Chapter 2 The Chemical Level of Organization

• Matter – Anything that has mass and takes up space

• Atom- The smallest particle into which a substance can be broken by ordinary chemical means.

• Element – Groups of the same type of atom• Compound – Two or more elements

chemically combined ex. H2O

MOLECULE- GROUPS OF ATOMS BONDED TOGETHER & ACTING AS A GROUP

ORGANELLES- BASIC STRUCTURES WITHIN CELLS – has a specific function

CELL- BASIC UNIT OF LIVING ORGANISMS

• TISSUE- TISSUES ARE GROUPS OF CELLS WITH A COMMON FUNCTION.

• ORGAN- OFTEN LARGE AND COMPOSED OF SEVERAL DIFFERENT TISSUES

• ORGAN SYSTEM- A GROUP OF ORGANS CARRYING OUT A MAJOR BODY PROCESS

• ORGANISM- (A GROUP OF ORGAN SYSTEMS IN AN INDIVIDUAL) – any living thing

TYPES OF BONDS(Bonds store energy)

• COVALENT BONDS- WHEN ATOMS SHARE ELECTONS (the strongest bond)– e.x. Peptide bonds – between C and N in proteins

• IONIC BONDS- ELECTRONS ARE TRANSFERRED FROM ONE ATOM TO ANOTHER AND IONS ARE FORMED

• HYDROGEN BONDS- A BOND BETWEEN HYDROGEN AND 2 SMALL ELECTRONEGATIVE ATOMS eg. F, N, O (the weakest bond)

Reactions• Chemical Reactions – the process of breaking

down chemical bonds and/or forming new ones (a chemical equations shows this)– To do this an activation energy is needed

( the energy that is needed to get the reaction going)• Exothermic – there is a net release of

energy (it feels warm)• Endothermic – there is a net absorption of

energy (feels cool)

1. Synthesis – small molecules are combined into larger molecules – always involves the formation of new chemical bonds

• Ex. A + B AB

Dehydration synthesis (condensation) – the formation of complex molecules by the removal of H2O

Ex A-B-C-H + HO-D-E A-B-C-D-E + H20

This is the opposite of hydrolysis

• Anabolism – the synthesis of complex organic compounds from simpler compounds (within the body) * requires energy (anabolic steroids)

2. Decomposition – breaks large molecules into smaller ones

• AB A + B– Ex. Food broken down– If water is used to breakdown the bonds

then it is called hydrolysis (opposite of dehydration synthesis)

Ex A-B-C-D-E + H20 A-B-C-H + HO-D-

E

• Catabolism – the breakdown of complex organic molecules into simpler components, it releases E that can do work

• Ex. Growth, movement, reproduction

3. Exchange (replacement) – Parts of the reacting molecules are moved around

AB + CD AD + CB

(decomp) (synthesis)

May absorb or release energy usually in the form of heat

4. Reversible –

A + B ⇌ AB

Equalibrium – the rates at which the two equations proceed in balance

Enzymes and Chemical Reactions

Activation Energy – the amount of E necessary to start a reaction.

Enzymes – protein in nature that catalyzes a specific biochemical reaction. (catalyst – accelerates chemical reactions – they enter into a reaction but do not become part of it). They do this by lowering the activation E …… this makes it “safe” for the cell

• Remember enzymes are made up of proteins enzyme

A + B AB

Inorganic Compounds

• Generally do not contain C– Include H2O, NaCl, CO2, NO, and CO– H2O – the universal solvent

• 67% of body is water• Dehydration synthesis and Hydrolysis• Lubrication (reduces friction)• High heat capacity (Carries heat away)• Requires a lot of E to change temp.

–So thermoregulation

– Hydrophilic – reacts with water (hydro – water philos – loving)

– Hydrophobic – doesn’t react w/water (phobic – fear)

Electrolytes – soluble inorganic compounds whose ions conduct electrical current in solution

ex NaCl Na+ Cl-

Mixtures

• Mixtures – two or more substances not chemically combined – therefore they retain their own properties– Solutions – evenly combined

• Solvent – does the dissolving ex. Water• Solute – the substance being dissolved ex.

Sugar

– Suspensions –The particles will spread out and eventually settle – large particles

• Example sand in water (whole blood)

-Colloid – a mixture that has medium particles – held in solution by their association with water ex. Liquid jello….. Mayonnaise

pH

• pH IS A WAY TO MEASURE THE ACIDITY OR ALKALINITY (BASICITY) OF A SUBSTANCE

• ACIDS HAVE A HIGH CONCENTRATION OF (H+) H3O+

• BASES HAVE A HIGH CONCENTRATION OF OH-

• Acids and bases are measured on a scale called the pH scale (power of Hydrogen). This scale measures how many hydronium ions (H3O+) are present in a solution (now called just H+). The more hydronium (hydrogen) ions the more acidic (lower) the pH, also the fewer the hydroxide ions (OH-) . The more hydroxide ions the higher the pH (more alkaline – meaning a base) and the fewer the hydronium ions

