Biology and Molecules of Life

Flashcards covering vocabulary from Chapter 1 (Invitation to Biology) and Chapter 2 (Molecules of Life), focusing on levels of organization, the scientific method, taxonomy, and basic atomic structure.

Biology

The scientific study of life

Atom

Fundamental building block of all matter (solid, liquid, gas, and plasma)

Molecule

An association of two or more atoms joined by chemical bonds

Cell

Smallest unit of life

Organism

An individual; consists of one or more cells

Population

Group of individuals of a species in a given area

Community

All populations of all species in a given area

Ecosystem

A community interacting with its environment

Biosphere

All regions of Earth that hold life

Energy

The capacity to do work

Nutrient

Substance that is necessary for survival that an organism cannot make itself

Producers

Organisms that make their own food using energy and simple raw materials from nonbiological sources

Consumers

Organisms that obtain energy and nutrients by feeding on other organisms

Homeostasis

Process by which an organism keeps its internal conditions within a range that favors survival by sensing and responding to change

Growth

Increase in size, volume, and number of cells in multicelled species

Development

Process by which the first cell of a new individual becomes a multicelled adult

Reproduction

Process by which individuals produce offspring

Inheritance

Transmission of DNA to offspring

DNA (deoxyribonucleic acid)

Carries hereditary (genetic) information that guides development and other activities; source of life’s diversity

Biodiversity

Scope of variation among living organisms

Nucleus

Saclike structure containing cell’s DNA

Prokaryotes

Single-celled organisms in which DNA is not contained in a nucleus

Bacteria

The most numerous organisms on Earth; a type of prokaryote

Archaea

A type of prokaryote more closely related to eukaryotes than to bacteria

Eukaryotes

Organisms whose DNA is contained within a nucleus

Protists

Simplest eukaryotes with great diversity

Fungi

Eukaryotic consumer that breaks down food externally

Plant

Usually a multi-celled, photosynthetic producer

Animal

Multi-celled consumer that ingests food or juices of other organisms

Taxonomy

Practice of naming and classifying species; developed by Linnaeus

Species

Organisms which share the same characteristics and are capable of exchanging genes and producing offspring

Genus

A group of species that share a set of unique traits

Taxon

A group of organisms that share a unique set of traits

Critical thinking

Deliberate process of judging the quality of information before accepting it

Science

Systematic study of the observable world

Pseudoscience

Beliefs, theories, or practices that have no scientific evidence and are often untestable

Hypothesis

Testable explanation for a natural phenomenon

Scientific method

Systematically making, testing, and evaluating hypotheses

Prediction

Statement, based on a hypothesis, about a condition that should exist if the hypothesis is correct

Model

Analogous system used for testing hypotheses

Experiment

Test designed to support or falsify a prediction

Variable

Characteristic that differs among individuals or over time

Experimental group

Group of individuals who have a certain characteristic or receive a certain treatment

Control group

Group not exposed to the independent variable being tested

Sampling error

Difference between results obtained from a subset and results from the whole

Probability

The chance a particular outcome will occur

Statistically significant

A result that is not likely to have occurred by chance alone

Scientific theory

Hypothesis that has not been disproven after many years of rigorous testing; can never be proven absolutely

Law of nature

Phenomenon observed to occur in every circumstance without fail, even without a complete scientific explanation

Charge

Electrical property of some subatomic particles; opposite charges attract and like charges repel

Electron ($e^-$)

Negatively charged subatomic particle that occupies orbitals around the atomic nucleus

Proton ($p^+$)

Positively charged subatomic particle found in the nucleus of all atoms

Neutron

Uncharged subatomic particle found in the atomic nucleus

Element

A pure substance that consists only of atoms with the same number of protons

Isotopes

Forms of an element that differ in the number of neutrons their atoms carry

Compound

Molecule that has atoms of more than one element

pH

A measure of the concentration of $H^+$ in a solution

Acid

Substance that releases $H^+$ ions and has a pH less than $7$

Base

Substance that releases $OH^-$ ions and has a pH greater than $7$

Buffer System

Compensates for changes in pH by absorbing or releasing ions; example is the bicarbonate buffer system