Chapter 2 Notes
-Why Study Chemistry?
-Food and medicine you take is made of up chemicals
-Every process in your body is a chemical reaction (Movement, digestion, heart pumping, etc)
-Matter= “Stuff” of the universe
-Anything that occupies space and has mass (weight)
-Gases, liquids, and solids
-What chemistry studies
-Physical vs. chemical changes
-Energy= ability to do work or put matter into motion
-What physics studies
DIGESTION- THE CHEMICAL BREAKING DOWN OF FOOD(COMPOUNDS) INTO ELEMENTS THAT CAN
DIFFUSEINTO OF OUT OF THE CELL MEMBRANES VIA VILLI
NERVOUS SYSTEM- MVMT. OF IONS ACROSS MEMBRANES TO CONDUCT AN IMPULSE.
MUSCULAR SYSTEM- ENERGY USED TO CONDUCT HEAT & MOVE THE SKELETON.
-Atoms do not exist in free state, but instead chemically combine with other atoms to form molecules
COMPOUNDS- TWO OR MORE DIFFERENT KINDS OF ATOMS CHEMICALLY COMBINED (components cannot be separated unless chemical bonds broken)
MIXTURES- TWO OR MORE SUBSTANCES THAT ARE PHYSICALLY INTERMIXED(Components can be separated by physical means)
TWO TYPES OF CHEMICAL BONDS
1.) IONIC- AN ATOM GAINS AN ELECTRON(ANION-negative charge)WHILE ANOTHER LOSES(CATIONpositive charge). Opposites attract forming ionic compound. NaCl and other salts are examples.
Crystals are held by ionic bonds
2.) COVALENT- ATOMS SHARE ELECTRONS TO ACHIEVE STABILITY.(water, ammonia, methane)
CHEMICAL REACTIONS TAKING PLACE INSIDE THE BODY:
I.SYNTHESIS REATIONS- molecules combining to form larger more complex molecules (amino acids building proteins, phosphate groups & sugars forming nucleic acids)

DEHYDRATION SYNTHESIS- WATER REMOVED IN SYNTHESIS
II. DECOMPOSITION REACTIONS- a molecule is broken down into smaller molecules (digestion of our foods)
III.EXCHANGE REACTIONS- involve both synthesis and decomposition. Bonds are made and broker. (ATP reacts with glucose it becomes ADP)
BIOCHEMISTRY:
I. Inorganic Compounds- do not contain carbon; small simple moelcules
Examples: water, salts, inorganic acids and bases
II. Organic Compounds- contain carbon; covalently bonded
Examples: carbohydrates, lipids, proteins, nucleic acids
A.
carbohydrates- all sugars and starches; 1-2% of cell mass.
Contains C, H, O. primary function is to provide fuel for cells. Secondary functions is structural (form part of the structure of nucleic acids)
B.
Lipids- insoluble in water. Also consist of C, H, O. Primary functions is to insulate body organs and provide a secondary source of energy for your cells
C.
Proteins- 10-30% of cell masses. C, H, O, N. Primary purpose is structural material of the body.
Also, to ensure normal cell function (enzymes). Also allows muscles to contract, carry O in blood
(hemoglobin) and regulate growth (hormones).
D.
Nucleic Acids- DNA and RNA. C, H, O, N, P. determines your traits by protein synthesis. RNA carries out DNA’s instructions.
ENERGY IS STORED IN THE BONDS OF ORGANIS COMPOUNDS. WHEN THE BONDS ARE BROKEN, THE
STORED ENERGY (POTENTIAL) IS RELEASED AND BECOMES KINETIC (ENERGY IN ACTION)
MOST FOODS WE EAT ARE CARBOHYDRATES(30-50% OF DIET)
3 KINDS OF CARBOHYDRATES THAT WE CONSUME MOST:
1.)SIMPLE SUGARS- MONOSACCHARIDES
(GLUCOSE, FRUSCTOSE, GALACTOSE) ABSORBED IMMEDIATELY BY BODY.
2.)DOUBLE SUGARS- DISACCHARIDES

