Other Modes of Transport: Facilitated Diffusion and Active Transport Campbell 5.17-5.21

What are plasma membranes made of?

Membrane Structure Made mostly of phospholipids These form a phospholipid bilayer Phosphate group Polar Hydrophilic Head Fatty Acid Non-polar Hydrophobic Tails

Large items and ions can’t cross membrane without gates!

Types of Membrane Transport Simple Diffusion Does NOT require energy High to low concentration Facilitated diffusion A membrane protein is needed Active transport Requires energy Low to high concentration Passive Transport – No energy Active Transport – requires energy

Passive transport

Types of Membrane Transport

Types of Transport Proteins Non-specific transporter Specific transporter

Aquaporins – facilitated diffusion - water is polar; won’t move on its own - aquaporin – pores that allow movement of water through channel protein Review protein structure

How glucose enters a cell - specific glucose transporter - facilitated diffusion – High to low – no energy! What model of protein binding is this?

Active Transport – requires energy

Sodium-Potassium Pump

Bulk Transport – large amounts of substances cross the membrane Exocytosis Endocytosis Release to outside Wastes, hormones, signals Phagocytosis (eat) Pinocytosis (drink) Clicking animation takes you to a great illustration from the Krogh textbook – use this! I tell students to think of phago/”food” (both begin with F sound), and pino/drink (like you drink a pina colada). Animation

Ex. Phagocytosis Video clip

Review Qs Why is kinetic E. important to balance? You smell smoke from a campfire across the street. Why is this diffusion but NOT osmosis? What kinds of molecules cross the membrane most easily? Given: 30% sucrose outside cell, 10% sucrose inside. Which is hypertonic? Which way does water move? How does swelling affect plants and animals differently? What process do white blood cells use to eat your body’s foreign invaders?

part 3

Arteries transport blood away from the heart. Veins transport blood towards the heart. Capillaries transport gasses, nutrients, and waste into and out of the blood stream.

Show me what would happen if this is a capillary bed in the muscle tissues of a dehydrated person. Exchange with cells or outside environment? Nutrients, waste, O2, CO2, H2O?

Form suits function

Transport in the circulatory system

Circulatory system overview

Two hearts in one

Capillaries (tissues) Human circulation Heart LV RA LA RV Pulmonary circuit Arteries Arteries Veins Veins Capillaries (lungs) Capillaries (tissues) Deoxygenated Oxygenated Systemic circuit

Alveoli are the site of gas exchange in the lungs. Why so many?