Biology Unit 2 - The Chemistry of Life

test is on 10/27/28. good luck!

What is biology?

The study of life and living organisms.

What is chemistry?

The study of matter and how it interacts.

How are chemistry and biology connected?

All life processes (like metabolism and DNA replication) are chemical reactions.

What is scientific notation?

A way to write very big or very small numbers easily using powers of 10.

What are significant figures?

Digits in a measurement that show precision (all certain digits + 1 estimated digit).

What is an ionic bond?

Electrons are transferred from a metal to a nonmetal.

What is a covalent bond?

Electrons are shared between two nonmetals.

What is a hydrogen bond?

A weak attraction between a slightly positive hydrogen and a slightly negative atom.

Polar vs. nonpolar?

Polar: uneven charge (e.g., water)

Nonpolar: even charge (e.g., oil)

What is cohesion?

Water molecules stick to each other → surface tension.

What is adhesion?

Water sticks to other surfaces → helps it climb plants.

What is capillary action?

Water moving upward in narrow spaces due to cohesion + adhesion.

Hydrophobic vs. Hydrophilic?

Hydrophobic = water-fearing (e.g., oil)

Hydrophilic = water-loving (e.g., salt)

What does “like dissolves like” mean?

Polar substances dissolve in polar solvents; nonpolar dissolve in nonpolar.

Properties of water (short list)?

Cohesion, adhesion, high specific heat, universal solvent, ice floats

What is a surfactant?

Molecule that has a water-loving and water-fearing end → helps mix oil and water.

What is pH?

Measures how acidic or basic a solution is.

What is the pH range for acids, neutral, bases?

0–6 = acidic

7 = neutral

8–14 = basic

What is a buffer?

A substance that keeps pH stable by absorbing or releasing hydrogen ions.

Monomer of carbohydrates?

Monosaccharide (e.g., glucose)

Polymer of carbohydrates?

Polysaccharide (e.g., starch, cellulose)

Function of carbohydrates?

Quick energy

Monomer of lipids?

Fatty acid

Polymer of triglycerides?

Triglyceride (3 fatty acids + glycerol)

Function of lipids?

Long-term energy storage, insulation, cell membranes

Structure and function of phospholipids?

Hydrophilic head + hydrophobic tails → form cell membranes

What are steroids?

4-ring structure → stabilize membranes, make hormones (e.g., cholesterol)

Monomer of nucleic acids?

Nucleotide (phosphate + sugar + base)

Polymer of nucleic acids?

Polynucleotide

DNA vs. RNA differences?

DNA: deoxyribose, double-stranded, A-T, G-C, stores genetic info

RNA: ribose, single-stranded, A-U, G-C, builds proteins

Base pairing rules?

DNA: A↔T, G↔C; RNA: A↔U, G↔C

Monomer of proteins?

Amino acid

Polymer of proteins?

Polypeptide chain

3 components of amino acid?

Amino group (NH₂), carboxyl group (COOH), R-group (variable)

4 levels of protein structure?

Primary, Secondary, Tertiary, Quaternary

What is denaturation?

Heat, pH, or chemicals change protein shape → loss of function