AP Bio Unit 1 - Chemistry of Life by Kori
Hypothesis: an explanation to a question, tested by an experiment or continues observation
Hypotheses can be disproven but not proven true
Theory: summarizes a group of hypotheses
Theories never become a law
Inductive reasoning: a process of reasoning going from specific to broad
Deductive reasoning: a process of reasoning going from broad to specific
Experimental group: a group that is tested with a changed variable
Scientific Law: statement of fact usually as a mathematical formula
Control Group: expected results of an experiment
Constants: all the factors that stay the same in an experiment
Mean: average of the data set
Median: middle number in a range of data points
Mode: value that appears most often in a data set
Independent variable: one factor that is changed or manipulated
Dependent variable: factor which is measured
Null hypothesis: no difference between two groups of data and experimental observations due to chance
Alternative hypothesis: opposing theory to the null hypothesis
Central tendencies: statistical measures that describe data trends
Variability: measure of how far a data set diverges from central tendency
Range: difference between largest and smallest values
Larger range is greater variability
Smaller range is less variability
Standard deviation: measure of how spread out the data is from the mean
Low standard deviation means data is closer to the mean, IV causes changes
High standard deviation means the data is farther from the mean, other factors cause changes
Standard error of the mean: determine precision and confidence in mean value
What is the difference between inductive and deductive reasoning? Inductive is specific to broad and deductive is broad to specific
What is the difference between a theory and a law? A theory summarizes a group of hypothesis while laws state scientific facts, usually a math equation
How are hypotheses formulated? They are formulated from a question to be proven or disproven, stating a null hypotheses and alternate hypotheses
What is the difference between null and alternative hypotheses? Null hypotheses state a hypotheses that suggests no effect or difference between variables, where alternative hypotheses propose different possible outcomes
Do you always need a null and alternate hypothesis? You need both null and alternate hypothesis because it tests all possibilities in the experiment and clarifies to focus of the experiment
How do researchers determine their independent and dependent variables? Independent and dependent variables are determined from what needs to be tested and what needs to remain consistent through the experiment, limiting variables
How are variables often graphed? Dependent variables are graphed on the y-axis and independent are graphed on the x-axis
Are constants the same as controls? No, they are not the same, because constants are factors/variables that do not change while controls are groups that serve as the standard of comparison
When should a positive control be used? A positive control should be used to compare experimental exposure to a known, effective exposure
When should a negative control be used? A negative control should be used to compare the effectiveness of exposure to no exposure
What types of data can be collected in an experiment? Quantitative (measured with instruments) and qualitative (measured with senses)
When should mean be used? Mean should be used to average the data and find a typical value to be compared to
When should median be used? Median should be used when a data set has extreme values or abnormal distribution
When should mode be used? Mode should be used when describing the distribution of data where mean and median are not appropriate
What is used to measure variability? Range and standard deviation measures variability
Is data more reliable with low or high standard deviation? Data is more reliable with a low standard deviation because it is closer to the mean and thus suggests that only the independent variable is causing data changes
Why do researchers use SEM? SEM is used because it verifies the accuracy of the mean
If error bars overlap, is the data significantly different? If error bars overlap, the data is not significantly different
Matter: takes up space and has mass
Element: matter cannot be broken down
Compound: Two or more elements
Octet rule: atoms gain, lose, or share electrons to achieve a stable 8 electrons
Capillary action: upward movement of water, occurs when adhesion is greater than cohesion
Chemical bonds: two atoms sharing the transfer of a valence electron
