Monday, Mar 3rd, 2014•Did you know…

•There's about 1.8m (6ft) of DNA inside every cell’s nucleus in our body. An average adult body contains ~50 trillion cells.

•Some migratory birds have a "magnetic compass" in their body (a sense called “magnetoreception”) to help them navigate using Earth's magnetic field.

Tuesday, Mar 4th, 2014

•Did you know…

•The catfish father keeps the eggs in his mouth until they are ready to be hatched.

•Corneas (in the eye) are the only tissues that don't require blood.

Do Now: Mar 4th

1. What’s the concentration of a solution w/ 8g lemonade mix in 2L of water?

2. What does passive mean?

3. Name one similarity & one difference btwn diffusion & osmosis.

Concentrations

•Solvent: does the dissolving▫E.g., water

•Solute: solid that’s dissolved▫E.g., salt

•Solution: solute + solvent

•Concentration = mass of solute in a volume of solution▫grams/Liters (g/L)

Concentration Problems

•Include the units!•12g salt dissolved in 3L water =

12g/3L = 4 g/L

•12g salt dissolved in 6L water = 12g/6L = 2 g/L

•Which is more concentrated?

Practice Concentrations1. 9g sugar; 1L water

2. Add 2L water

3. Add 3g sugar

4. Add 3g sugar

• Which is the least concentrated?• Which is the most concentrated?

1. Diffusion

•Particles naturally move high conc low conc

•Passive: no energy required

•Move until equilibrium (same conc throughout)

Diffusion

•Particles constantly move/collide▫Even in equilibrium, particles still move in

BOTH directions

•Rate depends on (1) conc difference & (2) temp difference

•E.g., O2, H2O, & CO2 passively move thru cell membrane

Diffusion Demo•Set up obs table on paper. 2-3 lines per row.

•Why did the progression that you observed occur?▫Diffusion rate depends on (1) conc difference

& (2) temp difference

0 min 3 min 6 min

Cold temp

Room temp

Hot temp

Low conc

Medium conc

High conc

Permeability Permeable: allows all substances thru

Selectively permeable/semipermeable: Some substances cross; others cannot E.g., cell membrane, cell wall,

nuclear envelope

Impermeable: no substances can cross

2. Osmosis

•Diffusion of water across membrane•Water movement from high water conc

(hypotonic) low water conc (hypertonic) until equilibrium (isotonic)

Osmosis•Isotonic: concs same on both sides of

membrane▫“Iso-”: equal▫Equilibrium

•Hypertonic: more conc solution ▫“Hyper-”: above▫Remember: hyperactivity = high amount of

activity

•Hypotonic: less conc solution ▫“Hypo-”: under▫Remember: hypothermic = under normal temp

Osmosis

•Passive: no energy required

•E.g., H2O moves thru cell membrane

•Cells are hypertonic (more conc) •Pure H2O is hypotonic (less conc)

= water moves into cells▫Animal cells burst b/c no cell wall▫Plant cell walls prevent bursting

3. Facilitated Diffusion

•“Facilitate”: to help•Particles move from high conc low conc

▫Molecules cannot cross membrane b/c size or charge (+ or -)

▫Helped by protein channels

•Passive: no energy required

Facilitated Diffusion Channels only help specific molecules Rate depends on

(1) conc difference, (2) temp difference, (3) # of protein channels

E.g., glucose passes thru protein channel to enter cell

http://www.youtube.com/watch?v=s0p1ztrbXPY

Transport Proteins

4. Active Transport•Molecules move against conc gradient (low

high conc) thru protein pumps in membrane▫Proteins change shape to

pump molecule across▫Requires energy (ATP)

•E.g., sodium (Na+) & potassium (K+) ions pumped against conc gradient into nerve cells

http://www.youtube.com/watch?v=STzOiRqzzL4

5. Endocytosis (Bulk Transport)

•Infolding of membrane takes in large molecules▫“Endo-”: in▫Forms new vacuoles

A.Phagocytosis: reaches out & swallows molecule▫“Phage-”: to eat

•E.g., immune cells engulf/swallow bacteria cells

Endocytosis

B.Pinocytosis: small pocket fills & pinches into cell

Vacuole

6. Exocytosis (Bulk Transport)•Release large materials from cell

▫“Exo-”: out/exit

•Vacuole fuses w/ membrane & inverts to dump contents out of cell

•E.g., export newly made hormones

•http://www.phschool.com/science/biology_place/biocoach/biomembrane2/cytosis.html

Transport Chart

Transport Particles Involved

Movement

Energy? Example

Diffusion

Osmosis

Facilitated Diffusion

Active Transport

Endocytosis

Exocytosis

Transport ChartTransport

Particles Involved

Movement Energy?

Example

Diffusion Small, nonpolar molecules

Down conc gradient (high low conc)

Passive (no energy)

O2, H2O, & CO2 move thru cell membrane

Osmosis Water Down water gradient (hypotonic [high water] hypertonic [low water])

Passive (no energy)

H2O moves thru cell membrane

Facilitated Diffusion

Medium molecules

Down conc gradient (high low conc) thru helper protein channels

Passive (no energy)

Glucose passes thru cell membrane via protein channels

Transport Chart (cont.)Transport Particles

InvolvedMovement Energy? Example

Active Transport

Large, polar molecules

Against conc gradient(low high conc)

Active (requires energy=ATP)

Sodium (Na+) & potassium (K+) ions use energy to pump against conc gradient in nerve cell membranes

Endocytosis

Giant molecules

Bulk movement into cell, creating vacuoles

Active (requires energy=ATP)

Immune cells engulf/swallow bacteria cells

Exocytosis Giant molecules

Bulk movement out of cell, releasing vacuole contents

Active (requires energy=ATP)

Exporting newly made hormones