ap bio ch26-28

Chapter 26: Evolution of Metabolism

• Glycolysis: Initial step in breaking down glucose for energy.

• Protein Pumps: Integral in cellular processes such as respiration.

• Electron Transport Chain (ETC) and Chemiosmosis: Key components of cellular respiration; generate ATP.

• Photosynthesis Splitting H2S: An early form of photosynthesis utilizing hydrogen sulfide.

• Photosynthesis Evolving O2: Later forms of photosynthesis produced oxygen as a byproduct.

• Aerobic Cellular Respiration: Process of producing cellular energy with oxygen.

• Causes of Mass Extinctions:

  • Asteroids

  • Climate change

  • Volcanic activity

  • Seismic activity (earthquakes)

  • Geological events

  • 6th Mass Extinction: Ongoing extinction driven by human activities.

Stages of Chemical Evolution of Life

1. Abiotic Synthesis of Monomers:

   • Formation of simple organic molecules (e.g., amino acids) from carbon and nitrogen.

2. Joining into Polymers:

   • Polymers formed by linking monomers (e.g., amino acids into proteins).

3. Protobiont Formation (Aggregation):

   • Formation of droplets with distinct chemical properties.

4. Origin of Heredity:

   • Development of mechanisms for replication.

Characteristics of First Organism

• Prokaryotic: Lack membrane-bound organelles; no nucleus.

• Chemoheterotrophic: Derived energy and carbon from organic compounds.

• Reproduced Asexually: Binary fission.

• Anaerobic Metabolism: Utilized in low-oxygen conditions.

Chapter 27: Three Domains of Life

• Bacteria

• Archaea:

  • More closely related to Eukarya due to cell wall composition and initiator amino acid.

• Eukarya

Bacterial Shapes

• Coccus: Spherical.

• Bacillus: Rod-shaped.

• Spirillum: Spiral-shaped.

Genophore

• Prokaryotic chromosome structure.

Gram Staining

• Gram Positive (+): More peptidoglycan; stains purple.

• Gram Negative (-): Less peptidoglycan; stains red/pink.

Means of Locomotion in Prokaryotes

• Flagella: Rotating tail structures for movement.

• Axial Filaments: Bundles of fibers extending along the length of the organism.

• Gliding Motility: Slime secretion facilitating movement.

• Pili: Non-locomotive, used for attachment.

Reproduction in Prokaryotes

• Asexual: Binary fission.

• Sexual: Conjugation via sex pilus; Transduction: DNA transfer through viruses.

Types of Metabolism

• Photoautotrophic: Light energy and CO2 as a carbon source.

• Chemoautotrophic: Inorganic chemicals as energy source; CO2 as carbon source.

• Photoheterotrophic: Light energy and organic compounds as carbon source.

• Chemoheterotrophic: Organic compounds for both energy and carbon source.

Prokaryote Diversity

• Important focus area for free-response questions (FRQ).

• Diversity Types: Nutrition, metabolism, environments (e.g., heterocysts in cyanobacteria for nitrogen fixation).

Importance of Prokaryotes

• Health Impact: Some produce antibiotics; others are pathogens.

• Bioremediation: Breakdown of environmental pollutants (e.g., plastics, oil spills).

• Nitrogen Fixation: Essential for converting atmospheric nitrogen for ecological use.

• DNA Technology: Utilization in recombinant technologies.

• Fermentation: Used in food products like pickles and bread.

Symbiosis in Prokaryotes

• Mutualism: E. coli in human gut.

• Parasitism: Pathogenic bacteria.

• Commensalism: Non-harming relationship.

Chapter 28: Endosymbiont Theory

• Origin of eukaryotic cells through engulfment of aerobic prokaryotes.

• Evidence includes: double membranes, ribosome similarity to prokaryotic forms, and the ability for binary fission.

• Double Membrane: Mitochondria and chloroplasts exhibit this characteristic.

Characteristics of Protists

• Highly diverse kingdom including:

  • Protozoans: Chemoheterotrophic, often motile (e.g., amoebas, ciliates).

  • Algae: Photoautotrophic, primarily unicellular (e.g., diatoms, green algae).

  • Fungi-like Protists: Decomposers (e.g., slime molds).

Diversity of Protists

• Classification by movement and structure (e.g., rhizopoda with pseudopods, apicomplexa as parasitic).

• Algal Classification: Based on cell wall composition (e.g., silica in diatoms).

Alternation of Generations

• Life cycles featuring both haploid and diploid stages.

  • Example: Humans briefly exhibit a haploid stage during gamete formation.

Importance of Protists

• Producers: Algae contribute to oxygen production.

• Decomposers: Organisms breaking down organic matter.

• Pathogens: Some cause diseases (e.g., Plasmodium for malaria).

• Industrial Use: Diatoms used in toothpastes.