Core I Biology BSC2010: Comprehensive Final Exam Study Guide

Scientific Process and General Chemistry

Scientific Process

The scientific process is a systematic approach to understanding natural phenomena through observation, hypothesis formation, experimentation, and analysis.

• Observation: Gathering data about the natural world.

• Hypothesis: A testable explanation for an observation.

• Experimentation: Testing hypotheses under controlled conditions.

• Analysis and Conclusion: Interpreting results to support or refute the hypothesis.

• Peer Review: Sharing findings for validation by the scientific community.

Types of Chemical Bonds

• Ionic Bonds: Formed when electrons are transferred from one atom to another, creating charged ions (e.g., NaCl).

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

• Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (e.g., between water molecules).

Properties of Water; pH

• Cohesion and Adhesion: Water molecules stick to each other and to other substances.

• High Specific Heat: Water resists temperature changes.

• Solvent Properties: Water dissolves many substances due to its polarity.

• pH: Measures hydrogen ion concentration; $\mathrm{pH} = -\log_{10}[\mathrm{H}^+]$

Organic Chemistry

Major Functional Groups

• Hydroxyl (-OH): Alcohols, increases solubility in water.

• Carbonyl (C=O): Found in aldehydes and ketones.

• Carboxyl (-COOH): Acts as an acid.

• Amino (-NH2): Acts as a base.

• Sulfhydryl (-SH): Important in protein structure.

• Phosphate (-PO4): Involved in energy transfer (e.g., ATP).

• Methyl (-CH3): Affects gene expression.

Macromolecules: Structure, Functions, and Examples

• Carbohydrates: Monomer: monosaccharides; Function: energy storage, structure; Example: glucose, cellulose.

• Lipids: Monomer: fatty acids and glycerol; Function: energy storage, membranes; Example: triglycerides, phospholipids.

• Proteins: Monomer: amino acids; Function: enzymes, structure, transport; Example: hemoglobin, enzymes.

• Nucleic Acids: Monomer: nucleotides; Function: genetic information; Example: DNA, RNA.

Cell Parts

Prokaryote vs. Eukaryote

• Prokaryotes: No nucleus, no membrane-bound organelles (e.g., bacteria).

• Eukaryotes: Nucleus and membrane-bound organelles (e.g., plants, animals).

Organelles; Functions; Plants vs. Animal Cells

• Nucleus: Contains genetic material.

• Mitochondria: Site of cellular respiration.

• Chloroplasts: Site of photosynthesis (plants only).

• Endoplasmic Reticulum (ER): Protein and lipid synthesis.

• Golgi Apparatus: Modifies and ships proteins.

• Lysosomes: Digestion (mainly in animal cells).

• Cell Wall: Structure and support (plants only).

Transport

Types of Transport

• Passive Transport: No energy required; includes diffusion, osmosis, and facilitated diffusion.

• Active Transport: Requires energy (ATP); moves substances against their concentration gradient.

• Bulk Transport: Endocytosis and exocytosis for large molecules.

Osmosis Terms

• Hypotonic: Solution with lower solute concentration than the cell; water enters the cell.

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

• Hypertonic: Solution with higher solute concentration; water leaves the cell.

Enzymes & Metabolism

How Enzymes Work

• Enzymes: Biological catalysts that speed up reactions by lowering activation energy.

• Active Site: Region where substrate binds.

• Induced Fit: Enzyme changes shape to fit substrate.

ATP Structure and Importance

• ATP (Adenosine Triphosphate): Main energy currency of the cell.

• Structure: Adenine, ribose, and three phosphate groups.

• Energy released when terminal phosphate bond is broken: $\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$

Cellular Respiration

ATP Production in Presence and Absence of Oxygen

• Aerobic Respiration: Uses oxygen; includes glycolysis, Krebs cycle, and electron transport chain (ETC).

• Anaerobic Respiration/Fermentation: No oxygen; less ATP produced.

ETC and Chemiosmosis

• Electron Transport Chain (ETC): Series of proteins in the mitochondrial membrane transfer electrons and pump protons.

