BIOL 141 Test 1 Study Notes: Chapters 1–3

7 Characteristics of Life

Cellular organization, ordered complexity, sensitivity, growth/development/reproduction, energy utilization, homeostasis, and evolutionary adaptation (Memory trick: C-O-S-G-E-H-E).

Emergent Property

A property that a complex system possesses, which its individual constituent parts do not have when isolated (e.g., individual heart cells cannot pump blood, but the whole heart can).

Inductive Reasoning

Moving from specific, individual observations to a general conclusion.

Deductive Reasoning

Moving from a general rule or principle to make a specific prediction.

Hypothesis

A proposed, testable explanation for an observation.

Scientific Theory

A well-supported explanation of a natural phenomenon backed by substantial evidence.

Natural Selection

The mechanism of evolution where individuals with advantageous heritable traits survive and reproduce more successfully, making those traits more common in subsequent generations.

Homologous Structures

Structures in different species that share a common evolutionary origin and underlying structure, though their functions may differ.

Analogous Structures

Structures that serve similar functions in different organisms but do not share a common evolutionary origin.

Atomic Number

The number of protons in an atom's nucleus, which uniquely defines the chemical element.

Mass Number

The total count of protons plus neutrons in an atom ($\text{Mass Number} \approx \text{Protons} + \text{Neutrons}$).

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Oxidation vs. Reduction

Oxidation is the loss of electrons; reduction is the gain of electrons (Memory trick: OIL RIG).

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Half-Life

The amount of time required for half of a radioactive isotope sample to decay.

Octet Rule

The tendency of atoms to gain, lose, or share electrons in order to achieve a full outer shell of 8 valence electrons.

Ionic Bond

A chemical bond formed when electrons are completely transferred from one atom to another, creating opposite charges that attract.

Covalent Bond

A chemical bond formed when two atoms share one or more pairs of valence electrons.

Polar Covalent Bond

A covalent bond where electrons are shared unequally between atoms due to differences in electronegativity.

Nonpolar Covalent Bond

A covalent bond where electrons are shared equally between atoms.

Cohesion

The property of water molecules sticking to other water molecules via hydrogen bonding.

Adhesion

The property of water molecules sticking to other polar or charged substances.

Buffer

A chemical substance that resists drastic changes in pH by accepting or donating $H^+$ ions.

Dehydration Synthesis

A chemical reaction that links monomers together into polymers by removing a molecule of $H_2O$.

Hydrolysis

A chemical reaction that breaks polymers down into individual monomers by adding a molecule of $H_2O$.

Four Major Biomolecules

Carbohydrates (energy/structure), Nucleic Acids (genetic information), Proteins (cellular work/structure), and Lipids (energy storage/membranes).

Primary Protein Structure

The specific, linear sequence of amino acids in a polypeptide chain.

Denaturation

The loss of a protein's functional 3-D shape due to external stressors like extreme heat, chemical exposure, or pH changes.

Saturated vs. Unsaturated Fatty Acids

Saturated fatty acids have no $C=C$ double bonds and straight chains (solid at room temp); unsaturated fatty acids have one or more $C=C$ double bonds creating bends (liquid at room temp).

Cellular Organization

The fundamental characteristic of life stating that all living organisms consist of one or more cells.

Ordered Complexity

The characteristic of living things where simple parts are organized into complex biological systems.

Sensitivity

The ability of living organisms to sense and respond to stimuli in their environment.

Growth, Development, and Reproduction

The processes by which organisms grow, change over their lifespan, and produce offspring.

Energy Utilization

The process by which organisms take in energy and transform it to perform biological work.

Homeostasis

The process of maintaining stable internal conditions despite changes in the external environment.

Evolutionary Adaptation

The process over generations where populations change as advantageous heritable traits become more common.

Hierarchical Organization of Life

The structural ranking from smallest to largest: Atoms $\rightarrow$ Molecules $\rightarrow$ Organelles $\rightarrow$ Cells $\rightarrow$ Tissues $\rightarrow$ Organs $\rightarrow$ Organ Systems $\rightarrow$ Organism $\rightarrow$ Population $\rightarrow$ Community $\rightarrow$ Ecosystem $\rightarrow$ Biosphere.

Emergent Property

A property that a complex system possesses which its individual constituent components do not have on their own.

Inductive Reasoning

Scientific reasoning that moves from specific, individual observations to form a general conclusion.

Deductive Reasoning

Scientific reasoning that moves from a general principle or law to predict specific outcomes.

Hypothesis

A proposed explanation for a scientific observation that can be tested through experimentation.

