General Biology Final Exam Study Guide (Chapters 1-7, 9-10, 12-17)

Cumulative Portion

Unifying Themes of Biology

Biology is the scientific study of life, and several unifying themes help organize biological knowledge.

• Organization: Life is organized into hierarchical levels, from molecules to the biosphere.

• Information: Genetic information is stored in DNA and governs the structure and function of organisms.

• Energy and Matter: Life requires the transfer and transformation of energy and matter.

• Interactions: Organisms interact with each other and their environment.

• Evolution: The core theme explaining the unity and diversity of life.

Domains of Life

• Bacteria: Prokaryotic, unicellular organisms with diverse metabolic pathways.

• Archaea: Prokaryotic, often extremophiles, genetically distinct from bacteria.

• Eukarya: Eukaryotic organisms, including protists, fungi, plants, and animals.

Natural Selection and Evolution

Natural selection is the process by which organisms with advantageous traits survive and reproduce more successfully. Evolution is the change in the genetic composition of a population over time.

• Key Points: Variation, inheritance, differential survival, and reproduction.

• Example: Darwin's finches with different beak shapes adapted to different food sources.

Chemical Bonds and Molecules

• Covalent Bonds: Atoms share electrons (e.g., H2O).

• Ionic Bonds: Transfer of electrons between atoms (e.g., NaCl).

• Polar Covalent Bonds: Unequal sharing of electrons (e.g., H2O).

• Nonpolar Covalent Bonds: Equal sharing of electrons (e.g., O2).

Acids, Bases, and pH

• Acids: Donate H+ ions, lower pH.

• Bases: Accept H+ ions, raise pH.

• pH Scale: Ranges from 0 (acidic) to 14 (basic), with 7 as neutral.

Macromolecules

• Carbohydrates: Sugars and polymers of sugars (e.g., starch, cellulose).

• Lipids: Hydrophobic molecules (e.g., fats, phospholipids, steroids).

• Proteins: Polymers of amino acids, diverse functions (e.g., enzymes, structure).

• Nucleic Acids: DNA and RNA, store and transmit genetic information.

Cell Structure and Function

• Prokaryotic Cells: No nucleus, simple structure (Bacteria, Archaea).

• Eukaryotic Cells: Nucleus, membrane-bound organelles (Eukarya).

• Organelles: Nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes.

Membrane Structure and Function

• Phospholipid Bilayer: Hydrophilic heads, hydrophobic tails.

• Selective Permeability: Allows some substances to cross more easily than others.

• Transport Proteins: Facilitate movement of molecules across membranes.

Metabolism and Enzymes

• Metabolism: All chemical reactions in a cell.

• Anabolism: Building complex molecules from simpler ones.

• Catabolism: Breaking down complex molecules to release energy.

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

Cellular Respiration and Fermentation

• Cellular Respiration: Process by which cells extract energy from glucose.

• Stages: Glycolysis, Krebs cycle (Citric Acid Cycle), Electron Transport Chain.

• Fermentation: Anaerobic process producing ATP without oxygen.

• Equation:

$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$

Photosynthesis

• Process: Conversion of light energy into chemical energy (glucose).

• Stages: Light reactions (produce ATP and NADPH), Calvin cycle (produces glucose).

• Equation:

$6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$

Cell Cycle and Mitosis

• Stages: Interphase (G1, S, G2), Mitosis (prophase, metaphase, anaphase, telophase), Cytokinesis.

• Purpose: Growth, repair, and asexual reproduction.

• Result: Two genetically identical diploid daughter cells.

Meiosis

• Purpose: Production of gametes (sperm and egg) for sexual reproduction.

• Stages: Meiosis I and II, each with prophase, metaphase, anaphase, telophase.

• Result: Four genetically unique haploid cells.

Unit 4 Portion: Genetics and Molecular Biology

Mendelian Genetics

• Key Terms: Character, trait, dominant, recessive, homozygous, heterozygous, monohybrid, dihybrid, F1, F2.

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

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

Punnett Squares

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

• Dihybrid Cross: Cross between individuals heterozygous for two traits.

• Test Cross: Cross between an individual with an unknown genotype and a homozygous recessive individual.

Non-Mendelian Inheritance

• Incomplete Dominance: Heterozygote has an intermediate phenotype.

• Codominance: Both alleles are fully expressed in the heterozygote.

• Pleiotropy: One gene affects multiple traits.

• Epistasis: One gene affects the expression of another gene.

• Polygenic Inheritance: Multiple genes influence a single trait.

Chromosomal Basis of Inheritance

• Sex-linked Traits: Traits controlled by genes on sex chromosomes (e.g., X-linked recessive traits).

• Linked Genes: Genes located close together on the same chromosome tend to be inherited together.

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

DNA Structure and Replication

• DNA: Double helix, antiparallel strands, complementary base pairing (A-T, G-C).

• Replication: Semi-conservative process; each new DNA molecule has one old and one new strand.

• Directionality: DNA and RNA synthesis occurs in the 5' to 3' direction.

Transcription and Translation

• Transcription: Synthesis of RNA from a DNA template.

• Translation: Synthesis of protein from an mRNA template.

• Codon: Three-nucleotide sequence on mRNA that codes for an amino acid.

• Anticodon: Three-nucleotide sequence on tRNA complementary to mRNA codon.

• Players: mRNA, tRNA, rRNA, ribosomes, amino acids.

Mutations

• Substitution: One base is replaced by another.

• Insertion/Deletion: Addition or loss of nucleotide(s), may cause frameshift.

• Effects: Can be silent, missense, nonsense, or frameshift mutations.

Summary Table: Types of Genetic Crosses

Type of Cross	Genotypes Involved	Expected Phenotypic Ratio
Monohybrid (heterozygous x heterozygous)	Rr x Rr	3:1
Dihybrid (heterozygous for two traits)	RrYy x RrYy	9:3:3:1
Test Cross	R_ x rr	1:1 (if R_ is heterozygous)

Summary Table: Types of Mutations

Type	Description	Possible Effect
Substitution	One base replaced by another	Silent, missense, or nonsense
Insertion	Extra base(s) added	Frameshift, altered protein
Deletion	Base(s) removed	Frameshift, altered protein

Additional info:

• Understanding the directionality (5' to 3') is crucial for all processes involving nucleic acids.

• Be able to interpret and construct Punnett squares for both monohybrid and dihybrid crosses, and for sex-linked traits.

• Know how to use a codon table to translate mRNA sequences into amino acid sequences.