Upload
kana
View
74
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Chapter 2 The Chemical Basis of Life. ( BIOCHEMISTRY) THE BULK OF PHYSIOLOGY INVOLVES CHEMICAL REACTIONS, BUILDING UP or BREAKING DOWN MOLECULES UTILIZING ENERGY or PRODUCING ENERGY . Basic Chemistry:. Key terms and concepts - PowerPoint PPT Presentation
Citation preview
Slide 2
Chapter 2The Chemical Basis of Life
(BIOCHEMISTRY)
THE BULK OF PHYSIOLOGY INVOLVES CHEMICAL REACTIONS,
BUILDING UP or BREAKING DOWN MOLECULES
UTILIZING ENERGY or PRODUCING ENERGY
Slide 3
Basic Chemistry:
Key terms and concepts ATOMS MOLECULES Elements and compounds Elements in the human body (table 2-1) PROTONS ELECTRONS NEUTRONS Electron shells / energy levels , octet rule,
attractions CHEMICAL BONDS: IONIC, COVALENT,
weak bonds – hydrogen CHEMICAL REACTIONS: SYNTHESIS,
DECOMPOSITION, EXCHANGE: REVERSIBLE
Slide 4
MORE KEY TERMS: METABOLISM : CATABOLISM vs.
ANABOLISM ENZYMES INORGANIC COMPOUNDS , such as H2O,
O2 ELECTROLYTES ; IONS: ANIONS,
CATIONS ph ACIDS, BASES, BUFFERS, SALTS ORGANIC COMPOUNDS: CARBOHYDRATES LIPIDS PROTEINS (&
Combos) NUCLEIC ACIDS: DNA, RNA,
NUCLEOTIDES ADENOSINE TRIPHOSPHATE (ATP)
Slide 5
BASIC CHEMISTRY
Element — simple form of matter; a substance that cannot be broken
down into two or more different substances
(PURE) ~118 of them (ref. periodic table)
ex . Hydrogen, oxygen, helium, carbon, gold, silver, copper, sodium,
molybdenum, nitrogen, calcium, phosphorus
Slide 7
Basic Chemistry There are 26 elements in the human body
THERE ARE 11 “MAJOR ELEMENTS,”4 OF WHICH ( OXYGEN, CARBON, HYDROGEN, & NITROGEN ) MAKE UP 96% OF THE HUMAN BODY (water, H2O is 60-80% of the body)
(the others are: sodium, potassium, chlorine,
calcium, phosphorus , sulfur, magnesium)
& There are 15 “trace elements” that make up less than 2% of body weight
Slide 8
Table 2-1:Elements in the human body 11 MAJOR elements:
Oxygen Carbon Hydrogen Nitrogen
Calcium Phosphorus Sodium Chlorine Potassium Sulfur Magnesium
Slide 9
Table 2-1‘trace’elements, but significant roles
Iron blood (Hemoglobin)
Copper many enzymes Iodine thyroid hormone several obscure others
**Basic unit of the elements:
the ATOM **
Slide 11
BASIC CHEMISTRY Compound—atoms of two or
more elements joined to form chemical combinations -- made up of MOLECULES
atoms MOLECULES
OO
OO
H
H OH
HO
H HH
H
Slide 12
Basic Chemistry ATOMIC STRUCTURE— ATOMS contain subatomic particles; the most
important are the following:
PROTONS (+ or p)—positively charged particles found in the nucleus
NEUTRONS (n)— neutral subatomic particles found in the nucleus
ELECTRONS (– or e)—negatively charged subatomic particles found in the electron cloud surrounding, moving about the nucleus
Slide 13
Basic Chemistry
Energy levels (cont.) a model resembling planets revolving around the sun,
useful in visualizing the structure of atoms
Exhibits electrons in concentric circles showing relative distances of the electrons from the nucleus
Each ring or shell represents a specific energy level and can hold only a certain number of electrons
Slide 14
Basic Chemistry
Energy levels (Figures 2-3 and 2-4)
The total number of electrons in an atom equals the number of protons in the nucleus (in a stable atom)
Thus, it is ‘neutral’ – has no electrical charge
ie.: Carbon: 6 protons, 6 neutrons, 6 electrons
The electrons form a “cloud” around the nucleus
Slide 15
The NUMBER and arrangement of Electrons
determine whether the atom is chemically active.
