Transcript Scientific Method

Scientific Method
Biology
Coach Hamilton
Introduction
 Science: A system for investigation.
 Biology: “The study of life”
The Scientific
Method involves
a series of steps
that are used to
investigate a
natural
occurrence.
Problem/Question
Observation/Research
Formulate a Hypothesis
Experiment
Collect and Analyze Results
Conclusion
Communicate the Results
Steps of the
Scientific Method
1. Problem/Question: Develop a
question or problem that can be
solved through experimentation.
Steps of the
Scientific Method
2. Observation/Research: Make
observations and research your
topic of interest.
Do you remember the
next step?
Steps of the
Scientific Method
 3. Formulate a Hypothesis:
Predict a possible answer to the
problem or question.
 Example: If soil temperatures
rise, then plant growth will
increase.
Steps of the
Scientific Method
 4. Experiment: Develop and follow
a procedure.
 Include a detailed materials list.
 The outcome must be measurable
(quantifiable).
Steps of the
Scientific Method
 5. Collect and Analyze Results:
Modify the procedure if needed.
 Confirm the results by retesting.
 Include tables, graphs, and
photographs.
Steps of the
Scientific Method
 6. Conclusion: Include a statement
that accepts or rejects the hypothesis.
 Make recommendations for further
study and possible improvements to
the procedure.
Steps of the
Scientific Method
 7. Communicate the Results: Be
prepared to present the project to an
audience.
 Expect questions from the audience.
Think you can name all
seven steps?
Problem/Question
Scientific Method
A system of steps that scientists use to investigate
questions.
– Observations: Questioning, wandering or
noticing something.
– Hypothesis: Explanation that might be true—
educated guess. IT MUST BE TESTABLE!
– Prediction: What you expect to happen if the
hypothesis is true. “If…then” statement.
– Experiment: Planned and controlled procedure
to test hypothesis.
Controlled experiment
 Control group: Group that receives no
experimental treatment. [What we may
think of as “Normal”]
 Experimental group: Receives some type of
experimental treatment.
– Independent variable: The variable that
changes or varies in an experiment.
[You change this variable]
– Dependent variable: Variable that is measured
in an experiment. What is observed in the end.
Scientific Method
– Conclusions: Decisions about whether
hypothesis was supported based on analysis of
data. Many experiments may lead to a theory.
Theory: Set of related hypotheses that have been
tested over and over by many different
scientists.
Which variable do you change in an
experiment?
A. Control group
B. Dependent variable
C. Experimental group
D. Independent variable
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Jim thinks that higher temperatures
will cause crickets to chirp more.
This is a(n)…
A. Conclusion
B. Experiment
C. Hypothesis
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D. Observation
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When Shawn performed the experiment, he kept one group
of flowers in regular light while increasing the amount of
light using grow bulbs with the other groups. He
monitored their color over three weeks. What is the
dependent variable?
A. Color of flowers
B. Three weeks
C. Different amt of light
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D. Group with regular
light
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Chemistry
 Atoms are composed of protons, neutrons
and electrons.
 The interaction between
the outer electrons
cause bonding.
Carbon
 Basis for all living thing is the Carbon atom.
 It has four outer electrons enabling it to
bond with other elements as well as itself.
 Carbon helps form millions of different
large/complex structures.
 It is organic if it contains carbon.
 Macromolecules containing carbon are
formed from polymerization.
 There are four that exist in living systems.
Lipids—Fatty acids
 Made mostly from Carbon and Hydrogen.
 Are not soluble in water.
 Can be saturated (C-C) or unsaturated
(C=C) which refers to the bonding.
Lipids Continued…
Carbohydrates
 Made from Carbon, Hydrogen and Oxygen
(O is typically spread throughout)
 Living things use carbohydrates as main
source of energy.
 Glucose is an instant
form of energy.
Proteins—Amino Acids
 Proteins are macromolecules that contain
Carbon, Hydrogen, Oxygen, and Nitrogen.
 Proteins are polymers of molecules called
Amino Acids.
 Proteins are needed by the body for growth
and repair and to make up enzymes.
Proteins Continued…
 These amino acids are compounds with an
amino group (NH2) on one end and a
carboxyl (-COOH) on the other end.
Nucleic Acids
 Nucleic Acids are macromolecules that
contain Carbon, Hydrogen, Oxygen,
Nitrogen, and Phosphorus.
 Nucleic acids are polymers assembled from
individual monomers known as
nucleotides.
 Two Types: Ribonucleic acid (RNA) and
Deoxyribonucleic acid (DNA).
 Nucleic acids store and transmit heredity, or
genetic, information.
Nucleic Acids Continued…
 Nucleotides consist of 3 parts: a 5-Carbon
Sugar, a Phosphate group, and a
Nitrogenous base.
Carbon is the basis for all living things.
A. True
B. False
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If something contains carbon, it is said
to be inorganic.
A. True
B. False
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There are three major macromolecules
that we will be discussing in this class.
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B. False
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Lipids are mostly carbon and oxygen.
A. True
B. False
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Carbohydrates, such as pasta, are used
as a good source of energy.
