Biology Lecture Notes

Introduction

• The lecture is based on a series of educational biology videos by Amoeba Sisters.
• Purpose: To provide a brief recap of key points across various biology topics to aid in studying.

Characteristics of Life

• Life is difficult to define with many exceptions.
• Characteristics of life are broad and varied.
• Biological levels of organization: cell -> tissue -> organ -> organ system -> organism -> population -> community -> ecosystem -> biome -> biosphere.

Biomolecules

• Four major macromolecules: carbohydrates, lipids, proteins, nucleic acids.
• Building blocks:
  • Carbohydrates: monosaccharides
  • Lipids: fatty acids & glycerol
  • Proteins: amino acids
  • Nucleic acids: nucleotides
• Functions of biomolecules are vital for life processes.

Enzymes

• Enzymes have active sites where substrates bind.
• Role: Speed up reactions, break down/build up substrates.
• Optimal conditions: specific temperature and pH.
• Denaturation occurs if conditions are unfavorable.

Cell Biology

• Prokaryotic vs. Eukaryotic cells:
  • Prokaryotes: No nucleus, no membrane-bound organelles (bacteria & archaea).
  • Eukaryotes: Have a nucleus and organelles (plants, animals, protists, fungi).
• Common features: DNA, cytoplasm, ribosomes, cell membrane.
• Importance of the cell membrane:
  • Made of phospholipids, controls movement in/out of the cell.
  • Types of transport: passive (simple/facilitated diffusion) and active.

Cellular Respiration and Photosynthesis

• Cellular respiration occurs in mitochondria, breaking down glucose for ATP.
• Photosynthesis happens in chloroplasts, producing glucose using sunlight.
• Chemical equations are not direct reverses of each other.

DNA Structure and Function

• DNA is a nucleic acid containing genetic information.
• Structure: Double helix, anti-parallel strands.
• Base pairing: Adenine-Thymine, Cytosine-Guanine.
• DNA replication is essential for cell division.

Cell Cycle

• Phases: G1, S, G2, M phase (mitosis and cytokinesis).
• Checkpoints regulate cycle, apoptosis if errors occur.
• Cancer cells bypass checkpoints, leading to uncontrolled division.

Mitosis vs. Meiosis

• Mitosis: Produces identical body cells.
• Meiosis: Produces gametes (sperm and eggs), involves crossing over and independent assortment.
• PMAT mnemonic for phases.

Genetics

• Mendelian genetics: Dominant vs. recessive alleles, Punnett squares.
• Non-Mendelian genetics: Incomplete dominance, codominance, sex-linked traits.
• Pedigrees track traits through generations.

Protein Synthesis

• Steps: Transcription (mRNA), Translation (polypeptide chain at ribosome).
• Involves mRNA, rRNA, tRNA, and codon reading.

Mutations

• Gene mutations: substitution, deletion, insertion (frameshift potential).
• Chromosomal mutations: duplication, deletion, inversion, translocation.

Evolution

• Natural selection: Traits enhancing fitness become more common.
• Genetic drift: Random events affect allele frequency.

Bacteria and Viruses

• Bacteria: Unicellular prokaryotes, can be autotrophs/heterotrophs.
• Viruses: Non-living, require a host, reproduce via lytic/lysogenic cycles.

Classification

• Three domains: Bacteria, Archaea, Eukarya.
• Taxonomy levels: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Plants

• Nonvascular vs. vascular plants: water transport methods.
• Photosynthesis: Requires water, carbon dioxide, light.
• Reproduction: Sexual (angiosperms) and asexual.

Ecosystems

• Energy pyramids: Trophic levels and energy transfer.
• Ecological succession: Primary vs. secondary.
• Nitrogen and carbon cycles: Importance for ecosystems.

Symbiotic Relationships

• Predation, competition, commensalism, parasitism, mutualism.

Human Body Systems

• Overview of 11 systems and their functions.
• Importance of interconnectedness of systems.

Conclusion

• Biology as an interconnected science; importance of understanding relationships.
• Encouragement to explore full videos for in-depth understanding.