Comprehensive Study Guide for Introductory Biology: Final Exam Review

CHAPTER 1: The Concept of Cell, Genetic Code, and Scientific Method

The Concept of Cell

The cell is the fundamental unit of life in all living organisms. Cells can be prokaryotic or eukaryotic, differing in complexity and internal structure.

• Cell Theory: All living things are composed of cells; cells are the basic unit of structure and function; all cells arise from pre-existing cells.

• Prokaryotic Cells: Lack a nucleus and membrane-bound organelles (e.g., bacteria).

• Eukaryotic Cells: Have a nucleus and membrane-bound organelles (e.g., plants, animals).

• Example: Escherichia coli is a prokaryotic cell; human skin cells are eukaryotic.

Genetic Code & Organization of Genetic Material

The genetic code is the set of rules by which information encoded in DNA is translated into proteins.

• DNA: Organized into chromosomes; contains genes.

• Genetic Code: Universal, triplet-based (codons).

• Example: The codon AUG codes for methionine.

Scientific Method

The scientific method is a systematic approach to inquiry in biology.

• Steps: Observation, hypothesis, experiment, analysis, conclusion.

• Example: Testing the effect of sunlight on plant growth.

CHAPTER 2: Chemical Context of Life

Compounds and Atomic Structure

Atoms combine to form compounds, which are substances with two or more elements in fixed ratios.

• Electric Nature of Atoms: Atoms consist of protons (+), neutrons (0), and electrons (-).

• Mass of Subatomic Particles: Protons and neutrons have similar mass (~1 amu); electrons are much lighter.

• Atomic Number: Number of protons in the nucleus; determines element identity.

• Example: Water (H2O) is a compound of hydrogen and oxygen.

CHAPTER 3: Water and Life

Polarity and Properties of Water

Water is essential for life due to its unique chemical properties.

• Polarity: Water molecules are polar, with partial positive and negative charges.

• Cohesion: Water molecules stick together via hydrogen bonds.

• Surface Tension: Results from cohesion; allows small insects to walk on water.

• Density Difference: Ice is less dense than liquid water due to hydrogen bonding.

• Effect of CO2 in Water: CO2 dissolves to form carbonic acid, affecting pH.

• Example: Water's high specific heat helps regulate temperature in organisms.

CHAPTER 4: Carbon and Molecular Diversity

Hydrophobic Substances and Organic Molecules

Carbon is the backbone of organic molecules, which can be hydrophobic or hydrophilic.

• Hydrophobic Substances: Repel water; nonpolar (e.g., oils).

• Role of Carbon: Forms four covalent bonds; allows for diverse structures.

• Alcohol Representation: Alcohols have a hydroxyl group (-OH).

• Enantiomers: Mirror-image isomers; important in pharmaceuticals.

• Example: Glucose and galactose are structural isomers.

CHAPTER 5: Structure and Function of Large Biological Molecules

Functional Groups, Dehydration, and Hydrolysis

Biological macromolecules are built from monomers via dehydration reactions and broken down by hydrolysis.

• Functional Groups in Amino Acids: Amino (-NH2) and carboxyl (-COOH) groups.

• Dehydration Reaction: Removes water to form bonds.

• Hydrolysis: Adds water to break bonds.

• Example: Formation of peptide bonds in proteins.

Polysaccharides: Glycogen, Starch, and Cellulose

• Glycogen: Storage polysaccharide in animals.

• Starch: Storage polysaccharide in plants.

• Cellulose: Structural polysaccharide in plant cell walls.

• Example: Humans digest starch but not cellulose.

CHAPTER 6: A Tour of the Cell

Genetic Information Flow and Cell Structures

Cells contain specialized structures for genetic information flow and energy production.

• Flow of Genetic Information: DNA → RNA → Protein.

• Prokaryotes: No nucleus; DNA in nucleoid.

• Mitochondrion: Site of cellular respiration.

• Ribosomes: Protein synthesis.

• Nucleoid: Region in prokaryotes where DNA is found.

• Maximum Size of a Cell: Limited by surface area-to-volume ratio.

• Plasmodesmata: Channels between plant cells.

• Gap Junctions: Channels between animal cells.

• Tight Junctions: Seal cells together.

CHAPTER 7: Membrane Structure and Function

Membrane Proteins and Transport

Cell membranes regulate transport and communication.

• Integral Membrane Proteins: Span the membrane; involved in transport.

• Diffusion: Passive movement of molecules.

• Aquaporins: Water channel proteins.

• Osmosis: Diffusion of water across a membrane.

• Phagocytosis: Cell engulfs large particles.

• Example: White blood cells use phagocytosis to ingest bacteria.

CHAPTER 8: Introduction to Metabolism

Thermodynamics and Enzyme Function

Metabolism involves energy transformations governed by thermodynamic laws.

• First Law: Energy cannot be created or destroyed.

• Second Law: Entropy increases in spontaneous processes.

• Exergonic Reactions: Release energy; spontaneous.

• Active Site: Region of enzyme where substrate binds.

• Noncompetitive Inhibition: Inhibitor binds elsewhere, altering enzyme function.