• THE pH SCALE RANGES FROM 1-14

• ON THE pH SCALE, 7 IS NEUTRAL

• A pH BELOW 7 IS ACIDIC

• A pH ABOVE 7 IS (BASIC) Alkaline• (see drawings on board)

• THE FARTHER A pH IS FROM 7, THE STRONGER THE SUBSTANCE IS

• BUFFERS ARE SUBSTANCES THAT HELP STABILIZE pH IN THE BODY

• BICARBONATE IS THE MOST Important buffer (how CO2 mostly appears in the blood – keeps the blood from becoming to acidic or alkaline)

ORGANIC MOLELCULES

• ALL ORGANIC MOLECULES CONTAIN CARBON AND ARE FOUND IN LIVING ORGANISMS

• THERE ARE 4 MAIN GROUPS– CARBOHYDRATES– PROTEINS– LIPIDS– NUCLEIC ACIDS

CARBOHYDRATES

• ARE SUGARS, STARCHES AND RELATED COMPOUNDS

• THEIR MOST IMPORTANT FUNCTION IS TO SERVE AS A FUEL SOURCE FOR CELLS

• THEY ARE ALSO COMPONENTS OF CELL MEMBRANES AND NUCLEIC ACIDS

• CARBOHYDRATES ARE CHAINS OF CARBON ATOMS THAT ARE BONDED TO HYDROXYL (OH) GROUPS AND HYDROGEN ATOMS (H)

• CARBOHYDRATES ARE MADE OF C, H & O

• C,H & O ARE IN A 1:2:1 RATIO

• THERE ARE 3 MAIN GROUPS OF CARBOHYDRATES

3 GROUPS OF CARBOHYDRATES

• MONOSACCHARIDES- SIMPLE SUGARS eg. GLUCOSE, FRUCTOSE, GALACTOSE

• DISACCHARIDES- 2 SIMPLE SUGARS eg, LACTOSE, SUCROSE, MALTOSE

• POLYSACCHARIDES- MANY SIMPLE SUGARS eg. STARCH, CELLULOSE, GLYCOGEN

• SUGARS END IN - OSE

MONOSACCHARIDES

• GLUCOSE, FRUCTOSE & GALACTOSE ARE ISOMERS.

• ALL HAVE THE CHEMICAL FORMULA C6H12O6

• ISOMERS- ARE MOLECULES WITH THE SAME CHEMICAL FORMULA, BUT A DIFFERENT ARRANGEMENT OF ATOMS.

MONOSACCHARIDES: GLUCOSE

• GLUCOSE- BLOOD SUGAR – cells use this for energy, which is metabolized during cellular respiration. Our major source is from fruits/plants. Plants produce during photosynthesis.

• NORMAL LEVEL IS 80-120 mg/100ml.

• BELOW THIS LEVEL CAN RESULT IN HYPOGLYCEMIA & ABOVE THIS LEVEL CAN RESULT IN DIABETES MELLITUS. DIABETES MELLITUS MEANS “SWEET URINE”

FRUCTOSE

FRUIT SUGARTHE SWEETEST OF ALL THE SUGARS

GALACTOSE

• NOT FOUND FREE IN NATURE, ONLY IN MILK

• WE CANNOT USE GALACTOSE BUT MUST CHANGE IT TO GLUCOSE

GALACTOSE GLUCOSE

ENZYME A (BIRTH)**

**ENZYME A IS MISSING IN CHILDREN WITH GALACTOSEMIA.

ENZYME B (ONE YEAR)

THIS DISORDER IS CALLED GALACTOSEMIA WHICH MEANS

GALACTOSE IN THE BLOOD.

Sx OF GALACTOSEMIA

• CLOUDING OF THE CORNEA AT ABOUT 4 WEEKS• ENLARGED LIVER AND SPLEEN AT ABOUT 4

MONTHS• CATARACTS AT ABOUT 6 MONTHS• MENTAL RETARDATION AT 12 MONTHS

• ALL ARE REVERSIBLE, EXCEPT MENTAL RETARDATION

HOW WOULD YOU TREAT GALACTOSEMIA?

FEED THE BABY A GALACTOSE FREE FORMULA, NO COW’S OR MOTHER’S MILK.

BOTH CONTAIN THIS SUGAR.

DISACCHARIDES – when two monosaccharides bond in a

dehydration synthesis reaction H+ and OH- are

removed and form water

LACTOSE: MILK SUGARGLUCOSE + GALACTOSE

SUCROSE: TABLE SUGARGLUCOSE + FRUCTOSE

MALTOSE: MALT SUGAR BREWING INDUSTRYGLUCOSE + GLUCOSE

POLYSACCHARIDES – three or more monosaccharides

STARCH: STORAGE FORM OF GLUCOSE IN PLANTS

GLYCOGEN: STORAGE FORM OF GLUCOSE IN ANIMALS

CELLULOSE: CELL WALLS OF PLANTS FOR STRENGTH

ALL 3 ARE LONG CHAINS OF GLUCOSE