In Chemical reactions, it is the electrons in the outer levels which participate in forming CHEMICAL BONDS
If an atom has 8 electrons in the outermost level, it is chemically ‘inert’, or inactive, and ‘unavailable’ .
(octet rule)
Electron energy levels, cont.
Slide 16
Basic Chemistry
Energy levels (cont.)
Octet rule — atoms with fewer (or more) than eight electrons in the outer energy level will attempt to lose, gain, or share electrons with other atoms to achieve stability.
{just like lonely MALE or FEMALE COLLEGE STUDENTS !!!! }
Slide 17
Basic Chemistry THESE Attractions between atoms
result in chemical bonds – (key concept in
Chemistry)
CHEMICAL REACTION — interaction between two or more atoms that occurs as a result of activity between electrons in their outermost energy levels
The result: Formation of: MOLECULES and COMPOUNDS
Slide 18
BASIC CHEMISTRY
Compound—atoms of two or more elements joined to form chemical combinations -- made up of
MOLECULES atoms
OO
OO
H
HOH
HO
H HH
H
Slide 19
BASIC CHEMISTRY MOLECULES , (COMPOUNDS)
can be
SIMPLE: such as; O2 H2O
CO2
COMPLEX C40H62N10O12
& in between C6H12O6
Slide 21
Basic Chemistry
Chemical bonds — unite atoms into molecules
two major types of chemical bonds:
IONIC BOND: formed by transfer of electrons; strong electrostatic force that binds positively
and negatively charged ions together
COVALENT BOND: formed by sharing of electron pairs between atoms
Slide 22
Ionic bond: donated electron
Slide 23
Covalent bonds, shared electrons
Hydrogen molecule H2Hh2
Carbon dioxide CO2
Slide 24
Other types of bonds HYDROGEN BOND
Much weaker than ionic or covalent bonds
Results from unequally shared electrons, and thus unequal charge distribution on molecules, it makes molecules ‘polar’
water is a good example: ( also DNA - has many H
bonds)
HH oO-
o-HH
Etc etc
+HH
+ +
++++
Slide 25
Chemical reactionsCHEMICAL REACTIONS Involve the formation or
breaking of chemical bonds There are three basic types of chemical reactions involved in
physiology:
SYNTHESIS REACTION — combining of two or more substances to form a more complex substance; formation of new chemical bonds: A + B → AB
DECOMPOSITION REACTION — breaking down of a substance into two or more simpler substances; breaking of chemical bonds: AB → A + B
EXCHANGE REACTION — decomposition of two substances and, in exchange, synthesis of two new compounds from them: AB + CD → AD + CB
(so it’s a combo. of the other two Rxn)
Slide 26
REVERSIBLE REACTIONS — occur in both directions
Most of the metabolic, physiologic chemical reactions of the body can and do take place in either direction,
So, in essence, a synthesis reaction, when reversed, becomes a decomposition reaction
Slide 27
Metabolism Metabolism — the sum total of all of the
chemical reactions that occur in body cells
Catabolism = decomposition
Anabolism = synthesis
Slide 28
CATABOLISMChemical reactions that break down complex
compounds into simpler ones and release energy;
HYDROLYSIS is the most common catabolic reaction,,,,,,,, WATER is added to a substance, resulting in its breakdown into smaller compounds
Ultimately, the end products of catabolism are carbon dioxide, water, and other waste products
More than half the energy released is transferred to ATP, which is then used to do cellular work
Slide 29
Metabolism Anabolism
Chemical reactions that join simple molecules together to form more complex molecules
The Chemical reaction most commonly responsible for anabolism is DEHYDRATION SYNTHESIS
Slide 31
Slide 32
MORE KEY TERMS METABOLISM : CATABOLISM
