Inquiring about the World of Life and The Chemical Context of Life

Vocabulary flashcards covering core biological concepts, hierarchy of organization, cell types, classification, scientific method, and chemical fundamentals based on the study guide.

Form Fits Function

The principle that the size, shape, composition, and behavior of biological structures correlate closely with their function due to the process of natural selection; also known as structure and function.

Natural Selection

The mechanism for evolutionary adaptation of populations to their environments, occurring when a population's heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others.

Emergent Properties

Properties that bridge the gap between a single structure and its ultimate function, such as cardiac tissue, nervous tissue, and blood vessels forming a structural heart whose emergent property is pumping blood throughout the entire organism.

Biosphere

The largest biological organizational level, defined as the sum total of living things on earth and the areas they inhabit.

Ecosystem

A functional system consisting of a community, its nonliving environment, and the interactions between them.

Community

A set of populations of different species together in a particular area.

Population

A group of individual species that live in a particular area.

Organism

An individual living thing.

Organ System

An integrated system of organs whose action is coordinated for a particular function.

Organ

A structure in an organism composed of several types of tissues and specialized for a particular function.

Tissue

A group of cells with common structure and function.

Cell

The smallest unit of living matter able to function independently, enclosed in a semi-permeable membrane.

Organelle

A structure inside a eukaryotic cell that performs a particular function.

Macromolecule

An organic compound large in size and important for life, such as proteins, lipids, and nucleic acids.

Molecule

A combination of two or more atoms chemically bonded together.

Atom

The smallest component of an element that maintains the element's properties.

ORGEHER

An acronym representing the seven characteristics of living things: Order, Reproduce, Grow and Develop, Energy Required, Homeostatic Regulation, Evolve, and Respond To Their Environment.

Characteristics Shared by All Cells

The four structural features present in all cells: enclosed by a membrane, DNA as genetic information, ribosomes, and cytoplasm.

Eukaryotic Cells

Cells with a 'True Nucleus' where DNA is enclosed by a nuclear membrane or envelope in linear strands; found in plants, animals, protists, and fungi.

Prokaryotic Cells

Simple cells lacking membrane-bound organelles with circular DNA; found in archaea and bacteria.

Producers (Autotrophs)

Organisms that make their own food using photosynthesis or chemicals, such as plants and algae.

Consumers (Heterotrophs)

Organisms that eat other living things because they cannot make their own food, such as humans, lions, and fish.

Decomposers (Heterotrophs)

Organisms that break down dead organisms and return nutrients to the soil, such as fungi, mushrooms, and bacteria.

Energy Flow vs. Nutrient Cycling

Energy flows one way through an ecosystem (sunlight to chemical energy in plants to work in organisms, with heat lost), whereas nutrients cycle and recycle (taken from soil and air by plants, passed to consumers, and returned to soil by decomposers).

Archaea

Single-celled prokaryotes measuring $2\,\mu \text{m}$ that live in extreme environments and can withstand high temperature, high pressure, or extreme pH levels.

Bacteria

Single-celled prokaryotes measuring $2\,\mu \text{m}$ with no nucleus and a peptidoglycan cell wall, found everywhere in soil, oceans, food, and inside the body.

Eukarya

Domain of eukaryotic organisms measuring $100\,\mu \text{m}$ with greater internal complexity and structural organization, divided into four highly diverse kingdoms.

Kingdom Plantae

Multicellular eukaryotic photoautotrophic producers with cellulose cell walls that use the green pigment chlorophyll to convert carbon dioxide and water into sugar (e.g., ferns, flowering plants, mosses).

Kingdom Fungi

Multicellular eukaryotic heterotrophic decomposers with chitin cell walls that secrete digestive enzymes outside their body to break down dead organic matter and absorb nutrients (e.g., mushrooms, molds).

Kingdom Animalia

Multicellular eukaryotic heterotrophic ingesters that ingest and break down food, lacking cell walls to allow flexibility for muscle and nervous tissue development (e.g., insects, fish, birds, amphibians, mammals).

Protista (Protists)

Single-celled eukaryotic organisms with a true nucleus that prefer wet environments (e.g., Amoeba, Paramecium).

Taxonomy

The branch of biology that names and classifies species according to a system of broader groups based on the concept 'Unified, yet Diverse.'

Scientific Method

A step-by-step process of scientific inquiry: Make Observation, Ask a Question, Form a Hypothesis ('If… then…'), Conduct an Experiment, Analyze Data and Draw Conclusions, and Report and Share Results.

Inductive Reasoning

Reasoning that starts with specific patterns or small clues and builds up to a broad guess or general conclusion (Conclusion = probable).

Deductive Reasoning

Reasoning that starts with established, absolute rules and applies them to a specific situation to narrow down to detail (Conclusion = Guaranteed).

