General Biology Semester Exam Review Guide: Key Concepts and Study Notes

Chapter 1: Biology – The Study of Scientific Life

Section 1.1: What is Life?

Biology is the scientific study of life, encompassing the structure, function, growth, origin, evolution, and distribution of living organisms.

• Definition of Life: Life is characterized by properties such as order, reproduction, growth and development, energy processing, response to environment, regulation, and evolutionary adaptation.

• Levels of Biological Organization: Life is organized from molecules to biosphere, including cells, tissues, organs, organisms, populations, communities, and ecosystems.

• Scientific Method: A systematic approach to inquiry involving observation, hypothesis formation, experimentation, and analysis.

Example: The process of photosynthesis in plants demonstrates energy processing and adaptation.

Section 1.4: The Process of Science

• Hypothesis: A testable explanation for a set of observations.

• Controlled Experiment: An experiment in which only one variable is changed at a time.

• Data Analysis: Interpretation of results to support or refute hypotheses.

Example: Testing the effect of sunlight on plant growth using control and experimental groups.

Chapter 2: The Chemical Basis of Life

Section 2.2 & 2.3: Structure of Water

Water is essential for life due to its unique chemical properties, which arise from its molecular structure and hydrogen bonding.

• Polarity: Water molecules have a partial positive charge on hydrogen and a partial negative charge on oxygen, making them polar.

• Hydrogen Bonding: Attraction between water molecules leads to cohesion, adhesion, and high specific heat.

• Importance: Water's properties support life by facilitating chemical reactions, temperature regulation, and transport of substances.

Equation: $H_2O$

Example: Water dissolves salts and sugars, enabling cellular processes.

Chapter 3: The Molecules of Cells

Section 3.1-3.4: Organic Compounds

Cells are composed of organic molecules, including carbohydrates, lipids, proteins, and nucleic acids.

• Organic vs. Inorganic Compounds: Organic compounds contain carbon and hydrogen; inorganic compounds do not.

• Macromolecules: Large molecules formed by polymerization of smaller units (monomers).

• Hydrolysis/Dehydration Synthesis: Hydrolysis breaks polymers into monomers; dehydration synthesis joins monomers to form polymers.

Example: Starch (a carbohydrate) is broken down into glucose by hydrolysis.

Chapter 4: A Tour of the Cell & Chapter 5: The Working Cell

Section 4.2-4.8: Cell Structure and Function

Cells are the basic units of life, with structures specialized for various functions.

• Prokaryotic vs. Eukaryotic Cells: Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have both.

• Cell Organelles: Nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, etc.

• Plasma Membrane: Regulates entry and exit of substances; composed of a phospholipid bilayer.

Example: Mitochondria are the site of cellular respiration, producing ATP.

Section 5.1-5.6: Membrane Transport and Energy

• Passive Transport: Movement of substances across membranes without energy input (diffusion, osmosis).

• Active Transport: Movement against concentration gradient, requiring energy (ATP).

• Enzymes: Biological catalysts that speed up chemical reactions by lowering activation energy.

Equation: $ATP + H_2O \rightarrow ADP + P_i + \text{energy}$

Example: Sodium-potassium pump maintains cell potential by active transport.

Chapter 6: How Cells Harvest Chemical Energy & Chapter 7: Photosynthesis

Section 6.1-6.4 & 7.1-7.4: Cellular Respiration and Photosynthesis

Cells obtain energy through cellular respiration and photosynthesis, converting chemical energy into usable forms.

• Cellular Respiration: Process by which cells break down glucose to produce ATP.

• Photosynthesis: Process by which plants convert light energy into chemical energy (glucose).

• Stages of Cellular Respiration: Glycolysis, Krebs Cycle, Electron Transport Chain.

• Stages of Photosynthesis: Light-dependent reactions, Calvin Cycle.

Equation (Cellular Respiration): $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy (ATP)}$

Equation (Photosynthesis): $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$

Example: Muscle cells use cellular respiration to generate energy for movement.

Chapter 8: The Cellular Basis of Reproduction and Inheritance

Section 8.1-8.13: Cell Division

Cell division is essential for growth, repair, and reproduction in living organisms.

• Mitosis: Division of a cell into two genetically identical daughter cells.

• Meiosis: Division that produces gametes with half the chromosome number of the parent cell.

• Chromosomes: Structures that carry genetic information.

• Cell Cycle: Series of events leading to cell division and duplication.

Example: Skin cells undergo mitosis for tissue repair.

Chapter 10: Molecular Biology of the Gene

Section 10.1-10.13: DNA Structure and Function

Genes are composed of DNA, which stores and transmits genetic information.

• DNA Structure: Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).

• Replication: Process by which DNA makes a copy of itself.

• Transcription: Synthesis of RNA from DNA template.

• Translation: Synthesis of proteins from RNA template.

Equation: $\text{DNA} \xrightarrow{\text{transcription}} \text{RNA} \xrightarrow{\text{translation}} \text{Protein}$

Example: Hemoglobin protein is synthesized from instructions encoded in DNA.

Additional info:

• Some topics and review questions reference diagrams and lab activities; students should consult their textbook or class materials for visual aids.

• Key terms such as "chromatid," "centromere," "spindle fibers," and "codon" are essential for understanding cell division and gene expression.