Biology in Focus Chapters 1-3

Matter

Anything that has mass and takes up space

Element

A pure substance made of only one kind of atom

Compound

A substance made up of atoms of two or more different elements combined in a fixed ratio

Essential Elements

An element required for an organism to survive
Humans need 25; plants need 17

Trace Elements

required by an organism in only minute quantities

Atom

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

Neutrons, Protons, Electrons

3 Subatomic particles that atoms are made up of

Atomic Nucleus

An atom's central core, containing protons and neutrons

Dalton

A unit of measurement for atoms and subatomic particles

Atomic Number

Number of protons in the nucleus

Mass Number

The total number of protons and neutrons in an atom

Isotopes

same element, different number of neutrons

Energy

Capacity to cause change

Potential Energy

Stored energy; the energy an object has due to its location or structure

Electron Shells

Depicted as simple circles around nucleus; each shell holds differing numbers of electrons

Table of Elements

All elements organized in a table

Valence Electrons

Electrons on the outermost energy orbital of an atom

Valence Shell

Outermost electron shell

Inert

Chemically inactive

Chemical Bonds

Attractions that hold atoms together

Covalent bond

The sharing of a pair of valence electrons by two atoms

Does not dissolve into water well

Molecule

Two or more atoms held together by covalent bonds

Ionic Bond

Formed when one or more electrons are transferred from one atom to another

Easily dissolves in water

Single Bond

2 atoms share a pair of electrons

Double Bond

4 electrons are shared

Valence

Bonding capacity of an atom
How many more electrons it can hold in its outer most shell

Electronegativity

Attraction an atom has for electrons
Higher Number = Stronger Attraction

Nonpolar

Electrons are shared equally

Polar

Electrons are not shared equally
Molecules have a partial negative and partial positive side

Ions

Charged atoms (+ & -)

Cation

Positively charged ion

Anion

Negatively charged ion

Ionic Bond Example

NaCl (Table Salt)

Ionic Compounds (Salts)

Compounds formed by ionic bonds

Hydrogen Bond

The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

Van Der Waal Forces

Attraction between the oppositely charged regions of nearby molecules

The shape H20 is in

"V"

Molecular shape

Determines how biological molecules recognize and respond to one another

Reactants

Starting material in a chemical reaction

Products

Ending materials in a chemical reaction

Conservation of Matter

The principle stating that matter is not created or destroyed during a chemical reaction

Reactions can only rearrange atoms

Cohesion

Attraction between molecules of the same substance

Aids in the transport of water & nutrients

Adhesion

Attraction between molecules of different substances

The clinging of one substance to another

Helps to counteract the pull of gravity

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid

Kinetic Energy

Energy of motion

Thermal Energy

Kinetic energy associated with the random movement of atoms or molecules

Temperature

Average kinetic energy

Calorie

Amount of energy needed to raise temperature 1 gram of water 1 degree C

Specific Heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius

Water has a high specific heat, meaning that it can help regulate temperature

Joule

Unit of energy

Heat of Vaporization

The quantity of heat a liquid must absorb for 1 g of it to be converted from a liquid to gas

[Water] Helps to moderate Earth's temp by having a high heat of vaporization

Water's Properties

High heat capacity, high heat of vaporization, polar, universal solvent

All impact life on Earth

Evaporative cooling

when a substance evaporates, the surface of the liquid that remains behind cools down

Unique Features of Ice

Less dense than water because of the crystalline lattice structure

Freezes from the top-down

Solution

A homogeneous mixture of two or more substances

Solvent

The dissolving agent

Solute

The substance that is dissolved

Aqueous Solution

A solution in which water is the solvent

Hydration Shell

The sphere of water molecules around each dissolved ion

Hydrophilic

Water loving

Easily mixes with water

Hydrophobic

Water fearing

Does not easily mix with water

Molecular Mass

The sum of the masses of all the atoms in a molecule

Mole

Avogadro's Number
6.02 x 10^23

Molarity

The number of moles of solute per liter of solution

pH

Hydrogen ion concentration
<7 Acid
>7 Base

Acid

A substance that increases the hydrogen ion concentration of a solution

Base

A substance that decreases the hydrogen ion concentration in a solution

Substance that resists changes in pH

Buffer

Organic Compound

Compounds that contain both carbon and hydrogen

Ex. C6H12O6 (glucose)

Inorganic Compounds

Compounds that do not contain both carbon & hydrogen

Ex. CO2 (Carbon Dioxide)

Macromolecules

A very large organic molecule composed of many smaller molecules

Carbon's Valence

4 (meaning it can bond with a max of 4 elements)

Hydrocarbon

Organic compounds composed of only carbon and hydrogen

Structural Isomers

Substances that have the same amount and type of atoms, but differ in structure

Cis-Trans Isomers

carbons have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds

Enantiomers

Isomers that are mirror images of each other

Types of Isomers

structural, cis-trans, enantiomers

Functional Groups

The components of organic molecules that are most commonly involved in chemical reactions

Hydroxyl Group

-OH
Name usually ends in -ol

Ex. alcohol

Hydrophilic

Carbonyl Group

>C=O

Compound names:
Ketone: Carbonyl group is within the carbon skeleton
Ex. Acetone

Aldehyde: Carbonyl group is on the end of the skeleton
Ex. formaldehyde

Carboxyl Group

-COOH

Compound name: Carboxylic acid, or organic acid

Forms acidic compounds

Ex. Vinegar

Hydrophilic

Amino Group

-NH2
^key feature

Compound name: Amine

Ex. Glycine

Sulfhydryl Group

-SH

Compound name: Thiol

Ex. Cysteine

Phosphate Group

Phosphorous atom bonded to 4 oxygen atoms

Compound name: Organic Phosphate

Ex. Glycerol Phosphate

Methyl Group

-CH3

Carbon bonded with 3 other hydrogen atoms

Ex. Methanol

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

Polymer

A long molecule consisting of many similar or identical monomers linked together by covalent bonds

Monomer

"Building blocks" of polymers

Simple compounds

Enzyme

A type of protein that speeds up a chemical reaction in a living thing

Dehydration Synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Glycosidic Linkage

A covalent bond formed between two monosaccharides by a dehydration reaction

Polysaccharides

Large macromolecules formed from 100+ monosaccharides

Serve as energy storage or cell building material

Macromolecules

A very large organic molecule composed of many smaller molecules

Carbohydrates

Used for short term energy, structure, raw material, and cell communication

Made of simple sugars

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

*not a polymer

Proteins

Nutrients the body uses to build and maintain its cells and tissues

Made of amino acids

Nucleus acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus

DNA

Monosaccharides

Single sugar molecules

Ex. Glucose

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

Ex. Lactose, maltose, sucrose