Chapter 2: Science, Matter, and Energy Flashcards

Vocabulary flashcards covering the scientific process, foundational chemistry, biological macromolecules, cells, and principles of energy based on the Chapter 2 lecture notes.

Science

A methodical, logical process based on careful observation and hypothesis testing used to gain knowledge about natural phenomena and explain how the natural world works.

Hypothesis

An educated guess or proposed explanation that attempts to explain an observation or answer a scientific question.

Deductive reasoning

Logical reasoning that proceeds from general principles to specific conclusions.

Inductive reasoning

Reasoning that moves from many specific observations to produce a general rule.

Manipulative experiment

An experiment in which conditions are actively controlled and manipulated by the investigator to directly test cause-and-effect relationships.

Natural experiment

An experimental approach or correlational study that relies on observing events or conditions that have already happened or naturally vary.

Independent variable

The factor in an experiment that the investigator varies to determine its effect on the dependent variable.

Dependent variable

The factor measured, counted, or recorded in an experiment that is hypothesized to be affected by the independent variable.

Control treatment

A treatment group in an experiment in which the independent variable is eliminated or set at a standard baseline value for comparison.

Controlled variables

Factors that are kept constant across all experimental treatments so that any effect on the dependent variable can be attributed solely to the independent variable.

Levels of treatment

The appropriate values or set amounts used for the independent variable during an experiment.

Replication

The repetition of an experiment numerous times to increase confidence in the results and enable the calculation of average data.

Matter

Anything that has mass and takes up space, existing in three physical states (solid, liquid, gas) and two chemical forms (elements and compounds).

Element

A basic chemical substance consisting of unique atoms that cannot be broken down or simplified by chemical means.

Compound

A chemical substance composed of two or more different elements bound in fixed proportions.

Atomic number

The number of protons contained within the nucleus of an atom.

Atomic mass

The combined total number of protons and neutrons in the nucleus of an atom.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different atomic mass numbers.

Molecule

A combination of two or more atoms of the same or different elements held together by chemical bonds.

Ion

An atom or group of atoms carrying a net positive or negative charge due to an unequal number of protons and electrons.

Cation

A positively charged ion formed when an atom loses one or more electrons, such as $\text{Na}^+$.

Anion

A negatively charged ion formed when an atom gains one or more electrons, such as $\text{Cl}^-$.

Chemical bond

An attractive force that holds atoms close together in molecules.

Covalent bond

A chemical bond formed when atoms share pairs of electrons.

Ionic bond

A chemical attraction between an anion and a cation formed after the complete transfer of one or more electrons.

Hydrogen bond

A weak attraction formed when a hydrogen atom covalently bonded to one electronegative atom (such as oxygen or nitrogen) is attracted to another electronegative atom.

pH

A logarithmic expression of solution acidity based on the hydrogen ion concentration, calculated as $\text{pH} = -\log[\text{H}^+]$.

Acid

A substance that dissociates in water to increase the concentration of hydrogen ions ($\text{H}^+$), resulting in a $\text{pH} < 7$.

Base

A substance that reduces the hydrogen ion ($\text{H}^+$) concentration or increases the hydroxide ion ($\text{OH}^-$) concentration in a solution, resulting in a $\text{pH} > 7$.

Macromolecules

Large organic molecules created as polymers when smaller subunit monomers are linked together.

Monosaccharide

The simplest single sugar monomer of carbohydrates, having the general formula $(-\text{CH}_2\text{O}-)$ such as glucose ($\text{C}_6\text{H}_{12}\text{O}_6$).

Amino acid

The monomer building block that links in specific sequences to form proteins.

Nucleotide

The repeating monomer subunit of nucleic acids, composed of a five-carbon sugar, a nitrogen-containing base, and a phosphate group.

Lipids

A diverse group of hydrophobic organic molecules—including fats, phospholipids, and steroids—that do not form polymers.

Saturated fat

A lipid composed of fatty acids with single bonds between all carbon pairs, having a lower ratio of hydrogen to carbon, and remaining solid at room temperature.

Unsaturated fat

A lipid composed of fatty acids containing one or more double bonds between carbon pairs, typically liquid at room temperature (oils).

Phospholipid

A membrane lipid consisting of two hydrophobic fatty acid tails and a hydrophilic phosphate head that self-assembles into a bilayer.

Prokaryotic cell

A simple cellular structure that lacks a membrane-bound nucleus and membrane-bound organelles.

Eukaryotic cell

A complex cell type that contains a distinct nucleus and membrane-bound organelles.

Gene

A segment of DNA on a chromosome that contains instructions to produce a specific protein.

Photosynthesis

The biological process converting light energy into chemical energy, represented by $6\,\text{CO}_2 + 12\,\text{H}_2\text{O} + \text{Light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\,\text{O}_2$.

Kinetic energy

Energy associated with the motion of matter, such as wind or flowing water.

Potential energy

Energy stored within matter due to its position, structure, or chemical composition.

First law of thermodynamics

The law stating that energy cannot be created or destroyed when transformed from one form to another during physical or chemical changes.

Second law of thermodynamics

The law stating that whenever energy is converted from one form to another, its quality is depleted and the entropy (disorder) of the universe increases.

High-quality matter

Matter that is highly concentrated, located near the Earth's surface, and has high potential for use as a resource.

Low-quality matter

Matter that is dispersed, located deep underground or in the atmosphere, and has little potential for use as a resource.

Physical change

A alteration in the state or appearance of matter without any change in its chemical composition.

Chemical change

A process or reaction that alters the original chemical composition of matter.

Law of Conservation of Matter

The principle stating that no atoms are created or destroyed whenever matter undergoes a physical or chemical change.