Chemistry, Matter, and Life

Chapter 2

Chap 1 discussed that lead to chap 2

Chemical level (levels of organization)Types of metabolism: catabolism and anabolismRequirements for life: water, O2, nutrients, heathomeostasis

Chemistry is the science that deals with the composition of matter and the changes that may occur in the

composition.

• Matter includes anything that has mass and takes up space• Includes solids, liquids and gases

• Our bodies are composed of matter

– All matter, living and non-living, is composed of elements.• Element is the simplest form of matter

• It cannot be broken down into a simpler form by ordinary chemical means

• Four elements are: carbon (C); oxygen (O); hydrogen (H), and nitrogen (N) make up 95% of the human body weight

• Chemical symbols are abbreviations used to identify elements

Atoms-An element is composed of atoms that are all of the same kind. An atom is the smallest particle of an element that still retains the properties of that element. An atom is made up of still smaller subunits or particles called protons, neutrons, and electrons.

A dense region called the nucleus contains the protons and neutrons.

Although an atom is the smallest unit of an element, it is made up of smaller subunits or subatomic particles

• These smaller units are: electrons, protons and neutrons. These particles have different properties.

– Electrons are tiny, very light particles that have a negative electrical charge (-). They are located in the space surrounding the nucleus (called energy levels or shells)

– Protons are much larger and heavier than electrons and have the opposite charge, protons have a positive charge. They are located in the nucleus. The number of protons in the nucleus is called the atomic number.

– Neutrons are large and heavy like protons, however neutrons have no electrical charge. They have the same mass as protons.

• Protons and neutrons together account for the mass of the atom and their number. This is called the mass number of an atom

• The number of electrons in an atom is always equal to the number of protons so that the atom is electrically neutral.

Atoms are held together by a force of chemical bonds. The two types of bonds are ionic and covalent.

• In chemical bonds, atoms can either transfer or share their electrons to form a molecule.

• Ionic bond: bond in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other.

• Because electrons have a negative charge atoms are no longer neutral when they gain or lose electrons.

• The charged particles that result when atoms lose or gain electrons are called ions.

• Cation: positively charged ion• Anions: negatively charged ion• Covalent bond: bond in which one or more pairs of electrons are

shared by two atoms.• The ionic and covalent bonds just described hold atoms together

within molecules. They are intramolecular bonds.

An ionic bond is an electrical attraction between two oppositely charged atoms or groups of atoms. It holds

atoms together within molecules.

• Normally atoms are neutral• When an atom loses or gains

electrons (electrons are negatively charged), it is no longer neutral

• The charged particles are called ions (electrically charged atoms or groups of atoms)

• Loses 1 or more electrons becomes + charged = cations

• Gains 1 or more electrons becomes – charged = anion

A covalent forms when 2 atoms share a pair of electrons. It holds atoms together within molecules.

• Each atom donates half of the electrons to be shared

• This sharing of electrons is a result of the electron attracting ability of the two bonded atoms

Do some examples on the board: ionic bonds hydroxide, bicarbonate, phosDo some examples on the board: covalent bonds, water, c dioxide, nito gas

Hydrogen Bond

• Attraction between 2 molecules

A compound is formed when two or more different types of atoms chemically combine.

• Water, salt and sugar are compounds

• When elements are joined, the atoms lose their individual properties

• They have different properties

• Water is the most abundant compound in living organisms

– Two-thirds of the weight of the adult human being

– It is a physiologically important, because it is a good solvent, breaks down molecules by hydrolysis

Molecular formula is a shorthand way to indicate the type and number of atoms in a molecule.

• Letter is the chemical symbol of the element

• The subscript number shows the # of atoms. If no subscript it implies 1 atom

Structural formulasShows how atoms are arranged and joined

together in the molecule

Chemical formula for aspirin

A chemical reaction is the process by which atoms or molecules interact to form new chemical combinations.

• The atoms and molecules present before the chemical reaction occurs are called the reactants.

