Biology 1 Honors

What is Life?

Characteristics of Life

  • Living organisms share key attributes that define life. These include:

    • Made of cells: All living things are composed of cells, which serve as the basic unit of life.

    • Metabolism: Living organisms convert energy and utilize it for their functions.

    • Respond to stimuli: Responding to environmental changes is essential for survival.

    • Grow and develop: Organisms will go through changes in their lifecycle.

    • Reproduce: The capacity to reproduce and generate offspring is fundamental to life.

    • Excretion: Living organisms eliminate waste products generated from metabolic processes.

    • Homeostasis: The ability to maintain stable internal conditions despite external changes.

Scientific Methodology

The Practice of Science

  • Goal: Utilize the scientific inquiry process to recognize and address problems.

The Seven Characteristics of Life

  1. All living things are made of cells.

  2. Living things exhibit an orderly structure.

  3. Reproduction is a common trait among all living things.

  4. Growth and development are observed in all living things.

  5. All organisms respond to stimuli.

  6. Energy utilization is essential for all living things.

  7. All living things contain DNA.

  • Scientific investigations begin with observations, which create a basis for questioning.

Key Definitions

  • Inference vs. Hypothesis: A hypothesis is testable, while an inference is a logical conclusion based on prior knowledge and observations.

  • Controlled Experiment: Involves a control group and independent/dependent variables.

  • Control Group vs. Experimental Group:

    • Control group receives the same treatment as the experimental group, but one variable is held constant.

    • Experimental group experiences changes in all variables.

  • Independent Variable: The variable that is deliberately altered in an experiment.

  • Dependent Variable: The variable that is measured and affected by changes in the independent variable.

Types of Data

  • Qualitative Data: Descriptive data.

  • Quantitative Data: Data that includes measurements.

Steps of Scientific Methodology

  1. Collect observations.

  2. Formulate a hypothesis.

  3. Conduct an experiment.

  4. Analyze the data.

  5. Form a conclusion.

Important Concepts

Scientific Bias

  • Bias occurs when a scientist’s personal views influence results.

  • Bias can be minimized through peer reviews.

Scientific Theory and Law

  • Scientific Theory: Broad explanations that incorporate numerous lines of evidence.

    • Describe why phenomena occur and predict outcomes under specific conditions.

  • Scientific Law: Summarizes consistent patterns observed in nature, often represented mathematically.

Important Vocabulary

  • Biology: The study of life.

  • Hypothesis: An educated guess that can be tested.

  • Experiment: A procedure to test hypotheses or demonstrate known facts.

  • Observation: Using the senses to gather information.

  • Analysis: The process of examining data in detail.

  • Conclusion: The final answer or solution to a scientific question.

  • Peer Review: Assessment of scientific work by others in the same field.

  • Reliability: Indicates consistent results over time.

Properties of Water

Water as Essential for Life

  • Hydrogen Bonding: Water's unique properties arise from interactions between hydrogen and oxygen atoms, creating a polar molecule.

  • Specific Heat Capacity: Water's high specific heat allows it to moderate temperature changes, crucial for cellular temperature regulation.

Polarity and its Effects

  • Cohesion: Attraction between like molecules, resulting in surface tension.

  • Adhesion: Attraction between water molecules and other substances, leading to capillary action.

States of Water

  • Water expands when frozen; ice is less dense than liquid water, allowing it to float and supporting aquatic life.

  • Universal Solvent: Water dissolves many substances, following the principle "like dissolves like."

Important Vocabulary Related to Water

  • Element: A pure substance with only one type of atom.

  • Polarity: Molecules with charged regions.

  • Hydrogen Bond: A weak bond due to the attraction of opposite charges.

  • Cohesion vs. Adhesion: Describes the attractive forces between similar vs. different molecules, respectively.

Biomolecules and Their Functions

Overview of Biomolecules

  • Carbohydrates: Provide energy and structural support; composed of monosaccharides, disaccharides, and polysaccharides.

  • Lipids: Nonpolar molecules for long-term energy storage and cell membrane formation.

  • Proteins: Made of amino acids; perform structural, enzymatic, and regulatory roles.

  • Nucleic Acids: DNA and RNA store and transmit genetic information.

Specific Terminology

  • Amino Acid: Building blocks of proteins with specific chemical groups.

  • Nucleotide: Basic units of nucleic acids, including a sugar, a phosphate, and a nitrogenous base.

  • Saccharide: Synonym for sugar molecules.

Enzyme Functionality

Catalysts in Biological Processes

  • Enzyme: A protein that accelerates chemical reactions without being consumed.

  • Activation Energy: The minimum energy needed to initiate a reaction, often reduced by enzymes.

Enzyme-Substrate Interaction

  • Enzymes bind to substrates at an active site, leading to the formation of products through metabolic reactions.

  • The lock and key model describes how specific substrates fit into their respective enzyme active sites.

Cell Theory and Structure

Fundamentals of the Cell

  • The Cell Theory consists of three core principles:

    1. All living organisms are made of one or more cells.

    2. Cells are the basic unit of structure and function.

    3. All cells arise from existing cells.

Types of Cells

  • Prokaryotic Cells: Simple cells lacking a nucleus and membrane-bound organelles (e.g., bacteria).

  • Eukaryotic Cells: Complex cells with a nucleus and organelles (e.g., plants and animals).

Major Eukaryotic Cell Organelles

  • Nucleus: Contains DNA and coordinates cell activity.

  • Mitochondria: Generates ATP through cellular respiration.

  • Chloroplasts: Conducts photosynthesis in plant cells.

  • Ribosomes: Synthesizes proteins.

  • Golgi Apparatus: Modifies and packages proteins and lipids.

The Cell Cycle and Mitosis

Overview of Cell Division

  • The cell cycle includes interphase (growth and DNA replication) and mitotic phase (cell division).

  • Most cellular time is spent in interphase, which consists of three stages:

    1. G1 Phase (First Gap): Growth and nutrient absorption.

    2. S Phase (Synthesis): DNA replication occurs here.

    3. G2 Phase (Second Gap): Additional growth and preparation for mitosis.

Phases of Mitosis

  1. Prophase: Chromatin condenses, spindle fibers begin to form.

  2. Metaphase: Chromosomes align at the metaphase plate.

  3. Anaphase: Sister chromatids are separated and pulled toward opposite poles.

  4. Telophase: Nuclear membranes form around each set of chromosomes; the cell prepares to split.

  5. Cytokinesis: Final division of the cytoplasm, creating two daughter cells.