ANABOLISM
INORGANIC COMPOUNDS , such as H2O, O2
ELECTROLYTES IONS, ANIONS, CATIONS
pH: ACIDS, BASES, BUFFERS, SALTS ORGANIC COMPOUNDS table 2-4 CARBOHYDRATES LIPIDS PROTEINS (&
Combos) ENZYMES NUCLEIC ACIDS DNA RNA
NUCLEOTIDES ADENOSINE TRIPHOSPHATE (ATP)
Slide 33
Organic and Inorganic Compounds ORGANIC MOLECULES
Have at least one carbon atom and at least one C–C or C–H bond in each molecule (they are complex molecules)
Can have a bunch of atoms
Often have functional groups attached to the carbon- containing core of the molecule
(ex: of functional groups): hydroxyl carbonyl carboxl amino
phosphate -OH -C=O -COOH -C=NH2 -
O-P=O(OH)2ATP: adenisine triphosphate
Slide 34
INORGANIC COMPOUNDS such as :
H2O O2 CO2electro-lytes: Na+ K+ Cl- Ca++
others
in contrast to organic molecules: inorganic Do not generally have carbon
atoms if so, there are NO C–C or C–H bond, (they are much more simple molecules)
60%-80% of your body is water
Slide 35
INORGANIC COMPOUNDS WaterThe body’s most abundant and important compound: where is water found in the body?:
Intracellular fluid (inside the body) Extracellular fluid (outside the body), to
include blood (intravascular) HOW IS WATER UTILIZED? a Solvent, ( thus a carrier) , for important
substances involved in a vital way in most chemical
reactions
Slide 37
WATER Important Properties of water (Table 2-
2)
Polarity — allows water to act as an effective solvent; ionizes substances in solution (Figure 2-8)
Ionized: to go from a solution to being dissolved The solvent allows transportation of essential
materials throughout the body (Figure 2-12) High specific heat — water can lose and gain large
amounts of heat with little change in its own temperature; ENABLES THE BODY TO MAINTAIN A RELATIVELY CONSTANT TEMPERATURE
High heat of vaporization—water requires absorption of significant amounts of heat to change from a liquid to a gas, ALLOWING THE BODY TO DISSIPATE EXCESS HEAT
Slide 38
Inorganic Compounds Oxygen and carbon dioxide—closely
related to cellular metabolism:
Oxygen —REQUIRED to complete decomposition
reactions necessary for the release of energy in the body
Carbon dioxide —produced as a waste product of
decompensation reactions also helps maintain the appropriate ACID-
BASE balance in the body
Slide 39
Inorganic Compounds Electrolytes
Large group of inorganic compounds, which includes acids, bases, and
salts
Substances that dissociate in solution to form IONS (these are NOT ‘Saturn’ cars,
LOL)
Positively charged ions are cations; negatively charged ions are anions
The major electrolytes are:Sodium (NA+) Potassium (K+) Chloride(CL-)
Carbon Dioxide (CO2) Calcium (Ca++) many others
Slide 40
Inorganic Compounds Electrolytes (cont.)
Acids and bases—common and important chemical substances that are chemical opposites
ACIDSAny substance that RELEASES A HYDROGEN ION (H+)
when in solution; Described as “proton donors”
Level of “acidity” depends on the number of hydrogen ions a particular acid will release
(low pH) pH: 6.9 and below is acidic impt. ex.: HCL hydrochloric acid in the stomach lactic acid builds up in tired muscles
Slide 41
BASESElectrolytes that dissociate to YIELD HYDROXIDE IONS (OH–) or other electrolytes that combine with hydrogen ions (H+)
Described as “proton acceptors”pH: 8.0 and above are basic (high pH) examples: NaOH, NaHCO3 , CaHCO3, Ammonia
Slide 42
pH scale—measuring acidity and alkalinity
pH indicates the degree of acidity or alkalinity of a solution
pH of 7 indicates NEUTRALITY (equal amts of H+ and OH–); a pH of less than 7 indicates ACIDITY;
