RAD 1110 EXAM 1 CHAP 2

Chemistry

Science that investigates matter and its interactions

Matter

Anything that takes up space and has mass

Mass

amount of matter an object contains

Matter is composed of substances called

elements

Smallest stable unit of matter is an

atom

Electron cloud is represented as

electron shell

The number of protons in an atom

atomic number

Atoms of an element with different numbers of neutrons in the nucleus are called

isotopes

mass number

Total of protons and neutrons in the nucleus

The average mass of an element’s atoms is the

atomic weight

another word for stable in an atom is called

inert

Chemical bonds

Atoms interact with each other to form larger structures; process forms molecules and compounds

Molecules

Contain more than one atom bonded together by shared electrons

Compounds

Made up of atoms of two or more different elements in a fixed proportion

Ions

Atoms or molecules that have an electric charge

Cation

positive ion

Anion

negative ion

Ionic Bonds

Chemical bonds created by the electrical attraction between anions and cations

Covalent bond

Formed by sharing of electrons between atoms

Single covalent bond

Sharing of one pair of electrons

Double covalent bond

sharing of two pairs of electrons

Nonpolar covalent bond

Formed when electrons are shared equally

Polar covalent bond

Formed by unequal sharing between atoms of different elements; form polar molecule where one end is slightly negative and other is slightly positive

Hydrogen bonds

weak attractive force; attraction between a slight positive charge on the hydrogen atom of one polar covalent bond and a slight negative charge on an oxygen or nitrogen atom of another polar covalent bond

Surface tension

hydrogen bonds that are too weak to create molecules but can alter shapes of molecules or pull molecules closer together; attraction between water molecules

Energy

capacity to perform work

kinetic energy

energy of motion

potential energy

stored energy

Hydrolysis reactions are

decomposition reactions involving water

Catabolism

Decomposition reactions of complex molecules within cells; release kinetic energy that can perform work

Dehydration synthesis (condensation reaction)

Forms a complex molecule by the removal of water

Anabolism

Synthesis of new compounds in the body; Requires energy

Exchange Reactions

Shuffle parts of reacting molecules; Reactant molecules break apart (decomposition); Resulting components interact to form new products (synthesis)

Equilibrium

the rates of the two reactions are balanced during a reversible reaction

Role of enzymes

Activation energy; Amount of energy required to start a reaction is lessened; Cells use enzymes to speed up reactions; Eliminates need for extreme temperature or pH changes

Enzymes are categorized as

catalysts; which Accelerate reaction without being permanently changed

Exergonic reaction

release energy; amount released greater than activation energy to start

Endergonic reaction

absorb energy; more energy needed to begin than it is to be released

Nutrients

Substances from food necessary for normal physiological functions; e.g.,, carbs, proteins, fats, minerals, water

Metabolites

Substances involved in (or by-product of) metabolism

Inorganic compounds

usually w/o carbon and hydrogen; include water, carbon dioxide, oxygens, acids, bases, salts

Organic compounds

Contain carbon covalently bonded with one or more other elements; Must have a C-H covalent bond

Chemical reactions in our bodies take place in

water

Water has a high or low heat capacity?

high

Solutions

Consist of a fluid solvent and dissolved solutes

If a solvent is water it forms

aqueous solution

Dissociation/ionization

Occurs when ionic compounds break apart into their charged ions in water

Electrolytes

Substances releasing ions when dissolved in water

Concentration of H+ in the body must be precisely regulated must be regulated because

very reactive and can break chemical bonds, change shapes of molecules, disrupt cell function

pH

represents the concentration of H+ in a solution

Blood and most body fluids pH is

between 7.35-7.45

Acid

Any substance that breaks apart in solution to release hydrogen ions

What are acids referred as

proton donors

Strong acid/strong base

dissociates completely

Base

A substance that removes hydrogen ions from a solution

Weak acids/weak bases

Acids and bases that do not dissociate completely in solution

Salt

Is composed of a cation that is not H+ and an anion that is not OH−; Is held together by ionic bonds; Dissociates in water

Substances whose ions can conduct an electrical current in solution are

electrolytes

Buffers

Compounds that stabilize pH by: Removing H+ out of solution or Replacing H+ into solution

Carbohydrates

Organic compounds with carbon, hydrogen, and oxygen in a ratio near 1:2:1; includes sugars and starches

Monosaccharides/simple sugars

Carbohydrate containing from 3 to 7 carbon atom; Building blocks for larger carbohydrates; Dissolve readily in water

Glucose

monosaccharide; most important fuel in body

Disaccharides

Two monosaccharides linked by covalent bonds; Example: sucrose (table sugar); Very soluble in water; Formed by dehydration synthesis; Broken down by hydrolysis; Must be broken down before providing energy

Polysaccharides

Multiple monosaccharides and/or disaccharides linked by covalent bonds; includes starches, cellulose, glycogen

Starches

manufactured by plants; important energy sources; easily broken down in digestive tract

Cellulose

component of plant cell walls; cannot be digested (humans have no enzyme for this substrate)

Glycogen-animal starch

composed of interconnected glucose molecules, the only polysaccharide stored in the body

Lipids

Contain a carbon-to-hydrogen ratio of 1:2; Oxygen content much lower than in carbohydrates; Include fats, oils, and waxes; Most are insoluble in water; Form essential parts of cell structure; Major types: fatty acids, fats, steroids, phospholipids

Fatty acid

Long chains of carbon atoms with: attached hydrogen atoms and a carboxyl group at the end

Carbon chain is also known as

hydrocarbon tail

Saturated fatty acid

Has only single covalent bonds on each carbon atom

Unsaturated fatty acid

Has one or more double covalent bonds between carbons

Monounsaturated fatty acid

only one double covalent bond

Polyunsaturated fatty acid

has multiple double covalent bonds

Fats

Formed by fatty acids attached to glycerol

Triglyceride

Glycerol attached to three fatty acids; Most common fat in the body

Steroids

Large lipid molecules composed of four connected rings of carbon atom

What is the most common steroid

Cholesterol

Cholesterol is

Component of cell membranes or plasma membranes; Precursor of sex hormones (testosterone and estrogen)

Phospholipids

Composed of Glycerol and two fatty acids linked to a nonlipid group by a phosphate group; most abundant lipid component in cell membranes

Proteins

Most abundant organic molecules in the human body

Proteins account for what % of body weight

20

Protein Support

Structural proteins create framework; Provide strength and organization

Protein Movement

Contractile proteins responsible for muscular contraction; Also allow movement of individual cells

Protein Transport

Transport proteins act as carriers in the blood for a variety of substances; Others transport materials between parts of a cell

Protein Buffering

Provide buffering action helping prevent changes in pH in body fluids

Protein Metabolic Regulation

Working as enzymes, speed up chemical reactions in living cells

Protein Coordination and control

Acting as hormones, influence metabolic activities and functions

Protein Defense

Antibodies protect from disease; clotting proteins restrict bleeding

What makes up a protein structure?

Long chains of amino acids

How many different amino acids in body

20 different acids

Typical protein has how many amino acids

1000

Peptides

A molecule of amino acids, connected by peptide bonds

Dipeptide

2 amino acids

Polypeptide

3 or more amino acids

100 or more amino acids is called a

Protein

Protein primary structure

Sequence of amino acids linked by peptide bonds

Protein secondary structure

Shape resulting from hydrogen bonding at points along polypeptide chain; May create alpha helix or beta sheet

Protein Tertiary structure

Complex coiling and folding giving three-dimensional shape; Results from interactions between R groups

Protein Quaternary Structure

Shape from interaction between polypeptide subunits forming protein complex