Ch. 5 Review

5.1 Passive Transport

Differentiate the terms solute and solvent. Solute = substance being dissolved Solvent = substance doing the dissolving

What is the solvent inside and outside of the cell? Water

What are the four components of the cell membrane? Phospholipids Carbs Proteins – both integral and peripheral Steroids (cholesterol)

What does selectively permeable or semi-permeable mean? Only certain things can pass through

What are the two main types of transport? What’s the difference between the two?

Passive transport Active transport

•No ATP needed

•Movement of particles from high to low concentration

•ATP needed

•Movement of particles from low to high concentration

List the four types of passive transport. Simple diffusion Osmosis Facilitated diffusion Diffusion through ion channels

Define diffusion. Why does it occur? Movement of particles from high conc. to low

Occurs naturally due to kinetic energy of particles

Give an example of diffusion. Food coloring in water Perfume/cologne Loss of helium from a balloon Smoke Oxygen, carbon dioxide, and other small

nonpolar molecules across the cell membrane

What is equilibrium? Particles are spread evenly throughout a

space

Do the particles stop moving in equilibrium? No!

Why not? They have kinetic energy!

What is osmosis? Movement of water from high to low conc.

through a membrane

Define hypertonic, hypotonic, and isotonic. Hypertonic = high solute Hypotonic = low solute Isotonic = same solute

In which of those solutions are the particles in equilibrium? Isotonic

Which way does water flow when cells are in a hypotonic solution? In

What happens to animal cells? Cytolysis

What happens to plant cells? Turgor pressure

What is cytolysis? Cell bursting

Why don’t plant cells experience cytolysis? They have cell walls

What is turgor pressure? Pressure of membrane pushing against the

cell wall

Which way does water flow when cells are in a hypertonic solution? Out

What happens to animal cells? Crenation

What happens to plant cells? Plasmolysis

What is crenation? Cell shrinking/shriveling

What is plamolysis? Cell membrane pulls away from cell wall

If you are stranded at sea, why shouldn’t you drink the ocean water? It’s too salty! You would be putting your cells

in a hypertonic environment which would cause them to lose water!!

What is facilitated diffusion? Assisted diffusion Movement of particles from high conc. to low

through a transport protein called a carrier protein

Do carrier proteins transport lots of different types of molecules or one type of molecule? One type… they are specific!

List the steps of facilitated diffusion. Carrier protein binds to molecule Carrier protein changes shape Molecule moves through Molecule released on other side; carrier

protein returns to original shape and is reusable

What types of molecules move by facilitated diffusion? Glucose Small polar molecules

What is diffusion through ion channels? Movement of ions from high conc. to low

through carrier proteins called ion channels or channel proteins

Ion channels are also specific – they only move one type of ion

What is the everyday word for an ion? electrolyte

Why can’t ions move through the cell membrane on their own? They are charged – repelled by nonpolar

interior of cell membrane

Some ion channels open and close. What are they called? Gated channels

What controls the opening/closing of gated ion channels? Cell membrane stretching Electrical signals Chemical signals

What are some common ions? sodium (Na+) potassium (K+) calcium (Ca2+) magnesium (Mg+) chlorine (Cl-) phosphate (PO4

-)

bicarbonate (HCO3-)

Why are ions important? Heartbeat and nerve function Fluid balance Oxygen delivery Acid-base balance

5.2 Active transport

What’s the difference between active and passive transport? Active transport moves substances against

the gradient Active transport requires ATP!!

List the types of active transport Protein pumps Endocytosis Exocytosis

What is a protein pump? Transport protein that moves molecules from

low to high conc. ; requires energy

What are the basic steps of how protein pumps work? Protein binds to molecule Protein changes shape; this requires ATP! Molecule moves through protein and is

released on the opposite side Protein returns to original shape and is

reusable

Give an example of a protein pump. Sodium-potassium pump

Cells must maintain higher sodium _______ and higher potassium _________ the cell. Outside Inside

Sodium and potassium always move in a ________ ratio.

3:2

Describe how the sodium-potassium pump works. 3 sodiums bind to the pump on the inside of the cell Protein splits a phosphate from ATP and releases

energy; the free phosphate binds to the pump causing it to change shape

3 sodiums move out

2 potassiums bind to pump on outside of cell Phosphate is released from pump causing it to

change shape Potassiums move in

Protein returns to original shape and is reusable

Define endocytosis. Talking bulky materials into a cell

What are the two types of endocytosis? Pinocytosis Phagocytosis

What’s the difference between the two? Pinocytosis – fluids, cell “drinking” Phagocytosis – solids, cell “eating”

How does endocytosis work? Cell membrane folds inward around material

to be ingested Membrane pinches off inside of cell forming a

vesicle Vesicle fuses with a lysosome to digest

materials

Define exocytosis. Forcing material out of the cell in bulk

How does it work? Vesicle containing material fuses with the cell

membrane releasing contents outside

The cell membrane changes shape… this requires ___________. Energy

Give three examples of materials released from a cell by exocytosis. Hormones Proteins Wastes