Anticipatory Set 9 15 11 Anticipatory Set 9

Anticipatory Set 9 -15 -11

Anticipatory Set 9 -21 -11 L 2&3

Cellular Transport

Selective Permeability ⌂ Selective permeability- the cell membrane’s ability to allow some substances to enter/ exit but not all. ⌂ Two processes that allow substances to enter/exit: • Passive transport – energy from kinetic energy and concentration gradient. • Active transport-ATP

Diffusion ⌂ Process depends on concentration gradient. • Particles will never stop moving, but when equilibrium is reached there will be no net change in their concentration. • Movement of particles is from [high] to [low] concentration. • Dependent on four factors: diameter, temperature, electrical charge (when applicable), and the concentration gradient. • Majority of materials enter cell through diffusion…energy conservation for other processes.

Cell Membrane & Diffusion ⌂ diffusion animation

Osmosis ⌂ Diffusion of water. ⌂ Water always travels from hypotonic to hypertonic ⌂ Solute always travels in opposite direction of water. ⌂ Osmosis Animation

Isotonic Solutions ⌂ Isotonic solutions-the same amount of solute exists inside and outside the cell. ⌂ Water moves in and out at the same rate.

Hypertonic Solutions ⌂ Hypertonic solutionshave more solutes in solution than inside the cell. ⌂ Water moves out of the cell to achieve equilibrium.

Hypotonic Solutions ⌂ Hypotonic solutionshave less solutes in them than inside the cell. ⌂ Water will enter the cell to try and achieve equilibrium. ⌂ Cells may lyse if too much water enters. ⌂ Plants combat this risk with their cell wall, and turgor pressure results.

Data Set 9

Level 1 and 1

Level 1 & 2

Level 1, 1, 2

Osmoregulation-water control ⌂ Turgid- enough water, plant cell rigid ⌂ Flaccid- lacking water, plant cell limp ⌂ Plasmolysis- cell membrane is ripped from cell wall

. Hypotonic solution Isotonic solution Hypertonic solution Animal cell H 2 O Turgid (normal) H 2 O Flaccid H 2 O Shriveled Normal Lysed Plant cell H 2 O Plasmolyzed

Water Potential- water’s ability to do work when going through the C. M. ⌂ Pressure Potential ⌂ Solute Potentialbased on solute • Positive pressure is the cell being pushed concentration • Negative Pressure- the cell being pulled (eg transpiration)

Positive Pressure Potential

Negative Pressure Potential

Solute Potential ΨS = -i. CRT -i (ionization constant) C (molar concentration) R (pressure constant) T (temperature in Kelvin)

Turgor pressure is ~100 psi, much more than a tire. The pressure is so great that plant cells would detach from one another if not for adhesive molecules known as pectins.

Facilitated Diffusion with Channel Proteins ⌂ Facilitated diffusionwithin the cell membrane are channel proteins that allow materials to pass into the cell. ⌂ Aquaporins- channel proteins that allow water to pass through, in addition to simple diffusion. • In kidneys and plants where water is essential • Channel Protein Animation

FD with Ion Channel Proteins ⌂ Channel protein let in ions. ⌂ When the protein shape changes, the gate will open. ⌂ Ions pass through based on size and charge. ⌂ Can be ligand gated or voltage gated. ⌂ Voltage gated channels depend on two things: • Concentration gradient of K § Concentration of K (usually higher inside cell) • Membrane potential due to charge imbalance.

Anticipatory Set 9 -22 -11 Level 3

Facilitated Diffusion with Carrier Proteins ⌂ Carrier proteins transport polar substances like amino acids and sugars. ⌂ When the carrier proteins become saturated the rate of diffusion is maxed out. ⌂ Animation: How Facilitated Diffusion Works

Figure 5. 12 A Carrier Protein Facilitates Diffusion (Part 1)

Filtration ⌂ Filtration- pressure driven system that pushes water and nutrients across cell membranes. ⌂ This is how urine is produced ⌂ Does not require energy.

Active Transport

Active Transport is Directional ⌂ Active transport always works against the concentration gradient. Going from a lower to higher concentration. ⌂ Requires energy. ⌂ Two types: primary and secondary active transport.

Membrane Proteins associated with Active Transport ⌂ Cell Pumps: ⌂ Uniports move a single substance in one direction. ⌂ Symports – move two substances in the same direction. ⌂ Antiports - move two substances in opposite directions. One into the cell, and one out of the cell. • e. g. Na. K pump • Coupled transporters are those that move two substances. Which of these are coupled?

