intro to bio exam 1

Biosphere

Includes all life and the places where it exists.

Ecosystems

Consists of all living organisms in a particular area and all the nonliving components of the environment with which life interacts.

Communities

All organisms in a particular area, such as a tide pool.

Populations

Various groups of interacting individuals of one species within a community.

Organisms

An individual living thing, such as an iguana.

Tissues

Groups of similar cells performing a specific function.

Cells

The smallest unit that can display all the characteristics of life.

Organelles

Functional components of cells such as the nucleus.

Molecules

Clusters of small chemical units.

Atoms

The chemical level in the hierarchy.

Natural Selection

Works at the population level; the environment selects certain heritable traits.

Scientific Method

A way of knowing, an approach to understanding the natural world based on inquiry.

Hypothesis

A tentative answer to a question or an explanation on trial.

Controlled Experiment

An experiment designed to compare an experimental group with a control group.

Matter

Anything that occupies space and has mass.

Element

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

Ionic Bond

The attractions between oppositely charged ions.

Covalent Bond

Forms when two atoms share one or more pairs of outer-shell electrons.

Polar Molecule

One with an uneven distribution of charge.

Chemical Reactions

Change substances into different substances by breaking and forming bonds.

Solvent

The dissolving agent in a solution.

Solute

Any substance that is dissolved in a solution.

pH Scale

A measure of the hydrogen ion concentration in a solution.

Buffers

Substances that minimize changes in pH by accepting or donating H+.

Organic Compounds

Carbon-based molecules.

Hydrocarbons

Organic molecules composed only of carbon and hydrogen.

Macromolecules

Four main classes of large biological molecules: carbohydrates, lipids, proteins, nucleic acids.

Polymers

Large molecules made by stringing together many small molecules.

Monomers

Small units that can join together to form polymers.

Denaturation

A process in which a protein unravels, losing its specific structure and function.

Gene

A specific stretch of DNA that programs the amino acid sequence of a polypeptide.

Eukaryotic Cells

Cells that are composed of protists, plants, fungi, and animals.

Ribosomes

Build proteins according to instructions from the genes.

Phospholipid Bilayer

Double layer of phospholipids that makes up plasma and organelle membranes.

Cytoskeleton

A network of fibers extending throughout the cytoplasm.

Kinetic Energy

The energy of motion.

ATP

An organic molecule consisting of adenosine plus three phosphate groups.

Active Site

Has a shape and chemistry that fit the substrate.

Transport Protein

Membrane proteins that help move substances across the membrane.

Diffusion

Movement of molecules spreading out evenly into available space.

Autotrophs

Organisms that produce their own food.

Cellular Respiration

The aerobic harvesting of chemical energy from organic fuels.

Glycolysis

The first step of cellular respiration.

Krebs Cycle

The second step of cellular respiration.

Electron Transport Chain

A sequence of electron carrier molecules that shuttle electrons.