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General Biology II: Molecular Genetics, Gene Expression, Viruses, and Biotechnology – Study Guide

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Study Guide - Smart Notes

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Course Overview

This course covers advanced topics in general biology, focusing on molecular genetics, gene expression, viruses, and biotechnology. The material is designed to provide a strong foundation for upper-level biology courses and includes both theoretical concepts and practical applications.

Molecular Basis of Inheritance

Initiation of DNA Replication

  • Origins of Replication: Specific sequences where DNA replication begins.

  • Replication Forks and Bubbles: Structures formed during the unwinding of DNA for replication.

  • DNA Polymerases: Enzymes that synthesize new DNA strands by adding nucleotides to a primer.

Elongation of New DNA Strands

  • Leading Strand: Synthesized continuously in the 5' to 3' direction.

  • Lagging Strand: Synthesized discontinuously as Okazaki fragments.

  • Priming DNA Synthesis: Short RNA primers are laid down to initiate synthesis.

  • DNA Replication Machinery: Includes helicase, primase, DNA polymerase, ligase, and single-strand binding proteins.

Proofreading and Repairing DNA

  • Proofreading: DNA polymerases check and correct errors during replication.

  • Repair Mechanisms: Include mismatch repair and nucleotide excision repair.

Telomeres and Telomerase

  • Telomeres: Repetitive DNA sequences at chromosome ends that protect genetic data.

  • Telomerase: Enzyme that extends telomeres, especially in germ cells and cancer cells.

Chromatin Packing in Eukaryotic Chromosomes

  • Chromatin: DNA-protein complex that packages DNA into a compact, dense shape.

  • Levels of Packing: Nucleosomes, 30-nm fiber, looped domains, and metaphase chromosome.

From Gene to Protein

Central Dogma of Molecular Biology

  • Central Dogma: Information flows from DNA → RNA → Protein.

Transcription (Initiation, Elongation, Termination)

  • RNA Polymerases: Enzymes that synthesize RNA from a DNA template.

  • Promoters: DNA sequences where RNA polymerase binds to initiate transcription.

  • Transcription Factors: Proteins that regulate the binding of RNA polymerase to DNA.

  • Termination: Sequence-dependent process that ends transcription.

RNA Processing in Eukaryotes

  • Splicing: Removal of introns and joining of exons.

  • Alternative RNA Splicing: Allows a single gene to code for multiple proteins.

Translation (Initiation, Elongation, Termination)

  • Ribosomes: Sites of protein synthesis, composed of rRNA and proteins.

  • tRNA: Transfer RNA brings amino acids to the ribosome.

  • Codons: Triplets of nucleotides in mRNA that specify amino acids.

  • Anticodon Recognition, Wobble: Flexibility in base pairing at the third codon position.

  • Mutations: Changes in DNA sequence that can affect protein function.

Regulation of Gene Expression

Regulation in Bacteria

  • Operons: Clusters of genes under control of a single promoter (e.g., lac operon).

  • Repressors and Activators: Proteins that inhibit or promote transcription.

Regulation in Eukaryotes

  • Chromatin Modification: Histone acetylation and DNA methylation affect gene accessibility.

  • Epigenetics: Heritable changes in gene expression not involving changes to DNA sequence.

  • Transcriptional Regulation: Involves enhancers, silencers, and transcription factors.

  • RNA Interference (RNAi): Small RNAs (miRNA, siRNA) regulate gene expression post-transcriptionally.

  • Genetic Changes and Cancer: Proto-oncogenes and tumor-suppressor genes regulate cell growth and division.

Viruses

Structure and Types

  • Capsids: Protein shells that enclose viral genomes.

  • Viral Genomes: Can be DNA or RNA, single- or double-stranded.

  • Viral Envelopes: Lipid membranes derived from host cells (present in some viruses).

Viral Life Cycles

  • Lytic Cycle: Virus replicates and lyses the host cell.

  • Lysogenic Cycle: Viral DNA integrates into host genome and replicates with it.

Animal Viruses and Vaccines

  • Classification: Based on genome type and replication method (Classes I-VI).

  • Vaccines: Biological preparations that provide immunity to specific viruses.

Biotechnology

DNA Manipulation

  • Next-Generation Sequencing: High-throughput methods for sequencing DNA.

  • Genome Editing (CRISPR): Technology for precise modification of DNA sequences.

Cloning Organisms

  • Reproductive Cloning: Producing genetically identical organisms.

  • Therapeutic Cloning: Producing stem cells for medical treatment.

Stem Cells

  • Embryonic Stem Cells: Pluripotent cells from early embryos.

  • Induced Pluripotent Stem Cells (iPS cells): Adult cells reprogrammed to a pluripotent state.

Genetic Recombination & Linkage

  • Genetic Recombination: Exchange of genetic material during meiosis, increasing genetic diversity.

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

Population Genetics and Evolution

  • Population Genetics: Study of genetic variation within populations and how it changes over time.

  • Evolution: Change in allele frequencies in a population over generations.

Ecology and Conservation Biology

  • Ecology: Study of interactions between organisms and their environment.

  • Conservation Biology: Science of protecting and managing biodiversity.

Grading Policy Table

Component

Percentage

Attendance

3.0%

Homework

10.0%

Top Hat Questions

5.0%

1st Exam

15%

2nd Exam

17%

Final Exam

50%

Exam and Topic Schedule Table

Topics

Start Date

Chapters

Genetic Recombination & Genetic Linkage

17 October

14, 15

Overview of Evolution

22 October

22

Population Genetics

31 October

23

Exam

7 November

Exam

History of Life, Phylogeny

10 November

25, 26

Ecology

19 November

54

Conservation Biology

3 December

All topics covered during second half of the semester

Final Exam, cumulative for 2nd half of semester

8 December, 8:00 – 10 AM

All topics covered during second half of the semester

Key Study Tips

  • Attend all lectures and participate actively.

  • Spend 9-12 hours per week outside of class studying the material.

  • Do all assigned homework and Top Hat questions to reinforce understanding.

  • Form study groups and seek help from the instructor or learning center as needed.

  • Review and test yourself regularly to retain information.

Important Definitions and Concepts

  • Operon: A unit of genetic function found in bacteria and phages, consisting of a promoter, an operator, and a coordinately regulated cluster of genes.

  • Epigenetics: The study of heritable changes in gene function that do not involve changes in the DNA sequence.

  • CRISPR: A genome editing tool that allows for precise, targeted changes to the DNA of living organisms.

  • Pluripotent Stem Cells: Cells that can develop into almost any type of cell in the body.

Key Equations

  • Hardy-Weinberg Equation (Population Genetics):

  • Where p and q are the frequencies of two alleles in a population.

Example: The lac Operon in Bacteria

  • The lac operon is an example of gene regulation in Escherichia coli. It is turned on in the presence of lactose and off when lactose is absent, allowing the cell to conserve energy.

Additional info: Some context and definitions have been expanded for clarity and completeness based on standard General Biology II curricula.

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