• Example: ATP hydrolysis is exergonic.

CHAPTER 9: Cellular Respiration and Fermentation

Redox Reactions and Energy Production

Cells extract energy from glucose via oxidation-reduction reactions.

• Oxidation/Reduction: Transfer of electrons; oxidation loses electrons, reduction gains.

• Glycolysis: Breakdown of glucose to pyruvate.

• Electron Transport Chain: Series of proteins that transfer electrons and produce ATP.

• Example: NAD+ is reduced to NADH during glycolysis.

CHAPTER 10: Photosynthesis

Autotrophs, Heterotrophs, and Light Energy

Photosynthesis converts light energy into chemical energy.

• Autotrophs: Produce their own food (e.g., plants).

• Heterotrophs: Consume other organisms for energy.

• Relationship: Photosynthesis produces O2 and glucose; cellular respiration uses them.

• Wavelength and Energy: Energy per photon is inversely proportional to wavelength.

• Equation: $E = \frac{hc}{\lambda}$

• Example: Shorter wavelengths (blue light) have more energy than longer wavelengths (red light).

CHAPTER 12: The Cell Cycle

Chromatids, Centromere, and Interphase

The cell cycle consists of phases for growth and division.

• Chromatids: Identical copies of a chromosome.

• Centromere: Region where chromatids are joined.

• Interphase: Cell grows and replicates DNA; includes G1 phase.

• Cell Plate: Forms during plant cell division.

• Example: G1 phase is a period of cell growth.

CHAPTER 16: Molecular Basis of Inheritance

DNA Structure and Replication

DNA is composed of nucleotide pairs and is replicated by specific enzymes.

• Pairing: C-G, T-A base pairs.

• Antiparallel Strands: DNA strands run in opposite directions.

• DNA pol III: Main enzyme for DNA synthesis in prokaryotes.

• Telomerase: Extends telomeres in eukaryotic chromosomes.

• Prokaryotic Chromosomes: Usually circular.

• Example: Human telomerase prevents chromosome shortening.

CHAPTER 13: Meiosis and Sexual Life Cycles

Genome, Chromosome Types, and Karyotype

Meiosis produces gametes and increases genetic diversity.

• Genome: Complete set of genetic material.

• Haploid vs Diploid: Haploid (n) has one set; diploid (2n) has two sets.

• Homologous Chromosomes: Pair of chromosomes with same genes.

• Karyotype: Chromosome display for an individual.

• Genetic Content of Gametes: Human gametes have 23 chromosomes.

• Independent Assortment: Chromosomes segregate independently during meiosis.

CHAPTER 14: Mendel and the Gene Idea

Genetic Crosses and Trait Inheritance

Mendelian genetics explains inheritance patterns.

• Monohybrid Cross: One trait; dihybrid cross: two traits.

• Dominant/Recessive Traits: Dominant masks recessive.

• Punnett Square: Diagram for predicting genetic outcomes.

• Example: Crossing Aa x Aa yields 3:1 ratio.

CHAPTER 15: Chromosomal Basis of Inheritance

Chromosome Theory, Linkage, and Mapping

Genes are located on chromosomes and can be linked.

• Chromosome Theory: Genes are carried on chromosomes.

• X-linked Traits: Traits on X chromosome (e.g., color blindness).

• Z-linked Traits: Found in birds; ZW system.

• Translocation: Chromosome segment moves to another chromosome.

• Gene Linkage: Genes close together are inherited together.

• Testcross: Cross with homozygous recessive to determine genotype.

• Recombination Frequency: Used to create linkage maps.

• Genetic Map Unit: 1% recombination = 1 map unit (centimorgan).

• Example: Linked genes show less recombination than unlinked genes.

CHAPTER 17: Gene Expression: From Gene to Protein

Transcription, Translation, and Genetic Code

Gene expression involves transcription and translation.

• Genetic Code: Codons specify amino acids.

• Transcription: DNA → RNA.

• Translation: RNA → Protein.

• Prokaryotes vs Eukaryotes: Prokaryotes couple transcription and translation; eukaryotes separate them.

• Example: mRNA is translated by ribosomes.

CHAPTER 17.5: Mutations and CRISPR-Cas9

Mutations and Genome Editing

Mutations alter genetic information; CRISPR-Cas9 enables targeted genome editing.

• Point Mutation: Single nucleotide change.

• Frameshift Mutation: Insertion/deletion alters reading frame.

• CRISPR-Cas9: Tool for precise gene editing.

• Example: Sickle cell anemia is caused by a point mutation.

Term	Definition	Example
Genome	Complete set of genetic material	Human genome: ~3 billion base pairs
Haploid	One set of chromosomes (n)	Human gametes (egg/sperm)
Diploid	Two sets of chromosomes (2n)	Human somatic cells
Enantiomer	Mirror-image isomer	L- and D-glucose
Exergonic Reaction	Releases energy	ATP hydrolysis
Point Mutation	Single nucleotide change	Sickle cell anemia
Frameshift Mutation	Insertion/deletion alters reading frame	Cystic fibrosis (ΔF508 mutation)