Biology Foundations: Elements, Water, and the Science of Life

Vocabulary flashcards covering the elements of life, the properties of water, the chemistry of carbon, and the foundational concepts of biological science.

Elements of Life

The six atoms essential to living organisms: carbon ($C$), hydrogen ($H$), nitrogen ($N$), oxygen ($O$), phosphorus ($P$), and sulfur ($S$).

Miller-Urey Experiment

A 1953 study demonstrating that the early atmosphere of Earth could produce organic molecules, such as urea, through reactions between water vapor, hydrogen gas, methane, and ammonia subjected to electrical shocks.

Biological Hierarchy

The levels of organization in living things, starting from atoms and progressing to molecules, cells, tissues, organs, organ systems, and eventually entire organisms.

Organic Chemistry

The scientific study of carbon-based molecules.

Valence Shell

The outermost electron shell of an atom; for carbon, it contains four electrons, allowing it to form four covalent bonds.

Isomers

Molecules that share the same chemical formula but differ in the structural arrangement or placement of their atoms and chemical bonds.

Structural Isomers

Molecules with the same atoms arranged in a different order, leading to different chemical properties.

Cis-trans Isomers

Isomers containing double bonds where functional groups are on the same side (cis) or opposite sides (trans) of the rigid bond.

Enantiomers

Molecules that are mirror images of each other arranged around an asymmetric center; they are designated as $L$ (laevus/left) or $D$ (dextro/right).

Functional Groups

Specific groups of atoms attached to a carbon backbone that confer distinct chemical properties and functions to the molecule.

Hydroxyl Group

A functional group ($-OH$) that adds polarity to molecules, allowing them to interact with water; molecules containing this group are known as alcohols.

Carbonyl Group

A functional group with a double-bonded oxygen atom; called an aldehyde if at the end of a molecule and a ketone if in the middle.

Carboxyl Group

A functional group that forms an acid in water by donating a hydrogen ion ($H^+$).

Amino Group

A functional group that acts as a base by attracting a proton; it is crucial for the formation of proteins.

Sulfhydryl Group

A functional group that can form crosslinks with others of its kind to create rigid 3D structures in proteins.

Methyl Group

A non-reactive functional group often involved in DNA methylation, which can cause a cell to ignore certain genes.

Phosphate Group

A group that allows carbon chains to interact with water and release energy, facilitating reactions in molecules like $ATP$.

Electronegativity

The tendency of an atom to attract shared electrons in a covalent bond; oxygen's high electronegativity creates a dipole moment in water.

Specific Heat Capacity

The amount of heat required to raise the temperature of one gram of a substance by one degree Celsius; for water, this value is $1\,calorie$.

Cohesion

The tendency of water molecules to stick to each other due to hydrogen bonding, which also creates surface tension.

Adhesion

The tendency of water molecules to stick to other polar objects or surfaces.

Capillary Action

The process by which liquid flows through a narrow space without external force, occurring when adhesion to the walls is stronger than the cohesion between molecules.

Hydrophilic

Describes polar substances or ions that interact readily with or dissolve in water.

Hydrophobic

Describes nonpolar molecules, such as oils and fats, that do not interact well with water.

pH Scale

An inverse logarithmic scale ranging from $0$ to $14$ that measures the concentration of hydrogen ions ($H^+$) in a solution.

Buffer

A substance that resists changes in $pH$ by absorbing or releasing hydrogen or hydroxide ions; for example, the carbonic acid-bicarbonate system in human blood.

Scientific Method

A research method with defined steps including observation, formulation of a hypothesis, repeatable experiments, and careful observation.

Hypothesis

A suggested, testable explanation for an event or observation.

Theory

A tested and confirmed explanation for observations or phenomena.

Inductive Reasoning

A form of logical thinking that uses related observations to arrive at a general conclusion; common in descriptive science.

Deductive Reasoning

A form of logical thinking that uses a general principle or law to predict specific results.

Basic Science

Also called "pure" science, it seeks to expand knowledge regardless of the short-term application or commercial value.

Applied Science

Also known as "technology," it aims to use science to solve real-world problems.

Peer-reviewed Manuscript

A scientific paper reviewed by a scientist’s colleagues or experts in the field to ensure the work is original, significant, and logical.

Bioethics

A field that defines ethical guidelines for biological research to ensure the dignity and safety of humans, animals, and the environment.

HeLa Cells

An "immortal" cell line created from the cervical cancer cells of Henrietta Lacks in 1951 without her knowledge or permission.

Homeostasis

The ability of an organism to maintain constant, stable internal conditions required for life.

Atom

The smallest and most fundamental unit of matter that retains the properties of an element; it consists of a nucleus (protons and neutrons) and electrons.

Isotope

Different forms of the same element that have the same number of protons but a different number of neutrons.

Radioisotope

An unstable isotope that emits radiation in the form of subatomic particles to attain a more stable atomic configuration.

Half-life

The time it takes for half of the original concentration of an isotope to decay back to its more stable form; for ${}^{14}C$, this is approximately $5,730\,years$.

Octet Rule

The principle that atoms are most stable energetically when they have eight electrons in their valence shell.

Ionic Bond

A chemical bond that forms between ions with opposite charges, such as a cation and an anion.

Covalent Bond

A strong bond formed when electrons are shared between atoms; can be polar (unequal sharing) or nonpolar (equal sharing).

Phylogenetic Tree

A diagram showing the evolutionary relationships among biological species based on genetic or physical traits.

Carl Woese

The microbiologist who used comparative gene sequencing of ribosomal $RNA$ to define the three domains of life: Bacteria, Archaea, and Eukarya.