Cell Transport Review Grab your folder and a highlighter on your way to your assigned seat. Take out something to write with.

Cell Transport A process that helps cells maintain homeostasis. It involves the movement of molecules across the cell membrane. Two types: Passive and Active

Homeostasis The process of maintaining a stable internal environment, even while the external environment is changing. A state of balance – equilibrium

Cell Membrane The Cell Membrane’s key function is to regulate particles moving in and out of a cell. Small particles may move through the phospholipid bilayer, while other particles must pass through a transport protein. Identify the following: -Phospholipids -Proteins -Hydrophobic tails -Hydrophilic heads

Concentration Gradient The difference between the concentration of solutes in solutions. Natural flow is from high to low. (with the concentration gradient)

Passive Transport Process by which molecules move with their concentration gradient. Molecules move from high to low concentrations. Requires NO ENERGY.

Simple Diffusion An example of passive transport in which molecules move from areas of high concentration to areas of low concentration until homeostasis is reached.

Facilitated Diffusion Diffusion with the assistance of a transport protein. Occurs when the molecule is too large or polar.

Passive Transport – Osmosis Type of passive transport Process in which WATER molecules moving across a permeable membrane. H 2 Osmosis

How Does Osmosis Work? WATER always moves from the side with more water to the side with less water. In other words, water will always move to the side that has a higher concentration of solutes. Which side of the tube will the water rise?

Hypertonic Solution A solution that has LESS WATER than the cell. Will this cell swell, shrink, or stay the same?

Hypotonic Solution A solution that has MORE WATER than the cell. Will this cell to shrink, swell, or stay the same?

Isotonic Solution A solution that has the SAME AMOUNT of water as the cell. Will this cell to shrink, swell, or stay the same?

Side-by-Side Comparison

How to do Osmosis predictions Tape or glue these steps in your lapbook below your 3 small sticky notes on the passive transport side. 1.Draw a picture if one is not provided. 2.Identify the values that are given. 3.Calculate the percentage of water by subtracting the solute percentage from Identify where the water concentration is HIGHER. 5.Draw arrows going from high to low water concentration.

Which direction will water move across the plasma membrane? Will the cell shrink or swell? Cell/Plasma Membrane 98% Water 88% Water

Which direction will water move across the plasma membrane? Will the cell shrink or swell? Cell/Plasma Membrane 60% Water 75% Water

Which direction will water move across the plasma membrane? Will the cell shrink or swell? Cell/Plasma Membrane 50% Water 50% Water

Which direction will water move across the plasma membrane? Will the cell shrink or swell? Cell/Plasma Membrane 50% Solute 30% Solute HINT: Subtract the percent of salt from 100% to get the percent of WATER.

Recap – PASSIVE TRANSPORT 3 Characteristics HIGH TO LOW NO ENERGY WITH concentration gradient 3 Types Simple Diffusion: Movement of particles WITHOUT the assistance of a PROTEIN Facilitated Diffusion: Must be assisted by a PROTEIN Osmosis: Movement of WATER molecules ONLY

Active Transport Process by which particles move AGAINST their concentration gradient Movement from LOW TO HIGH concentrations Requires ENERGY

Sodium-Potassium Pump (Na +/ K + pump) Naturally, Sodium (Na + ) and Postassium (K + ) ions diffuse across the cell membrane, WITH the concentration gradient, which DOES NOT require energy. The Na +/ K + pump reverses this process sending Na + ions out of the cell and K + ions into the cell AGAINST the concentration gradient, which REQUIRES energy (ATP)., from a low to a high ceontration. Would there be a need for Na +/ K + pump the Na + and K + ions were not continuously diffusing across the cell membrane? Why or why not?

Active Transport 2 types of active transport: Endocytosis Exocytosis Can you figure out what each terms means?

Endocytosis Cell membrane folds inwards moving substances INTO the cell Receptor-mediated endocytosis: uptake of substances by the cell is targeted to a single type of substance that binds at the receptor on the external cell membrane Phagocytosis: the cell membrane surrounds the particle and pinches off to form an intracellular vacuole Pinocytosis: the cell membrane surrounds a small volume of fluid and pinches off, forming a vesicle

Exocytosis Exocytosis: a vesicle migrates to the cell membrane, binds, and releases its contents moving substances OUT of the cell

PASSIVE TRANSPORT: * NO ENERGY required * HIGH TO LOW * WITH con. gradient Examples: Diffusion Facilitated Diffusion Osmosis ACTIVE TRANSPORT: * ENERGY required * LOW TO HIGH * AGAINST con. gradient Examples: Endocytosis Exocytosis Sodium-Potassium pump ANALOGY: Passive vs. Active Transport

Recap – ACTIVE TRANSPORT 3 Characteristics LOW TO HIGH ENERGY REQUIRED AGAINST concentration gradient 3 Types Protein Pumps: Movement of particles WITH the assistance of a PROTEIN Endocytosis: Particles ENTERING the cell Exocytosis: Particles EXITING the cell

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