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AP Bio - Semester 1 Review Cheat Sheet by

Charac­ter­istics of Life

1) Living things have cells
2) Living things need energy (ATP)
3) Living things respond to their enviro­nment (Stimulus & Response)
4) Living things adapt to their enviro­nment (evolu­tion)
5) Living things develop & grow
6) Living things reproduce (sexually and/or asexually)

Divisions of Life

Ordered largest to smallest

Levels of Biological Organi­zation

Multic­ellular Organism
Organized smallest to largest


Show evolution over time of different animals based on physical and/or genetic simila­rities

Scientific Method

1) Define problem
2) Collect info on problem
3) Form a hypoth­esis, null hypothesis = opposite of the hypothesis
4) Design an experiment that includes a control group, dependent variable, and indepe­ndent variable
5) Preform experi­ment, observe and record data
6) Draw conclu­sions, a theory could be developed if hypothesis is proved correct
7) Report results
- Scientific method can only answer objective questions based on quanti­tative facts from experi­ments
- Experi­mental design = design an experiment to test a hypothesis and/or answer a question
- Data gathering = Observe and record quanti­tative and/or qualit­ative data from experiment
- Data analysis = Make a conclusion as to whether or not the data from the experiment proves the hypothesis incorrect or correct

Science v. Pseudo­science v. Non-Sc­ience

Study of natural world
Theories about the natural world that appear scient­ific, but are not
An area of study that is not scientific

Matter & Units of Matter

Anything that takes up space
Pure substance, cannot be broken down
Smallest unit of matter
An atom with a different number of neutrons
An atom with more or less electrons than proteins
Atoms bonded together


Giving or losing electrons
Sharing electrons

Properties of Water

Universal solvent
High cohesion
High specific heat (= thermal stability)
High heat of vapori­zation (= cooling mechanism)
Buffer, 7 on pH scale


- Concen­tration of hydrogen ions
- Basic = 8-13, less hydrogen ion concen­tration
- Neutral = 7
- Acidic = 0-6, more hydrogen ion concen­tration
- 7 to 6 = 10x more acidic, 7 to 5 = 100x more acidic and so on

Chemical Rxt

Dehydr­ation Synthesis
Form water that is ultimately removed to form bonds
Split compou­nds­/large molecules by adding water

Inorganic v. Organic Compounds

Inorganic Compounds
Any compound that lacks a carbon atom, ex. O2, H2O
Organic Compounds
Compounds from living things, ex. Hydroxyl, Carboxyl Acid, Methyl, Amine


Carbon is important to life because it is common in most compounds required for life and can be bonded a variety of ways because it only needs four more electrons to complete an octet.

Biological Molecules

Simple sugar used for short term energy, polysa­cch­arides (Starch, glycogen, cellulose) + monosa­cca­rides (glucose)
Fats, oils, and waxes used for long term energy storage. Two parts: Glycerol & fatty acids. Two kinds: Saturated & unsatu­rated (double bonded carbons). Ex. Phosph­olipid
Made up of one or more polype­ptides folded and coiled onto each other
Nucleic Acid
Used for storing genetic inform­ation, two kinds: RNA & DNA


- Polype­ptide = Polymer of amino acids
- Amino Acids = Organic molecule with an amino acid group and a carboxyl group
- Proteins work by their shape so change the shape = Destroy the protein (denature)

Structures of a Protein

1) Primary Structure
Chain of amino acids
2) Secondary Structure
Coils and folds of a polype­ptide chain, hydrogen bonds determine of pleated or helix
3) Tertiary Structure
Shape caused by intera­ctions between R groups, shape can be determined by ionic bonding, disulfide bonds, hydrogen bonding, and hydrop­hobic attraction
4) Quaternary Structure
Overall protein structure, 2+ tertiary structures put together

Functions of Proteins

1) Enzyme­/Ca­talyst = Speeds up reactions by lowering the amount of energy needed, allosteric site = working sites of enzymes
2) Structure = Protein fibers (filam­ents), cytosk­eleton in cells
3) Hormones = Slow commun­ication system, quorum sensing = bacterial cells commun­icate with each other by releasing hormones


Used to do work in cells such as:
1) Mechanical Work
2) Transport Work
3) Chemical Work (catalysts = lower the amount of energy required)
How does an enzyme work?
1) Induced Fit = Putting two reactants together to lower energy
2) pH = Modifies pH of the system­/re­action for a favorable sponta­neous reaction
What affects enzyme function?
1) Temper­ature
2) pH
3) Cofactor = A mineral is needed for an enzyme to work, changes the shape of the allosteric site
4) Inhibitors = Substance that blocks the allosteric site of an enzyme, ex. negative feedback loops, positive feedback loops, penicillin

Other Proteins

Defensive Proteins
Protection against diseases, ex. antigens & antibodies
Receptor Proteins
Located on the phosph­olipid bilayer of a cell or organe­lle's membrane, function: response to compounds


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