General Biology I: Study Guide for Introduction, Chemistry, and Biomolecules

Introduction to Biology

Key Themes in Biology

Biology is the scientific study of life and living organisms. Understanding what it means to be alive and the organization of life is foundational to all biological sciences.

• What does it mean to be alive? Living things exhibit organization, metabolism, homeostasis, growth, reproduction, and response to stimuli.

• Scientific method: A systematic approach to inquiry involving observation, hypothesis formation, experimentation, and conclusion.

• Levels of biological organization: Atoms → Molecules → Cells → Tissues → Organs → Organ systems → Organisms → Populations → Communities → Ecosystems → Biosphere.

• Hierarchical organization: Each level builds upon the previous, with emergent properties at each step.

• Biological systems: Interconnected networks of biological components that interact to sustain life.

Chemistry

Key Themes in Chemistry for Biology

Chemistry underpins all biological processes. Understanding atomic structure, bonding, and chemical reactions is essential for studying life at the molecular level.

• Review of basics: Matter is composed of elements, which consist of atoms.

• Atomic structure: Atoms have a nucleus (protons and neutrons) and electrons in orbitals.

• Types of bonds:

  • Covalent bonds: Sharing of electron pairs between atoms.

  • Ionic bonds: Transfer of electrons from one atom to another, creating charged ions.

  • Hydrogen bonds: Weak attractions between a hydrogen atom and an electronegative atom (e.g., oxygen or nitrogen).

• Valence shells and electron pairing: Atoms are most stable when their outermost electron shell is full.

• Polarity and electronegativity: Polarity arises when atoms in a molecule have different electronegativities, leading to unequal sharing of electrons.

• Elements essential for life: Carbon, Hydrogen, Oxygen, Nitrogen (C, H, O, N) are the most abundant elements in living organisms.

• Water's unique properties: Cohesion, adhesion, high specific heat, and solvent abilities due to hydrogen bonding.

• Hydrophobic vs. hydrophilic: Hydrophobic substances repel water; hydrophilic substances interact well with water.

• Functional groups: Specific groups of atoms within molecules that have characteristic properties (e.g., hydroxyl, carboxyl, amino, phosphate).

• Introduction to chemical reactions: Chemical reactions involve the making and breaking of bonds; balancing equations is essential.

• Acids and bases:

  • Acid: Substance that donates protons (H+).

  • Base: Substance that accepts protons (H+).

  • pH scale: Measures the concentration of H+ ions; lower pH = more acidic, higher pH = more basic.

Biomolecules

Key Themes in Biomolecules

Biomolecules are the building blocks of life, including carbohydrates, lipids, proteins, and nucleic acids. Their structure and function are central to all biological processes.

• Monomers and polymers: Monomers are small molecules that join to form polymers (e.g., amino acids form proteins).

• Carbohydrates:

  • Monosaccharides: Simple sugars (e.g., glucose, fructose). Aldose vs. ketose refers to the position of the carbonyl group.

  • Polysaccharides: Long chains of monosaccharides (e.g., starch, glycogen, cellulose).

  • Functions: Energy storage and structural support.

• Lipids:

  • Hydrophobic molecules: Include fats, oils, phospholipids, and steroids.

  • Phospholipids: Have hydrophilic heads and hydrophobic tails; form cell membranes.

• Proteins:

  • Amino acids: Building blocks of proteins; 20 standard amino acids.

  • Peptide bonds: Covalent bonds linking amino acids.

  • Protein structure:

    • Primary: Sequence of amino acids.

    • Secondary: Alpha helices and beta sheets formed by hydrogen bonding.

    • Tertiary: 3D folding due to side chain interactions.

    • Quaternary: Association of multiple polypeptide chains.

  • Denaturation: Loss of protein structure and function due to environmental changes.

• Nucleic acids:

  • DNA and RNA: Polymers of nucleotides; store and transmit genetic information.

  • ATP: Adenosine triphosphate, the primary energy carrier in cells.

Example Table: Types of Bonds in Biology

Bond Type	Description	Example
Covalent	Sharing of electron pairs	Peptide bond in proteins
Ionic	Transfer of electrons, forming ions	NaCl (table salt)
Hydrogen	Weak attraction between H and electronegative atom	Between water molecules

Key Equations and Concepts

• Balancing chemical equations: The number of atoms for each element must be equal on both sides of the equation.

• pH calculation:

$\text{pH} = -\log_{10}[\text{H}^+]$

• ATP hydrolysis: Releases energy for cellular processes.

$\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$

Additional info: Some details, such as the specific structures of ATP or the full list of functional groups, were inferred based on standard biology curricula.