biological molecules the chemistry of living things
TRANSCRIPT
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.
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.
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.