BIO 110 test 1 study guide

Levels of Biological Organization

Atom → molecule → cell → tissue → organ → organism → population → community → ecosystem → biosphere

Atom

The smallest unit of an element that retains its properties

Molecule

Two or more atoms chemically bonded together

Cell

The smallest unit of life

Tissue

A group of similar cells working together

Organ

A structure made of multiple tissues working together

Organism

An individual living thing

Population

Members of the same species living in the same area

Community

All populations of different species living in an area

Ecosystem

A community plus its nonliving environment

Biosphere

All regions of Earth where life exists

Taxonomy

The classification and naming of organisms

Three Domains of Life

Bacteria

Bacteria

Prokaryotes that generally have cell walls containing peptidoglycan

Archaea

Prokaryotes distinct from bacteria that often live in extreme environments

Eukarya

Organisms whose cells have a nucleus and membrane-bound organelles

Binomial Nomenclature

A system that gives each species a two-part scientific name

Genus

The first part of a scientific name

Species Descriptor

The second part of a scientific name

Genome

An organism's complete genetic information

Proteome

The complete set of proteins produced by an organism or cell

Homologous Structures

Structures inherited from a common ancestor that have been modified for different functions

Atom

The basic unit of an element

Chemical Element

A substance made of atoms with the same number of protons

Proton

A positively charged subatomic particle located in the nucleus

Neutron

A neutral subatomic particle located in the nucleus

Electron

A negatively charged subatomic particle found around the nucleus

Atomic Number

The number of protons in an atom

Mass Number

The total number of protons and neutrons

Ion

An atom with a net charge because it gained or lost electrons

Isotope

Atoms of the same element with different numbers of neutrons

Mass

The amount of matter in an object

Weight

The force of gravity acting on an object

CHON

Carbon

Electron Shell

An energy level where electrons are found

First Electron Shell

Can hold up to 2 electrons

Second Electron Shell

Can hold up to 8 electrons

Valence Electrons

Electrons in the outermost electron shell

Period

A row on the periodic table; elements have the same number of occupied electron shells

Group

A column on the periodic table; elements generally have similar chemical properties

Covalent Bond

A bond formed when atoms share electrons

Hydrogen Bond

A weak attraction involving a partially positive hydrogen and an electronegative atom

Ionic Bond

A bond formed by the attraction between oppositely charged ions

Octet Rule

Atoms tend to form bonds to achieve 8 valence electrons

Cation

A positively charged ion

Anion

A negatively charged ion

Salt

An ionic compound made of positive and negative ions

Free Radical

An atom or molecule with an unpaired electron

Enzyme

A substance that lowers activation energy and speeds up chemical reactions

Hydrophilic

Attracted to water

Hydrophobic

Repelled by or does not mix well with water

States of Water

Solid

Specific Heat

The amount of energy needed to change a substance's temperature

High Specific Heat of Water

Allows water to absorb a lot of heat without changing temperature quickly

Surface Tension

The resistance of water's surface caused by hydrogen bonds

Acid

A substance that increases H⁺ concentration in a solution

Base

A substance that decreases H⁺ concentration or increases OH⁻ concentration

pH

A measure of hydrogen ion concentration in a solution

Acidic

A solution with a pH below 7

Neutral

A solution with a pH of 7

Basic

A solution with a pH above 7

pH and H⁺ Concentration

More H⁺ means lower pH; less H⁺ means higher pH

Organic Molecule

A carbon-based molecule commonly associated with living organisms

Macromolecule

A very large molecule

Carbon

An element that can form four stable covalent bonds

Isomer

Molecules with the same molecular formula but different arrangements of atoms

Structural Isomer

An isomer with a different arrangement of atoms and bonds

Stereoisomer

Molecules with the same atom connections but different three-dimensional arrangements

Cis-Trans Isomer

A stereoisomer that differs in the arrangement of groups around a double bond or ring

Enantiomer

A mirror-image stereoisomer

Monomer

A small building-block molecule used to make a polymer

Polymer

A large molecule made of repeating monomers

Dehydration Reaction

Joins molecules by removing water

Hydrolysis

Breaks molecules apart by adding water

Four Major Organic Molecules

Carbohydrates

Carbohydrates

Organic molecules generally made of carbon

Monosaccharide

A single sugar molecule

Pentose

A sugar with five carbon atoms

Hexose

A sugar with six carbon atoms

Disaccharide

A sugar made of two monosaccharides

Polysaccharide

A carbohydrate made of many monosaccharides

Lipids

Mostly hydrophobic organic molecules

Four Major Types of Lipids

Fats

Triglyceride

A molecule made of one glycerol and three fatty acids

Saturated Fatty Acid

A fatty acid with no carbon-carbon double bonds

Unsaturated Fatty Acid

A fatty acid with one or more carbon-carbon double bonds

Saturated Fat

A fat that tends to be solid at room temperature

Unsaturated Fat

A fat that tends to be liquid at room temperature

Phospholipid

A lipid with a hydrophilic head and hydrophobic tails

Lipid Bilayer

Two layers of phospholipids with heads facing water and tails facing inward

Steroid

A lipid with four fused carbon rings

Examples of Steroids

Cholesterol

Protein

A functional molecule made from one or more folded polypeptides

Amino Acid

The building block of proteins

Amino Group

The nitrogen-containing group in an amino acid