BIOL 1201 Final Exam Study Guide: Key Concepts and Applications

Chapter 2: The Chemical Context of Life

Atomic Structure and Subatomic Particles

Atoms are the fundamental units of matter, composed of three main subatomic particles: protons, neutrons, and electrons. Understanding their arrangement is essential for grasping chemical properties and reactions.

• Protons: Positively charged particles located in the nucleus. The number of protons determines the atomic number of an element.

• Neutrons: Neutral particles also found in the nucleus. The sum of protons and neutrons gives the atomic mass (mass number).

• Electrons: Negatively charged particles orbiting the nucleus in electron shells.

• Atomic Number (Z): Number of protons in the nucleus.

• Atomic Mass (A): $A = Z + N$ (where N = number of neutrons).

• Example: Carbon has 6 protons (atomic number 6) and typically 6 neutrons (atomic mass 12).

Chapter 3: Water and Life

pH and Hydrogen Ion Concentration

The pH scale measures the concentration of hydrogen ions in a solution, which is crucial for biological processes.

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

• Relationship: As [H+] increases, pH decreases (more acidic).

• Example: If $[H^+] = 1 \times 10^{-7}$ M, then $\text{pH} = 7$.

• Application: Solve for [H+] given pH, or vice versa.

Chapter 4: Carbon and the Molecular Diversity of Life

Functional Groups

Functional groups are specific groups of atoms within molecules that determine the chemical properties of those molecules.

• Hydroxyl (-OH): Found in alcohols; polar.

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

• Carboxyl (-COOH): Found in acids; can donate H+.

• Amino (-NH2): Found in amino acids; acts as a base.

• Phosphate (-PO4): Found in nucleic acids; contributes negative charge.

• Sulfhydryl (-SH): Found in proteins; forms disulfide bonds.

• Methyl (-CH3): Nonpolar; affects gene expression.

• Example: The carboxyl group in amino acids gives them acidic properties.

Chapter 5: The Structure and Function of Large Biological Molecules

Macromolecules and Their Monomers

Biological macromolecules are polymers made from specific monomers. Their structure determines their function.

• Carbohydrates: Monomer = monosaccharide (e.g., glucose). Function: energy storage, structural support.

• Lipids: Not true polymers; composed of fatty acids and glycerol. Function: energy storage, membrane structure.

• Proteins: Monomer = amino acid. Function: enzymes, structural, transport.

• Nucleic Acids: Monomer = nucleotide. Function: genetic information storage (DNA, RNA).

• Example: Starch (a carbohydrate) is a polymer of glucose.

Chapter 6: A Tour of the Cell

Major Cellular Structures and Functions

Cells contain specialized structures (organelles) that perform distinct functions necessary for life.

• Cytoskeleton: Provides structural support and facilitates movement.

• Endoplasmic Reticulum (ER): Rough ER synthesizes proteins; smooth ER synthesizes lipids.

• Lysosome: Contains digestive enzymes; breaks down waste.

• Mitochondrion: Site of cellular respiration; produces ATP.

• Nucleus: Contains genetic material; controls cell activities.

• Example: Mitochondria are abundant in muscle cells due to high energy demand.

Chapter 7: Membrane Structure and Function

Osmosis and Solute Concentrations

Osmosis is the movement of water across membranes in response to solute concentration differences.

• Intracellular vs. Extracellular: Water moves from areas of low solute concentration to high solute concentration.

• Hypertonic Solution: Higher solute outside; water leaves cell.

• Hypotonic Solution: Lower solute outside; water enters cell.

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

• Example: Red blood cells in a hypotonic solution swell and may burst.

Chapter 8: An Introduction to Metabolism

Energetics of Chemical Reactions

Metabolic reactions involve energy changes, often illustrated by graphs showing reactants, products, and activation energy.

• Exergonic Reaction: Releases energy; products have lower energy than reactants.

• Endergonic Reaction: Requires energy input; products have higher energy.

• Activation Energy: Energy needed to start a reaction.

• Example: ATP hydrolysis is exergonic.

• Graph Interpretation: Identify activation energy, energy difference between reactants and products.

Chapter 9: Cellular Respiration and Fermentation

Stages of Cellular Respiration

Cellular respiration is a multi-stage process that converts glucose into ATP.

• Glycolysis: Occurs in cytoplasm; input: glucose; output: pyruvate, ATP, NADH.

• Citric Acid Cycle (Krebs Cycle): Occurs in mitochondria; input: acetyl-CoA; output: CO2, ATP, NADH, FADH2.

• Electron Transport Chain: Occurs in mitochondrial membrane; input: NADH, FADH2; output: ATP, H2O.

• Example: One glucose molecule yields up to 36-38 ATP.

Chapter 10: Photosynthesis

Stages and Locations of Photosynthesis

Photosynthesis converts light energy into chemical energy in plants, occurring in chloroplasts.

• Light Reactions: Occur in thylakoid membranes; produce ATP and NADPH.

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

• Example: Oxygen is produced during light reactions.

Chapters 12 & 13: The Cell Cycle and Meiosis

Chromosome Number, Homologous Pairs, and DNA Amount

The cell cycle and meiosis involve changes in chromosome number, homologous pairs, and DNA content.

• Cell Cycle: DNA content doubles during S phase; chromosome number remains constant.

• Meiosis: Reduces chromosome number by half; homologous pairs separate.

• Example: Human somatic cells have 46 chromosomes; gametes have 23.

• DNA Amount: Doubles before cell division, halves after meiosis.

Chapters 14 & 15: Mendel and the Gene Idea; Chromosomal Basis of Inheritance

Genetics Terminology and Crosses

Understanding genetic terms and predicting offspring ratios is fundamental in genetics.

• Homozygous: Two identical alleles for a gene.

• Heterozygous: Two different alleles for a gene.

• Phenotype: Observable traits.

• Genotype: Genetic makeup.

• Gene: Unit of heredity.

• Allele: Variant form of a gene.

• Monohybrid Cross: Cross between individuals heterozygous for one gene.

• Phenotypic Ratio: Complete dominance: 3:1; incomplete dominance: 1:2:1; co-dominance: 1:2:1.

• Sex Linkage: Traits linked to sex chromosomes; different ratios in males and females.

• Example: Crossing Aa x Aa yields 1 AA: 2 Aa: 1 aa genotypic ratio.

Chapter 16: The Molecular Basis of Inheritance

DNA Structure and Directionality

DNA is a double helix with antiparallel strands and specific directionality.

• Double Helix: Two strands twisted together.

• Backbone: Sugar-phosphate; strands run 5' to 3' and 3' to 5'.

• Base Pairing: Adenine with thymine, cytosine with guanine.

• Example: The 5' end has a phosphate group; the 3' end has a hydroxyl group.

Chapter 17: Gene Expression: From Gene to Protein

Transcription and Translation

Gene expression involves transcription (DNA to RNA) and translation (RNA to protein).

• Transcription: DNA is copied into mRNA; directionality is 5' to 3'.

• Translation: mRNA is decoded by ribosomes to synthesize proteins.

• Components of Translation: Ribosome (site), tRNA (carries amino acids), mRNA (template), amino acids (building blocks).

• Example: The codon AUG codes for methionine, the start amino acid.