Transcript CH2

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MATTER AND ELEMENTS
• ANYTHING THAT HAS WEIGHT & OCCUPIED
SPACE IS MATTER.
• ALL MATTER IS COMPOSED OF CHEMICAL
ELEMENTS THAT CANNOT BE BROKEN DOWN
BY CHEMICAL MEANS INTO SIMPLER
SUBSTANCES.
• THERE ARE 92 NATURAL ELEMENTS, ONLY 26
OF THEM ARE FOUND IN HUMAN BODY.
• ABOUT 96% OF THE HUMAN BODY WEIGHT IS
MADE OF FOUR ELEMENTS:
• OXYGEN– CARBON – HYDROGEN - NITROGEN
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THE ATOM
IS THE SMALLEST UNIT OF AN ELEMENT THAT
PARTICIPATE IN A CHEMICAL REACTION.
• IT IS MADE OF THREE SUBATOMIC STRUCTURES:
*PROTON = POSITIVE CHARGE
*ELECTRON = NEGATIVE CHARGE
*NEUTRON = NO CHARGE.
• PROTONS & NEUTRONS ARE FOUND IN THE ATOM
•
NUCLEUS, ELCTRONS ORBIT THE NUCLEUS.
THE NUMBER OF PROTONS AND ELECTRONS IS
EQUAL WHICH MAKE THE ATOM ELECTRICALLY
NEUTRAL.
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Figure 02.01
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THE ATOM
ATOMS ARE CHARACTERIZED BY:
• ATOMIC NUMBER
IS THE NUMBER OF PROTONS.
• SYMBOL
IS A SHORTHAND REFERENCE.
• ATOMIC WEIGHT
IS THE SUM OF PROTONS & NEUTRONS
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ISOTOPES
• AN ATOM OF AN ELEMENT WITH A
DIFFERENT NUMBER OF NEUTRONS IS
CALLED AN ISOTOPE.
• ISOTOPES WITH UNSTABLE NUCLEI THAT
EMITS HIGH-ENERGY RADIATION ARE
CALLED RADIOISOTOPES.
• CERTAIN RADIOISOTOPES ARE USED TO
TREAT CANCER AND FOR DIAGNOSIS.
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PET
SCAN
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THE MOLECULE
• ATOMS COMBINE CHEMICALLY TO FORM
MOLECULES.
• A MOLECULE IS THE SMALLEST UNIT OF
A COMPOUND.
• A MOLECULE CAN BE A CHEMICAL
COMPOUND WHEN IT IS COMPOSED OF
TWO ELEMENTS CHEMICALLY COMBINED
IN A FIXED RATIO.
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CHEMICAL FORMULAS
• EXPRESS THE CHEMICAL COMPOSITION
OF A MOLECULE.
• CHEMICAL SYMBOLS INDICATE THE
ELEMENTS OF THE ATOMS, SUBSCRIPTS
IDENTIFY THE NUMBER OF ATOMS.
• EXPRESS BOTH THE COMPOSITION OF A
SINGLE MOLECULE & OF A COMPOUND.
• WATER = H2O
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A CHEMICAL BOND
• IS A FORCE OF ATTRACTION BETWEEN
TWO ATOMS FORMED BY ELECTRONS TO
FILL THE ATOM VALENCE SHELL
(OUTERMOST) WITH EIGHT ELCTRONS.
• FORMED BY EITHER:
• IONIC BONDS.
• COVALENT BONDS.
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IONIC BONDS
• FORMED BY ATOMS DONATING ELECTRONS
OR RECEIVING ELECTRONS.
• ATOMS DONATING ELECTRONS BECOME
POSITIVELY CHARGED IONS (CATIONS).
• ATOMS RECIVING ELECTRONS BECOME
NEGATIVELY CHARGED IONS (ANIONS).
• THE FORCE OF ATTRACTION THAT HOLD
THESE IONS IS AN IONIC BOND.
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FORMATION OF AN IONIC BOND
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COVALENT BONDS
• FORMED BY ATOMS SHARING ELECTRONS.
• NON-POLAR COVALENT BONDS: EQUAL
SHARING OF THE ELECTRONS & THE
MOLECULE IS NEUTRAL OR NON-POLAR.
• POLAR COVALENT BONDS: UNEQUAL SHARING
OF ELECTRONS & THE MOLECULE IS CHARGED
OR POLAR
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FORMATION OF A COVALENT BOND
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HYDROGEN BONDS
• A WEAK ATTRACTION FORCE BETWEEN A
SLIGHTLY POSITIVE HYDROGEN ATOM &
A SLIGHTLY NEGATIVE OTHER ATOM.
