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General Biology: Foundations, Classification, Chemistry, and Water

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Introduction to Biology

What is Biology?

Biology is the scientific study of living organisms and life processes. It encompasses the structure, function, growth, origin, evolution, and distribution of living things.

  • Definition: The study of living organisms (life).

  • Example: Investigating how plants convert sunlight into energy through photosynthesis.

Homeostasis

Homeostasis is the ability of an organism to maintain a stable internal environment despite changes in external conditions.

  • Key Point: Organisms regulate temperature, pH, and other vital conditions to survive.

  • Example: Humans sweat to cool down when body temperature rises.

Cell Theory

Cell theory is a fundamental concept in biology stating that all living things are composed of cells, and all cells arise from pre-existing cells.

  • Key Point: The cell is the basic unit of life.

  • Example: Bacteria, plants, and animals are all made up of cells.

Classification of Life

Taxonomic Hierarchy

Organisms are classified into a hierarchical system to show relationships and evolutionary history. The main ranks are Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

  • Mnemonic: "Dear King Philip Came Over For Good Soup" helps remember the order.

Classification of Humans

Rank

Name

Domain DE

Eukaryota (organisms with a nucleus in their cells)

Kingdom KA

Animalia (animals)

Phylum PC

Chordata (animals with a spinal cord)

Class CM

Mammalia (mammals)

Order OP

Primates (primates)

Family FH

Hominidae (great apes and humans)

Genus GH

Homo (modern and extinct humans)

Species SH

Homo sapiens

Domains and Kingdoms

  • Three Domains: Bacteria, Archaea, Eukarya

  • Four Kingdoms in Eukarya: Protists, Fungi, Plantae, Animalia

Scientific Method and Hypotheses

Science and Scientific Method

Science is the systematic study of the natural world through observation, experimentation, and the creation of testable explanations called theories.

  • Key Components: Observation, hypothesis, experiment, data collection, analysis, and conclusion.

  • Scientific Method Steps: Ask a question, form a hypothesis, test with an experiment, analyze data, draw a conclusion.

Hypothesis and Theory

  • Hypothesis: A testable or educated guess of the outcome of an experiment or observation based on knowledge.

  • Theory: A well-tested, comprehensive explanation for a broad range of observations, supported by a large body of evidence.

  • Prediction: A specific, expected outcome based on a hypothesis.

  • Control: A standard for comparison in an experiment, kept constant to isolate the effect of the variable being tested.

Traits of Living Things

  • Eight Characteristics of Life (ORRGERCE):

    • Organization

    • Reproduction

    • Response to environment

    • Growth and development

    • Energy processing

    • Regulation (homeostasis)

    • Cells

    • Evolution

Evaluating Science

  • Testable and Falsifiable (free of bias)

  • Relies on evidence (recent, peer-reviewed)

  • Systematic and community-based (peer review, collaboration)

  • Objective and self-correcting

Atoms, Elements, and Chemical Bonds

Structure of Atoms

Atoms are the smallest units of matter that retain the properties of an element. They are composed of protons, neutrons, and electrons.

Particle

Charge

Mass (amu)

Location

Proton

+1

1

Nucleus

Neutron

0

1

Nucleus

Electron

-1

~0

Electron cloud

Ions and Isotopes

  • Ion: An atom or molecule that has a positive or negative electric charge due to loss or gain of electrons.

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

  • Radioactive Isotope: An unstable atom that releases energy as it decays.

Atomic Number and Mass Number

  • Atomic Number: Number of protons in the nucleus. # of P

  • Mass Number: Sum of protons and neutrons. P+N

Electron Shells

  • First shell: 2 electrons

  • Second shell: 8 electrons

  • Third shell: 18 electrons

Types of Chemical Bonds

  • Ionic Bonds: Transfer of electrons between atoms, forming charged ions.

  • Covalent Bonds: Sharing of electrons between nonmetal atoms.

  • Hydrogen Bonds: Weak attractions between partially charged regions of molecules, especially in water.

Water and Its Properties

Importance of Water Chemistry

Water's unique properties make it essential for life. Its polarity and hydrogen bonding contribute to its behavior as a solvent and its role in biological processes.

Properties of Water

  • High heat of vaporization

  • High specific heat

  • Solvent abilities

  • Cohesion and adhesion

  • Density (ice is less dense than liquid water)

Acids, Bases, and pH

  • Acid: Substance with a pH below 7; donates hydrogen ions (H+).

  • Base: Substance with a pH above 7; accepts hydrogen ions or donates hydroxide ions (OH-).

  • pH Scale: Measures how acidic or basic a solution is, ranging from 0 (most acidic) to 14 (most basic).

Solutions

  • Solution: Homogeneous mixture of two or more substances.

  • Solvent: The dissolving agent (e.g., water).

  • Solute: The substance being dissolved (e.g., salt).

Additional Key Terms and Concepts

  • Trace Elements: Chemical elements required in small amounts for essential physiological functions (e.g., iron, iodine).

  • Energy: The capacity to do work, such as moving matter or breaking chemical bonds.

  • Reactant: Starting material in a chemical reaction.

  • Product: Ending material in a chemical reaction.

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard biology curricula.

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