Principles of Cell Biology Study Guide (Weeks 1-3)

Vocabulary flashcards covering themes of biology, requirements and categories of life, scientific design, and foundation chemistry concepts from BIO-1500 study guide.

Biology

The scientific study of life and the processes that make life possible.

Biological Hierarchy

The organized levels of living systems: biosphere $\rightarrow$ biome $\rightarrow$ ecosystem $\rightarrow$ organism $\rightarrow$ organ system $\rightarrow$ organ $\rightarrow$ tissue $\rightarrow$ cell $\rightarrow$ organelle $\rightarrow$ molecule.

Biosphere

The total of all ecosystems on Earth.

Biome

A large geographic region defined by climate and characteristic organisms, such as a desert or rainforest.

Ecosystem

Interacting organisms plus the nonliving physical environment in one area.

Organism

One individual living thing.

Organ System

Multiple organs working together, such as the nervous or digestive system.

Cell

The smallest unit that is alive.

Organelle

A specialized structure inside a cell, such as the nucleus or mitochondrion.

Molecule

Atoms joined together that cells use for structure, energy, information, and reactions.

DNA

The hereditary information used by all known organisms, containing coded instructions used to make proteins.

Mutualism

An interaction between species in which both species benefit.

Commensalism

An interaction in which one species benefits and the other is not significantly affected.

Parasitism

An interaction in which one species benefits while the host is harmed.

Predation

An individual feeding interaction where one organism captures and consumes another, distinct from a long-term host relationship like parasitism.

Evolution

The process that explains both the unity and diversity of life, where shared features reflect common ancestry and differences arise over generations.

Natural Selection

The process by which individuals with heritable traits that improve survival or reproduction in a particular environment tend to leave more offspring.

Divergent Evolution

The evolutionary pattern in which related groups become increasingly different after splitting from a common ancestor.

Homologous Features

Structures or traits in different organisms that reflect shared ancestry.

Convergent Evolution

The evolutionary pattern in which unrelated groups independently evolve similar solutions under similar environmental pressures.

Analogous Features

Structures that have similar function but different evolutionary origin, such as wings in insects, birds, and mammals.

Five Requirements of Life

The essential criteria for living systems: grow, reproduce, maintain internal balance, sense and respond, and obtain and use energy.

Sexual Reproduction

Reproduction that combines gametes and creates genetically varied offspring.

Asexual Reproduction

Reproduction producing offspring from one parent without gamete fusion, resulting in offspring that are usually genetically identical except for mutations.

Homeostasis

The active regulation of internal conditions to maintain them within usable ranges around a set range through feedback.

Bacteria

A domain of prokaryotic, usually single-celled organisms with no nucleus, including disease-causing species and many beneficial species.

Archaea

A domain of prokaryotic, single-celled organisms genetically and chemically distinct from bacteria, many of which tolerate extreme environments.

Eukarya

A domain of organisms whose cells have a nucleus and membrane-bound organelles, including animals, plants, fungi, and protists.

Prokaryotes

Organisms with smaller, internally simpler cells that lack a membrane-bound nucleus and contain DNA in a nucleoid region.

Eukaryotes

Organisms with cells that compartmentalize tasks in organelles, such as a nucleus housing DNA and mitochondria performing aerobic metabolism.

Compartmentalization

The organization of cellular tasks into organelles, which increases efficiency and supports larger cells and specialized multicellular organisms.

Scientific Theory

A broad, well-supported explanation built from extensive evidence, rather than a casual guess.

Testable Hypothesis

A specific, measurable, and falsifiable statement predicting a cause-and-effect relationship, formatted as: If [independent variable changes], then [dependent variable will change], because [mechanism].

Independent Variable

The factor deliberately changed or the main explanatory factor—the proposed cause—in an experiment.

Dependent Variable

The measured response—the proposed effect—in an experiment.

Controlled Variables

Conditions intentionally kept consistent throughout an experiment.

Confounding Variable

An uncontrolled factor related to the independent variable that can also affect the dependent variable, creating an alternative explanation.

Correlation

A relationship in which two variables change together, which does not by itself demonstrate causation.

Negative Control

An experimental group that does not receive the active treatment and is expected not to show the experimental effect, revealing background change.

Positive Control

An experimental group that receives a condition known to produce the expected response, confirming that the procedure and measurement system work.

Placebo

An inactive treatment that resembles the real one, used in human trials as a negative control to account for expectations.

Element

A pure substance that cannot be broken into another substance by ordinary chemical reactions.

Atom

The smallest unit that retains an element's chemical identity.

Atomic Number

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

Ion

An atom or group of atoms that has gained or lost electrons, creating a positive or negative charge.

Trace Elements

Elements occurring in small amounts in an organism that are essential for life, such as iron required for oxygen transport in hemoglobin.

Compound

A substance containing two or more elements in a fixed relationship with properties distinct from its constituent elements.

Valence Electrons

Electrons in the outermost occupied shell of an atom that largely determine its chemical behavior.

Covalent Bond

A chemical bond formed when atoms share pairs of electrons.

Nonpolar Covalent Bond

A covalent bond in which electrons are shared about equally.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally.

Cation

A positively charged ion produced by the loss of one or more electrons.

Anion

A negatively charged ion produced by the gain of one or more electrons.

Ionic Bond

An attraction between oppositely charged ions formed by electron transfer, resulting in compounds with neutral overall charge such as $K^+ + Br^- \rightarrow KBr$ or $3\,Ca^{2+} + 2\,P^{3-} \rightarrow Ca_3P_2$.

Electronegativity

An atom's tendency to attract shared electrons in a chemical bond, which creates partial negative ($\delta^-$) and partial positive ($\delta^+$) charges.