Scientific Theory

A comprehensive, well-supported explanation of a natural phenomenon backed by substantial scientific evidence.

Basic Research

Scientific research aimed primarily at expanding foundational knowledge and understanding.

Applied Research

Scientific research that utilizes scientific knowledge to solve practical, real-world problems.

Natural Selection

The mechanism of evolution where individuals with advantageous heritable traits survive and reproduce more successfully.

Homologous Structures

Anatomical structures in different species that share a common evolutionary origin, though they may perform different functions.

Analogous Structures

Anatomical structures that perform similar functions but evolved independently with different evolutionary origins.

Proton

A positively charged subatomic particle found in the atomic nucleus.

Neutron

A neutral subatomic particle with no charge found in the atomic nucleus.

Electron

A negatively charged subatomic particle orbiting outside the atomic nucleus.

Atomic Number

The total number of protons in an atom, which uniquely defines the chemical element.

Mass Number

The combined sum of protons and neutrons within an atom's nucleus.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Oxidation

The loss of electrons from an atom or molecule during a chemical reaction.

Reduction

The gain of electrons by an atom or molecule during a chemical reaction.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Half-Life

The time required for half of a sample of a radioactive isotope to decay.

Valence Electrons

Electrons located in the outermost energy level of an atom that determine bonding and reactivity.

Octet Rule

The principle that atoms tend to gain, lose, or share electrons to complete an outer shell of 8 valence electrons.

Ionic Bond

A chemical bond formed by the complete transfer of electrons, creating oppositely charged ions that attract.

Covalent Bond

A chemical bond formed when two atoms share one or more pairs of electrons.

Nonpolar Covalent Bond

A covalent bond in which electrons are shared equally between atoms.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally due to differences in electronegativity.

Electronegativity

An atom's relative affinity or pulling strength for shared electrons in a chemical bond.

Catalyst

A substance that increases the rate of a chemical reaction by lowering its activation energy without being consumed.

Hydrogen Bond

A weak attraction between a slightly positive hydrogen atom in a polar molecule and a slightly negative atom in another.

Cohesion

The attractive force that causes water molecules to stick to other water molecules.

Adhesion

The attractive force that causes water molecules to stick to other polar substances.

Capillary Action

The movement of water up narrow tubes caused by the combined forces of cohesion and adhesion.

Acid

A substance that increases the concentration of $H^+$ ions in solution, lowering pH below 7.

Base

A substance that decreases the concentration of $H^+$ ions in solution, raising pH above 7.

Buffer

A chemical compound that stabilizes pH by accepting or releasing $H^+$ ions in response to pH changes.

Structural Isomers

Molecules sharing the same molecular formula but differing in the covalent arrangement of their atoms.

Stereoisomers

Molecules sharing the same covalent bonds but differing in their 3-D spatial arrangement.

Chiral Molecule

A molecule that lacks symmetry and is not superimposable on its mirror image.

Dehydration Synthesis

A chemical reaction that combines monomers into polymers by removing a water molecule ($H_2O$).

Hydrolysis

A chemical reaction that breaks polymers into monomers by adding a water molecule ($H_2O$).

Monosaccharide

The simplest carbohydrate monomer, such as glucose, fructose, or galactose.

Polysaccharide

A complex carbohydrate polymer composed of long chains of monosaccharides.

Starch

A storage polysaccharide found in plants used to store energy.

Glycogen

A storage polysaccharide found in animals used to store energy in liver and muscle cells.

Cellulose

A structural polysaccharide that forms the tough cell walls of plant cells.

Chitin

A structural polysaccharide found in fungal cell walls and arthropod exoskeletons.

Nucleotide

The monomer of nucleic acids composed of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Primary Structure

The linear sequence of amino acids held together by peptide bonds in a protein chain.

Secondary Structure

Localized spatial arrangements in a polypeptide chain, such as $\alpha$-helices and $\beta$-pleated sheets.

Tertiary Structure

The overall 3-D shape of a single folded polypeptide chain.

Quaternary Structure

The functional protein structure resulting from the assembly of two or more polypeptide chains.

Denaturation

The loss of a protein's functional 3-D shape due to disruption by heat, pH, or chemical conditions.

Saturated Fatty Acid

A fatty acid with no carbon-carbon double bonds, resulting in straight chains that solidify at room temperature.

Unsaturated Fatty Acid

A fatty acid containing one or more double bonds ($C=C$), producing kinks that keep it liquid at room temperature.

Phospholipid

A lipid composed of glycerol, two hydrophobic fatty acid tails, and a hydrophilic phosphate head, forming membrane bilayers.