AP Biology Unit 1 Vocabulary

Molecule

Two or more atoms bonded together covalently

Cell

The smallest unit of life that can survive and reproduce on its own

Community

All populations of all species occupying a given area

Ecosystem

The interaction of a community and the physical environment

Organ system

Interaction of organs physically or chemically to perform a common task

Organ

Interaction of two or more tissues to perform a common task

Population

Group of individuals of the same species occupying a specific area

Biosphere

All the regions on Earth that hold organisms

Tissue

Organized array of cells that interact for a specific task

Atom

The smallest unit that retains an element's properties

Multi-celled organism

Individual composed of different types of cells

Homeostasis

Maintenance of a constant internal environment

Reproduction

The mechanism by which parents transmit DNA to offspring

Development

The orderly transformation of the first cell of a new individual to an adult

Inheritance

The actual transmission of traits from parent to offspring

Archaea

Single celled; lack a nucleus; most ancient lineage; most closely related to more derived multi-celled organisms; often located in extreme environments, like hydrothermal vents and frozen desert rocks

Eukarya

Includes plants, animals, fungi, protists, and all multi-celled organisms; contains a nucleus in each cell

Control group

Group in an experiment that are not exposed to the independent variable

Data

Experimental results

Deductive reasoning

Using a general idea to make a conclusion

Dependent variable

In an experiment, a variable that is presumably affected by the independent variable being tested

Experimental group

Group in an experiment that are exposed to the independent variable

Hypothesis

Testable explanation of natural phenomenon

Independent variable

Variable that is controlled in an experiment

Inductive reasoning

Drawing a conclusion based on an observation

Model

Analogous system used to test hypothesis

Prediction

Based on a hypothesis, statement about a condition that should exist if the hypothesis is correct

Variable

In an experiment, characteristic or event that differs among individuals over time

Apoplast

Movement through cell walls and space between cells

Casparian strip

Waxy substance found on rood endodermal cells that prevents the movement of water between cells

Osmosis

Diffusion of water

Plasmolysis

This occurs when the cytoplasm shrivels and plasma membrane pulls away from the cell wall

Root hairs

Root epidermal cells of plants specialized for the uptake of water

Stomata

Pores in a leaf created by guard cells through which gas exchange occurs

Symplast

Movement through the cytoplasmic continuum between cells connected by plasmodesmata

Tension

Negative pressure

Transpiration

Loss of water through the leaves and stems of plants

Turgor pressure

Pressure exerted by the plasma membrane against the cell wall and cell wall against the protoplast

Water potential

Measure that combines the effect of solute and pressure; determines the direction of water movement

Xylem

Water conducting tissue in plants

Atomic number

Determines the identity of an element

Compound

Substance consisting of two or more different elements in constant proportion

Covalent bond

Two atoms with similar electronegativity and sharing a pair of electrons

Electronegativity

Measure of an atom's ability to pull electrons away from another atom

Hydrogen bond

Weak molecular interaction formed between hydrogen and another element

Ionic bond

Strong mutual attraction between two oppositely charged atoms with a large difference in electronegativity

Isotopes

Atoms having the same atomic number but different mass numbers

Mass number

Number of protons and neutrons in an atom

Nonpolar covalent bond

Bond formed by an equal sharing of electrons

Polar covalent bond

Bond formed between nonmetal atoms having different electronegativities

Polarity

Any separation of charge into distinct positive and negative regions

Salt

Compound consisting of a metal and a nonmetal

Acid

Proton donor

Base

Proton acceptor

Buffer

Substance that can absorb excess hydrogen ions without resulting in a drastic change in pH

Hydrophilic

Substances that can interact with water molecules

Hydrophobic

Substance that does not interact with water

pH

Measure of the hydrogen ion concentration of a solution

Solvent

The dissolving agent of a solution

Specific heat

Amount of heat that must be absorbed or lost for 1 g of substance to change its temperature by 1 degrees Celsius