Figure 5. 13 Three Types of Proteins for Active Transport

Primary Active Transport ⌂ ATP is hydrolyzed and drives the movement of ions against the concentration gradient. ⌂ Sodium potassium pump is an example of 1 AT. Because the ions move against the concentration gradient. (Na leaves cell, although more Na outside cell, same with K more in cell, but K still enters) ⌂ Na. K Pump located in all animal cells; antiport; coupled transporter ⌂ Na. K Pump Simple Animation ⌂ Na K Pump Animation

Figure 5. 14 Primary Active Transport: The Sodium–Potassium Pump

Membrane Potential ⌂ Membrane Potential aka Voltage Gradient allows the cell to do work. ⌂ DNA is negative inside cell(-), Na. K pumps extra Na out of the cell (+). ⌂ Difference in charge allows molecules to be transported using ATP. ⌂ E. g. glucose enters through because of membrane potential ⌂ Secondary AT Animation

H Pumps ⌂ Most important pump for cell respiration and photosynthesis. ⌂ H+ pumped out of cell, and ions can now diffuse in ⌂ Pumping H requires little energy, and they help sugars enter the cell by AT

What if the macromolecules are too large, charged, or polar to enter through the membrane? ⌂ Is this a good problem or not? ⌂ Which organelle is responsible for substance transport?

Endocytosis ⌂ Processes that bring substances into the cell such as macromolecules and smaller cells. ⌂ Three types of endocytosis: • Phagocytosis • Pinocytosis • Receptor-Mediated Endocytosis

Figure 5. 16 Endocytosis and Exocytosis (A) Phagocytosis • Cell eating • Part of cell membrane engulfs particles/cells • Phagosome fuses with a lysosome and digestion occurs

Endocytosis ⌂ Phagocytosis- process fairly nonspecific ⌂ Only a few cells can do this ex. WBC • Must be able to change shape and form pseudopodia. • WBC will attach to bacteria engulf bacteria with pseudopodia lysosomes with enzymes digest it residual waste is exocytosed. • Pinocytosis- same process just with liquids. Also fairly nonspecific. • WBC and Phagocytosis Animation

Receptor-Mediated Endocytosis ⌂ Specific process that utilizes integral membrane proteins to bind to specific molecules in the cell’s environment. ⌂ Receptor proteins are substance specific, aka coated pits. Coated with protein , formed by CM depressions. ⌂ When a ligand binds to the receptor protein, it invaginates and forms a vesicle. ⌂ E. g. cholesterol uptake in mammals rd. 113 -114

Figure 5. 17 Formation of a Coated Vesicle (Part 1)

Figure 5. 17 Formation of a Coated Vesicle (Part 2) Receptors will form a new vesicle and be recycled back to plasma membrane.

Exocytosis ⌂ Anything that comes in must go out. ⌂ Materials are packaged into vesicles, which fuse with the cell membrane via a membrane protein. ⌂ The two membranes fuse, contents expelled, and the CM incorporates vesicle membrane.

Endocytosis and Exocytosis Animation Hyper, Hypo, Iso

Other Cell Membrane Functions ⌂ Some organelle membranes help transform energy. ⌂ Some membrane proteins organize chemical reactions. ⌂ Some membrane proteins process information.

Plasmolysis ⌂ Net loss of a cell’s volume due to a hypertonic environment. ⌂ Plasmolysis Animation

Water Potential ⌂ Tendency of water to leave one place in favor of another. ⌂ Always moves from higher to lower water potential. ⌂ Affected by pressure and solute ⌂ Water potential ( ) = pressure potential ( p) + solute potential ( s) ⌂ Solute Potential = s=–i. CRT • i = The number of particles the molecule will make in water; for Na. Cl this would be 2; for sucrose or glucose, this number is 1 • C = Molar concentration (from your experimental data) • R = Pressure constant = 0. 0831 liter bar/mole K • T = Temperature in degrees Kelvin = 273 + °C of solution ⌂

Water Pot. and Plasmolysis

Lab: Plasmolysis ⌂ Perform a serial dilution of salt (100, 50, 25, 0% solution) ⌂ Predict which solution will yield the fastest plasmolysis results. ⌂ Perform Experiment with each solution and time results.

Lab: Water Potential ⌂ Perform a serial dilution of sugar ( 100, 50, 25, 0). Label solutions. ⌂ Core equal lengths of 2 vegetables. ⌂ Record lengths, mass, and vegetable type in table. ⌂ Predict what will happen to length and mass by tomorrow.

Anticipatory Set 10 -10 -11 Level 2