3 and 4th lecture bio stuff :)

Vocabulary flashcards covering key terms from the lecture notes on the scientific method, chemistry of life, and properties of water.

Biology

The scientific study of life.

Science

An evidence-based approach to understanding the natural world, based on inquiry.

Scientific method

A general process of using evidence to answer questions, explain phenomena, and test hypotheses.

Observation

Information gathered by the senses or from existing knowledge and results.

Question (in science)

A specific inquiry that arises from observations.

Hypothesis

A testable explanation derived from observations or questions; a general statement that leads to predictions.

Prediction

A statement about a relationship between variables, usually written as an if–then statement.

Testable hypothesis

A hypothesis for which data can be collected to support or reject it.

Discovery science

An approach based on careful observations of the natural world to gather data.

Data

Information collected during investigations.

Control group

The group that does not receive the treatment, used for comparison.

Treatment group

Group(s) that receive the experimental treatment.

Peer review

Independent evaluation by experts to assess the validity and quality of a manuscript.

Journal

A publication in which scientific articles are published after review.

Manuscript

A written draft of a scientific paper submitted for publication.

Editorial assessment

In-house evaluation by an editor before or during the review process.

Matter

The substance that occupies space and has mass.

Element

A pure substance that cannot be broken down into simpler substances by chemical reactions.

Atom

The smallest unit of an element that retains its properties; composed of protons, neutrons, and electrons.

Nucleus

Central part of an atom containing protons and neutrons.

Proton

Positively charged subatomic particle in the nucleus.

Neutron

Uncharged subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle that orbits the nucleus.

Electron cloud

Region around the nucleus where electrons are likely to be found.

Atomic number

Number of protons in an atom.

Atomic mass

Mass of an atom, measured in atomic mass units (amu).

Mass number

Protons plus neutrons in an atom; varies for isotopes.

Isotope

Atoms of the same element with different numbers of neutrons.

Protium

Hydrogen-1: 1 proton, 0 neutrons.

Deuterium

Hydrogen-2: 1 proton, 1 neutron.

Tritium

Hydrogen-3: 1 proton, 2 neutrons.

Ion

An atom with a net electric charge due to gain or loss of electrons.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Ionic bond

Electrostatic attraction between oppositely charged ions; transfer of electrons.

Covalent bond

Bond formed when atoms share electrons; can be single, double, or triple.

Single covalent bond

One pair of shared electrons.

Double covalent bond

Two pairs of shared electrons.

Triple covalent bond

Three pairs of shared electrons; strongest covalent bond.

Electronegativity

Tendency of an atom to attract shared electrons.

Polar covalent bond

Covalent bond with unequal sharing of electrons, creating partial charges.

Water (H2O)

Molecule with polar O–H bonds; δ− on oxygen and δ+ on hydrogens.

Hydrogen bond

A weak electrostatic attraction between a hydrogen atom and a highly electronegative atom; important in water and biomolecules.

Cohesion

Attraction between molecules of the same substance (e.g., water).

Adhesion

Attraction between molecules of different substances (e.g., water to surfaces).

Surface tension

Tendency of a liquid surface to resist external force due to cohesive forces.

Solvent

The dissolving agent in a solution.

Solute

Substance dissolved in the solvent.

Solution

A homogeneous mixture of two or more substances.

Aqueous solution

A solution in which water is the solvent.

Like dissolves like

Polar solvents dissolve polar molecules; nonpolar solvents dissolve nonpolar substances.

Periodic table

A chart listing elements in order of increasing atomic number with symbols and properties.

Major body elements

Oxygen (65%), Carbon (18.5%), Hydrogen (9.5%), Nitrogen (3.3%) make up about 96% of body weight.

Trace elements

Elements required in very small amounts but essential for life.

Iodine

A trace element essential for thyroid hormones; deficiency can cause goiter; often supplied by iodized salt.

Cofactor

A helper molecule or ion essential for an enzyme's activity.

Iron (Fe)

Trace element essential for hemoglobin to carry oxygen.

Fluoride

Additive to dental products and drinking water to support bones and teeth.

Dalton (Da) / Atomic mass unit (amu)

Unit of mass; 1 Da is the mass of a hydrogen atom (1 amu).

Kilodalton (kDa)

1,000 Daltons; used to express the molecular weight of large molecules.

Goiter

Enlarged thyroid due to iodine deficiency.