Biology Chapter 1: Understanding Life

Ideas and Understanding: Week One

• Living organisms exhibit homeostasis, organization, metabolism, reproduction, and evolution.
• Life on Earth evolved from chemical processes over vast time scales.
• Early Earth conditions included high temperatures, CO2, N2, H2O vapor, H2, H2S, NH3, and CH4.
• Key characteristics of life include homeostasis, organization, metabolism, and reproduction.

What is Life?

• There's no strict definition of life, but all living things share certain characteristics:
  • Homeostasis: maintaining internal stability (e.g., temperature, pH)
  • Organization: well-structured, often symmetrical cellular organization
  • Metabolism: energy transformation within the organism
  • Evolution (not an absolute necessity but observed in nature)
  • Reproduction: creating offspring

How Did Life Begin?

• The Earth is approximately 4.5 billion years old.
• Early Earth conditions were different from present day (high temperatures, no free oxygen, etc)
• Possible energy sources included geothermal heat, UV radiation, volcanism, lightning, and meteorites.
• Stanley Miller's experiment simulated early Earth conditions and produced amino acids, proving simple biological molecules could form from inorganic material.

The Prokaryotic Cell

• Prokaryotes are single-celled organisms, lacking a nucleus and membrane-bound organelles.
• They come in various shapes (coccus, bacillus, spiral).
• Genetic material is a single circular chromosome in a nucleoid region.
• Plasmids are small, extrachromosomal DNA molecules, that can be transferred between bacteria.
• Cell walls, often containing peptidoglycan, define the bacterial structure.
• Can be classified as Gram positive or Gram negative based on cell wall characteristics and staining.

The Eukaryotic Cell

• Eukaryotes are organisms with membrane-bound organelles and a nucleus.
• Organelles like nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, and chloroplasts are key features.
• These organelles carry out specific tasks, leading to improved efficiency within the cell.
• Endosymbiotic theory proposes that mitochondria and chloroplasts evolved from free-living prokaryotes.

Ideas and Understanding: Week Two

• The central dogma of biology describes the flow of information from DNA to RNA to protein.
• Differentiate prokaryotic and eukaryotic cells.
• Identify Gram-positive and Gram-negative bacteria through Gram staining.
• Distinguish between animal and plant cells.
• Highlight the endomembrane system's structure and function (nucleus, endoplasmic reticulum, Golgi, lysosomes, vacuoles).
• Contrast mitochondria and chloroplasts in function (respiration and photosynthesis, respectively).
• Outline the endosymbiotic theory.

Ideas and Understanding: Week Three

• Identify the functional groups in molecules and their influence on properties.
• Define chiral centers and stereoisomers.
• Understand the chemical structures of the four major biological molecules (carbohydrates, fats, proteins, and nucleic acids).
• Explain how to synthesize large polymers from monomers (dehydration reactions).
• Differentiate between starch and cellulose and their evolutionary significance.
• Explain the functions of carbohydrates.
• Understand fats and lipids and their types.
• Describe the importance of lipids in biological systems.

Ideas and Understanding: Week Four

• Identify the structure of nucleotides and nucleic acids.
• Understand the base pairing rules in DNA (A-T, G-C).
• Understand the double helix structure of DNA.
• Describe the Hershey-Chase experiment and its significance.
• Understand gel electrophoresis and the visualization of DNA.

Ideas and Understanding: Week Five

• Define and describe amino acid structure.
• Identify the 20 amino acids and their properties.
• Describe the hierarchical levels of protein structure (primary, secondary, tertiary, and quaternary).
• Explain protein folding and Anfinsen's experiment.
• Explain that the primary structure of a protein determines its three-dimensional structure and thus its function.

Ideas and Understanding: Week Six

• Describe the energy exchange in chemical reactions (endergonic, exergonic, Gibbs free energy).
• Explain how ATP is used in coupled reactions.
• Explain the role of enzymes as catalysts and factors affecting enzyme activity.
• Describe factors impacting enzyme activity.