General Biology Final Exam Study Guide: Key Concepts and Topics

Scientific Inquiry and Experimental Design

Independent and Dependent Variables

Understanding variables is essential for designing and interpreting experiments in biology.

• Independent Variable: The factor that is changed or manipulated in an experiment.

• Dependent Variable: The factor that is measured or observed; it responds to changes in the independent variable.

• Example: In a plant growth experiment, the amount of sunlight (independent) affects plant height (dependent).

The Chemical Context of Life

Atoms, Subatomic Particles, and Chemical Bonds

All matter is composed of atoms, which consist of subatomic particles and form chemical bonds.

• Atoms: The basic units of matter, made of protons, neutrons, and electrons.

• Subatomic Particles: Protons (positive charge), Neutrons (neutral), Electrons (negative charge).

• Types of Chemical Bonds: Covalent (sharing electrons), Hydrogen (weak attraction between polar molecules).

• Example: Water molecules are held together by covalent bonds; hydrogen bonds form between water molecules.

Water and Life

Biological Molecules

Macromolecules and Their Functions

Large biological molecules are essential for structure and function in living organisms.

• Types: Carbohydrates, lipids, proteins, nucleic acids.

• Structure: Built from monomers (building blocks) joined by covalent bonds.

• Function: Energy storage, structural support, catalysis, genetic information.

• Example: DNA stores genetic information; enzymes (proteins) catalyze reactions.

Cell Structure and Function

Cell Membranes and Transport

Cell membranes regulate the movement of substances in and out of cells.

• Phospholipid Bilayer: Forms the basic structure of cell membranes.

• Transport Mechanisms: Diffusion (passive movement), Osmosis (water movement), Active Transport (requires energy).

• Example: Glucose enters cells via facilitated diffusion through membrane proteins.

Metabolism and Energy

Enzymes and Metabolic Pathways

Metabolism includes all chemical reactions in cells, often regulated by enzymes.

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

• ATP: The main energy currency of the cell.

• Example: Cellular respiration produces ATP from glucose.

Cellular Respiration and Photosynthesis

Energy Transformation in Cells

Cells convert energy through respiration and photosynthesis.

• Cellular Respiration: Converts glucose and oxygen into ATP, water, and carbon dioxide.

• Photosynthesis: Converts light energy, water, and carbon dioxide into glucose and oxygen.

• Equation for Cellular Respiration:

$\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP}$

• Equation for Photosynthesis:

$6\text{CO}_2 + 6\text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$

Cell Division and Genetics

Mitosis, Meiosis, and Mendelian Genetics

Cell division is crucial for growth, repair, and reproduction. Genetics explains inheritance patterns.

• Mitosis: Produces two identical daughter cells for growth and repair.

• Meiosis: Produces four genetically unique gametes for sexual reproduction.

• Mendelian Genetics: Explains inheritance using dominant and recessive alleles.

• Punnett Squares: Used to predict genotype and phenotype ratios.

• Example: Crossing Aa x Aa yields a 3:1 ratio of dominant to recessive phenotypes.

Gene Expression and Regulation

DNA, RNA, and Protein Synthesis

Genetic information flows from DNA to RNA to protein.

• Transcription: DNA is copied into messenger RNA (mRNA).

• Translation: mRNA is decoded to build proteins at ribosomes.

• Regulation: Genes are turned on/off in response to signals.

• Example: The lac operon in bacteria regulates lactose metabolism.

Evolution and Natural Selection

Mechanisms of Evolution

Evolution explains the diversity of life through genetic change over time.

• Natural Selection: Individuals with advantageous traits survive and reproduce.

• Genetic Drift: Random changes in allele frequencies, especially in small populations.

• Gene Flow: Movement of genes between populations.

• Example: Peppered moth coloration changed due to industrial pollution.

Classification and Diversity of Life

Taxonomy and Phylogeny

Organisms are classified based on evolutionary relationships.

• Taxonomic Hierarchy: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

• Phylogenetic Trees: Diagrams showing evolutionary relationships.

• Example: Humans are classified as Homo sapiens.

Animal and Plant Diversity

Major Groups and Characteristics

Plants and animals are diverse, with unique adaptations and life cycles.

• Plant Groups: Mosses, ferns, gymnosperms, angiosperms.

• Animal Groups: Invertebrates (e.g., arthropods, mollusks), vertebrates (e.g., fish, mammals).

• Example: Mammals have hair and produce milk; angiosperms produce flowers and seeds.

Ecology and Environmental Biology

Population, Community, and Ecosystem Dynamics

Ecology studies interactions among organisms and their environments.

• Population Ecology: Examines population size, growth, and regulation.

• Community Ecology: Focuses on interactions among species.

• Ecosystem Ecology: Studies energy flow and nutrient cycling.

• Example: Food webs illustrate energy transfer in ecosystems.

Table: Comparison of Mitosis and Meiosis

Feature	Mitosis	Meiosis
Number of Divisions	1	2
Number of Daughter Cells	2	4
Genetic Identity	Identical to parent	Genetically unique
Function	Growth, repair	Sexual reproduction

Additional info:

• Some topics (e.g., animal phyla, plant groups, ecological principles) were expanded for clarity and completeness.

• Genetics problems (Punnett squares, probability) are foundational for understanding inheritance.

• Classification examples and evolutionary mechanisms were inferred from standard biology curricula.