McGraw-Hill Biology Ch. 2 Chemistry of Life

Matter

Substance that takes up space and is made of atoms.

Elements

A pure substance that cannot be broken down further.

Atom

A particle of matter. Composed of protons, neutrons, and elections.

Protons

Particle in an atom's nucleus. Has positive charge. Has a measurable mass.

Neutrons

Particle in an atom's nucleus. Has no charge.Has measurable mass.

Electrons

Negatively charged particle that orbits an atom's nucleus. No measurable mass.

Nucleus

Central part of an atom. Contains protons and neutrons.

Atomic number

Number of protons in an atom's nucleus

Atomic mass

Average mass of all isotopes of an element.

Isotope

Different forms of an element that contain different numbers of neutrons. A radioactive isotope is unstable.

Mass number

Total number of protons and neutrons in the nucleus

Ion

atom that gains or loses an election. (Loses an e-, positive. Gains and e-, negative)

Molecule

Two or more atoms joined together by chemical bonds

Compound

Two or more atoms of different elements joined together by chemical bonds

Valence electrons

electrons on the atom's outermost shell. Shell is full with 8 e-

Ionic bonds

an attraction between two oppositely charged ions, which form when one atom strips one or more electrons from another atom.

Hydrogen bond

an attraction between two oppositely charged ions, which form when one atom strips one or more electrons from another atom. Weakest type of bond. Represented by - - - - - . Bond can quickly be broken and replicated. Needed for DNA.

Covalent bonds

Two types: polar and nonpolar. form between atoms that can fill their valence shells by sharing one or more pairs of electrons. Strongest bond. Represented by solid dash

Polar covalent bonds

One atom takes e- from another and keeps them. One atom is more electronegative than another, and the electroneg one steals the e- of the other. Closer an atom is to having a full outer shell (8 e-) the more electroneg. it is.

Nonpolar covalent bonds

Atoms share e- equally

Water is cohesive and adhesive

sticks to itself and to other things.

Solution

a solute (salt) dissolved in a solvent (water) = solution saltwater

Hydrophillic/hydrophobic

attracted to water (polar and charged)/repelled by water (nonpolar)

Water helps regulate temperature because...

It is resistant to temperature change and evaportation. Large bodies of water help keep coastal climates mild.

Chemical reaction

A reaction in which bonds break and new bonds form.

Acid

atom that releases hydrogen into a solution (cells, water, stomach, etc). Traits: gritty, sour taste (lemon juice, vinegar). pH below 7.

Base

an atom that either releases hydroxide ions into a solution or removes hydrogen from a solution. Traits: slippery (soap, ammonia)

Pure water

Has equal number of H+ and OH-. It is neutral.

Alkaline

having a pH greater than 7

Buffers

weak acid-base pairs that maintain the pH ranges of body fluids by either accepting H or releasing H.

Monomer

Single unit of a polymeric molecule. Monomers make up polymers.

Polymer

A long molecule composed of similar sub-units (monomers). Made through condensation reactions, broken down through hydrolysis reactions.

Dehydration synthesis or Condensation reaction

Linking monomers to form polymers by removing a water molecule.

Hydrolysis reaction

Splitting a molecule by adding water. This breaks polymers into monomers.

Carbohydrates

Provide energy and structural support. Consist of carbon, hydrogen, and oxygen in the proportions 1:2:1. Ex: sugars (any *saccharide)

Monosaccharides

Simple sugars. Type of simple carb. Ex: Glucose and fructose. Provide quick energy.

Disaccharide

Two convalently bonded monosaccharides. Still a simple sugar. Provide quick energy. Ex: Maltose, lactose, sucrose

Polysaccharides

Are polymers. Complex carbs made from hundreds of monosaccharides. Provide support and store energy. Long term energy. Ex: glycogen, starch, cellulose, chitin

Types of functional groups

Hydroxl group (OH), Carboxyl group (COOH), Methyl group (CH3)

Hydroxl group (OH)

OH is usually negative (OH-). It is polar. It can mix with water. It is NOT an ion. Mainly characterizes alcohol and carbohydrates.

Carboxyl group (COOH)

Mainly characterizes organic acids.

Methyl group (CH3)

NONpolar. Tends to make molecules hydrophobic (e.g. lipids).

Glucose

animal blood sugar and that most common monosaccharide used for energy in living organisms. Basis of the food chain. Plants make it, animals eat it, we eat animals. Glucose and fructose are isomers of each other. ISO means equal. Glucose is equal to fructose in number of atoms, but shaped differently.

Fructose

fruit sugar. Has a different shape than glucose so it responds to our taste buds differently—sweeter. Glucose and fructose are isomers of each other. ISO means equal. Glucose is equal to fructose in number of atoms, but shaped differently.

Lactose

Disaccharide. Glucose + Galactose (in milk)

Maltose

Disaccharide. Glucose + Glucose (in beer)

Sucrose

Disaccharide. Glucose + Fructose (made in nature, ex: sugar cane)

Glycogen

Polysaccharide. "animal starch." animals store surplus glucose as glycogen in liver and muscle tissue. This is a long term energy reserve. If not needed, will turn to fat.

Starch

Polysaccharide. plants store surplus glucose as starch in roots, stems, and seeds. Stored in roots and stems so that the plant can repair itself if damaged. Stored in seeds because a seed has no way of creating its own energy to grow.

Cellulose

Structural polysaccharide. major component of cell walls.most abundant organic molecule on Earth. Humans cannot break it down (fiber). Animals break it down thru symbiotic relationships with bacteria/protists in their guts.

Chitin

a structural polysaccharide used to form the exoskeleton of arthropods (pronounced "kite-in"

Isomers

molecules that have the same types and numbers of atoms, but different structures. Ex: fructose (5C sugar) and glucose (6C sugar)

Lipids

hydrophobic compounds consisting mainly of carbon and hydrogen. Contains Methyl group (CH3)

Proteins

consist of amino acids, which join into polypeptides by forming peptide bonds through dehydration synthesis.

Denatured protein

A protein's 3-D shape is vital to its function. A denatured protein has a ruined shape.

Polypeptide

Long polymer of amino acids