UNIT 1 - ap bio

What is a testable question in an experiment?

A clear, measurable question that can be investigated.

What is a hypothesis?

A prediction about the relationship between variables.

What is the independent variable (IV)?

The factor you change in an experiment.

What is the dependent variable (DV)?

The factor you measure in an experiment.

What are constants in an experiment?

Variables kept the same to ensure a fair test.

What is a control group?

A baseline group used for comparison.

What are experimental groups?

Groups that receive different treatments.

Why is replication important?

To ensure reliability and account for natural variation.

Why must an experiment have a detailed procedure?

So it can be repeated by others.

What is the proper format for graphing a title?

"Effect of [IV] on [DV]."

When should you use a bar graph vs. a line graph?

Bar = comparing categories; Line = continuous data or changes over time.

Which axis is the IV and which is the DV?

IV = x-axis, DV = y-axis.

How do you calculate rate from a graph?

Slope = rise/run = Δy/Δx.

What is a null hypothesis (H₀)?

A statement predicting no effect or no difference between observed and expected results.

What is the chi-square formula?

χ² = Σ((O – E)² / E), where O = observed, E = expected.

How do you calculate degrees of freedom (df)?

df = number of categories – 1.

How do you use the critical value in chi-square?

Compare χ² to the critical value at p = 0.05 to accept/reject H₀.

How do you interpret a p-value?

p < 0.05 → reject H₀; p ≥ 0.05 → fail to reject H₀.

How does surface area affect gill function?

Increased surface area allows more efficient gas exchange.

What does it mean for gill tissue to be highly vascular?

Lots of blood vessels for fast oxygen uptake.

How does water temperature affect dissolved oxygen?

As temperature increases, dissolved oxygen decreases.

How does temperature affect metabolism in ectotherms vs. endotherms?

Ectotherms: metabolism depends on external temp; Endotherms: metabolism largely independent.

Why are controlled experiments important?

To ensure only the IV affects the DV.

What is a constant?

A factor kept the same across all experimental groups.

How many bonds does H, O, N, C, P, and S have in CHNOPS?

H = 1, O = 2, N = 3, C = 4, P = 5 (expandable), S = 2 or 6.

What is electronegativity?

An atom’s ability to attract shared electrons in a bond.

What is the periodic trend for electronegativity?

Increases across a period and up a group.

Difference between polar and nonpolar covalent bonds?

Nonpolar = equal sharing; Polar = unequal sharing, partial charges.

Why is water polar?

Oxygen pulls electrons more strongly than hydrogen → δ– on O, δ+ on H.

Difference between interatomic bonds and intermolecular attractions?

Interatomic = within a molecule; Intermolecular = between molecules (e.g., H-bonds).

Define cohesion and adhesion.

Cohesion = water sticks to itself; Adhesion = water sticks to other surfaces.

How do H-bonds contribute to water’s high specific heat?

H-bonds absorb energy, resisting temperature changes.

How do extreme pH solutions affect proteins like anthocyanin?

Disrupt hydrogen/ionic bonds → denaturation (loss of structure/function).

Each pH unit represents what change in [H⁺]?

Tenfold (10×) increase/decrease.

[H⁺] of pH 8?

10⁻⁸ M.

How much more basic is pH 12 than pH 3?

10⁹ times.

How much more acidic is pH 2 than pH 5?

10³ = 1000×.

How does water maintain neutrality?

[H⁺] = [OH⁻] = 10⁻⁷ M → pH 7.

Relationship between H⁺ and OH⁻ in acids/bases?

Acid: [H⁺] > [OH⁻]; Base: [OH⁻] > [H⁺].

Dilution formula?

M₁V₁ = M₂V₂.

Why does water’s high heat of vaporization aid in evaporative cooling?

Evaporation removes heat energy → cools organisms.

What does it mean that all biological molecules are organic?

They are carbon-based.

Are all organic molecules biological?

No (e.g., plastics, fossil fuels).

How does carbon’s tetravalency help in biomolecules?

Allows complex chains, rings, and branching.

Hydrocarbon chains?

Chains of C–H bonds, nonpolar, hydrophobic.

Isomers?

Same formula, different structures (e.g., glucose vs galactose).

Amino group property?

Basic, can pick up H⁺ → positive charge.

Carboxyl group property?

Acidic, can donate H⁺ → negative charge.

Hydroxyl group property?

Polar, forms H-bonds.

Phosphate group property?

Strong negative charge; stores energy in ATP covalent bonds.

Dehydration synthesis?

Removes water → joins monomers into polymers.

Hydrolysis?

Adds water → breaks polymers into monomers.

Monomer → Polymer examples

Carbs: monosaccharide → polysaccharide; Proteins: amino acid → polypeptide; Nucleic acids: nucleotide → DNA/RNA; Lipids: glycerol + fatty acids → triglycerides.

Why are proteins the most diverse biomolecule?

Sequence & folding determine function; many shapes and functions.

Four levels of protein structure?

Primary = amino acid sequence; Secondary = α-helices & β-sheets (H-bonds); Tertiary = 3D folding (H-bonds, ionic bonds, hydrophobic interactions, disulfide bridges); Quaternary = multiple polypeptides.

Role of disulfide bridges?

Strong covalent bonds between cysteines → stabilize 3D shape.

How are secondary and tertiary structures achieved?

Secondary: H-bonds between backbone → helices/sheets; Tertiary: R-group interactions, disulfide bridges, ionic bonds, hydrophobic interactions.