Controlled Experiment

A scientific test where only one variable is changed at a time while all other conditions are kept exactly the same.

Independent Variable

The single factor in an experiment that the scientist deliberately changes or manipulates to see what happens (the cause).

Dependent Variable

The factor in an experiment that is measured or observed to gather data, which depends entirely on the independent variable (the effect).

Controlled Variables (Constants)

Variables in an experiment that are kept exactly identical across all groups.

Experimental Group vs. Control Group

The experimental group receives the independent variable or treatment, whereas the control group serves as the unchanged baseline receiving no treatment.

HONC

An acronym for the four elements—Hydrogen, Oxygen, Nitrogen, Carbon—that make up $96\%$ of living matter.

Simplified Model of an Atom

A structural model showing how subatomic particles join together inside cells to form molecules that build cell parts and run life processes.

Atomic Shell Diagrams

Diagrams illustrating the arrangement of electrons orbiting in shells for Hydrogen, Oxygen, Nitrogen, and Carbon atoms.

Subatomic Particles

The fundamental components of an atom: Neutrons (neutral charge, located in atomic nucleus), Protons (positive charge, located in atomic nucleus), and Electrons (negative charge, orbiting in shells).

Neutron

A subatomic particle with a non (neutral) charge located within the atomic nucleus.

Proton

A subatomic particle with a positive charge located within the atomic nucleus.

Electron

A subatomic particle with a negative charge located orbiting around the nucleus within structures called shells.

Atomic Number ($Z$)

The number of protons within an atom's nucleus, which never changes and defines the chemical identity of an element (e.g., Carbon always has $6$ protons).

Atomic Mass ($A$)

The sum of protons and neutrons added together in an atom, expressed in daltons ($\text{amu}$), where each proton and neutron equals $1\,\text{amu}$ ($1\,\text{dalton}$).

Ion

An atom that has gained or lost electrons, resulting in a net electrical charge and a completed valence shell.

Cations vs. Anions

Cations are positively charged ions formed by losing electrons; anions are negatively charged ions formed by gaining electrons.

Ionic Compound Example (Sodium Chloride)

Sodium loses its lone valence electron to become a positive cation ($\text{Na}^+$), while Chlorine gains it to become a negative anion ($\text{Cl}^-$); opposite charges attract like magnets to form Sodium Chloride ($\text{NaCl}$).

Isotope

Different forms of an element that have the same number of protons and electrons but a different number of neutrons, resulting in different mass numbers while keeping the same chemical identity.

Isotope Examples

$\text{Carbon-12}$ ($6$ protons, $6$ neutrons) and $\text{Carbon-14}$ ($6$ protons, $8$ neutrons); Magnesium isotopes include $^{24}\text{Mg}$ ($12$ neutrons), $^{25}\text{Mg}$ ($13$ neutrons), and $^{26}\text{Mg}$ ($14$ neutrons).

Isomer

Molecules that have the exact same number and types of atoms as another molecule, but whose atoms are arranged in a different shape or structure, making them distinct chemical substances.

Subatomic Particle Calculations

Protons equal Atomic Number ($Z$); Neutrons equal Atomic Mass minus Atomic Number ($A - Z$); Electrons equal protons in a neutral atom, or Atomic Number minus ion charge in an ion.

Radioactive Isotopes

Unstable isotopes that decay spontaneously, emitting particles and radiation; used in science for fossil dating, targeted organ imaging, CT thyroid diagnostics (using Iodine), and PET tumor scanning.

Single Bond vs. Double Bond

A single bond occurs when two atoms share one pair of electrons ($\text{H-H}$); a double bond occurs when two atoms share two pairs of electrons ($\text{H=H}$).

Non-Polar Covalent Bond

A strong bond formed when atoms share electrons equally to complete their valence shells because they have similar pulling power.

Polar Covalent Bond

A strong bond formed when atoms with differing electronegativities share electrons unequally.

Ionic Bond

A chemical connection formed when one atom completely transfers one or more electrons to another atom, creating attractions between cations and anions.

Hydrogen Bond

A weak chemical attraction between a slightly positive hydrogen atom (covalently bonded to an electronegative atom) and another electronegative atom.

Van Der Waals Bonds

Very weak, temporary attractions occurring when transiently positive and negative regions of molecules attract each other due to electrons clustering on one side of an atom by chance.

Biological Roles of Strong vs. Weak Bonds

Strong covalent bonds provide a stable structural backbone for biological molecules, whereas weak bonds allow flexible, temporary interactions that drive dynamic cellular processes.

Molecular Shape and Biological Function

A biological molecule's 3D shape determines how molecules recognize and respond to one another with specificity, as shown by morphine mimicking natural endorphins to bind brain cell endorphin receptors.