Chapter 1: What Does It Mean to Say That Something Is Alive?

Characteristics of Living Organisms

Biologists define life by a set of shared characteristics. These features distinguish living things from non-living matter.

• Cells: All organisms are made up of cells.

• Replication: Organisms replicate themselves.

• Genetic Information: DNA/RNA stores hereditary information.

• Energy: Organisms acquire and use energy to stay alive.

• Evolution: Populations of organisms are continually evolving.

Viruses are not considered alive because they do not fulfill all these criteria.

Levels of Biological Organization

Life can be divided into different levels of biological organization:

• Biosphere: All environments on Earth.

• Ecosystem: Living and nonliving things in a given area.

• Community: All organisms in an ecosystem.

• Population: Individuals of a species.

• Organism: A single living individual.

• Organ System: Groups of organs working together.

• Organ: A structure with a specific function.

• Tissue: A group of similar cells.

• Cell: The fundamental unit of structure and function.

• Molecule: A chemical structure consisting of atoms.

Theory and Hypothesis

• Cell Theory: All organisms are made of cells, which are separated from the environment by a membrane barrier.

• Evolution Theory: Where do organisms come from? All cells come from preexisting cells.

• Anton van Leeuwenhoek: Founded "animalcules" (living organisms).

• Cells: Separated from the environment by a membrane barrier.

• DNA: The genetic material; double helix structure made of four building blocks (A, T, G, C).

• Genes: Segments of DNA; each strand is self-sufficient.

• Central Dogma: Genetic information flows from DNA to RNA to protein.

• Mutations: Changes in DNA can lead to changes in proteins and traits.

• Eukaryotes: Have a true nucleus.

• Prokaryotes: Do not have a true nucleus.

• Fungi and most plants: Absorb food from the environment.

• Animals: Create their own food using photosynthesis.

Chapter 2: Evolution and Natural Selection

Darwin & Wallace: Claims and Natural Selection

Darwin and Wallace proposed that species are related by common ancestry and that characteristics are related in species.

• Natural Selection: Organisms must be heritable and certain versions of these heritable traits help individuals reproduce more successfully than others.

• Fitness: Traits that increase fitness are favored by natural selection.

Phylogenetic Tree

• Depicts evolutionary history and relationships.

• Shows genealogical relationships.

• Example: Shark and Exocet fish are not the same; anatomy and DNA must be analyzed.

Taxonomy and Classification

• Taxonomy: Naming and classifying organisms.

• Genus: Species share well-varying species (e.g., Homo sapiens, E. coli).

• Noble gases: Very stable atomic structure.

Chapter 3: Chemical Bonds and Water

Atoms and Elements

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

• Carbon: 12th most abundant isotope; half-life.

• Covalent Bonds: Electrons are shared between atoms.

• Ionic Bonds: Electrons are transferred between atoms.

• Polar Covalent Bonds: Electrons are shared unequally.

• Hydrogen Bonds: Weak and temporary bonds between water molecules.

Properties of Water

• Hydrophilic: Water-loving substances.

• Hydrophobic: Water-fearing substances.

• Cohesion: Attraction between like molecules.

• Adhesion: Attraction between unlike molecules.

Acids, Bases, and pH

• Acids: pH less than 7.

• Bases: pH more than 7.

• Buffers: Help maintain pH balance.

Thermodynamics in Biology

• Entropy: The amount of disorder in a system.

• Thermal Energy: Kinetic energy of molecular motion.

• Spontaneous Reactions: Occur if they proceed on their own.

Chapter 4: Proteins and Amino Acids

Structure of Amino Acids

Amino acids are the building blocks of proteins. Each amino acid has a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and an R group (side chain).

• R Group: Determines the properties and solubility of the amino acid.

• Polarity: Charged groups are hydrophilic; non-polar groups are hydrophobic.

Protein Structure

• Primary Structure: Sequence of amino acids.

• Secondary Structure: Alpha helix and beta sheet.

• Tertiary Structure: 3D folding driven by R group interactions.

• Quaternary Structure: Multiple polypeptide chains.

Protein Function

• Proteins act as enzymes, structural components, and transporters.

• Examples: Myosin & Actin (muscle contraction).

Chapter 5: Nucleic Acids and DNA

Nucleic Acid Structure

• Nucleotides: Monomers of nucleic acids; consist of a phosphate group, five-carbon sugar, and nitrogenous base.

• DNA: Double helix structure; stores genetic information.

• RNA: Usually single-stranded; involved in protein synthesis.

Chapter 6: Carbohydrates and Lipids

Carbohydrates

• Starch: Storage polysaccharide in plants.

• Glycogen: Storage polysaccharide in animals.

• Cellulose: Structural component of plant cell walls.

• Peptidoglycan: Structural polysaccharide in bacteria.

Lipids and Phospholipids

• Phospholipids: Consist of glycerol linked to phosphate group and two hydrocarbon chains.

• Function: Form cell membranes; amphipathic nature.

Chapter 7: Membranes and Transport

Membrane Structure and Fluidity

• Phospholipid bilayer forms the basic structure of cell membranes.

• Fluidity and permeability are affected by temperature and lipid composition.

Transport Across Membranes

• Osmosis: Water moves quickly across lipid bilayers.

• Hypertonic Solution: Water moves out of the cell; cell shrinks.

• Hypotonic Solution: Water moves into the cell; cell swells.

• Isotonic Solution: No net water movement; cell remains the same size.

Specialized Membrane Proteins

• Proteins facilitate diffusion and active transport.

• Channels open or close in response to signals.

• Example: Aquaporin protein allows water to move rapidly through membranes.

Chapter 8: Eukaryotic Cell Structure

Organelles and the Nucleus

• Nucleus: Contains most genetic material; controls cell activities.

• Ribosomes: Protein synthesis machinery; found in cytoplasm and on rough ER.

• Endomembrane System: Organelles participate in the secretory pathway.

How Do Molecules Enter the Nucleus?

• Most proteins must be transported into the nucleus via nuclear pores.

• Endomembrane system transports proteins to compartments inside the cell.

Chapter 9: Cytoskeleton and Cell Movement

Cytoskeletal Elements

• Actin Filaments: Involved in cell movement and shape.

• Microtubules: Largest cytoskeletal elements; involved in transport and cell division.

• Intermediate Filaments: Provide structural support.

Cell Division and Movement

• Cytokinesis: Splitting of the cytoplasm during cell division.

• Cell Crawling: Movement via actin filaments.

• Chloroplasts: Move in a circular direction by actin.

Cellular Respiration

• Sodium loss and electron becomes a cation.

• Burning methane forms carbon and hydrogen.

Key Table: Types of Chemical Bonds

Key Equations

• DNA Double Helix:

• pH Calculation:

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