BIO105K tutoring Thursdays 1:00 – 2:00in the Fish Bowl = room 153 Science BuildingSam Giles

Day Date Subject To be read prior to this class period: M 1/14 no class - Snow Day!W 1/16 Evolution: Unity and Diversity Chapter 1

M 1/21 no class – Rev. Martin Luther King, Jr. DayW 1/23 Water and the Chemical Environment Chapter 2 (except pp30-35)

M 1/28 Quiz #1 on Ch. 1 and parts of Ch. 2 and related lectures/handouts(no make ups for missed quiz)Cell Membranes Chapter 6

W 1/30 Macromolecules Chapter 3 (except pp63-69)M 2/4 Macromolecules

W 2/6 Quiz #2 on Ch. 3 and 6 and related lectures/handouts(no make ups for missed quiz)The Cell Chapter 7

M 2/11 BioenergeticsW 2/13 Cell Respiration Chapter 9M 2/18 no class - Winter BreakW 2/20 no class - Winter BreakM 2/25 EXAM I Chapters 1, 6,7, parts of 2, 3

Aquaporin protein makes a water channel through the cell (plasma) membrane.

The function of Aquaporin is to allow the passive diffusion of water across the cell membrane. The structure ofAquaporin is a donut and water goesthrough the donut hole.

Aquaporin increases the rate ofosmosis.

Chapter 3 is about protein structure and function.

In Chapter 3, the material on pages 63 -69 is not really covered until after the first test. That means you need to read it now but you don’t need to study it until after the first test. Also, I will talk about this material in class but not until after the first test.

The example will we use is the protein Aquaporin.

Major Sites of Expression and Function of Human AquaporinAquaporin-0 Eye: lens fiber cells Fluid balance within the lensAquaporin-1 Red blood cells Osmotic protection

Kidney: proximal tubule Concentration of urine Eye: ciliary epithelium Production of aqueous humor Brain: choriod plexus Production of cerebrospinal fluid Lung: alveolar epithelial cells Alveolar hydration state

Aquaporin-2 Kidney: collecting ducts Mediates antidiuretic hormone activityAquaporin-3 Kidney: collecting ducts Reabsorbtion of water into blood

Trachea: epithelial cells Secretion of water into tracheaAquaporin-4 Kidney: collecting ducts Reabsorbtion of water

Brain: ependymal cells CSF fluid balance Brain: hypothalamus Osmosensing function? Lung: bronchial epithelium Bronchial fluid secretion

Aquaporin-5 Salivary glands Production of saliva Lacrimal glands Production of tears

Aquaporin-6 Kidney Very low water permiability; function?Aquaporin-7 Testis and spermAquaporin-8 Testis, pancreas, liver, othersAquaporin-9 Leukocytes

Aquaporin creates a channelthrough the cell membrane that onlylets H Othrough.

2

Some examples of endocytosis and exocytosis:

1) Aquaporin-2 in human kidney cells 2) neurotransmitter vesicles in all human nerve cells3) phagocytosis of bacteria by human white blood cells4) receptor-mediated endocytosis and cholesterol traffic in humans

membrane traffic in cells

Some examples of endocytosis and exocytosis:

1) Aquaporin-2 in human kidney cells 2) neurotransmitter vesicles in all human nerve cells3) phagocytosis of bacteria by human white blood cells4) receptor-mediated endocytosis and cholesterol traffic in humans

membrane traffic in cells

Some examples of endocytosis and exocytosis:

1) Aquaporin-2 in human kidney cells 2) neurotransmitter vesicles in all human nerve cells3) phagocytosis of bacteria by human white blood cells4) receptor-mediated endocytosis and cholesterol traffic in humans

membrane traffic in cells

Some examples of endocytosis and exocytosis:

1) Aquaporin-2 in human kidney cells 2) neurotransmitter vesicles in all human nerve cells3) phagocytosis of bacteria by human white blood cells4) receptor-mediated endocytosis and cholesterol traffic in humans

membrane traffic in cells

Low-density lipoprotein (LDL) belongs to the lipoprotein particle family. Diameter is about 22 nm, Mass is about 3 million Daltons (one Hydrogen atom = 1 Dalton)But vary in size (A few large LDL are healthier than many small LDL.)Each LDL contain:1) one B-100 protein molecule (It’s big: 4536 amino acid residues) B-100 binds to the LDL receptor on cells.2) a highly-hydrophobic core consisting of linoleate, a fatty acid, and about 1500 cholestrol molecules3) surrounded by a shell of phospholipids