• Chemiosmosis: Protons flow back through ATP synthase, generating ATP.

• Overall equation: $\mathrm{C_6H_{12}O_6} + 6\mathrm{O_2} \rightarrow 6\mathrm{CO_2} + 6\mathrm{H_2O} + \text{energy (ATP)}$

Photosynthesis

Light Reactions vs. Calvin Cycle

• Light Reactions: Occur in thylakoid membranes; convert light energy to chemical energy (ATP, NADPH).

• Calvin Cycle: Occurs in stroma; uses ATP and NADPH to fix CO2 into sugars.

Main Products of Photosynthesis

• Glucose (C6H12O6): Main energy storage molecule.

• Oxygen (O2): Byproduct released into the atmosphere.

• Overall equation: $6\mathrm{CO_2} + 6\mathrm{H_2O} + \text{light energy} \rightarrow \mathrm{C_6H_{12}O_6} + 6\mathrm{O_2}$

Mitosis

Stages and Control of the Cell Cycle

• Stages: Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.

• Control: Checkpoints (G1, G2, M) regulate progression.

Animal vs. Plant Mitosis

• Animal Cells: Cleavage furrow forms during cytokinesis.

• Plant Cells: Cell plate forms to divide the cell.

Meiosis

Crossing-Over and Stages

• Crossing-Over: Exchange of genetic material between homologous chromosomes during Prophase I; increases genetic diversity.

• Stages: Meiosis I (separates homologous chromosomes), Meiosis II (separates sister chromatids).

Gametogenesis in Humans

• Spermatogenesis: Produces four sperm cells from one precursor.

• Oogenesis: Produces one egg and three polar bodies from one precursor.

Genetics

Mendel’s Laws

• Law of Segregation: Each individual has two alleles for each gene, which separate during gamete formation.

• Law of Independent Assortment: Genes for different traits assort independently during gamete formation.

Exceptions to Mendelian Inheritance

• Incomplete Dominance: Heterozygote shows intermediate phenotype.

• Codominance: Both alleles are fully expressed.

• Pleiotropy: One gene affects multiple traits.

• Polygenic Inheritance: Multiple genes affect a single trait.

Genetic Problem Solving

• Use Punnett squares to predict genotype and phenotype ratios.

• Apply probability rules for complex crosses.

Molecular Biology

DNA Replication

• Semiconservative Replication: Each new DNA molecule has one old and one new strand.

• Key Enzymes: DNA polymerase, helicase, ligase.

Transcription and Translation

• Transcription: DNA is transcribed to mRNA in the nucleus.

• Translation: mRNA is translated into protein at the ribosome.

Gene Regulation in Eukaryotes

• Regulated at multiple levels: chromatin structure, transcription, RNA processing, translation.

• Examples: enhancers, silencers, alternative splicing.

Modern Molecular Biology Techniques and Biotechnology

• PCR (Polymerase Chain Reaction): Amplifies DNA sequences.

• Gel Electrophoresis: Separates DNA fragments by size.

• Gene Cloning: Inserting genes into plasmids for replication.

• CRISPR: Genome editing technology.

Evolution

Theories of Descent with Modification, Common Ancestry, and Speciation

• Descent with Modification: Species change over time, giving rise to new species.

• Common Ancestry: All life shares a common ancestor.

• Speciation: Formation of new species through reproductive isolation.

Theory of Natural Selection

• Individuals with advantageous traits survive and reproduce more successfully.

• Over time, these traits become more common in the population.

Genetic Basis/Mechanism for Evolution

• Mutation, gene flow, genetic drift, and natural selection drive evolution.

Microevolution vs. Macroevolution

Microevolution	Macroevolution
Small-scale changes within a population (e.g., allele frequency shifts)	Large-scale changes leading to new species or higher taxa

Patterns of Change Driven by Natural Selection

• Directional Selection: Favors one extreme phenotype.

• Stabilizing Selection: Favors intermediate phenotypes.

• Diversifying Selection: Favors both extremes.

Additional info: This guide is based on the provided exam outline and includes expanded academic context for each topic to ensure comprehensive coverage for exam preparation.