Biology Chapter Overview

Diversity of Life

• Biology is the study of living things.
• Living things are diverse and grouped into kingdoms based on similar features.
• Different kingdoms have distinct members.

Properties of Life

• Living things must exhibit certain properties:

  • Cellular organization: Composed of one or more cells.
  • Metabolism: Process energy for activities.
  • Homeostasis: Maintain stable internal conditions.
  • Growth and reproduction: Grow and reproduce.
  • Heredity: Pass genetic information to offspring.

• Living things interact and function on multiple levels (cellular, organismal, populational).

• Emergent properties, like metabolism and consciousness, appear at higher levels.

Biological Themes

• Biology is studied through themes.
• Five key biological themes:
  • Evolution: Genetic change in species over time, driven by natural selection.

Atoms and Matter

• All matter has mass and occupies space.
• Matter is composed of atoms.
• Atoms have a nucleus (protons and neutrons) and orbiting electrons.

Atomic Structure

• Atomic number: Number of protons, determining an element's chemical properties.

• Mass number: Number of protons plus neutrons.

• Electrons determine chemical behavior.

• Electrons occupy energy levels (electron shells/orbitals).

• Atoms with incomplete outer electron shells are reactive.

• Chemical bonding results from atoms gaining, losing, or sharing electrons to fill outer shells.

Organic Molecules & Macromolecules

• Organic molecules have carbon-based cores and attached functional groups.
• Macromolecules (proteins, nucleic acids, carbs, lipids) are large molecules essential for life.
• Macromolecules are polymers made from monomers using dehydration synthesis and broken down by hydrolysis.
• Proteins are polymers of amino acids, linked by peptide bonds.

Cell Theory

• Cell theory states all organisms are composed of one or more cells, cells are the smallest living things, and cells arise only from pre-existing cells.
• Historical contributions include Hooke's, Schleiden's, and Schwann's discoveries.

Cell Size and Efficiency

• Most cells are small to maximize surface area-to-volume ratio for efficient material exchange.
• Larger cells are less efficient due to longer diffusion distances.

Resolution and Microscopy

• Cell size requires microscopes to observe details.
• Resolution is the minimum distance between separate points.
• Microscopes (light & electron) increase magnification and resolution.

Movement Across Biological Membranes

• Diffusion is the movement of molecules from high to low concentration until equilibrium.
• Membranes fold to transport substances.
• Membrane proteins facilitate movement of substances that can't diffuse freely.

Diffusion

• Molecules move randomly, spreading out.
• Nonpolar molecules can easily diffuse.
• Polar molecules need protein channels.
• Water moves through aquaporins.

Osmosis

• Osmosis is water movement across a membrane from low to high solute concentration.
• Solutions with equal osmotic concentration are isotonic.
• Hypertonic solutions have higher solute concentration.
• Hypotonic solutions have lower solute concentration.
• Osmosis generates osmotic pressure.