• The new atoms and molecules that are created as a result of the reaction are called the products.

• Chemical equations are an abbreviated method of showing the reactants and products in the chemical reaction.

Chemical equation: reactions between molecules

Left side of equation is the reactantsRight side of the equation is the products

Types of Chemical Reactions

1. Synthesis reactions: When 2 or more simple reactants combine to Form a new, more complex product Called synthesis, combination or composition reaction

A + B ABIs this anabolic for catabolic?

DEHYDRATION SYNTHESIS: when 2 simple molecules combine to Form a more complex molecule by the removal of water

Many reactions in the body are this type: glucose to glycogen exp

2. Decomposition Reactions: When the bonds in a complexReactant break to form new, simpler products.

Are these catabolic or anabolic?

AB A + B

HYDROLYSIS REACTION: When water is used to break the bondsExample is digestion

REACTION RATESChemical reactions occur at different rates.

Forming of rust or tarnishing a silver are exp slowburning of paper or setting of epoxy are exp of fast

some are explosive like of dynamite going off.

Influences of reaction rates are:Nature of reacting substance

SubstancesTemperature

ConcentrationCatalysts

Surface area

• Certain substances are more reactive than others depending on how readily bonds are broken and formed exp covalent and ionic bonds.

• As temperature increases the speed of most chemical reactions also increases. The opposite is also true. If temp decreases, reaction rates decrease.

• Within limits the greater the concentration of the reactions, the faster will be the speed of the reaction.

• A catalyst is a substance that changes the rate of a reaction without itself being chemically altered in the process. Enzymes are catalysts.

• Surface area: exp charcoal briquette vs coal dust, chewing up asa or antacids

Mixtures, solutions and suspensions

• Mixture- a combo of 2 or more substances that can be separated by ordinary physical means. The substances retain their original properties after they have been combined in a mixture.

• Solutions-mixtures in which the component molecules remain evenly distributed. Solutions are clear and they exist of 2 parts:

• Solute: the substance that is present in the smaller amounts and that is being disolved

• Solvent: is the component that is present in the larger amount and that does the dissolving

Water is the most common solvent or the universal solvent

If alcohol is used as theSolvent the solution is Called a tinctureExp. when iodine is Dissolved In alcohol.

Suspensions-settles unless continually shaken. If sand is mixed with water sand particles will settle at bottom. A suspension is cloudy and it’s particles settle. Blood cells form a suspension in plasma.

Electrolytes, Acids, Bases, and Buffers

• Electrolytes are substances that breakup in a solution to form charged particles or ions.

• These compounds are called electrolytes, because the ions can conduct an electrical current.

• Electrolytes form cations and anions

The Na positively charged ion is attracted to the negatively charged oxygenEnd of the water molecule.

Acids-OJ, lemon juice, vinegar coffee, and aspirin all contain acids• Acids taste sour and defined as a proton donor• It gives away hydrogen ions (proton) in water• The strength of an acid depends on the degree to which

it dissociates in water.• Hydrochloric acid (acid in the stomach) is a strong acid,

because it dissociates readily to produce an abundance of hydrogen ions.

• Carbonic acid is a weak acid, because most of the molecules remain intact in water and only a few dissociate into hydrogen ions and bicarbonate ions.

• pH less than 7

BASES

• Bases feel slippery and taste bitter• Examples are household ammonia, mom, and egg

whites. • Defined as a proton acceptor

BASES HAVE A PH GREATER THAN 7

THE pH SCALE IS USED TO INDICATE THE EXACTSTRENGTH OF AN ACID OR A BASE.

The greater # Hydrogen ions more acidic and the lowerIs the pH

Fewer hydrogen ions more basic solutions with higher pH number.

Pure water has a pH of 7Blood has a pH of 7.4,

Is blood slightly acidic or alkalotic?

