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BIOL 115 Principles of Biology: Final Exam Study Guide

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Study Guide - Smart Notes

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Genetic Inheritance

Basic Inheritance of Mendelian Traits

Genetic inheritance describes how traits are passed from parents to offspring through genes. Mendelian inheritance follows specific patterns first described by Gregor Mendel.

  • Punnett Squares: Used to predict the probability of offspring inheriting particular alleles.

  • Dominant and Recessive Alleles: Dominant alleles mask the effect of recessive alleles in heterozygotes.

  • Phenotype vs. Genotype: Phenotype is the observable trait; genotype is the genetic makeup.

  • Monohybrid and Dihybrid Crosses: Monohybrid crosses involve one gene; dihybrid crosses involve two genes.

  • Quantitative Inheritance: Traits influenced by multiple genes, showing continuous variation (e.g., height).

Example: Crossing two heterozygous pea plants (Yy) for yellow seeds results in a 3:1 ratio of yellow to green seeds in the offspring.

Evolution and Natural Selection

Mechanisms of Evolution

Evolution is the change in allele frequencies in a population over time. Natural selection, genetic drift, mutation, and gene flow are key mechanisms.

  • Natural Selection: Differential survival and reproduction of individuals due to differences in phenotype.

  • Types of Selection: Directional, stabilizing, and disruptive selection.

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

  • Gene Flow: Movement of alleles between populations.

  • Speciation: Formation of new species through reproductive isolation.

Example: The evolution of antibiotic resistance in bacteria is a result of natural selection.

Experimental Design

Scientific Method and Hypothesis Testing

Experimental design is the process of planning a scientific investigation to test hypotheses.

  • Hypothesis: A testable statement about the natural world.

  • Variables: Independent (manipulated), dependent (measured), and controlled variables.

  • Prediction: Expected outcome if the hypothesis is correct.

Example: Testing whether light affects plant growth by comparing plants grown in light versus darkness.

Atoms and Chemical Bonds

Structure of Atoms

Atoms are the basic units of matter, composed of protons, neutrons, and electrons.

  • Protons: Positively charged particles in the nucleus.

  • Neutrons: Neutral particles in the nucleus.

  • Electrons: Negatively charged particles orbiting the nucleus.

Covalent Bonds

  • Polar Covalent Bonds: Electrons are shared unequally, creating partial charges (e.g., H2O).

  • Non-polar Covalent Bonds: Electrons are shared equally (e.g., O2).

Macromolecules

Proteins (Polypeptides)

  • Monomer: Amino acid

  • Levels of Structure: Primary, secondary, tertiary, quaternary

Nucleic Acids (DNA/RNA)

  • Monomer: Nucleotide

  • Base Pairing: A-T, G-C (DNA); A-U, G-C (RNA)

Carbohydrates

  • Monomer: Monosaccharide (simple sugar)

Lipids

  • Monomer: Fatty acid + glycerol

Cells and Organelles

Prokaryotic vs. Eukaryotic Cells

  • Prokaryotes: No nucleus, simple structure (e.g., bacteria)

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

Membrane Structure and Function

Phospholipid Bilayer

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

  • Transport Proteins: Facilitate movement of molecules across the membrane.

  • Osmosis: Diffusion of water across a selectively permeable membrane.

Cellular Processes

Cellular Respiration

  • Aerobic Respiration: Uses oxygen to produce ATP.

  • Anaerobic Respiration: Does not use oxygen (e.g., fermentation).

  • ATP Synthase: Enzyme that synthesizes ATP during cellular respiration.

Photosynthesis

  • Light Reactions: Capture energy from sunlight to produce ATP and NADPH.

  • Calvin Cycle: Uses ATP and NADPH to synthesize glucose from CO2.

Gene Expression and Regulation

Central Dogma of Molecular Biology

  • DNA Replication: Copying DNA before cell division.

  • Transcription: DNA → mRNA by RNA polymerase.

  • Translation: mRNA → Protein by ribosomes and tRNA.

Gene Regulation

  • Prokaryotes: Operons (e.g., lac operon) regulate gene expression.

  • Eukaryotes: More complex regulation involving enhancers, silencers, and transcription factors.

Mitosis and Meiosis

Cell Division

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

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

  • Chromosome Number: Predicting chromosome number in progeny cells.

  • Key Terms: Haploid, diploid, gamete, somatic cell.

Example: Human somatic cells are diploid (2n = 46); gametes are haploid (n = 23).

Summary Table: Macromolecules and Their Monomers

Macromolecule

Monomer

Example

Protein

Amino acid

Enzyme

Nucleic Acid

Nucleotide

DNA, RNA

Carbohydrate

Monosaccharide

Glucose

Fatty acid + Glycerol

Triglyceride

Key Equations

  • Photosynthesis:

  • Cellular Respiration:

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard General Biology curriculum.

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