BIOL 1011K Mid-Term Exam Study Guide

🔬 Unit 1: Introduction to Biology

a. Levels of Organization (Hierarchy of Life)

1. Cell – Basic unit of structure and function in living things.

2. Tissue – Group of cells with similar structure and function (e.g., muscle tissue).

3. Organ – Composed of multiple tissues performing a specific function (e.g., heart).

4. Organ System – Multiple organs working together (e.g., circulatory system).

5. Organism – A single living entity.

6. Population – All individuals of a species living in a given area.

7. Community – All populations in a defined area (only living things).

8. Ecosystem – All living organisms + abiotic factors (water, soil, climate).

9. Biosphere – All ecosystems on Earth (zone of life).

b. Characteristics of Living Things

• Order/Organization

• Reproduction

• Growth & Development

• Energy Processing (Metabolism)

• Homeostasis (Maintaining Internal Stability)

• Response to Environment

• Evolutionary Adaptation

Prokaryotes vs. Eukaryotes

c. Process of Science

• Experimental Design – Uses a control group (baseline for comparison) and experimental group (contains variable being tested).

• Theory – Broad explanation supported by a large body of evidence (e.g., Cell Theory, Evolutionary Theory).

• Hypothesis – Testable and falsifiable proposed explanation. To be valid, it must:

  • Be specific.

  • Predict measurable outcomes.

d. Taxonomy

• Domains:

  • Bacteria – Unicellular prokaryotes with peptidoglycan cell walls.

  • Archaea – Unicellular prokaryotes living in extreme environments.

  • Eukarya – All eukaryotic organisms (plants, animals, fungi, protists).

⚛ Unit 2: The Chemistry of Life

a. Matter and Atomic Structure

• Subatomic Particles:

  • Proton (positive, nucleus)

  • Neutron (neutral, nucleus)

  • Electron (negative, orbitals)

• Isotopes – Same element, different neutron count (affects atomic mass).

• Atomic Mass – Number of protons + neutrons.

b. Chemical Bonds

• Covalent Bonds – Sharing electrons (strongest).

• Ionic Bonds – Transfer of electrons creating charged ions (medium strength).

• Hydrogen Bonds – Weak attraction between partial charges (very important in water, DNA).

c. Properties of Water

• Polar Covalent Bonds within the water molecule.

• Hydrogen Bonds between water molecules.

• Cohesion – Water molecules stick to each other (surface tension).

• Adhesion – Water sticks to other surfaces (capillary action).

• pH Scale:

  • Acid (pH < 7) – More H+ ions.

  • Base (pH > 7) – Fewer H+ ions.

  • Buffers – Stabilize pH by absorbing or releasing H+ ions (critical in blood).

d. Biological Macromolecules

• Amino Acids differ by their R-group.

• Phospholipids – Form membranes (hydrophilic head, hydrophobic tails).

• Nucleotide components – Sugar + Phosphate + Nitrogenous Base.

• Hydrogen bonds stabilize 3D shape of DNA (base pairing) and protein folding (secondary/tertiary structure).

🧬 Unit 3: Cell Structure and Function

a. Cell Theory

• All living things made of cells.

• Cell = basic unit of life.

• Cells arise from pre-existing cells.

b. Microscopes

• Light Microscope – View live cells, lower magnification.

• Electron Microscope – Higher magnification, requires dead samples.

c. Prokaryotes vs. Eukaryotes

d. Animal vs. Plant Cells

e. Organelle Functions

• Nucleus – Stores DNA.

• Mitochondria – ATP production (cellular respiration).

• Chloroplast – Photosynthesis (plants).

• Golgi Apparatus – Packages and modifies proteins.

• Endoplasmic Reticulum:

  • Rough ER – Protein synthesis.

  • Smooth ER – Lipid synthesis.

• Peroxisome – Breaks down fatty acids and toxins (like hydrogen peroxide).

f. Membrane Structure

• Phospholipids form bilayer.

  • Hydrophilic heads face water.

  • Hydrophobic tails hide from water.

• Self-assemble in water (due to amphipathic nature).

⚡ Unit 4: How Cells Obtain Energy

a. Exergonic vs. Endergonic

• Exergonic – Releases energy (spontaneous).

• Endergonic – Requires energy input (non-spontaneous).

b. Metabolic Pathways

• Anabolic – Build complex molecules (consume energy).

• Catabolic – Break down molecules (release energy).

c. Enzymes

• Active Site – Where substrate binds.

• Competitive Inhibitor – Blocks active site.

• Non-competitive Inhibitor – Binds elsewhere (allosteric site), changes enzyme shape.

d. Cellular Respiration (Aerobic)

1. Glycolysis (cytoplasm):

   • Glucose ➡ 2 Pyruvate + 2 ATP + 2 NADH.

2. Citric Acid Cycle (mitochondrial matrix):

   • Pyruvate ➡ CO2 + NADH + FADH2 + 2 ATP.

3. Electron Transport Chain (inner mitochondrial membrane):

   • Uses NADH & FADH2 to pump H+ across membrane.

   • Oxygen = final electron acceptor.

   • H+ gradient powers ATP Synthase ➡ 32-34 ATP.

e. Anaerobic Respiration

• Fermentation (no oxygen):

  • Glycolysis ➡ Pyruvate.

  • Pyruvate is converted to:

    • Alcohol + CO2 (yeast).

    • Lactic Acid (animals).

• Obligate Anaerobes – Die in oxygen (oxygen is toxic).