Biology Flashcards 8/14/25

Observation

the act of gathering information using one's senses, or with the aid of instruments, to gain knowledge about a phenomenon or event

Inference

Making an educated guess based on the evidence and reasoning one has.

Hypothesis

a testable prediction on the relationship of two variables

null hypothesis

a statement that there is no significant effect or relationship between variables

alternative hypothesis

a statement that contradicts the null hypothesis, proposing a specific effect, difference, or relationship between variables

controlled experiment

a scientific investigation where all factors (variables) are kept constant except for the one being tested

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

dependent variable

The measurable effect, outcome, or response in which the research is interested.

data

Facts, figures, and other evidence gathered through observations.

theory

a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experimentation

Law

a statement that describes what always happens under certain conditions in nature, based on repeated observations and experiments

experiment

a systematic procedure designed to test a hypothesis and gather empirical evidence

constant

a value or quantity that remains unchanged, either throughout a specific experiment or in general within a defined system or context

control group

a standard of comparison, a group that is not exposed to the experimental treatment or variable being tested

experimental group

a group of participants or subjects that receives the specific treatment or intervention being tested

Mass

the quantity of matter in an object, a fundamental property that determines how much an object resists changes in its motion

Matter

Anything that has mass and takes up space

Atom

the smallest unit of matter that retains the chemical properties of an element

Element

a pure substance that cannot be broken down into simpler substances by chemical means

covalent bond

a type of chemical bond where atoms share one or more pairs of electrons to achieve a more stable electron configuration, typically by filling their outer (valence) electron shells

ionic bond

a type of chemical bond formed through the electrostatic attraction between oppositely charged ions

chemical reaction

a process where one or more substances, called reactants, are transformed into one or more different substances, called products, through a chemical change

Lipid

a diverse group of organic molecules that are broadly characterized by their insolubility in water

Protein

large, complex molecules composed of amino acids that play a crucial role in the structure, function, and regulation of the body's tissues and organs

Carbohydrate

a group of organic compounds, primarily composed of carbon, hydrogen, and oxygen, often with a hydrogen-to-oxygen ratio of 2:1

Nucleic Acid

biological macromolecules, specifically polymers of nucleotides, that are essential for all known forms of life

Nucleotide

a fundamental building block of nucleic acids like DNA and RNA

Products and reactants

reactants are the substances that enter a chemical reaction, while products are the substances that are formed as a result of the reaction

Molecule

two or more atoms held together by chemical bonds, representing the smallest unit of a compound that retains its chemical properties

Macromolecule

large, complex molecules essential for life, built from smaller subunits called monomers

Monomer

a small molecule that serves as a building block for larger molecules called polymers

polymer

large macromolecules composed of repeating monomer subunits

primary structure

the linear sequence of amino acids in a polypeptide chain

secondary structure

the local folding of a polypeptide chain into specific shapes, primarily alpha helices and beta pleated sheets, due to hydrogen bonding between amino acids

tertiary structure

its overall three-dimensional shape, resulting from the folding and interactions of its secondary structures

quaternary structure

the way multiple polypeptide chains (subunits) assemble to form a multi-subunit protein complex

reaction diagram

visually represents the energy changes that occur during a chemical reaction

enzyme

a biological catalyst, specifically a protein, that speeds up chemical reactions within living organisms without being consumed in the process

substrate

the molecule upon which an enzyme acts, facilitating a specific chemical reaction

hydrogen bonding

a weak chemical interaction between a hydrogen atom and a highly electronegative atom (like oxygen, nitrogen, or fluorine) in a separate molecule or a different part of the same molecule

polarity

the uneven distribution of electrical charge within a molecule, creating partially positive and partially negative regions

cohesive behavior/cohesion

the tendency of water molecules to stick together due to hydrogen bonding, resulting in a strong attraction between like molecules

adhesive behavior/adhesion

the tendency of different molecules or substances to stick together due to attractive forces between them

specific heat capacity

the amount of energy required to raise the temperature of one gram of a substance by one degree Celsius (or one Kelvin)

density

the number of individuals of a species per unit area or volume in a specific habitat

dissolve

the process where a solute (solid, liquid, or gas) mixes with a solvent (usually a liquid) to form a solution

solvent

a substance, usually a liquid, that can dissolve other substances (solutes) to form a solution

solute

a substance that is dissolved in a solvent to form a solution

solution

a homogeneous mixture where a solute (the substance being dissolved) is dissolved in a solvent

pH

a scale that measures the acidity or alkalinity of a solution, with a range from 0 to 14

chi square

a statistical tool used to determine if there's a significant difference between observed data from an experiment and expected data based on a hypothesis

degrees of freedom

the number of independent pieces of information available to estimate a parameter

critical value

The critical values table is given to you.

To use the critical values you need to know:

1) Desired significance level (usually 0.05)

2) The number (N) of participants

3) Whether the hypothesis is directional or non-directional

standard deviation

a measure of variability that describes an average distance of every score from the mean

standard error of the mean

the standard deviation of the sampling distribution of sample means