Introduction to Biology: Scientific Inquiry, Chemical Foundations, and Biological Macromolecules

Vocabulary practice flashcards covering scientific inquiry, chemical bonding, aqueous solutions, and the four major classes of biological macromolecules.

Scientific inquiry

A systematic, evidence-based way of investigating the natural world.

Hypothetico-deductive reasoning

A scientific method used to test how microscopic structures dictate macroscopic survival.

Hypothesis

A testable and falsifiable explanation for an observed phenomenon.

Independent variable

The variable that is intentionally manipulated in an experiment.

Dependent variable

The variable that is being measured to assess the effect of the manipulation.

Controlled variables

Variables that are kept constant to ensure that results are due solely to the independent variable.

Confounding variables

Unexpected variables that could skew the experimental data if not properly managed.

Claim

The direct answer to a research question (the "what") that can potentially be proven wrong.

Evidence

Specific, numerical measurements (the "data") needed to move an argument past an opinion.

Reasoning

The rationale (the "why") that uses established scientific principles to explain how evidence supports the claim.

Biological models

Simplified representations of reality that allow scientists to simulate, visualize, and predict biological processes.

Standard deviation

A measure of the data's spread or variation; a low standard deviation indicates very consistent results, whereas a high standard deviation indicates inconsistency.

Null hypothesis

The baseline statistical assumption that there is no real effect or difference.

P-value

A probability score with a standard cutoff of $0.05$; when it is low, the null hypothesis is rejected.

Error bars

Visual graphical representations that depict the spread or uncertainty of experimental data.

Atomic number

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

Isotopes

Atoms of the same element that have differing numbers of neutrons.

Atomic weight

The total sum of protons and neutrons in an atom.

Electronegativity

A measure describing how strongly an atom attracts electrons in a chemical bond.

Nonpolar covalent bond

A bond where atoms share electrons equally, typically exhibiting an electronegativity difference between $0$ and $0.4$.

Polar covalent bond

A bond where electrons are shared unequally due to an electronegativity difference of $> 0.4$ and $< 1.8$, creating partial positive and partial negative charges.

Ionic bond

A chemical bond formed when the electronegativity difference is $\ge 1.8$, transferring electrons to form oppositely charged ions held together by electrostatic attraction.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Hydrogen bond

A weak intermolecular bond that forms between a partial positive charge on a hydrogen atom and a partial negative charge on another atom.

Hydrophilic

A property of polar and charged substances that allows them to readily dissolve or interact with water.

Hydrophobic

A property of nonpolar molecules that do not react well with water, causing them to group together rather than dissolve.

pH

A measurement of the acidity or alkalinity of a solution determined by the concentration of hydrogen ions ($H^+$).

Acid

A substance that increases the concentration of hydrogen ions ($H^+$) in a solution.

Base

A substance that provides either hydroxide ions ($OH^-$) or other negatively charged ions that combine with hydrogen ions.

Amiphilic

A molecule possessing both hydrophobic and hydrophilic properties.

Carbohydrates

Polar, hydrophilic macromolecules used for energy storage, consisting of a sequence of carbons with multiple $-OH$ groups forming straight chains or ring structures.

Triacylglycerol

A lipid composed of three fatty acid hydrocarbon chains linked to a single glycerol molecule, functioning in long-term energy storage.

Nucleic acids

Polar, hydrophilic polymers that store genetic information, composed of nucleotides joined by phosphodiester bonds along a sugar-phosphate backbone and paired by hydrogen bonds between nitrogenous bases.

Saturated fats

Lipids with straight hydrocarbon chains containing no double bonds, making them pack tightly and remain solid at room temperature.

Unsaturated fats

Lipids containing double bonds that introduce bends into their hydrocarbon chains, increasing membrane fluidity and remaining liquid at room temperature.

Phospholipids

Molecules featuring a polar hydrophilic head and two nonpolar hydrophobic fatty acid tails that self-assemble into a bilayer in aqueous environments.

Steroids

A group of hydrophobic lipids characterized by a carbon skeleton composed of four fused rings.