A. True
B. False
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Proteins contain carbon, hydrogen,
oxygen, and a Nitrogen group.
A. True
B. False
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Nucleic Acids contain carbon,
oxygen, nitrogen, hydrogen, but no
phosphorus.
A. True
B. False
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This is a Carbohydrate.
A. True
B. False
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This is a Nucleic Acid.
A. True
B. False
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This is an example of a lipid.
A. True
B. False
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This is a Nucleic Acid.
A. True
B. False
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This is a Nucleic Acid.
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This is a Carbohydrate.
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Energy
 Ability to cause changes on matter.
 Chemical reactions either use or give off
energy.
 Metabolism includes all chemical and
physical reactions that occur to make
energy available to an organism.
 Homeostasis is our bodies ability to
maintain a balance.
Examples of Homeostasis
– Blood pressure
– Body temperature
– Blood sugar levels
 Metabolism helps us maintain homeostasis.
Which is not an example of how the
body maintains homeostasis?
A. Maintaining proper
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blood pressure
B. Getting a haircut
C. Keeping constant body
temperature
D. Keeping blood sugar
levels balanced.
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Chemical Energy in the Body
 Homeostasis and metabolism depend on the
chemistry of the body.
 Enzymes assist with keeping metabolism
and homeostasis balanced.
Enzymes
 Enzymes help chemical reactions take
place.
 Enzymes: are proteins that help speed up
chemical reactions (catalyst) by lowering
activation energy—energy needed to start
reactions.
 They bond based on size and shape.
 They end in –ase and if they don’t work
properly it could result in death.
Induced Fit Model
 This model states that the active site of the
enzyme will slightly change shape in order
to firmly bind with the substrate.
The substrate bound
to the active site
makes up the
“Enzyme-Substrate
Complex”
 Things that alter enzymes:
– Enzymes can be denatured (structure gets
broken down and they don’t do their job) by
temperature or pH changes.
– Temperature: Extreme temperatures cause
enzymes to change shape and they can’t
function
– pH: scale runs 0-14 with 7 being neutral. Low
numbers are acids and high numbers are bases.
– Poisons denature enzymes leaving them unable
to function resulting in death in many instances.
Types of Enzymes
 Amylase: an enzyme that catalyzes the
breakdown of starch into smaller sugars.
 Protease: an enzyme that helps to
breakdown or digest proteins.
 Sucrase: an enzyme that catalyzes the
breakdown of sucrose (a type of sugar) to
glucose and fructose.
 Lipase: an enzyme that catalyzes the
breakdown of lipids (fats).
Carbonic Anhydrase
 Carbonic anhydrase: an enzyme that
catalyzes the rapid conversion of carbon
dioxide and water to bicarbonate and
protons.
Which is not a characteristic of an
enzyme?
A. Catalyst
B. Protein
C. Sugar
D. Lower activation
energy
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According to the graph, how does the reaction
change with enzymes?
Speeds up
Slows down
Uses more energy
Stops the reaction
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Chemistry Continued…
 Matter is composed of atoms.
 Atoms interact with one another to form
compounds.
 Electrons around the outside of atoms
interact to form bonds.
Three Types of Bonds
– Ionic Bond: When atoms gain or lose electrons
to form compounds. Na+1 loses its one electron
to Cl-1 which only needs one.
– Covalent Bond: Atoms can share electrons so
that each of their outer shells are full part of the
time because the electrons are in constant
motion.
– Hydrogen Bond: Weak bonds form between
hydrogen and other atoms. Ex: bonds holding
water molecules together. Ex. H2O
Acids/Bases
 Acid: Will form H+ (hydrogen ions)
when dissolved in water.
 Base: Will for OH- (hydroxide ions) when
dissolved in water.
 pH: A measure of the amount of H+ ions
in solution.
 The scale goes from 0-14 with the low end
of the scale (below pH of 7) being acidic
and the high end (above pH of 7) being
basic. 7 is neutral (ex. Pure water)
More H+,
Less OH-
Less H+,
More OH-
Which pH would be considered acid
rain?
A. 6.4
B. 7.0
C. 7.2
D. 7.6
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Which pH would represent the
strongest base?
A. 6.0
B. 7.8
C. 11.5
D. 12.4
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Which pH would represent the
strongest acid?
A. 2.0
B. 1.3
C. 12.2
D. 7.0
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Alice decides to conduct an experiment
with only basic solutions. Which
solution would she not use?
A. Solution A (10.0)
B. Solution B (13.5)
C. Solution C (6.9)
D. Solution D (7.1)
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Which would have a higher
concentration of H+ ions?
A. Pure Water
B. Liquid Drain Cleaner
C. Lemon Juice
D. Black Coffee
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Which of the following would have
the highest concentration of OHions?
25%
A. Pure Water
25%
25%
25%
B. Liquid Drain Cleaner
C. Lemon Juice
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 Describe cell regulation (enzyme
function, diffusion, osmosis,
homeostasis);
 Predict consequences of internal/external
environmental change on cell
function/regulation.