• FORMED WHEN SHARED ELECTRONS
SPEND LESS TIME IN THE HYDROGEN
ATOM - WHICH BECOME POSITIVE – AND
MORE TIME IN THE OTHER ATOM WHICH
BECOME NEGATIVE.
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WATER
FORMED BY
HYDROGEN
BONDS
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HUMAN BODY COMPOUNDS
INORGANIC COMPOUNDS
• CONTAIN EITHER CARBON OR
HYDROGEN IN THE SAME MOLECULE BUT
NOT BOTH.
ORGANIC COMPOUNDS
• CONTAIN BOTH CARBON AND HYDROGEN
AND ALSO USUALLY OXYGEN.
• CARBON ATOMS FORM THEIR BACKBONE.
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MAJOR INORGANIC COMPOUNDS
WATER
• MOST ABUNDANT COMPOUND IN THE BODY.
FUNCTIONS:
• ABSORB AND RELEASE HEAT.
• SOLVENT FOR POLAR MOLECULES AND IONS
(HYDROPHILIC OR HYDROPHOBIC)
• MEDIUM FOR CHEMICAL REACTIONS.
• LUBRICANT BETWEEN INTERNAL BODY PARTS.
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WATER COMPARTMENTS
• INTRACELLULAR FLUID (ICF ) (65%)
WATER INSIDE THE CELLS.
• EXTRACELLULAR FLUID (ECF ) (35%)
WATER OUTSIDE THE CELLS. INCUDE:
• PLASMA: FLUID PORTION OF THE BLOOD
• INTERSTITIAL FLUID: WATER IN TINY SPACES
BETWEEN THE CELLS.
• LYMPH AND SPECIALIZED FLUIDS
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MAJOR INORGANIC COMPOUNDS
ACIDS AND BASES
• AN ACID INCREASES HYDROGEN IONS
CONCENTRATION OF A SOLUTION BY
DISSOCIATING TO RELEASE (H+)
• A BASE DECREASES HYDROGEN IONS
CONCENTRATION IN SOLUTION BY
COMBINING WITH H+ DIRECTLY OR BY
RELEASING HYDROXIDE IONS (HO-)
• pH IS A MEASURE OF H+ CONCENTRATION
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A pH SCALE
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BUFFERS
• CHEMICALS THAT PICK UP EXCESS (H+)
OR RELEASE (H+) TO KEEP THE pH OF
THE BODY CONSTANT (7.35-7.45)
• ACIDOSIS: pH = 7.0-7.3. THE PATIENT
FEELS TIRED AND DISORIENTED.
• ALKALOSIS: pH = 7.5-7.8. THE PATIENT
FEELS AGITATED AND DIZZY.
• GREATER VARIATIONS ARE FATAL.
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MAJOR INORGANIC COMPOUNDS
MINERAL SALTS
• IONIC COMPOUNDS THAT DISOCIATE IN
WATER.
• MOST IMPORTANT IN THE BODY ARE: SODIUM
– POTASSIUM – CALCIUM
• ESSENTIAL FOR BODY FUNCTIONS SUCH AS
BLOOD CLOTTING, pH, WATER BALANCE,
MUSCLE AND NERVE FUNCTIONS.
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MAJOR ORGANIC COMPOUNDS
CARBOHYDRATES
• A PRIMARY SOURCE OF ENERGY FORMED
FROM CARBON, HYDROGEN & OXYGEN.
• CLASSIFIED ACCORDING TO THEIR
MOLECULAR SIZE INTO:
• MONOSACCHARIDES : (SIMPLE SUGARS)
GALACTOSE, GLUCOSE AND FRUCTOSE.
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CARBOHYDRATES
DISACCHARIDES
• FORMED BY CHEMICAL COMPINATION OF
TWO MONOSACCHRIDES. INCLUDE:
• MALTOSE = GLUCOSE + GLUCOSE
• SUCROSE = GLUCOSE + FRUCTOSE
• LACTOSE = GLUCOSE + GALACTOSE
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CARBOHYDRATES
POLYSACCHARIDES
• FORMED BY CHEMICAL COMBINATION OF
MANY MONOSACCHARIDES. INCLUD:
• GLYCOGEN: ANIMALS STORED GLUCOSE
• STARCH: PLANTS STORED GLUCOSE
• CELLULOSE: PLANTS CELL WALLS.
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CARBOHYDRATES
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MAJOR ORGANIC COMPOUNDS
LIPIDS
• CARBON ATOMS MAKE THEIR BACKBONE
AND THERE ARE MANY MORE HYDROGEN
THAN OXYGEN ATOMS IN THEM.
