Welcome Back! Please do the following: pick up the handouts from the front table pick up glue if you did the extra credit assignment, it is due in the tray have out your notebook get started on your bell ringer

We will investigate & explain the transport of molecules. I will be able to explain the direction water will move through celery.

CELL TRANSPORT How molecules get in and out of cells

saltwater solution

We need to move molecules because… People need nutrients People need to get rid of waste Cells also need nutrients Cells also need to get rid of waste

What part of the cell regulates the entry and exit of molecules?

The Cell Membrane is made of… Proteins and Lipids and some Carbohydrates

The Cell Membrane is Semi-Permeable Semi-Permeable means that only certain sized molecules can pass through the cell membrane Think of the cell membrane as a chain link fence!

The cell membrane maintains homeostasis… By allowing proper nutrients into the cell By getting rid of wastes from within the cell Membranes also allow cells to communicate with other cells & the outside world. This allows the cells to respond to their environment & each other!

Quick Review What protective barrier of cells controls the entry and exit of molecules? What is this barrier made of? The cell membrane is semi-permeable. Explain what this means. How does the cell membrane maintain homeostasis?

Two Types of Transport Cells move substances through the cell membrane by a process called transport. 1.Passive Transport For small, uncharged molecules 2.Active Transport For large molecules Energy

Diffusion is Passive Transport Requires no energy from the cell Molecules move from high → low concentration Molecules move with the concentration gradient Energy High Concentration Low Concentration

Examples of Diffusion Dye added to liquid Odors In both cases, molecules move from areas of high concentration to low concentration until a balance is reached! We call this balance on both sides EQUILIBRIUM! In both cases, molecules move from areas of high concentration to low concentration until a balance is reached! We call this balance on both sides EQUILIBRIUM!

How does diffusion happen in a cell?

Cell Membrane

Osmosis is the diffusion of water Cell Membrane

Water has to be able to move… We are over 75% water Water is an important solvent in our body (water dissolves a lot of stuff in our body) If our cells are in an environment that robs them of water, we dehydrate! YIKES! Can you die from drinking too much water?

Effects of Passive Transport 100% Distilled Water 80% H 2 O 70% Water 30% Dissolved Substances 80% H 2 O 80% Water 20% Dissolved Substances 80% H 2 O

Which way did the water move? 70% Water 30% Dissolved Substances 80% H 2 O Why did the cell get so small?

Which way did the water move? 80% Water 20% Dissolved Substances 80% H 2 O Why did the cell stay the same size?

Which way did the water move? 100% Distilled Water 80% H 2 O Why did the cell get so big?

Real life example with red blood cells A change in cell shape is a change in cell function!

Facilitated Diffusion I’m a Channel, I can help! Channel and carrier proteins help substances (glucose) pass through the cell membrane. Still passive transport - no energy required.

Facilitated Diffusion I’m a Channel, I can help! Channel and carrier proteins help substances (glucose) pass through the cell membrane. Still passive transport - no energy required.

Quick Review What are the two types of transport and which one requires the input of ATP energy? How is osmosis and facilitated diffusion different from each other? How are hypotonic and hypertonic solutions different from each other?

Active Transport Requires energy from the cell Molecules move from low → high concentration Molecules move against the concentration gradient Energy High Concentration Low Concentration

Endocytosis Cells take in large particles changing the shape of the cell membrane. – Phagocytosis (cell eating) – Pinocytosis (cell drinking)

Exocytosis How the cell gets rid of waste

Quick Review What type of transport requires energy and moves molecules from low to high concentration? What process allows cells to get rid of large particles like waste? What process allows cells to get take in large molecules?

SUMMARY Compare Passive Transport to Active Transport ENERGY OR NO ENERGY LOW TO HIGH OR HIGH TO LOW WITH OR AGAINST CONCENTRATION GRADIENT