bio exam 1

Chapter 1: Introduction to Biology

1. Science: A method for understanding the natural world through observation and experiments.

Biology: The study of living things and their interactions.

2. Importance of Biology: Helps us understand life, medicine, the environment, and genetics.

3. Characteristics of Life: Growth, reproduction, response to stimuli, metabolism, homeostasis, adaptation, organization.

4. Hierarchy of Life: Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Organism → Population → Community → Ecosystem → Biosphere.

5. Scientific Discovery Process: Observations → Questions → Hypothesis → Experiment → Data Analysis → Conclusion.

6. Hypothesis vs. Theory: A hypothesis is a testable statement; a theory is a well-supported explanation backed by evidence.

7. Variable: A factor that can change in an experiment.

• Independent: What you change.

• Dependent: What you measure.

• Controlled: Kept constant.

8. 4 Unifying Themes of Biology: Evolution, Energy Flow, Information Flow (DNA), Structure & Function Relationship.

Chapter 2: Chemistry of Life

1. Atom Structure: Made of protons (+), neutrons (0), and electrons (-).

2. Subatomic Particles:

• Protons: Positive, in nucleus.

• Neutrons: Neutral, in nucleus.

• Electrons: Negative, orbit nucleus.

3. Atomic Number vs. Atomic Mass:

• Atomic number = protons.

• Atomic mass = protons + neutrons.

4. Atoms vs. Isotopes: Isotopes have the same number of protons but different numbers of neutrons.

5. Importance of Isotopes: Used in medicine (e.g., radiation therapy, medical imaging).

6. Energy Levels: Electrons exist in shells around the nucleus, moving to higher shells requires energy.

7. Octet Rule: Atoms are stable with 8 outer electrons.

8. Ions: Atoms that gain or lose electrons to become charged.

9. Chemical Identity: Determined by the number of protons.

10. Redox Reactions:

• Oxidation = losing electrons.

• Reduction = gaining electrons.

11. How Molecules Form: Chemical bonds (ionic, covalent, hydrogen).

12. Bond Types:

• Ionic: Electrons transferred.

• Covalent: Electrons shared.

• Hydrogen: Weak bond between molecules.

13. Polar vs. Nonpolar Covalent Bonds:

• Polar: Unequal sharing (water).

• Nonpolar: Equal sharing (oxygen gas).

14. Electronegativity: An atom’s ability to attract electrons.

15. Water’s Importance: Essential for life due to cohesion, adhesion, and solvent abilities.

16. Water Ionization: Breaks into H+ and OH-.

17. Acids vs. Bases:

• Acids: Donate H+ (e.g., lemon juice).

• Bases: Accept H+ (e.g., baking soda).

18. pH Scale: 0-6 acidic, 7 neutral, 8-14 basic.

19. Buffers: Help maintain a stable pH in biological systems.

Chapter 3: Biological Molecules

1. Carbon Chemistry: Carbon can form four bonds, making complex molecules.

2. 4 Biological Macromolecules: Carbohydrates, lipids, proteins, nucleic acids.

3. Chemical Composition:

• Carbs: C, H, O

• Lipids: C, H, O

• Proteins: C, H, O, N

• Nucleic Acids: C, H, O, N, P

4. Functional Groups: Groups of atoms affecting molecule behavior (e.g., hydroxyl, carboxyl).

5. Monomers & Polymers:

• Carbs: Monosaccharides → Polysaccharides.

• Proteins: Amino acids → Polypeptides.

• Nucleic Acids: Nucleotides → DNA/RNA.

6. Dehydration vs. Hydrolysis:

• Dehydration: Removes water to build molecules.

• Hydrolysis: Adds water to break molecules.

7. Monosaccharides (simple sugars): Glucose, fructose.

8. Disaccharides (two sugars): Sucrose, lactose.

9. Polysaccharides (many sugars): Starch, cellulose, glycogen.

10. Isomers: Same formula, different structure (e.g., glucose vs. fructose).

11. Cellulose vs. Chitin: Both structural carbs, but cellulose is in plants and chitin in fungi/insects.

12. DNA vs. RNA: DNA stores genetic info, RNA helps make proteins.

13. Amino Acid Structure: Contains an R group that defines its properties.

14. Protein Structure:

• Primary: Amino acid sequence.

• Secondary: Helix or sheet.

• Tertiary: 3D shape.

• Quaternary: Multiple protein units.

15. Saturated vs. Unsaturated Fats:

• Saturated: Solid, single bonds.

• Unsaturated: Liquid, double bonds.

16. Lipids: Hydrophobic molecules like fats, oils, and phospholipids.

17. Lipids vs. Starches: Lipids store more energy per gram.

Chapter 4: Cells

1. Why Cells Are Small: Large surface area helps transport materials efficiently.

2. Plasma Membrane: Controls what enters/exits.

3. Cell Theory:

• All living things are made of cells.

• Cells are the basic unit of life.

• Cells come from existing cells.

4. Prokaryotic vs. Eukaryotic:

• Prokaryotic: Simple, no nucleus (bacteria).

• Eukaryotic: Complex, has nucleus (animals, plants).

5. Eukaryotic Organelles & Functions:

• Nucleus: DNA storage.

• Ribosomes: Make proteins.

• ER: Processes molecules.

• Golgi: Packages proteins.

• Mitochondria: Energy production.

• Lysosomes: Break down waste.

6. Cytoskeleton: Provides structure.

7. Plant vs. Animal Cells: Plants have cell walls, chloroplasts, and vacuoles.

8. Endosymbiotic Theory: Mitochondria and chloroplasts originated from bacteria.

Chapter 5: Membranes & Transport

1. Phospholipids: Make up cell membranes.

2. 4 Components of Membranes: Phospholipids, proteins, carbs, cholesterol.

3. Fluid Mosaic Model: Membrane is flexible with moving proteins.

4. Membrane Proteins: Transport, enzymes, receptors.

5. Passive Transport: No energy needed (diffusion, osmosis).

6. Active Transport: Requires energy (pumps, endocytosis).

7. Osmosis: Water moves to balance solute concentration.

8. Endocytosis: Cell takes in material (e.g., phagocytosis).

9. Exocytosis: Cell releases material.

10. Selective Permeability: Only some substances pass through membranes.