scientific method biology coach hamilton. introduction science: a system for investigation. ...
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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
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.
Steps of the Scientific Method
Do you remember the next step?
¨ 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
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 MethodA 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?
Contro
l gro
up
Dep
enden
t var
iabl
e
Exp
erim
enta
l gro
up
Inde
pende
nt var
iable
0% 0%0%0%
A. Control group
B. Dependent variable
C. Experimental group
D. Independent variable
20
Jim thinks that higher temperatures will cause crickets to chirp more. This is a(n)…
Concl
usion
Exp
erim
ent
Hyp
othe
sis
Obse
rvat
ion
0% 0%0%0%
A. Conclusion
B. Experiment
C. Hypothesis
D. Observation
20
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?
Colo
r of f
lower
s
Thre
e w
eeks
Diff
eren
t am
t of l
ight
Gro
up with
regula
r lig
ht
0% 0%0%0%
A. Color of flowers
B. Three weeks
C. Different amt of light
D. Group with regular light
20
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
True
False
0%0%
If something contains carbon, it is said to be inorganic.
True
False
0%0%
A. True
B. False
There are three major macromolecules that we will be discussing in this class.
True
False
0%0%
A. True
B. False
Lipids are mostly carbon and oxygen.
True
False
0%0%
A. True
B. False
Carbohydrates, such as pasta, are used as a good source of energy.
True
False
0%0%
A. True
B. False
Proteins contain carbon, hydrogen, oxygen, and a Nitrogen group.
True
False
0%0%
A. True
B. False
Nucleic Acids contain carbon, oxygen, nitrogen, hydrogen, but no phosphorus.
True
False
0%0%
A. True
B. False
This is a Carbohydrate.
True
False
0%0%
A. True
B. False
This is a Nucleic Acid.
True
False
0%0%
A. True
B. False
This is an example of a lipid.
True
False
0%0%
A. True
B. False
This is a Nucleic Acid.
True
False
0%0%
A. True
B. False
This is a Nucleic Acid.
True
False
0%0%
A. True
B. False
This is a Carbohydrate.
True
False
0%0%
A. True
B. False
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?
Mai
ntain
ing p
roper
b...
Get
ting
a hai
rcut
Kee
ping
cons
tant b
o..
Kee
ping
blood
sugar
...
0% 0%0%0%
A. Maintaining proper blood pressure
B. Getting a haircut
C. Keeping constant body temperature
D. Keeping blood sugar levels balanced.
20
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?
Cat
alys
t
Pro
tein
Sugar
Lower
act
ivat
ion
ener
gy
0% 0%0%0%
A. Catalyst
B. Protein
C. Sugar
D. Lower activation energy
20
According to the graph, how does the reaction change with enzymes?
Spee
ds u
p
Slo
ws
down
Use
s m
ore e
nerg
y
Sto
ps th
e re
actio
n
0% 0%0%0%
A. Speeds up B. Slows downC. Uses more energyD. Stops the reaction
20
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 Acidic
MoreBasic
Neutral
More H+, Less OH-
Less H+, More OH-
Which pH would be considered acid rain?
6.4 7. 7.
27.
6
0% 0%0%0%
A. 6.4
B. 7.0
C. 7.2
D. 7.6
20
Which pH would represent the strongest base?
6.7.8
11.512.4
0% 0%0%0%
A. 6.0
B. 7.8
C. 11.5
D. 12.4
Which pH would represent the strongest acid?
2.1.3
12.2 7.
0% 0%0%0%
A. 2.0
B. 1.3
C. 12.2
D. 7.0
Alice decides to conduct an experiment with only basic solutions. Which solution would she not use?
Solution A (1
0...
Solution B (1
3...
Solution C (6
....
Solution D
(7....
0% 0%0%0%
A. Solution A (10.0)
B. Solution B (13.5)
C. Solution C (6.9)
D. Solution D (7.1)
Which would have a higher concentration of H+ ions?
Pure Wate
r
Liquid D
rain Cleaner
Lemon Ju
ice
Black Coffee
0% 0%0%0%
A. Pure Water
B. Liquid Drain Cleaner
C. Lemon Juice
D. Black Coffee
Which of the following would have the highest concentration of OH- ions?
Pure Wate
r
Liquid D
rain C...
Lemon Ju
ice
Black Coffee
25% 25%25%25%A. Pure Water
B. Liquid Drain Cleaner
C. Lemon Juice
D. Black Coffee
¨ Describe cell regulation (enzyme function, diffusion, osmosis, homeostasis);
¨ Predict consequences of internal/external environmental change on cell function/regulation.