Chapter 1 Lesson 3

"Chemicals That Are Important for Life"

Materials:

• Cans of food and/or food lables if you have them. Give them out at the beginning of class.(10:30)

Objective:

• Students will explain why water is important to life.
• Students will describe how living things use carbohydrates, fats, and proteins.
• Students will discuss the importance of eating a variety of foods.

Alaska Standards:

• AK SCI A-9 Students will understand the transfers and transformations of matter and energy that lik living things and their physical environment, from molecules to ecosystems (Flow of Matter and Energy)
• AK SCI A-15 Students will use science to understand and describe the local environment.
• AK SCI D-1 Students will apply scientific knowledge and skills to understand issues and everyday events.

Anticipatory Set:

If a person is stranded on a small deserted island with no fresh water and surrounded by salt water as well as no food on the Island what are they most likely to die from?

Humans can not drink salt water because the salt water will pull water with lower concentrations of salts from their cells.

Explain, Humans can survive up to several weeks without food. However, they can survive only a few days without water. A person needs abut 2.5 liters of water daily. This is about the sameamount that is lost through respiration, perspiration, and excretion. People need to drink about 2 liters of liquids a day and maintain a healthy diet in order to remain properly hydrated.

Two thirds of a cell is made of water. How many cells are we talking about? (100 trillion)

Bring out several cans of food and ask the student what information food lables contain.

Teacher Input: Water is important because it pulls polar molecules apart. Polar molecules have a charge on one end. Many substances are broken down by water in a process called dissolving. Demonstrate by making kool-aide. Emphasize three points:

• Solute - the substance being dissolved (sugar)
• Solvent - the water or the liquid that is pulling the particles apart.
• Solution - The mixture in which the particles are evenly mixed.

What are the particles that your cells dissolve or break down in your cells (nutrients)

Teacher Modeling:

Ask about injuries where a student may have tasted blood. How does it taste?(salty) The fluid in body cells and body fluids is not pure water. Many different substances make up your body fluids. Some of the most important things in the fluids are known as NUTRIENTS.

From pages 13-15 or food lables can you name some nuitrients. (carbohydrates, fats, proteins, aminoacid, minerals, vitamins.

Check for Understanding: Begin a discussion about diabieties. Draw a chart that describes to students how the body deals with simple sugars, complex sugars, and fats over time. (see worksheet)

Guided Practice:

Use at series of questions with the excel spreadsheet to determine if the students understand them.

Chart showing breakdown of calories in the body.

Chart showing insuline reaction to simple sugars.

Chart showing insulin reaction to complex sugars.

Little or no insulin reaction to fats.

Closure:

Redefine Nutrient and look at the definitions of the following words and how it fits in the lesson.

Nutrient, Vitamin, Mineral, Amino acid, protein, fat, carbohydrate, solution.

Independent Practice:

Students will write down and study the definitions of the words above P12-13, read the section, and take the quiz on Chapter 1 Lesson 3.

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).