Neutralization reactions

* The hydrogen ion from the acid reacts with the hydroxide ion from The base to form water* The acid removes or neutralizes the effect of the base and vice versa. The other product is salt*Salts are ionic compounds produced from neutralization reactions* Neutralization reactions help maintain the proper pH of blood

BUFFERS: a solution that resists changein pH when either an acid of base is added.

Buffers are one of the homeostatic control mechanisms that maintain a normal pH

In the Human body, acid-base balance is regulated by chemical buffer systems, the lungs and the kidneys.

The five major groups of organic compounds that are important to the human body are: carbohydrates,

proteins, lipids, nucleic acids and adenosine triphosphate.

CARBOHYDRATESCarbs-important energy source in the body, it forms a reserve supply of stored energy.

The simplest carbs are the monosaccharides or simple sugars: it is composed of 1 carbon atom, 2 hydrogen atoms and 1 oxygen atomCH2O

The most important simple sugar is glucoseIt has 6 carbons atoms, 12 hydrogen atoms and 6 oxygen atomsC6H12O6

Because it has 6 carbons it is called a hexose

Other simple sugars are fructose and galactose.

Glucose requires no digestion therefore it can be given IV D 50

SEE PG 34 IN TEXT

Disaccharide: when 2 hexose monosaccharides are linked also called a double sugar

3 common disaccharides1. Sucrose: table sugar2. Maltose: malt sugar3. Lactose: milk sugar

Polysaccharides: long chains of monosaccharaides linked together

3 important polysaccharides1. starch: storage food in plants2. Cellulose: supporting tissue of plants (humans breakdown)3. glycogen: animal starch, storage form of carbs in the body

Proteins: all contain the elements:C, H, O and N

• The building blocks of protein are amino acids.

There is 20 total amino acids in the body, 11 can be man made, 9 must be eaten

Proteins is the basic structural material of the body.

FUNCTIONS OF PROTEINS

1. proteins can act as antibodies in the fight against disease2. Muscles contain specific proteins that assist with contraction

3. Provide identification marks and receptor sites on cell membranes4. They provide a source of energy

• Hemoglobin-large protein molecule inside RBCs transports O2 to body tissues

Lipids: composed of CHO

Characteristics:

--Very similar to carbohydrates but have a lower oxygen content--Insoluble in water but are generally soluble in alcohol

See table 2-6 pt 361.Triglycerides: fats are most common, a concentrated source of

energy, they provide protection, padding and insulation the components are glycerol and fatty acids ( see pt 36 in book for

saturated and unsaturated fats)2.Phospholipids: contain a phosphate group and nitrogen group,

important in cell membranes in the body and are abundant in nerve and muscle cells.

3.Steroids: have 4 interconnected rings of carbon atoms, the most common steroid is cholesterol. Also included are the sec

hormones and vitamin D

Nucleic Acids: C,H,O,N,P

• The building blocks of nucleic acids are nucleotides

• A nucleotide consists of a five carbon sugar, an organic nitrogenous base, and a phosphate group

• Nucleotides are joined together by dehydration synthesis to form the nucleic acid

2 types of Nucleic Acids

DNA: deoxyribonucleic acid: Genetic Material of the Cell1.The sugar in the DNA is deoxyribose and 4 nitrogen bases are adenine, thymine cytosine and guanine. The sequence of the nitrogen base is the genetic code. 2. Two chains loosely joined together by H bonds and then twisted into a double helix

2nd type RNA: ribonucleic acid

Single Strand

functions in the synthesis Of proteins with in the cell. Sugar is ribose

Nitrogenous bases are: adenine, uracil, cytosine, and guanine. The DNA material gives the instructions For making proteins.

ADENOSINE TRIPHOSPHATEATP

HIGH ENERGY COMPOUND COMPOSED OF ADENINE, RIBOSE AND 3 PHOSPHATE GROUPS.

PHOSPHATE GROUP LINKED TOGETHER BY HIGH ENERGY BONDSTHAT RELEASE CHEMICAL ENERGY WHEN BROKEN.

THE CHEMICAL ENERGY IS USABLE BY THE CELLS OF THE BODY