Chapter 1: Introduction to Biology

Properties of Life

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

• Order: Living things exhibit complex but ordered organization.

• Regulation: Organisms maintain stable internal conditions (homeostasis).

• Growth and Development: Organisms grow and develop according to specific instructions coded in their DNA.

• Energy Processing: Living things obtain and use energy for growth and maintenance.

• Response to Environment: Organisms respond to environmental stimuli.

• Reproduction: Organisms reproduce their own kind.

• Evolutionary Adaptation: Populations evolve over generations.

Levels of Biological Organization

Biology can be studied at various levels, from molecules to the biosphere.

• Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

Reductionism breaks down complex systems into simpler components, while systems biology studies interactions within biological systems.

Feedback Regulation

• Positive Feedback: The end product speeds up its own production (e.g., blood clotting).

• Negative Feedback: The end product slows or stops the process (e.g., regulation of blood glucose).

Classification of Life

Organisms are classified into three domains and several kingdoms.

• Domains: Bacteria, Archaea, Eukarya

• Kingdoms (Eukarya): Protista, Fungi, Plantae, Animalia

Scientific Method Terminology

• Hypothesis: A testable explanation for an observation.

• Theory: A broad explanation supported by a large body of evidence.

• A stPrediction: statement about what will happen under specific conditions.

Additional info: Evolution and natural selection are fundamental concepts but are not required in detail for this section.

Chapter 2: The Chemical Context of Life

Atoms, Molecules, and Compounds

• Atom: The smallest unit of matter retaining the properties of an element.

• Molecule: Two or more atoms held together by covalent bonds.

• Compound: A substance consisting of two or more different elements combined in a fixed ratio.

Atomic Structure

• Protons: Positively charged particles in the nucleus.

• Neutrons: Neutral particles in the nucleus.

• Electrons: Negatively charged particles orbiting the nucleus.

Atomic number = number of protons. Mass number = protons + neutrons.

Valence Electrons and Reactivity

• Valence electrons are electrons in the outermost shell and determine chemical reactivity.

Radioactive Isotopes

• Isotopes are atoms of the same element with different numbers of neutrons.

• Radioactive isotopes decay spontaneously, giving off particles and energy.

• Half-life: The time it takes for half of the radioactive atoms to decay.

Age calculation formula:

Where is the remaining quantity, is the initial quantity, is time, and is the half-life.

Chemical Bonds

• Covalent Bonds: Sharing of electron pairs between atoms.

• Polar Covalent Bonds: Unequal sharing of electrons.

• Nonpolar Covalent Bonds: Equal sharing of electrons.

• Ionic Bonds: Transfer of electrons from one atom to another, creating ions.

• Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom.

• Van der Waals Interactions: Weak attractions due to transient local charges.

Orbitals and Molecular Shape

• Orbitals are regions where electrons are likely to be found.

• The shape of molecules is determined by the arrangement of orbitals.

Chapter 3: Water and Life

Hydrogen Bonds and Water Properties

• Hydrogen bonds form between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another.

• These bonds are responsible for water's unique properties.

Four Emergent Properties of Water

• Cohesion: Water molecules stick together, aiding transport in plants.

• Moderation of Temperature: Water absorbs and releases heat slowly.

• Expansion Upon Freezing: Ice is less dense than liquid water.

• Versatility as a Solvent: Water dissolves many substances.

Solution Preparation and Molar Mass

• Molar mass: The mass of one mole of a substance (g/mol).

• To prepare a solution: weigh the molar mass and dissolve in enough solvent to make 1 liter.

pH and Hydrogen Ion Concentration

• pH measures hydrogen ion concentration in a solution.

• pH and [H+] are inversely related:

• The product of [H+] and [OH-] is always at 25°C:

Buffers

• Buffers minimize changes in pH by accepting or donating H+ ions.

Chapter 4: Carbon and the Molecular Diversity of Life

Chemical Groups

• Seven major chemical groups: hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl.

• Functional groups affect molecular function by being directly involved in chemical reactions.

Isomers

• Structural Isomers: Differ in covalent arrangements.

• Cis-trans Isomers: Differ in arrangement around a double bond.

• Enantiomers: Mirror images of each other.

Chapter 5: The Structure and Function of Large Biological Molecules

Dehydration and Hydrolysis Reactions

• Dehydration: Monomers join to form polymers by removing water.

• Hydrolysis: Polymers break down into monomers by adding water.

• For a polymer of n monomers, (n-1) water molecules are involved in its formation or breakdown.

Biomolecules: Monomers, Bonds, and Functions

Carbohydrates

• Monosaccharides: Simple sugars (e.g., glucose).

• Disaccharides: Two monosaccharides joined (e.g., sucrose).

• Polysaccharides: Many monosaccharides (e.g., starch, cellulose, glycogen).

• Cellulose and glycogen differ in structure and function.

Proteins

• Four levels of structure: primary, secondary (alpha helix, beta sheet), tertiary, quaternary.

• Hydrogen bonds, ionic bonds, disulfide bridges, and hydrophobic interactions stabilize structures.

Nucleic Acids

• Monomers: nucleotides (sugar, phosphate, nitrogenous base).

• Function: store and transmit genetic information.

Lipids

• Saturated fats: No double bonds, solid at room temperature.

• Unsaturated fats: One or more double bonds, liquid at room temperature.

Chapter 6: A Tour of the Cell

Prokaryotic vs. Eukaryotic Cells

• Prokaryotic cells: No nucleus, DNA in nucleoid region, lack membrane-bound organelles.

• Eukaryotic cells: DNA in nucleus, contain membrane-bound organelles.

Major Organelles of Eukaryotic Cells

• Nucleus: Contains genetic material.

• Mitochondria: Site of cellular respiration.

• Chloroplasts: Site of photosynthesis (plants and algae).

• Endoplasmic Reticulum (ER): Protein and lipid synthesis.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

• Lysosomes: Digestion and waste removal.

• Peroxisomes: Breakdown of fatty acids and detoxification.

• Ribosomes: Protein synthesis.

• Plasma Membrane: Selective barrier for the cell.

• Vacuoles: Storage and support (large in plant cells).

Additional info: No need to label prokaryotic cells or know about cell junctions for this section.