(SUCROSE-TABLE SUGAR, LACTOSE-MILK SUGAR, MALTOSE- GRAIN SUGAR, THESE MUST BE FIRST
BROKEN DOWN INTO SIMPLE SUGARS TO BE ABSORBED. Need ENZYMES to speed up their breakdown.
Sucrase; lactase; and maltase are the enzymes that released the small intestine.
HYDROLYSIS REACTION- LACTOSE IS BROKEN DOWN INT GLUCOSE AND GALACTOSE. It involves the addition of water molecules to each other molecule bond that is broken.
3.) POLYSACCHARIDES- MANY SUGARS, CANNOT DIGEST THEM AT ALL AS WE LACK THE EMZYMES TO
SPEED US THEIR BREAKDOWN. CELLULOSE- plant fiber; we still need in our diet as they provide fiber or bulk in our diet.
If lactose intolerant you lack the ability to make lactase- so what happens?
Lactose is not broken down so it is left “whole”. It will pull water from your small intestine so bloating and gas occurs. Diarrhea and cramping also occurs. Adding lactase or “lactaid drops” gives you the enzyme so that lactose is broken down.
THIS IS AN INHERITED TRAIT! IT IS AND AUTOSOMAL RECESSIVE TRAIT. WHAT DOES THAT MEAN?
EVOLUTION- IT IS BELIEVED THAT PEOPLE WHO KEPT DAIRY ANIMALS OVER THOUSANDS OF YEARS
BECAME LACTOSE TOLERANT AS MABEY THEY HAD A SELECTIVE ADVANTAGE OVER OTHERS WHO DID
NOT KEEP CATTLE. EUROPEANS FIRST STARTED RAISEING CATTLE.
PROTEINS- organic compounds containing C, H, O, and N.
Two types of proteins found in the body:
I. FIBROUS PROTEINS- have extended, strandlike appearance. Forms the structural framework and mechanical support of tissues. Examples:
Collagen- forms cement of bones; tensile strength of tendons and ligaments
Actin & myosis- contractile proteins in muscles
Keratin- fibrous protein of hair, nails and waterproofs skin
II. GLOBULAR PROTEINS- compact, spherical proteins. Water soluble, mobile, and chemically active proteins. Examples:
Buffers- prevent wide swings in pH levels
Hormones- reglulate growth, activity and development of body organs of the ENDOCRINE SYSTEM.
Examples are growth hormone, insulin, thyroxin, estrogen, testosterone, and many others in pp.318-
319.

Antibodies- recognize and inactivate bacteria and toxins; function in the immune response(LYMPHATIC
SYSTEM)
Enzymes- globular proteins that increase the rate od chemical reactions by a millionfold!! They are not used up or changed in chemical reaction. They are very specific to a single chemical reaction. Vital for important physiological functions like digestion. Most enzymes end in the suffix –ase such as lactase, galactase, amylase. Try the “Prove It To Yourself” on p. 49. Crackers + saliva = amylase breaking down
starch.
NUCLEIC ACIDS- organic compounds containing C, H, O, N, & P. they are the largest biological molecules in the body. Their building blocks are NUCLEOTIDES which consist of 3 parts: nitrogen base;sugar; & phosphate group. The nitrogen bases are A adenine, T thymine, C cytosine, G guanine, & U uracil.
Remember that A and T pair up and C and G pair up in DNA.
TWO MAJOR KINDS OF NUCLEIC ACIDS ARE:
I.
RNA-ribonucleic acid. Single stranded, stays outside the nucleus, contains sugar called ribose, has 4 bases- A, U, C, & G.(no thymine). Its role is to take the message from DNA
(mRNA), to the ribosome (rRNA) and then transfer the message by arranging amino
II.
acids in a certain sequence so the correct protein molecule is made. (tRNA)
DNA- deoxyribonucleic acid. Double stranded, inside nucleus; blueprint for life. It ensures that cell is copied correctly & builds the correct protein.
1.)
2.)
3.)
4.)
INORGANIC COMPOUNDS
Inorganic compounds are the small, simple molecules in the body that do not contain carbon. They work in conjunction with organic compounds to become living cells, tissues, organs, and organ systems.
There are 4 major types of inorganic compounds:
Water- most abundant on earth and in body. 67% of body weight.
Salts- any ionic compound that dissociates into charged articles when dissolved in water
Acids- a substance that releases hydrogen ions when in an aqueous solution
Bases- a substance that accepts hydrogen ions
WATER is the MOST IMPORTANT inorganic compound
Properties of water include: its heat capacity (prevents sudden changes in body temperature)
-acts as the universal solvent so chemical reactions can occur
-acts as a chemical reactant in hydrolysis reactions (lactose lab)
-protects & cushions some organs (cerebrospinal fluid; amniotic fluid)
- has a pH of 7- neutral-equal amount of H+ and OH- ions
SALTS are plentiful in the body especially those containing Ca and P (teethe and bones). On p. 28 there is a list of salts commonly found in the body such as sodium and potassium that dissociate easily into ions

so that nerve impulses can be conducted & muscles contraction can occur. All salts are ELECTROLYTES
(can ionize & conducted electrical currents in solution).
ACIDS & BASES ARE ELECTROLYTES. Acids and bases are used to maintain an organism’s pH level. pH refers to the concentration of hydrogen ions in body fluids.
ACIDS- release hydrogen ions (H+); proton donors; sour tasting; dissolves metals; burns membranes.
Some acids found in the body include hydrochloric(stomach); acetic(saliva); carbonic(blood in lungs).
Number 0-6.99 on pH scale.
Common acids include citrus juices; coffee; milk; vinegar and tomatoes.
BASES- proton acceptors; tale up hydrogen ions; releases hydroxyl ions (OH-); slippery to touch; bitter tasting. Numbers 7.01-14 on pH scale.
Common bases include seawater; blood; semen; ammonia; bleach; milk of magnesia & lye. pH levels are very specific in various parts of the body. BUFFERS take up the extra H+ and OH- ions when necessary to maintain homeostasis. Common body pHs include:
BLOOD pH 7.35-7.45 STOMACH pH 2-3
MOUTH- pH 6.5-6.9 S.INTESTINE pH 6.5-7.8