The document discusses a biology lab on testing for the four main types of biomolecules - proteins, carbohydrates, lipids, and nucleic acids. It provides information on the structure, function, and tests used to identify each biomolecule. The lab involves putting different food sources in test tubes and applying various reagents to test for the presence of proteins, carbohydrates, and lipids. The document explains what students will learn about biomolecules and the lab procedures and questions they will discuss.

1. Biology 10/15
Homework: finish lab guide and
2.4 wkst
Turn in graphi

2. Section 2.3 Biomolecules
What are the four types of
biomolecules?

3. Today you will:
• Learn about each type of biomolecule
• Learn how to test for the presence of each
biomolecule in different food substances.

4. Questions to discuss
• In this lab you will put different food
sources in a test tube to test for the
presence of various macromolecules. Why
will one of your test tubes be filled with
distilled water?
• What is the dependent variable? What is
the independent variable?

5. Biomolecules
• Molecules are either inorganic compounds
or organic compounds
– Organic-has carbon
– Inorganic-no carbon
• Why is carbon so special?
– It can form 4 bonds with other atoms. It loves
to COVALENTLY BOND!
– It can form single, double, and triple bonds.

6. Biomolecules
• There are 4 types of
biomolecules in our bodies
– Carbohydrates
– Lipids (fats)
– Proteins
– Nucleic acid (DNA)
• These are large molecules
(polymer) that are made up of
smaller building blocks
(monomers)
• Polymers are made of
monomers.
• http://www.phschool.com/scie
nce/biology_place/biocoach/bi
oprop/monomers.html

7. Proteins
• Elements: C, H, O, N, or S (sulfur)
• Structure: look for N or S
• What do they do
– Hemoglobin in your blood that carries oxygen
– Muscles, tendons, hair
– Defend body from microorganisms
– Control chemical reactions-enzymes
– Carry out almost all of the body’s everyday functions
• Building block-amino acids

8. Proteins
• A protein’s shape is
very important
• You change the shape
of a protein, you
change the function or
lose the function

9. Testing for proteins
• You will use a biuret
reagent
• It will turn a blue
violet color in the
presence of a protein.
• You will add each
substance to a test
tube and then add a
few drops of biuret
reagent.

10. Carbohydrates
• Elements-C, H, O
• Function: Main source of
energy, gives plants tough
structure
• Examples: sugars and
starches, glycogen,
sucrose, glucose,
cellulose
• Shape-rings connected
• Building Block-
monosaccharide or simple
sugars (glucose)

11. Different types of carbohydrates
• Based on size
– Monosaccharide-one sugar
• Glucose, galactose (found
in milk), fructose (found
in fruit)
– Disaccharide-two sugars
• lactose
– Polysaccharide-many
sugars
• Cellulose-makes plants
have a rigid structure
• Glycogen-animal starch

12. Two carbohydrate tests-starch
and simple sugars
• Starch
– Iodine will turn black or
purple in the presence of
starch
• Benedict’s solution
– Add substances to tube
with benedict’s solution
– Heat for 3 to 5 minutes to
look for color change
– The redder the more simple
sugar (glucose) present
– Will form a percipitate

13. Lipids (Fats)
• Not a polymer
– Why?
• Elements-C, H, O
• Has the most energy but
we can’t consume tons of
fat; part of membranes;
insulation
• Structure-long chain of
carbons attached
• Examples: cholesterol,
wax, steroids, oils
• Building Block-fatty
acids and glycerol

14. Saturated vs. Unsaturated
• Saturated-bad for you;
causes cholesterol
problems, clogged
arteries; solid at room
temperature; lard
• Unsaturated-liquid at
room temperature; not as
bad for you; olive oil,
canola oil, peanut oil
• Trans fat-type of
unsaturated; causes
coronary heart disease

15. 2 ways to test for lipids
• Brown paper bag
– Substance will
leave an oil spot if
present
• Sudan 4 test
– Substance will turn
red

16. Nucleic Acids
• Tell your cells how to
function
• Contains the genetic
information
• DNA (deoxyribose
sugar) and RNA
(ribose sugar)
• Building blocks:
nucleotides
• Elements: C, H, O,
N, P