Hydrogen bonds: charged hydrogen in a polar covalent molecule, strongest bond
Covalent bond: two or more atoms sharing electrons
Polar: not equally shared
Nonpolar: equally shared
Ionic bonds: oppositely charged bonds, usually a metal and nonmetal
Cohesion: attraction of molecules for the molecules of the same kind
Electronegativity: atom’s ability to attract electrons
Adhesion: Clinging of one molecule to a different molecule
Atomic mass: number of protons + neutrons
Solute: product that the solvent dissolves
Solution: product of solute and solvent
Solvent: dissolving agent in a solution
Valence electrons: outmost electrons in outmost valence shells
Molecule: atoms bonded together
Acid: molecule that can donate or accept a proton
Base: molecule that can accept hydrogen ions in water
What is the difference between a solute, solvent, and solution? Solute is dissolved, solvent dissolves the solute, and the solution is the product
What are two examples of covalent bonds? Carbon dioxide, glucose
What are two examples of ionic bonds? Sodium chloride, lithium fluoride
Hydrogen bonds are different from other bonds because they bond to a Hydrogen ion in a polar covalent molecule, they are also the weakest
How does electronegativity affect the interactions between water molecules? Oxygen pulls electrons and hydrogen closer and causes polarity in the molecules
If O and H had the same electronegativity, what would that do to the properties of water? Hydrogen would not be pulled as close to Oxygen and the water would not be polar
Adhesion: attractive forces between molecules of different types
Cohesion: attractive forces between molecules of the same type
Surface tension: adhesion that allows liquid to condense and resist external force
Adhesion can benefit plant cells by penetrating the cell wall
Cohesion can benefit plants by moving water up the xylem against gravity
Surface tension can benefit organisms that float on water
Functional groups: chemical groups attached to carbon skeleton that participate in chemical reactions
Organic chemistry: study of compounds with covalently bonded carbon
Organic compounds: compounds that contain Carbon and Hydrogen
Hydrocarbons: organic molecules of only carbon and hydrogen
ATP: Adenosine triphosphate, a source of energy and storage at a cellular level
Macromolecule: compounds such as carbohydrates, proteins, nucleic acids, and lipids
Why is carbon such a versatile element? It can form long chains and carbon skeletons to support organic molecules
How many valence electrons does carbon have? 4
How do functional groups affect the structure and behavior of organic molecules? It affects the reactivity and polarity of an organic molecule
What is the difference between hydrocarbons and other organic molecules? Hydrocarbons only contain Carbon and Hydrogen, while other organic molecules contain Carbon, Hydrogen, and Oxygen
Dehydration reaction: bonds two monomers with the loss of H2O
Hydrolysis: breaks bonds by adding H2O
Polymers: chain-like macromolecules of similar or identical repeating units
Monomers: repeating units that make up polymers
Differentiate between a hydrolysis and dehydration reaction. Hydrolysis breaks bonds by adding H2O, as the Hydrogen in H2O bonds to a monomer and OH bonds to the other monomer. Dehydration reaction bonds two monomers with the loss of H2O as OH of one monomer bonds to H as H2O is produced and released
Disaccharide: two monosaccharides joined by covalent bonds
Monosaccharide: simple sugars formed with multiple units of CH2O
Polysaccharide: polymer with many sugars joined via dehydration reactions
Carbohydrate: sugars and polymers of sugars containing a carbonyl group and many hydroxyl groups made of Carbon, Hydrogen, and Oxygen
Proteins: molecules consisting of polypeptides folded into a 3D shape
Amino Acids: molecules that have an amino group and a carboxyl group
Polypeptide: many amino acids linked by peptide bonds
Cellulose: polysaccharide that is the structural component of the cell wall
Glycogen: polysaccharide of glucose stored in the body as an energy storage
Hydrophobic: repel water
Hydrophilic: attracts water
Glycosidic linkage: covalent bonding connecting a carbohydrate to another group
Starch: polysaccharide of glucose stored as energy in plants
How many monomers of proteins are there? 20
How do the R groups of amino acids contribute to the protein structure? They interact and determine the shape and function of the protein
The hydrophilic head is polar
The hydrophobic tails are nonpolar
