phosphorylating enzymes – add or remove phosphate groups and are known as phosphorylases or phosphatases

27. chemical reactions catalyzed
Enzymes that add or remove carbon dioxide – carboxylases or decarboxylases
Enzymes that rearrange atoms in a molecule – mutases or isomerases
Hydrases – these add water to a molecule without splitting it, as do hydrolases

28. General Functions of Enzymes
Most enzymes are specific in their action (key-in-a-lock action).

29. Enzymes
Various physical and chemical agents activate or inhibit enzyme reaction by changing the shape of the enzyme. An allosteric effector is any molecule or agent that alters the function of the enzyme by changing it’s shape.

30. Some allosteric effectors are: 1. antibiotic drugs 2. changes in pH 3
Some allosteric effectors are: 1. antibiotic drugs 2. changes in pH 3. changes in temperature 4. inhibition or activation molecules Most enzymes catalyze a chemical reaction in both directions.

31. Growth and Reproduction of Cells
The Cell Life Cycle G1 Phase – first growth phase; protein synthesis occurs; synthesis of large organelles and plasma membrane S Phase – synthesis phase; DNA replication occurs G2 Phase – second growth phase; continued growth and synthesis of other molecules and organelles

32. Mitosis means nuclear division.
Prophase – chromosomes coil; centrioles move to opposite poles, spindle fibers begin to form; nuclear membrane and nucleolus diappear
Metaphase – chromosomes align across the equator of the spindle fibers and attach to them

33. Mitosis
Anaphase – centromeres split detaching two chromatids which are then pulled to opposite poles of the cell
Telophase/Cytokinesis – Nuclear envelope and nucleolus reappear around each set of chromosomes; spindle fibers disappear; chromosomes uncoil; plasma membrane divides into two new identical cells

38. Meiosis
Meiosis is the process of reducing the chromosome number in half to form gametes (egg or sperm). 46 chromosome (23 pair) to 23 chromosomes
Meiosis I
Meiosis II

39. Regulating the Cell Cycle
The cell cycle is regulated by cyclins and cyclin-dependent kinases (CDKs). The number of CDK enzyme molecules stays about the same throughout the cell’s life cycle, but the number of cyclin molecules varies widely. Cyclins act as mechanisms that triggers the CDK and moves the cell from one phase to the next.

40. Cellular Disease Cystic fibrosis Duchenne muscular dystrophy
Disorders Involving Cell Transport
Cystic fibrosis
Duchenne muscular dystrophy
Disorders Involving Cell Membrane Receptors
Diabetes mellitus (type 2 diabetes)

41. Cellular Disease Cancers Sickle-cell anemia Hemophelia
Disorders Involving Cell Reproduction
Cancers
Disorders Involving DNA and Protein Synthesis
Sickle-cell anemia
Hemophelia
Infections
Bacteria and viruses

42. Cytoplasm and Organelles
The cytoplasm is the gel-like internal substance (cytosol) of cells that contains many tiny suspended structures called organelles (little organs). Organelles are classified as either membranous or nonmembranous. The cytoplasm is a medium in which chemical reactions occur.

43. Membranous organelles
Endoplasmic reticulum (ER): rough Er synthesizes proteins; smooth ER synthesizes lipids, steroid hormones, and carbohydrates used in forming glycoproteins

44. Membranous organelles
Golgi apparatus: synthesizes carbohydrates to combine with proteins; packages products to be sent out of the cell

45. Membranous organelles
Lysosomes: bags of digestive enzymes break down worn cell parts and ingested particles; a cell’s digestive system

46. Membranous organelles
Peroxisomes: contain enzymes that detoxify harmful substances

47. Membranous organelles
Mitochondria: Catabolism; ATP synthesis; a cell’s power plant

48. Nonmembranous
Ribosomes: site of protein synthesis; a cell’s protein factory

49. Nonmembranous
Cytoskeleton: acts as a framework to support the cell and its organelles; functions in cell movement; forms cell extensions (microvilli, cilia, flagella) Cell fibers
*Microfilaments: smallest cell fibers; cellular muscles; run parallel to the long axis of the cell; found and function mostly in muscle cells
*Intermediate filaments: slightly thicker fibers; form much of the supporting framework in most cells
*Microtubles: thickest fibers; form tubes; “engines of the cell” because they move things around in the cell or move the cell itself

50. Cytoskeleton

51. Nonmembranous
Centrosome

52. Nonmembranous Cell Extensions
Microvilli: minute, fingerlike extensions of the plasma membrane that project from a free, or exposed, cell surface; they increase the surface area of the membrane
Cilia: hair-like extension of the membrane used in moving substance
Flagella: tail-like extensions used for movement

53. Cell Nucleus Nucleolus: produces ribosomes Chromatin: uncoiled DNA
Chromosomes: coiled DNA
Chromatids: Duplicated DNA