General Biology Final Exam Study Guide: Key Concepts and Processes

Chapters 1-5: Foundations of Biology and Biochemistry

Enzymes and Chemical Reactions

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy barrier. Understanding their role is essential for grasping metabolic processes.

• Activation Energy: The minimum energy required to start a chemical reaction.

• Enzyme Function: Enzymes bind substrates and facilitate their conversion to products.

• Example: Catalase breaks down hydrogen peroxide into water and oxygen.

Redox Reactions and Energy Flow

Redox reactions involve the transfer of electrons, crucial for energy flow in biological systems.

• Oxidation: Loss of electrons.

• Reduction: Gain of electrons.

• Energy Flow: Energy moves from sun to producers (photosynthesis) and then to consumers.

Atomic Structure and Chemical Bonds

Atoms consist of protons, neutrons, and electrons. Chemical bonds form when atoms share or transfer electrons.

• Covalent Bonds: Atoms share electrons.

• Ionic Bonds: Atoms transfer electrons.

• Hydrogen Bonds: Weak attractions between polar molecules.

Properties of Water

Water's unique properties are vital for life, including high specific heat, cohesion, and solvent abilities.

• High Specific Heat: Water resists temperature changes.

• Cohesion: Water molecules stick together.

• Solvent: Water dissolves many substances.

DNA Structure

DNA is the molecule of heredity, composed of nucleotides forming a double helix.

• Nucleotide: Consists of a sugar, phosphate, and nitrogenous base.

• Double Helix: Two strands held together by hydrogen bonds between bases.

Chapters 6-10: Cellular Respiration, Photosynthesis, and Membrane Function

ATP, NADH, FADH2, and O2 in Aerobic Respiration

Cells use ATP as energy currency, produced during cellular respiration. NADH and FADH2 are electron carriers.

• ATP: Adenosine triphosphate, provides energy for cellular processes.

• NADH/FADH2: Carry electrons to the electron transport chain.

• O2: Final electron acceptor in aerobic respiration.

Osmolarity and Cell Solutions

Osmolarity affects water movement across cell membranes, influencing cell volume and function.

• Hypertonic Solution: Higher solute concentration outside the cell; cell shrinks.

• Hypotonic Solution: Lower solute concentration outside; cell swells.

• Isotonic Solution: Equal solute concentration; no net water movement.

Electron Transport and ATP Production

Electrons from NADH and FADH2 pass through the electron transport chain, creating a proton gradient that drives ATP synthesis.

• Electron Transport Chain: Series of protein complexes in mitochondria.

• ATP Synthase: Enzyme that synthesizes ATP using the proton gradient.

Photosynthesis

Photosynthesis converts light energy into chemical energy in plants.

• Light Reactions: Produce ATP and NADPH.

• Calvin Cycle: Uses ATP and NADPH to fix carbon dioxide into glucose.

Membrane Structure and Function

Cell membranes are composed of a phospholipid bilayer with embedded proteins, regulating transport and communication.

• Fluid Mosaic Model: Describes membrane structure.

• Transport Proteins: Facilitate movement of substances across the membrane.

Chapters 12-15: Cell Cycle, Mitosis, Meiosis, and Inheritance

Mitosis and Meiosis

Mitosis and meiosis are processes of cell division, essential for growth, repair, and reproduction.

• Mitosis: Produces two identical daughter cells.

• Meiosis: Produces four genetically unique gametes.

• Phases: Prophase, Metaphase, Anaphase, Telophase (Mitosis); Meiosis I and II.

Genetic Variation

Genetic variation arises from independent assortment, crossing over, and random fertilization.

• Independent Assortment: Random distribution of chromosomes.

• Crossing Over: Exchange of genetic material between homologous chromosomes.

Law of Segregation and Law of Independent Assortment

Mendel's laws explain inheritance patterns.

• Law of Segregation: Each gamete receives one allele of each gene.

• Law of Independent Assortment: Genes on different chromosomes are inherited independently.

Chapters 16-17 & 23: Molecular Genetics and Evolution

DNA Replication

DNA replication ensures genetic information is accurately passed to daughter cells.

• Helicase: Unwinds DNA.

• Primase: Synthesizes RNA primers.

• DNA Polymerase: Synthesizes new DNA strands.

• Ligase: Joins Okazaki fragments.

• Leading vs. Lagging Strand: Leading strand is synthesized continuously; lagging strand in fragments.

Gene Expression and Regulation

Gene expression involves transcription and translation, regulated at multiple levels.

• Transcription: DNA is transcribed to mRNA.

• Translation: mRNA is translated to protein.

• Regulation: Promoters, enhancers, repressors, and transcription factors control gene expression.

Mutations and Chromosomal Rearrangements

Mutations alter genetic information, while chromosomal rearrangements can affect gene function.

• Types of Mutations: Substitution, insertion, deletion, inversion, duplication.

• Effects: Can be silent, missense, or nonsense; may lead to genetic disorders.

Evolutionary Mechanisms

Evolution is driven by natural selection, genetic drift, gene flow, and mutation.

• Natural Selection: Differential survival and reproduction.

• Genetic Drift: Random changes in allele frequencies.

• Gene Flow: Movement of alleles between populations.

Speciation and Phylogeny

Speciation is the formation of new species; phylogeny traces evolutionary relationships.

• Allopatric Speciation: Occurs due to geographic isolation.

• Sympatric Speciation: Occurs without physical separation.

• Phylogenetic Trees: Diagrams showing evolutionary relationships.

Divergence and Convergence

Divergent evolution leads to differences from a common ancestor; convergent evolution leads to similarities in unrelated groups.

• Divergent Evolution: Example: Darwin's finches.

• Convergent Evolution: Example: Wings in bats and birds.

Additional Info

• Some topics were expanded for clarity and completeness, including definitions and examples.

• Key processes such as DNA replication and gene regulation were described in more detail for exam preparation.