Where can phospholipids be found in a cell? They are found in the cell membrane
What role do phospholipids perform? They allow cellular processes to happen by signaling proteins and protect the cell from outside offenses
What are the monomers of polysaccharides? Monosaccharides bonded by glycosidic bonds
How are polysaccharides important to animals and plants? They can store starch and glycogen and form cellulose or chitin
How does saturation affect fatty acid structure and function? Saturated fats have no double bonds which allows more hydrogen and decreases fluidity
What elements are found in Carbohydrates? Carbon, Hydrogen, and Oxygen
What elements are found in proteins? Carbon, Hydrogen, Oxygen, Nitrogen, and Sulfur
What elements are found in nucleic acids? Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus
What elements are found in lipids? Carbon, Oxygen, and Hydrogen
Primary Structure: linear chain of amino acids determined via genes, dictating secondary and tertiary forms
Secondary Structure: coils up and folds due to hydrogen bonding within the backbone of the polypeptide
Tertiary Structure: 3D folding due to interactions between the side chains of the amino acids
Quaternary Structure: association of two or more polypeptides only found in some proteins
Lipid: class of small, nonpolar molecules that do not include true polymers
Fats: composed of glycerol and fatty acids
Fatty Acid: long carbon chains with a carboxyl group at the end
Phospholipid: component of cell membranes, two fatty acids attached to glycerol and phosphate
Denature: unfolding of a protein and modifying the structure
Steroid: molecules that regulate cellular functions like reproduction and development
How was the double helix structure of DNA discovered? X-Ray diffraction by Rosalind Franklin showed the shadow of two helixes in DNA
What forms the backbone of DNA? Sugar-phosphate backbone
Why are DNA strands antiparallel? DNA strands are complementary to each other from base pairing
What determines the primary structure of a protein? The sequence of amino acids
How does the primary structure affect the other structural levels? The location of certain amino acids in the primary structure lays the foundation for the shape of other structural levels
Would the function of a protein change if the amino acid sequence changed? Some changes may not have any different results but some can result in a protein losing its function
What interactions occur in the secondary structure? Hydrogen bonding of polypeptides
What interactions occur in the tertiary structure? Outside polar hydrophilic hydrogen and ionic bond interactions and internal hydrophobic interactions between nonpolar amino acid side chains
What interactions occur in the quaternary structure? Ionic bonding, hydrogen bonding, disulfate bonds, and dispersion forces
What causes a protein to denature? Chemical action, heat, or agitation
What happens to a protein if it is denatured? It cannot function as the primary structure is destroyed and the protein is broken down to monomers
What macromolecule would both starch and cellulose be considered? A carbohydrate
Antiparallel: DNA strands run in opposite directions parallel to one another 3’-5’
DNA: deoxyribonucleic acid, carries genetic information for the development and functioning of an organism
RNA: ribonucleic acid, a nucleic acid used to produce proteins
Nucleotide: compound of a nitrogenous base, pentose, and a phosphate group which acts as a monomer for nucleic acids
Nucleic Acid: polymers made of nucleotides which function as storage, transmitters, and expression of hereditary information
Genes: basic unit of heredity passed from parent to child made of DNA sequences
Pyrimidine: One ring with 6 atoms (Cytosine, Thymine, Uracil)
Purine: One ring with 6 atoms bonded to another ring with 5 atoms (Adenine, Guanine)
What are the three components of a nucleotide? Nitrogenous base, pentose sugar, and phosphate group
What is the monomer called if it is lacking a phosphate group? A nucleotide
What are the possible nitrogenous bases that can be found in nucleotides? Adenine, Thymine, Guanine, Cytosine, Uracil
What does DNA have that RNA does not? It has a double helix, deoxyribose, uses thymine, and stores/transfers genetic information
What does RNA have that DNA does not? It has a single helix, ribose, uses uracil, and codes proteins
Where can DNA be found in a cell? Cell nucleus
Where can RNA be found in a cell? Cytoplasm or nucleus
What functional group defines the 5’ end? Phosphate group
What functional group defines the 3’ end? Hydroxyl group