Exam 1 BIO 104

Chapter 1 - Process of Science
Define “science” as described in Biology 104
Science is a process
Science uses observations to draw conclusions
Anecdotal vs. scientific evidence
Anecdotal evidence is not verified, not reliable, but very persuasive
State the five steps of the scientific process
Make an observation
Make a hypothesis
Experiment
Analyze data
Draw conclusion
State the two facets of a scientific hypothesis
A hypothesis must be testable and falsifiable
Testable: Supported or rejected by experiments
Falsifiable: Can be ruled out by data
Hypotheses are never proven; they are accepted until data shows otherwise
What is an experiment?
Carefully designed tests that will support or reject the hypothesis
Define the following terms:
experimental group
The group that experiences manipulation
control group
The group that doesn’t experience manipulation
independent variable
The variable that is being manupulared
Placebo
Fake treatment that control group recieves
dependent variable
The result being measured
statistical significance
Helps quantify whether a result is likely due to chance or to some factor of interest
scientific theory
A carefully thought-out explanation for observations of the natural world that has been constructed using the scientific method
peer-reviewed publication
An article that was reviewed by experts before publication
Epidemiology
Study of disease patterns in populations, including risk factors
Describe the difference(s) between correlation and causation.
Correlation is a consistent relationship between two variables
Causation is a relationship of cause and effect between two variables
Define and explain the relevance of sample size in experimentation
Sample size is the number of participants or trials in an experiment
A larger sample size increases the accuracy of an experiment
Design a randomized controlled trial for the hypothesis: cell phone cause cancer in humans.
Independent Variable: Mice will get exposed to 7 hours of radiation a day
Dependent Variable: The presence or absence of cancer in the mice
Experimental Group: The group of mice that receive radiation
Control Group: The group of mice that don’t receive radiation
Placebo: Since we are experimenting with mice, there is no placebo since mice don’t realize they are in a study
Be able to answer AND justify your answer to the following question:Do cell phones cause cancer?
There is not a consistent dose-response relationship between phone use and cancer. In studying the epidemiology of this question, while phone usage has increased in the 30 years, the incidence of brain cancer has stayed constant.

Chapter 2 - Chemistry of Life
State the five functional traits of life. Why is it hard to define life by these traits?
Grow
Homeostasis
Obtain and use energy
Reproduce
Sense and respond to stimuli
It’s hard to define life with these traits because there are exceptions. There are some women who are infertile, yet they are still alive.
What is an element?
A substance that can’t be chemically broken down
Contains only one type of atom

What is the periodic table?
An organization of elements based on their atomic number
Define the following terms.
Atomic number
The number of protons in the nucleus of an element
Atoms
Smallest unit of an element
Protons
Subatomic particle with a positive charge in the nucleus of an atom
Neutrons
Subatomic particle with a neutral charge in the nucleus of an atom
Electrons
Subatomic particle with a negative charge that orbits the nucleus of an atom
Negligible mass
Nucleus
Center of an atom that contains protons and neutrons
What is a bond?
Attraction of atoms
A molecule?
Two or more atoms joined together by a covalent bond
covalent bonds?
The sharing of electrons between two or more atoms
Which element can form many covalent bonds?
Carbon can form 4 covalent bonds
What are ions? Ionic bonds?
Ions: An atom or group of atoms that has a charge
Ionic bonds: When a positively charged ion forms a bond with a negatively charged ion, one atom donates electrons to the other
Describe the difference between organic and inorganic molecules and be able to give examples.
Organic molecules are molecules with a C-C or C-H bond
Ex: Glucose (C₆H₁₂O₆), Methane (CH4)
Inorganic molecules are molecules without a C-C or C-H bond
Ex: Carbon Dioxide (CO2), Water (H2O)
Be able to name each of the 4 molecules of life, and their sub-unit(s).
Lipids: No sub-units
Carbohydrates: Glucose
Nucleic Acids: Nucleotides
Proteins: Amino Acids
Be able to draw a cell membrane and describe the layers of this structure

The cell membrane is a phospholipid bilayer. The heads of the layer are hydrophilic, meaning they like water. The tails of the layer are hydrophobic, meaning they dislike water.
Be able to state why water is so important for life. What does polarity refer to?
All of life’s reactions happen in water.
A polar molecule is a molecule where electrons in bonds are not shared equally between atoms.
When a partial negative charge attracts a partial positive charge, it is called a hydrogen bond. Hydrogen bonds are weak but important.
Hydrogen bonds give water its properties. Cohesion is when water molecules stick to themselves. Adhesion is when water molecules stick to other substances.
Draw a water molecule, and label the polarity.

What are ions?
An ion is an atom or a molecule that is charged because the number of protons and electrons is different.
Covalent bonding involves the sharing of electrons between two or more atoms. Ionic bonds form when two or more ions come together and are held together by charge differences.

Be able to state the differences regarding hydrogen ions for acids and bases.
As a solution gets more acidic, it gains more H+, and it gets lower on the pH scale.
As a solution gets more basic, it gains more OH-, and it gets higher on the pH scale.

Be able to define solvent and solute.
A solvent is a substance that other substances can dissolve in. Water is a good solvent. A solute is a dissolved substance. A solution is a mixture of solute in a solvent.
Chapter 3 - Cell Function and Structure
In general terms, define antibiotics. Who discovered the first antibiotic?
An antibiotic is a medicine that kills bacteria.
Sir Flemming discovered Penicillin in the early 1900s.
State the facets of cell theory
1- All living things are made of cells.
2- Every new cell comes from the division of pre-existing cells.
3- There are many sizes and shapes of cells.
Define the term organelle.
An organelle is a small structure in a cell that has a job.
Name three differences between prokaryotic and eukaryotic cells.
Prokaryotic cells don’t have a nucleus, their DNA is floating around. Prokaryotic cells don’t have organelles. Prokaryotic cells have a cell wall made of peptidoglycan. The cell wall surrounds the cell membrane and makes it rigid.

Be able to complete the below diagram (some of this is independent study)

Describe how cell walls differ from cell membranes. What is peptidoglycan?

Be able to state the difference gram + and gram – bacteria.

For the following organelles define function, and be able to label (independent study)
Nucleus
Ribosome
Mitochondria
Endoplasmic reticulum (smooth and rough)
golgi apparatus/body
Define the ways substances can enter cells-diffusion (simple diffusion), facilitated diffusion, and active transport.
Which require energy?
How are these affected by concentration gradients?