Biological MoleculesThe Chemistry of

Living Things

How to take notes

Molecule Type

# of calories

Food sources

How to test for...

Uses in the body

Composed of...

Other important information

Organic Compounds--Organic compounds are compounds that contain carbon and hydrogen.

--99% of all living things are composed of the elements Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, and Sulfur (CHNOPS).

--The four major molecules in living things are:

1. Carbohydrates

2. Fats

3. Proteins

4. Nucleic Acids

CarbohydratesCarbohydrates are sources of quick energy. They are composed of smaller sugar molecules. They are composed of carbon, hydrogen, and oxygen. Provide 4 cal/gram food energy.

Carbohydrates continued...

Monosaccharides are single sugar carbohydrates;

glucose and fructose are examples.

Disaccharides are made from two sugar molecules

linked together. Sucrose, maltose, and lactose are

examples. Monosaccharides and disaccharides are

called simple sugars.

Carbohydrates continued...

Polysaccharides are made from many

monosaccharides bonded together. These

are called complex carbohydrates.

Cellulose, glycogen, and starch are

examples.

Important carbohydratesStarch is produced in plants as an energy

storing molecule. Starch molecules are

long, straight, twisted molecules.Glycogen

is an energy storing molecule produced in

the liver of animals and is made of chains of

smaller carbohydrates.

Foods containing carbohydrates

sugars

grains and breads

pasta

potatoes

Carbohydrates dissolve in water

Testing for carbohydratesCarbohydrates are tested by adding iodine stain. Add 5 drops to a food or a solution. If the color turns dark blue, starch is present.

Testing for glucose (simple sugar)

Add 3ml of Benedict’s solution to 5ml of your sugar solution.

Heat in a hot water bath on a hot plate . If there is a color change to brown then glucose is present.

FatsFats are large molecules of carbon, hydrogen, and oxygen that store energy.

Fats do not dissolve in water and are composed of 3 fatty acid molecules and one glyceride molecule.

Fats continued...Fats have 5 major functions:

1. Store and release energy

2. Make cell membranes

3. Make hormones which allow communication

4. Vitamins are carried in and out of cells by fats

5. Protection and insulation

Fats continued...Fats with no double bonds are called saturated fats. Fats with double bonds are unsaturated and easier to break down.

Cholesterol and steroids are both fats.

Unused carbohydrates are stored as fats.

Fats provide 9 cal/gram food energy.

Foods containing fats

meat nuts oils

butter milk

anything that tastes good!

Testing for fats

Smear the food sample on a piece of brown paper bag. If a ring is left, after the substance dries, then fat is present.

ProteinsProteins come from the Greek

meaning, “of first importance”.

Proteins are the most complex of the

basic molecules.

Proteins provide 4 cal/gram food

energy.

Proteins continued... Serve many functions in living organisms:

1. Structure: make muscles, etc. (building blocks)

2. Enzymes: help reactions occur

3. Antibodies: fight disease

4. Transportation: carry molecules around

5. Regulation: control chemical reactions

Proteins continued...Proteins are composed of many amino acids in a long chain.

Proteins contain carbon, hydrogen, oxygen, and nitrogen.

Proteins are made of combinations of only 20 different amino acids.

Proteins continued...

Many amino acids link together to form a polypeptide. Polypeptides, once they have a three dimensional shape, are called proteins.

Amino acids must be obtained from foods. Animals can not make them.

Sources of proteinMeat Cheese

Fish Nuts

Beans (amino acids)

Rice (amino acids)

Testing for proteins

Add 5 drops of Biuret’s Solution to a food source. A change in color of light blue to purple indicates the presence of a protein.

Nucleic AcidsDeoxyribonucleic Acid (DNA) and

Ribonucleic Acid (RNA) are molecules in

cells that carry the genetic code. The

work done in cells is largely done by

proteins but DNA directs the work being

done by the proteins.

Nucleic Acids continued...

DNA and RNA are made of nucleotides.

1. a five carbon sugar (deoxyribose in

DNA) (ribose in RNA)

2. a nitrogen base (a pyrimidine or purine)

3. and a phosphate group

Nucleic Acids continued...

ATP and ADP are nucleotides that

are energy transfer molecules in

cells.

Press here

Press to see ATP molecule

Making other moleculesThe human body is very efficient. It reuses molecules, and breaks many things down to rebuild needed molecules.

The process of breaking down is called hydrolysis.

The process of building is called dehydration synthesis or condensation.

These processes go on in carbohydrates, fats, and proteins.

Making bigger molecules

When two molecules bond, energy is stored and water molecules are produced. This process is called dehydration synthesis. Water is removed, thus dehydration. A new and larger molecule is made, thus synthesis.

Making smaller moleculesWhen a large molecule is broken down a

water molecule is needed. The process is

called hydrolysis. A water molecule is broken

(lysis) and the parts used to form the smaller

molecule, thus the name hydrolysis. Hydro-

meaning water, -lysis meaning to break.

You Are What You Eat !

Purpose/problem: What basic nutrients are in different foods?

Hypothesis: Select 5 foods and guess what nutrients are in them. Put in If..Then format for each food, using what you know about testing for different nutrients.

Materials: Some possible materials are:

beakers test tubes/test tube rack hot plate

Biuret’s solution iodine solution

Benedict’s solution graduated cylinder test tube clamp

brown paper eye dropper

Procedure: Give a detailed set of procedures showing how you are going to test. Get approval of the teacher before testing.

Data: Make a data table to show display your results.

Conclusion: Write a conclusion that answers your hypothesis, discusses the data, and suggests further study.

Also, tell which foods, if any, contained more than one nutrient. And, which foods would be considered nutritious and why.