Chapter 1: Introduction to Biology

Hierarchy of Life and Characteristics of Living Organisms

This section introduces the organization of life from the simplest to the most complex levels and the defining features of living organisms.

• Hierarchy of Life: Life is organized in increasing complexity: atom → molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.

• Genetic Code: All forms of life use DNA as their genetic material, which encodes the instructions for life processes.

• Reductionism vs. Systems Biology: Reductionism breaks down complex systems into simpler components, while systems biology studies interactions within biological systems.

• Prokaryotic vs. Eukaryotic Organisms: Prokaryotes (Bacteria, Archaea) lack a nucleus and membrane-bound organelles; eukaryotes (plants, animals, fungi, protists) have both.

• Domains and Kingdoms: Three domains: Bacteria, Archaea, Eukarya. Eukarya includes four kingdoms: Animalia, Plantae, Fungi, Protista.

• Kingdom Characteristics:

  • Animals: Multicellular, ingest food.

  • Plants: Multicellular, autotrophic, cell walls made of cellulose.

  • Fungi: Heterotrophs, absorb digested food, cell walls of chitin.

  • Protists: Diverse, mostly unicellular or simple multicellular.

• Scientific Method: Steps include observation, hypothesis, experiment, data collection, and conclusion. A control group is used for comparison; independent and dependent variables must be identified.

• Qualitative vs. Quantitative Data: Qualitative data describes qualities (e.g., color, texture); quantitative data involves numbers (e.g., mass, length).

Chapter 2: Atomic Structure and Chemical Bonds

Atomic Structure and Electron Arrangement

This section covers the structure of atoms, electron configuration, and the basis of chemical bonding.

• Atomic Structure: Atoms consist of a nucleus (protons and neutrons) and electrons in orbitals.

• Electron Shells: The first shell holds 2 electrons; the second and third shells hold up to 8 electrons each.

• Atomic Number and Mass: Atomic number = number of protons; atomic mass = protons + neutrons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Valence Electrons: Electrons in the outermost shell determine chemical reactivity.

• Periodic Table Trends: Elements in the same column (group) have similar properties due to similar valence electron configurations.

• Covalent Bonds: Atoms share electrons; can be polar (unequal sharing) or non-polar (equal sharing).

• Electronegativity: The ability of an atom to attract electrons in a bond. Differences in electronegativity determine bond polarity.

• Common Elements in Biology: Oxygen, nitrogen, hydrogen, carbon are the most abundant in living organisms.

• Molecules: Formed by covalent bonds between atoms.

• Chemical Properties: Determined by atomic structure, electron configuration, and bond type.

Chapter 3: Water and Its Properties

Hydrogen Bonding and Water’s Unique Properties

This section explains the chemical properties of water, its role in biology, and the importance of hydrogen bonding.

• Hydrophobic vs. Hydrophilic Compounds: Hydrophobic substances do not dissolve in water (e.g., oils); hydrophilic substances do (e.g., salts, sugars).

• Hydrogen Bonds: Weak attractions between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another.

• Emergent Properties of Water:

  • Cohesion and adhesion

  • High specific heat

  • High heat of vaporization

  • Expansion upon freezing

  • Versatility as a solvent

• Mole Concept: 1 mole = molecular mass in grams = molecules.

• Making Solutions: Steps include calculating the required mass, dissolving in solvent, and adjusting volume.

• Acids and Bases: Acids donate H+; bases accept H+.

• pH Scale: Measures H+ concentration; .

• Dissociation Constant (Kw): at 25°C.

• Comparing Solutions: Solutions with different pH values have different H+ concentrations.

• Buffers: Substances that minimize changes in pH by accepting or donating H+ ions.

Chapter 4: Carbon and Organic Molecules

Carbon Chemistry and Functional Groups

This section explores the unique properties of carbon, the diversity of organic molecules, and the importance of functional groups.

• Importance of Carbon: Carbon can form four covalent bonds, allowing for complex and diverse organic molecules.

• Electron Configuration of Carbon: 1s2 2s2 2p2; four valence electrons.

• Hydrocarbons: Molecules consisting only of carbon and hydrogen; nonpolar and hydrophobic.

• Isomers: Compounds with the same molecular formula but different structures. Types include structural isomers, cis-trans isomers, and enantiomers.

• Functional Groups: Specific groups of atoms that confer characteristic chemical properties to organic molecules. Examples include hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl groups.

Additional info: The original file is a list of study questions and key concepts for exam preparation in a General Biology course, covering foundational topics in biological organization, chemistry, and molecular biology.