Weekly Announcements

• No Homework today

• Notebook Check today

• Quiz on Cellular Respiration Tuesday Next week

• Lab on Chlorophyll Monday Next week

• Test on Chapter 4 Friday Next week

10/7/13

• Do Now: Take out any graded papers from your bags and notebooks and place in your folder

• HW: No HW

10/8/13

• Do Now: What is Energy and how to we obtain it?

• HW: – Read pages 51 -52 – Put vocabulary in your own words from

beginning of chapter 4

10/9/13

• Do Now: What would happen if nutrients were only able to enter cells and never leave?

• HW: Read pages 53 - 54

Diffusion & Osmosis

Diffusion

The movement of molecules from an area in which they are highly concentrated to an area in which they are less concentrated.

Diffusion

Osmosis

• The diffusion of water across a selectively permeable membrane.

• Osmosis is a type of Passive Transport.

• Osmosis requires NO ENERGY.

OsmosisOsmosis

• Hypertonic- a solution that causes a cell to shrink because of Osmosis.

• Hypotonic- a solution that causes a cell to swell because of Osmosis.

• Isotonic- a solution that causes no change in the size of the cell

Osmosis

• In this picture a red blood cell is put in a glass of distilled water. Because there is a higher concentration of water outside the cell, water enters the cell by OSMOSIS.  In this case too much water enters and the cell swells to the point of bursting open. 

Selectively Permeable

• A membrane that allows only certain materials to cross it

• Materials pass through pores in the membrane

Summary

• Diffusion is the movement of molecules from an area of higher concentration to an area of lesser concentration.

• Osmosis is the movement of water thru a semi permeable membrane.

• Active transport requires energy. (molecules move from an area of lesser to higher concentration)

• Passive transport needs NO ENERGY! (molecules move from an area of higher to lesser concentration).

Why are osmosis & diffusion important?

• All living things have certain requirements they must satisfy in order to remain alive – maintain homeostasis

• These include exchanging gases (usually CO2 and O2), taking in water, minerals, and food, and eliminating wastes.

• These tasks happen at the cellular level.• Molecules move through the cell membrane by

diffusion• A balance, or EQUILIBRIUM, must be

maintained.

10/10/13

• Do Now: What would you think the difference is between active and passive transport?

• HW: – Read pages 55-56– Complete “Check Your Understanding” on

page 57

Active and Passive Transport

• Passive Transport = The diffusion of certain molecules through the cell membrane occurs passively, or without help.

• Osmosis Takes place through passive transport.

• Active Transport = Movement through the cell membrane that is the opposite of diffusion and requires energy (ATP)

Cellular Respiration

• The process by which cells release energy from food.

• Cellular respiration releases energy.

• Water and carbon dioxide are byproducts

10/11/13

• Do Now: How do plants get energy?

• HW: – Read pages 57-58– Complete “Check Your Understanding” on

page 59

Photosynthesis & Respiration

What is Photosynthesis?

The process of photosynthesis is a chemical reaction.

It is the most important

chemical reaction on our planet.

What is the Equation for the Chemical Reaction of

Photosynthesis?

What is the equation for the chemical reaction of

photosynthesis?

What is the equation for the chemical reaction of

photosynthesis?

Six molecules of carbon dioxide react with six molecules of water to form 1 molecule of

glucose and six molecules of oxygen.

Describe Photosynthesis

Describe Photosynthesis

• The process of changing light energy to chemical energy

• Energy stored as sugar

• Occurs in plants and some algae

• Plants need light energy, CO2, and H2O

• Takes place in the chloroplasts, using chlorophyll, the green pigment in plants

What happens during photosynthesis?

What happens during photosynthesis?

• Plants capture light energy and use that energy to make glucose

• Sunlight provides the energy needed by chlorophyll to change molecules of carbon dioxide and water into glucose

• Oxygen is also released in this reaction

What happens during photosynthesis?

• Carbon dioxide enters the leaf through holes called stomata

• CO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose

• The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants

• Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue

Why is this important to us?

Why is this important to us?

We cannot make our own food (glucose, energy), we must get our food from plants.

Plants are the first step in the food chain.

Why is this important to us?

The oxygen released during photosynthesis is necessary for all living things.

Learn more about photosynthesis at:

http://www.ftexploring.com/me/photosyn1.html

What is Cellular Respiration?

What is Cellular Respiration?

The release of chemical energy for use by cells.

What is Cellular Respiration?

Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a a form that can be used by the organism.

This process is cellular respiration.

Describe Cellular Respiration

Describe Cellular Respiration

• The breakdown of glucose molecules to release energy

• Takes place in all living things

• Is a step by step process

What is the chemical equation for cellular respiration?

What is the chemical equation for cellular respiration?