• MOST ABUNDANT IN THE BODY ARE:
• TRIGLYCERIDES
• PHOSPHOLIPIDS
• STEROIDS
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LIPIDS
TRIGLYCERIDES
• CONSIST OF ONE GLYCEROL MOLECULE AND
THREE FATTY ACID MOLECULES.
• ARE THE MOST CONCENTRATED ENERGY
SOURCE IN THE BODY & ARE HYDROPHOBIC.
• CLASSIFIED AS:
• SATURATED (ANIMAL FAT)
• UNSATURATED (PLANT FATS)
(MONOUNSATURATED) OR (POLYUNSATURATED)
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A TRIGLYCERIDE MOLECULE
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LIPIDS
PHOSPHOLIPIDS
• CONSIST OF ONE GLYCEROL MOLECULE,
TWO FATTY ACIDS MOLECULES AND ONE
PHOSPHATE - CONTAINING GROUP.
• MAJOR CELL MEMBRANES COMPONENTS.
• HYDROPHILIC DUE TO PRESENCE OF THE
PHOSPHATE GROUP.
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TRIGLYCERIDE
&
PHOSPHOLIPIDE
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LIPIDS
STEROIDS
• CONSIST OF FOUR CARBON RINGS.
• MADE FROM CHOLESTROL WHICH IS AN
ESSENTIAL COMPONENT OF BODY CELLS.
• CHOLESTROL+TRIGLYCERIDE+PROTEIN
= LOW-DENSITY-LIPOPROTEIN (LDL) OR
HIGH-DENSITY-LIPOPROTEIN (HDL)
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Figure 02.09
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MAJOR ORGANIC COMPOUNDS
PROTEINS
• MADE OF AMINO ACIDS COMPOSED OF
CARBON,HYDROGEN,OXYGEN,NITROGEN
• AMINO ACIDS JOIN BY PEPTIDE BONDS
TO FORM DIPEPTIDES, TRIPEPTIDES OR
POLYPEPTIDES.
• HYDROGEN BONDS CAUSE POLYPEPTIDE
CHAINS TO FOLD & FORM 3-D PROTEINS.
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AMINO ACIDS STRUCTURE
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PROTEINS
CLASSIFIED AS
• STRUCTURAL PROTEINS: MAKE PART OF
THE BODY CELLS AND TISSUES SUCH AS
MUSCLES, TENDONS AND LIGAMENTS.
• FUNCTIONAL PROTEINS: PERFORM SOME
SPECIFIC FUNCTION IN THE BODY SUCH
AS ANTIBODIES AND ENZYMES.
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PROTEINS
•
•
•
•
ENZYMES
CATALIZE CHEMICAL REACTIONS BY BINDING
TO SUBSTRATES & WEAKENING THE CHEMICAL
BONDS TO BREAK EASILY
ENZYME MUST FIT INTO THE SUBSTRATE TO
FORM THE PRODUCTS.
THE UNALTERED ENZYME IS RECYCLED.
ENZYME DENATURATION OCCURS WHEN THE
HYDROGEN BONDS ARE BROKEN OR ALTERED.
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ENZYME
CATALYSIS
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NUCLEIC ACIDS
DEOXYRIBONUCLEIC ACID
• CONSIST OF REPEATING UNITS CALLED
•
•
NUCLEOTIDES MADE OF A FIVE-CARBON
SUGAR, A PHOSPHATE GROUP AND AN
ORGANIC BASE EACH.
TWO STRANDS OF NUCLEOTIDES JOINED BY
HYDROGEN BONDS TWIST AND FORM ONE
STRAND OF DNA.
DNA CARRY THE GENETIC CODE IN NUCLEUS.
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NUCLEIC ACIDS
RIBONUCLEIC ACID
• CONSIST OF A SINGLE STRAND OF THE
SAME REPEATING NUCLEOTIDES.
• CARRY THE CODED INSTRUCTIONS FROM
DNA TO THE CELLULAR MECHINARY
THAT IS INVOLVED IN PROTEIN
SYNTHESIS.
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NUCLEOTIDE
UNITS
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DNA MOLECULE STRUCTURE
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ADENOSINE TRIPHOSPHATE
(ATP)
• MADE OF ADENOSINE AND THREE
PHOSPHATE GROUPS JOINED BY TWO
HIGH – ENERY BONDS.
• PROVIDE ENERGY TO POWER THE CELL
CHEMICAL REACTIONS.
• REMADE REPEATEDLY FROM ADENOSINE
DIPHOSPHATE & A PHOSPHATE GROUP
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ATP BREAKDOWN & SYNTHESIS
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