GEN SCI MAJORSHIP HANDOUT

Science and the Scientific Method

• Science: A systematic pursuit of knowledge about the natural world.

• Scientific Method Steps:

  • Step 1: Ask a question.

  • Step 2: State a hypothesis.

  • Step 3: Conduct an experiment.

  • Step 4: Analyze the results.

  • Step 5: Make a conclusion.

Variables

• Variables: Characteristics that can assume different values.

  • Qualitative Variables: Distinct characteristics (e.g., gender, color).

  • Quantitative Variables: Numerical and can be ordered (e.g., age, height).

  • Independent Variable: Variable being manipulated (cause).

  • Dependent Variable: Changes depending on manipulations (effect/result).

  • Controlled Variable: Held constant to ensure a fair test.

Characteristics of Life

• Homeostasis: Ability to maintain internal balance.

• Organization: Biological structures organized at various levels.

• Metabolism: Sum of all chemical reactions in a cell.

• Growth and Development: Changes in size and form throughout life.

• Adaptation: Adjustments to environment for survival.

• Reproduction: Ability to produce new individuals.

• Response to Stimulus: Ability to react to environmental changes.

Branches of Biology

• Anatomy: Study of body parts and their locations.

• Physiology: Functions of body parts.

• Morphology: Forms of organisms.

• Histology: Study of tissues.

• Biochemistry: Chemical processes in living systems.

• Cytology: Study of cells.

• Ecology: Interactions with ecosystems.

• Genetics: Genes and heredity.

• Microbiology: Microorganisms.

• Mycology: Study of fungi.

• Phycology: Study of algae.

• Parasitology: Study of parasites.

• Taxonomy: Classification of organisms.

• Botany: Study of plants.

• Zoology: Study of animals.

• Ethology: Study of animal behavior.

• Ichthyology, Ornithology, Entomology: Studies specific to fishes, birds, and insects, respectively.

• Paleontology: Study of fossils.

• Phylogeny: Evolutionary history of organisms.

• Pathology: Study of diseases.

• Endocrinology: Study of hormones.

Contributions of Famous Individuals in Biology

• Robert Hooke: Discovered cells; coined the term "cell".

• Robert Brown: Discovered the cell's nucleus.

• Louis Pasteur: Father of microbiology; developed pasteurization.

• Alexander Fleming: Discoverer of penicillin.

• Robert Koch: Germ Theory of Disease.

• Edward Jenner: Developed smallpox vaccine.

• Anton Van Leuwenhoek: Father of microscopy.

• Gregor Mendel: Founder of genetics.

• Carolus Linnaeus: Father of taxonomy.

• Charles Darwin: Developed the theory of natural selection.

Cell Types

• Somatic Cells: All body cells except sex cells; undergo mitosis.

  • Diploid (2n): Contains two sets of chromosomes.

• Sex Cells/Gametes: Sperm and egg cells; haploid (n).

Cell Theory (Schwann, Schleden, Virchow)

1. All organisms are composed of cells.

2. A cell is the basic unit of structure and function.

3. Cells arise from pre-existing cells.

Cellular Structure and Function

1. Plasma Membrane: Selective barrier controlling nutrient and waste passage.

2. Nucleus: Contains most of the cell's genetic material; largest organelle.

   • Nucleolus: Site of ribosome production.

3. Cytoplasm: Gel-like fluid where organelles reside.

4. Ribosomes: Protein synthesis sites.

5. Endoplasmic Reticulum (Rough/Smooth): Biosynthetic factory.

6. Golgi Apparatus: Packaging and shipping center.

7. Mitochondrion: Powerhouse converting food to energy (ATP).

8. Lysosomes: Digestive compartments for waste.

9. Chloroplast (in plants): Site of photosynthesis.

10. Cell Wall: Protective layer in plant and fungi cells.

11. Central Vacuoles: Storage and maintenance of cell shape in plants.

12. Cytoskeleton: Provides support and facilitates movement.

13. Cilia and Flagella: Hair-like structures for movement.

Cellular Transport Mechanisms

1. Passive Transport: No energy required; substances move along concentration gradient.

   • Example: Diffusion, facilitated diffusion, osmosis.

   • Hypotonic: Cell swells; Isotonic: No net movement; Hypertonic: Cell shrinks.

2. Active Transport: Energy required to move substances against the gradient.

3. Bulk Transport: Transport of large particles (e.g., phagocytosis, pinocytosis).

Cell Division

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

• Meiosis: Produces four genetically varied haploid gametes (sexual reproduction).

• Aneuploidy: Abnormal number of chromosomes leading to syndromes like Down's or Turner’s.

Common Elements in Living Organisms

• Oxygen (65%), Carbon (18%), Hydrogen (10%), Nitrogen (3%).

• Calcium: Most abundant mineral in the human body.

Organic and Inorganic Molecules

• Inorganic Compounds: Water, acids (e.g., HCl), bases (e.g., NaOH), salts (e.g., NaCl).

• Organic Compounds: Carbohydrates, proteins, lipids, nucleic acids.

Macromolecules

1. Carbohydrates: Energy source; includes monosaccharides, disaccharides, and polysaccharides.

2. Proteins: Composed of amino acids; roles in structure and function.

3. Nucleic Acids: DNA and RNA; essential for heredity and protein synthesis.

4. Lipids: Glycerol and fatty acids as building blocks; function as energy sources and insulation.

Taxonomy and Classification

• Carolus Linnaeus: Developed binomial nomenclature. 8 levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

• Two Kingdom System (Plantae and Animalia); later expanded to five including Fungi, Monera, and Protista.

Viruses

• Not considered living; consist of genetic material and protein coats.

• Types: Bacteriophages, DNA viruses, RNA viruses, retroviruses (e.g., HIV).

Ecology and Ecosystem Roles

• Autotrophs: Producers (e.g., plants); Heterotrophs: Consumers (e.g., humans). Saprotrophs: Feed on decomposing matter (e.g., fungi).

• Energy in Ecosystems: 1st law (energy conservation), 2nd law (inefficiency in transformation).

• Photosynthesis: Converts sunlight into glucose; oxygen as a byproduct.

Types of Ecosystems and Biomes

1. Biosphere: Global ecological system.

2. Biomes: Tundra, Taiga, Temperate Forest, Tropical Rainforest, Grasslands, Deserts.

3. Ecological Succession: Primary (new habitat) and secondary (disturbed habitat).

Adaptation and Evolution

• Evolution: Change in heritable traits over generations.

• Natural Selection: Process where organisms better adapted survive and reproduce.

Genetics and Heredity

• Gregor Mendel: Father of genetics; laws of inheritance (segregation, independent assortment, dominance).

• Non-Mendelian Inheritance: Includes incomplete dominance, codominance, polygenic traits.

Planetary Science

• Solar System: General characteristics of planets, inner vs outer planets.

  • Inner Planets: Mercury, Venus, Earth, Mars.

  • Outer Planets: Jupiter, Saturn, Uranus, Neptune.

Earth Systems and Geology

• Lithosphere: Crust, mantle, core; types of rocks (igneous, sedimentary, metamorphic).

• Hydrosphere: Water cycle; precipitation types.

Atmospheric and Meteorological Concepts

• Atmospheric Layers: Troposphere, Stratosphere (ozone), Mesosphere, Thermosphere, Exosphere.

• Physical and Chemical Changes: Processes such as melting, freezing, and evaporation.

Physics Principles

• Newton’s Laws of Motion: Inertia, acceleration, and action/reaction principles.

• Thermodynamics: Heat transfer methods; conservation of energy.