General Biology Study Guide: Foundations, Chemistry, Water, and Organic Molecules

Chapter 1: Introduction to Biology and the Scientific Method

Key Terms and Concepts

This chapter introduces the foundational principles of biology and the scientific method, which is essential for conducting biological research.

• Terms: Hypothesis, Prediction, Experimental Variables, Control Variables, Constants/Controls, Independent Variable, Dependent Variable, Natural Selection, Adaptation, Descent with Modification, Evolution

Scientific Method

• Definition: A systematic process for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.

• Steps: Observation, Question, Hypothesis, Experiment, Data Collection, Analysis, Conclusion.

• Experiment: A controlled procedure carried out to test a hypothesis.

• Variables: Independent variable is manipulated; dependent variable is measured.

• Graphing: Independent variable on the x-axis, dependent variable on the y-axis.

Properties of Life

• Characteristics: Organization, metabolism, homeostasis, growth, reproduction, response to stimuli, adaptation through evolution.

Evolution and Natural Selection

• Charles Darwin: Proposed the theory of natural selection, explaining how species evolve over time.

• Natural Selection: Process by which organisms better adapted to their environment tend to survive and produce more offspring.

• Descent with Modification: Passing traits from parent to offspring, with changes accumulating over generations.

• Unity and Diversity: Evolution explains both the similarities and differences among living organisms.

Example

• Example: Darwin’s finches on the Galápagos Islands evolved different beak shapes to exploit different food sources.

Chapter 2: Chemistry and Biology

Essential Elements and Atomic Structure

This chapter covers the basic chemical principles underlying biological processes, including atomic structure, chemical bonds, and isotopes.

• Terms: Element, Compound, Atom, Subatomic Particle, Proton, Neutron, Electron, Atomic Number, Mass Number, Isotope, Ion, Atomic Mass/Weight, Radioactive Isotope, Half-life, Radioactive Dating, Kinetic Energy, Potential Energy, Valence Shell, Valence Electron, Electronegativity, Covalent Bond, Ionic Bond, Hydrogen Bond, Van der Waals Forces, Hydrophobic Interaction, Chemical Reaction, Chemical Equilibrium

Essential Elements

• Definition: Elements required for life, such as carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.

• Application: These elements are found in the human body and are vital for biological molecules.

Atomic Structure

• Atoms: Consist of protons, neutrons, and electrons.

• Atomic Number: Number of protons in the nucleus.

• Mass Number: Sum of protons and neutrons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Radioactive Isotopes: Unstable isotopes that decay over time, used in dating fossils and medical imaging.

• Half-life: Time required for half of the radioactive atoms to decay.

Chemical Bonds

• Covalent Bond: Sharing of electron pairs between atoms.

• Ionic Bond: Transfer of electrons from one atom to another, resulting in charged ions.

• Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom.

• Van der Waals Forces: Weak interactions due to transient charges.

• Hydrophobic Interaction: Nonpolar molecules aggregate to avoid water.

Chemical Reactions and Equilibrium

• Chemical Reaction: Process that changes one set of chemicals into another.

• Chemical Equilibrium: State where the rate of forward and reverse reactions are equal.

Example

• Example: Water formation: $2H_2 + O_2 \rightarrow 2H_2O$

Chapter 3: Water and Its Properties

Importance and Properties of Water

This chapter explores the unique properties of water that make it essential for life, including its molecular structure, physical states, and behavior in biological systems.

• Terms: Solid, Liquid, Gas, Polar Molecule, Cohesion, Adhesion, Surface Tension, Temperature, Calorie, Kilocalorie, Specific Heat, Evaporation, Evaporative Cooling, Solution, Solute, Solvent, Aqueous Solution, Hydrophilic, Hydrophobic, Molecular Mass, Molarity, Hydrogen Ion, Hydroxide Ion, Acid, Base, Buffer

Physical States and Properties

• States: Water exists as solid (ice), liquid, and gas (vapor).

• Polarity: Water is a polar molecule, allowing it to form hydrogen bonds.

• Cohesion: Water molecules stick together due to hydrogen bonding.

• Adhesion: Water molecules stick to other surfaces.

• Surface Tension: Water has a high surface tension due to hydrogen bonds.

• Specific Heat: Water can absorb or release large amounts of heat with little temperature change.

• Density: Ice is less dense than liquid water, allowing it to float.

Water in Biological Systems

• Solvent Properties: Water dissolves many substances, making it a universal solvent.

• Acids and Bases: Water can dissociate into hydrogen ions ($H^+$) and hydroxide ions ($OH^-$).

• Buffers: Substances that minimize changes in pH.

Example

• Example: Water’s high specific heat helps regulate temperature in living organisms.

Chapter 4: Organic Chemistry and Biological Molecules

Carbon Chemistry and Functional Groups

This chapter discusses the chemistry of carbon, the backbone of organic molecules, and the functional groups that define biological macromolecules.

• Terms: Organic Chemistry, Hydrocarbon, Fat, Structural Isomers, Cis-trans Isomer, Enantiomer, Functional Group, Ethyl, Carboxyl, Amino, Sulfhydryl, Phosphate, Methyl

Carbon and Organic Molecules

• Carbon: Forms the backbone of all life; can form simple or complex molecules.

• Isomers: Molecules with the same formula but different structures (structural, cis-trans, enantiomers).

Functional Groups

• Definition: Specific groups of atoms within molecules that determine chemical properties.

• Examples: Hydroxyl (-OH), Carboxyl (-COOH), Amino (-NH2), Sulfhydryl (-SH), Phosphate (-PO4), Methyl (-CH3).

Biological Importance

• Miller’s Experiment: Demonstrated that organic molecules could form under prebiotic conditions.

• Valence Electrons: Determine bonding capacity of carbon and other atoms.

• Functional Groups in Biology: Play key roles in the structure and function of biomolecules.

• ATP: Adenosine triphosphate, the energy currency of the cell.

Example

• Example: Amino acids contain both amino and carboxyl groups, essential for protein structure.

Table: Comparison of Chemical Bonds

Bond Type	Description	Strength	Example
Covalent	Electron sharing between atoms	Strong	H2O, CH4
Ionic	Electron transfer, forming ions	Moderate	NaCl
Hydrogen	Attraction between H and electronegative atom	Weak	Between water molecules
Van der Waals	Transient charge interactions	Very Weak	Gecko feet adhesion

Additional info:

• Expanded definitions and examples were added for clarity and completeness.

• Table inferred from context to compare chemical bonds as referenced in the notes.