Good Morning! Please sit at your
lab table with you lab notebook.
Biology
Study of life
Is it ALIVE?

Biology is the study of life, but how can you tell if something is alive?
All living organisms exhibit certain properties that biologists
look for to classify it as alive.
Properties of Life
All living organisms have the following properties
present at some point in their life:

Cells
 Reproduction
Homeostasis
Metabolism
Heredity
 Evolution
 Interdependence



Lets start small…

What are we made of?
Water

Water is essential for life
◦ Living organisms are made mostly
of water
 70%-90%

Resistant to temperature
change
◦ Homeostasis

Expands when frozen
◦ Less density than l form
◦ Turnover in lakes
Water
Adhesive (adhere to surfaces)
Cohesive (adhere to each other)
The universal solvent
Water can dissolve ions and polar
molecules. Non-polar molecules do
not dissolve well in water (oil, fats).
Remember like dissolves like (polar
dissolves polar, non-polar dissolves
non-polar).
Adhesion
•
Because water molecules
are polar, they have a
tendency to stick to other
polar substances.
• Glass may carry a partial
charge along its surface.
• That’s why rain droplets
stick to windows.
Why does water
have these special
properties???
…because water is POLAR!
Polar molecules have
uneven charges.
This attracts ions and other
polar molecules
It is also the reason water is a
universal solvent
Capillary Action

Polarity
◦ water uses cohesive and
adhesive properties to
climb up capillaries in
plants

This makes it possible
for the tops of the trees
to obtain water
Chemistry of Life
The Essential Ingredients for Life
Ingredients for Life
1.
2.
3.
4.
5.
Water
Carbohydrates
Lipids
Proteins
Nucleic Acids
Carbon Compounds



Organic (carbon) compounds are found in living things
Carbon has four valence electrons ready for bonding
Carbon can form chains, chains with branches or rings
What does it all mean???
Carbon can bond with itself and with
many other elements
 Form large organic molecules called
biomolecules

◦ Small chains are called monomers
◦ Large chains made of monomers are called
polymers
Carbon

Monomer

Polymer
Carbon forms:
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acid
1.
Carbohydrates
- made of Carbon, Hydrogen and Oxygen in 1:2:1 ratio
(C6H12O6)
- major source of energy found in most foods
- monosaccharides are simple sugars and the building block
of carbohydrates (glucose and fructose)
- polysaccharides are large molecules made of many sugars
that store energy.
plants – starch
animals - glycogen
Carbohydrate - Sugar

Monosaccharide– glucose

polysaccharide- starch
Lipids
-
non-polar molecules
- Is it soluble in H2O?
- fats, phospholipids,
steroids, oils,
waxes…
- important part of
cell membranes
- lipids are used by
cells for energy
storage
- Insulation
Lipids

Saturated fatty acid – no double bonds between
carbon- carbon bonds, straight molecule, solid at
room temperature
 Unsaturated fatty acid – double bonds that make
the molecule kinked, liquid at room temperature
Proteins - Amino Acids
There are 20 different amino acids
Amino Acids bonded together form a chain called a
polypeptide chain.
Amine Group: -NH2
A polypeptide chain folds into a protein
The way a protein folds is important to its function
Mad Cow Disease
Functions of Protiens
Transport:
cells
 Movement:
 Structural:
 Enzymes:

hemoglobin in red blood
muscles
membranes, hair, nails
cellular reactions
Enzymes
Enzymes are proteins
 Speed up chemical reactions
 Lower activation energy
 They work on a specific substrate

Some reactions in
your body would
not occur without
enzymes.
4. Nucleic Acids –
Long chains of nucleotides (sugar, phosphate, base)
- Contain genetic/heredity information in code
-
- DNA- (deoxyribonucleic acid) found in
nucleus of cells. Have genes that contain
hereditary info (traits). 2 strands
- RNA – (ribonucleic acid) can act as an
enzyme or help in protein synthesis. 1 strand
Nucleic acids – Genetic Material
Nucleic acids are
composed of
long chains of
nucleotides
Identifying Organic
Compounds Lab
Introduction
The most common organic compounds found in
living organisms are lipids, carbohydrates,
proteins, and nucleic acids.
Substances called indicators can be used to test
for the presence of organic compounds. An
indicator is a substance that changes color in
the presence of a particular compound. In this
investigation, you will use several indicators
to test for the presence of lipids,
carbohydrates and proteins in various foods.
Materials
8 Test tubes
Test tube holder
Test tube rack
Hot plate
Brown paper towel
Labeling tape

-
For each organic
compound test you need:
5 drops egg white
5 drops lettuce/water
5 drops apple juice
5 drops corn oil
5 drops Spinach/water
5 drops peanut butter
5 drops potato/water
5 drops water
Starch test: Iodine solution
Sugar test: Benedicts
solution
Protein: Biuret solution
Lipid Test
1. Divide a piece of brown paper towel into 8 equal sections. In
each section, write the name of one test substances, as shown.
1.Distilled
Water
2.Egg White
3.Corn Oil
4. Spinach
5.Peanut
Butter
6.Apple
Juice
7.Potato &
Water
8.Fish
2. In each section, place a small drop of the identified food onto the
brown paper towel. With another paper towel, wipe off any excess
pieces of food that may stick to the paper. Set aside for 10-15
minutes
3. Hold paper to light or window. If food sample produces a
translucent or see-through spot, there is a presence of a LIPID.
Carbohydrate Test - Starch
1. Label test tubes: water, egg, oil, Spinach, peanut, apple,
potato, fish
2. Add 5 drops of each food sample to its proper test
tube.
3.Add 5 drops of iodine solution to each test tube and
shake.
*Iodine will change color from yellow brown →blue
black in presence of STARCH.
4. Record data on table.
5. Wash test tubes thoroughly!
Carbohydrate Test - Sugar
1. Set up hot water bath: Fill half the beaker with tap water
and heat to a gentle boil.
2. While water bath is heating, fill each cleaned test tube with
5 full drops of the appropriate food sample.
3. Add 10 drops of Benedicts solution and shake.
4. Place test tubes in hot water bath and heat for 3-5 minutes.
5. Caution: Remove test tubes from water bath with test tube
holder!
*When heated, Benedicts solution will change color from
blue → green, yellow, orange, or red in the presence of
SUGAR.
6. Record any color changes on data table.
7. Wash test tubes thoroughly!
Protein Test
1. Put 5 drops of appropriate food samples in each labeled
test tube.
2. Add 5 drops of Biuret solution to each test tube and gently
shake.
Caution: Biuret contains NaOH, a strong base. If you splash
any on yourself, wash with water and notify your teacher
immediately!
*Biuret changes color from light blue→blue-violet in the
presence of PROTEIN.
3. Record any color change on data table.
4. Wash test tubes thoroughly!
Data chart
All should have before and after descriptions!
Food Sample
Egg white
Corn Oil
Potato
Peanut Butter
Water
Apple Juice
Fish
Spinach
Lipid
Starch
Sugar
Test
Test
Test
AA or Protein Test