General Biology: Foundations, Chemistry of Life, and Properties of Water

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Introduction to Biology

Properties of Life

Biology is the study of living organisms and their interactions with the environment. All living things share certain properties that define life.

Order: Living things exhibit complex but ordered organization. Example: The structure of a sunflower.
Regulation: Organisms regulate their internal environment. Example: Birds maintaining constant body temperature.
Growth and Development: Organisms grow and develop according to specific instructions coded in their DNA. Example: A caterpillar transforming into a butterfly.
Energy Processing: Living things obtain and use energy. Example: Plants performing photosynthesis.
Response to Environment: Organisms respond to environmental stimuli. Example: Venus flytrap closing when touched.
Reproduction: Organisms reproduce their own kind. Example: Birds laying eggs.
Evolutionary Adaptation: Populations evolve over generations. Example: Camouflage in insects.

Emergent Properties

Emergent properties are new characteristics that arise at each level of biological organization, due to the arrangement and interactions of parts as complexity increases.

Example 1: A functioning bicycle emerges only when all necessary parts are connected in the correct way.
Example 2: The brain's ability to think and feel emerges from the interactions of billions of neurons.

Biological Organization

Levels of Biological Organization

Life is organized in a hierarchy from the largest to the smallest scale:

Biosphere: All life on Earth and all places where life exists.
Ecosystem: All living things in a particular area, along with nonliving components.
Community: All organisms in an ecosystem.
Population: All individuals of a species within an area.
Organism: An individual living thing.
Organ/Organ System: Body parts that perform a specific function.
Tissues: Groups of similar cells performing a function.
Cells: The basic unit of life.
Organelles: Functional components within cells.
Molecules: Chemical structures consisting of two or more atoms.

Cell Types

Eukaryotic Cell: Contains a nucleus and membrane-bound organelles.
Prokaryotic Cell: Lacks a nucleus and membrane-bound organelles.

Genetic Information

DNA: The molecule that stores genetic information.
Genes: Units of inheritance made of DNA.
Genome: The complete set of genetic material in an organism.

Feedback Mechanisms

Negative Feedback: A process in which a system is regulated by reducing the output or activity when it exceeds a set point.
Positive Feedback: A process in which the end product of an action causes more of that action to occur.

Evolution and Classification

Domains of Life

All life is classified into three domains:

Domain	Characteristics
Bacteria	Prokaryotic, unicellular, diverse environments
Archaea	Prokaryotic, often in extreme environments
Eukarya	Eukaryotic, includes plants, animals, fungi, protists

Levels of Classification

From broadest to most specific:

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Darwin's Theory of Evolution

Main Points: Species show evidence of "descent with modification" from common ancestors; natural selection is the mechanism for evolution.
Natural Selection: Individuals with traits best suited to their environment are more likely to survive and reproduce.

The Process of Science

Data and Hypotheses

Data: Recorded observations or items of information.
Quantitative Data: Numerical measurements (can be graphed).
Qualitative Data: Descriptions (e.g., field sketches).
Hypothesis: A testable explanation for an observation.
Qualities of a Scientific Hypothesis: Must be testable and falsifiable.
Scientific Hypotheses: Are never proved, only supported or refuted by evidence.

Basic Chemistry for Biology

Matter and Elements

Matter: Anything that takes up space and has mass.
Element: A substance that cannot be broken down to other substances by chemical means.
Compound: A substance consisting of two or more elements in a fixed ratio.
Essential Element: An element required for an organism to survive, grow, and reproduce.
Trace Element: An element required by an organism in only minute quantities.

Atomic Structure

Proton: Positively charged subatomic particle in the nucleus.
Neutron: Neutrally charged subatomic particle in the nucleus.
Electron: Negatively charged subatomic particle orbiting the nucleus.
Atomic Number: Number of protons in an atom.
Atomic Mass: Sum of protons and neutrons.

Electron Shells and Energy

Electrons are arranged in shells around the nucleus.
Valence electrons are those in the outermost shell and are involved in chemical reactions.
Potential Energy: Energy that matter possesses because of its location or structure.

Chemical Bonds

Covalent Bond: Sharing of electron pairs between atoms.
Nonpolar Covalent Bond: Electrons are shared equally.
Polar Covalent Bond: Electrons are shared unequally, leading to partial charges.
Ionic Bond: Transfer of electrons from one atom to another, resulting in oppositely charged ions.
Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom.
Van der Waals Interactions: Weak attractions between molecules or parts of molecules that result from transient local partial charges.

Electronegativity

Electronegativity: The attraction of a particular atom for the electrons of a covalent bond.

Table: Molecules and Compounds

Substance	Molecule?	Compound?	Molecular Formula	Structural Formula
Water	Yes	Yes	H2O	H-O-H
Carbon dioxide	Yes	Yes	CO2	O=C=O
Methane	Yes	Yes	CH4	H \| H-C-H \| H
O2	Yes	No	O2	O=O

Chemical Reactions in Biology

Chemical Reaction: The making and breaking of chemical bonds, leading to changes in the composition of matter.
Photosynthesis Equation:

Reactants: Carbon dioxide and water
Products: Glucose and oxygen

Properties of Water

Polarity and Hydrogen Bonding

Water is a polar molecule, with oxygen being more electronegative than hydrogen.
Hydrogen bonds form between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another.

Emergent Properties of Water

Cohesion: Water molecules stick together due to hydrogen bonding.
Adhesion: Water molecules stick to other substances.
Surface Tension: A measure of how difficult it is to stretch or break the surface of a liquid.
High Specific Heat: Water can absorb or release a large amount of heat with only a slight change in its own temperature.
Heat of Vaporization: The quantity of heat a liquid must absorb for 1 g to be converted to gas.
Expansion upon Freezing: Ice is less dense than liquid water, so it floats.
Versatile Solvent: Water dissolves more substances than any other liquid.

Solvent of Life

Solution: A liquid that is a homogeneous mixture of two or more substances.
Solvent: The dissolving agent of a solution.
Solute: The substance that is dissolved.
Hydrophilic: Substances that have an affinity for water.
Hydrophobic: Substances that do not have an affinity for water.

Biological Importance of Water's Properties

Moderation of temperature helps maintain stable environments for organisms.
Ice floating insulates bodies of water, protecting aquatic life in winter.
Water's solvent abilities facilitate chemical reactions in cells.

Additional info: These notes are based on foundational concepts in introductory biology, including the chemistry of life and the unique properties of water essential for life on Earth.