Transcript Section 1.2 Summary – pages 11-18

Bio- molecules
Life
Two or more atoms
bonded together
• Bio-molecules are large molecules that make up
living things.
Carbohydrates
Proteins
(sugars)
Nucleic Acids
Lipids (fats)
What is a controlled experiment?
• Suppose you wanted to learn how a certain fertilizer
affects the growth of different varieties of plants.
• Your hypothesis states that the presence of this
fertilizer will increase the growth rate of each plant
variety.
What is a controlled experiment?
• An experimental crop setup is designed to
test the hypothesis.
• Fertilizer is present in the soil with the
experimental plants, but not in the soil with
the controls.
• All other conditions that are kept the same for
both groups- soil, light, water- are constants
Designing an experiment
• The single thing in an experimental group that is
different is the independent variable
Think of the definition of “independent”
• What is the independent variable in the plant
experiment?
Designing an experiment
• During the experiment, the thing you are trying to
measure is the dependent variable.
Think of the definition of “dependent”
The dependent variable occurs as a result of the independent variable
• What is the dependent variable in the plant
experiment?
(What are we measuring as a result of the fertilizer)
PRE- LAB INFORMATION FOR:
ENZYME ACTION LAB
For this lab, we are going to focus on the bio-molecule:
Protein….specifically, Enzymes
A protein is a large, complex polymer composed of
smaller subunits called amino acids.
So what? Why are proteins important????
You are composed of proteins- your skin, hair, eyes
contain proteins….organs, muscles, bones…
(everything that makes you…you.)
• All actions, such as eating, running, and even thinking,
depend on proteins called enzymes.
• Enzymes are proteins in your body that control the
chemical reactions needed for life.
(breaking stuff down and putting stuff together)
Why is this important???
Without enzymes….
PRE- LAB INFORMATION FOR:
ENZYME ACTION LAB
There is an enzyme called Catalase found in MOST
organisms.
This enzyme has the ability to break down H O
(which is Hydrogen Peroxide)
2
2
Hydrogen Peroxide is toxic to most
living organisms.
H O is naturally produced in organisms
as a by-product of cellular respiration
(when your cells are making energy).
2
2
Catalase quickly arrives on the scene
to destroy the Hydrogen Peroxide
before it can do too much damage.
Catalase speeds up the process of breaking down the
Hydrogen Peroxide molecule into water and oxygen.
2 H2O2
2 H2O + O2
2 H2O2
2 H2O
2 H2O2
O2
We will be using
CHICKEN LIVERS
which naturally contains the
enzyme protein CATALASE in its
cells.
We can measure the rate of this chemical reaction by
measuring the rate of the appearance of oxygen (O2)
You will need to choose an independent variable to use.
So brainstorm things you think you can of that could possibly affect the
rate of the chemical reaction
For instance: I wonder how the amount of chicken liver affects the rate
of the chemical reaction.
Hypothesis, the more chicken liver I use in a trial, the faster the
hydrogen peroxide will break down into water and oxygen.