a pH of more than 7 indicates ALKALINITY
***** ‘normal’ pH of the blood (body) is 7.4 ******
****** this is important !!!!!!!
Slide 44
Inorganic Compounds Buffers
Maintain the constancy of the pHMinimize changes in the concentrations of H+
and OH– ionsAct as a “reservoir” for hydrogen ions
most important buffer for maintaining acid-base balance in the blood is the
carbonic-acid-bicarbonate buffer. H+ + -HCO3 >< H2CO3><
H2O + CO2 Gives up hydrogen ions
Slide 45
Inorganic Compounds
Salts (Table 2-3)Compounds that result from chemical
interaction of an acid and a base
Reaction between an acid and a base to form a salt and water is called a neutralization reaction
NaOH + HCL >> NaCl + H2O base acid salt water
Slide 46
Organic Molecules (Figure 2-14; Table 2-4) “Organic” describes compounds
that contain C–C or C–H bonds. (complex)
in the Human Body, the key ORGANIC COMPOUNDS are:
CARBOHYDRATES LIPIDS, INCLUDING STEROIDS PROTEINS NUCLEOTIDES, NUCLEIC ACIDS,
ATP
Slide 48
Slide 49
2 East Texas farmers:
#1: MR DUCKS #2: MR KNOT #1: OSAR, CM
WANGS #2 : LIB, MR
DUCKS
Slide 51
***ORGANIC MOLECULES (compounds)***(4 major types in the body
CarbohydratesLipidsProteinsNucleotides
Slide 52
the impt. ORGANIC COMPOUNDS CARBOHYDRATES
a. simple sugars, ie glucose deoxyribose, ribose
( as usable in the cells)
b. disaccharides: sucrose, lactose
(as found in food, must be broken down)
c. polysaccharides: GLYCOGEN (starch) (a large polymer OF GLUCOSE MOLECULES, AS STORAGE)
LIPIDS (TRIGLYCERIDES, PHOSPHOLIPIDS,
STEROIDS, PROSTAGLANDINS)
Slide 53
ORGANIC MOLECULES CARBOHYDRATES—organic
compounds containing carbon, hydrogen, and oxygen; commonly called sugars and starchesMonosaccharides—simple sugars with short
carbon chains; those with six carbons are hexoses (e.g.,
glucose), whereas those with five are pentoses (e.g., ribose, deoxyribose)
Disaccharides and polysaccharides—
two (di-) or more (poly-) simple sugars that are bonded together through a synthesis reaction
Slide 54
MORE ORGANIC COMPOUNDS: LIPIDS
Lipids (Table 2-6)Water-insoluble organic molecules that are critically important biological compounds
Major roles:Energy sourceStructural roleIntegral parts of cell membranes
Slide 55
LIPIDS Lipids : 1) triglycerides, 2)steroids , 3)
prostaglandins
TRIGLYCERIDES, or fats abundant lipids and the most concentrated
source of energy
The building blocks of triglycerides are glycerol (the same for each fat molecule)
and fatty acids (different for each fat, they determine its chemical nature)
Slide 57
More LIPIDS Phospholipids
Fat compounds similar to triglyceride
One end of the phospholipid is water-soluble (hydrophilic); the other end is fat-soluble (hydrophobic)
Phospholipids can join two different chemical environments (Hydrophilic, Hydrophobic)
Phospholipids may form double layers called bilayers that make up cell membranes !!!
Slide 59
Lipids, STEROIDSSteroids Main component is steroid nucleus
Involved in many structural and functional
roles
Slide 60
Lipids : PROSTAGLANDINS
Prostaglandins Commonly called “tissue hormones”; produced by cell membranes throughout the body
Effects are many and varied; however, they are released in response to a specific stimulus and are then inactivated
Slide 61
MOST Proteins are of TWO basic types:
A. STRUCTURAL fundamental components of large portions of the body (muscle)
B. FUNCTIONAL ; involved in the chemical reactions of the body, these proteins are also called ENZYMES
( a few proteins are structural components of the cell, AND have functional capacity as well - they do both)
PROTEINS: POLYMERS OF AMINO ACIDS
Slide 62
PROTEINS
Proteins (Table 2-5) are the Most abundant organic
compoundsChainlike polymers AMINO ACIDS — are the building blocks
of proteins
Amino acids consist of a carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a side chain
Mosby items and derived items © 2007, 2003 by Mosby, Inc.
Protein structure PROTEINS are considered
POLYPEPTIDES, because they are long
polymers (chains) Of Amino acids, joined byPEPTIDE BONDS***Peptide bonds join amino acids
together to form proteins.
Slide 63
Slide 64
PROTEINS can be either STRUCTURAL AND FUNCTIONAL (sometimes both)
Structural proteins form many of the structures of the body
(such as muscle)
Functional proteins cause chemical changes in the molecules, and are called ENZYMES. Very active in all the chemical reactions of the body
Shape of a protein’s molecules determines its function (Figure 2-21) Denatured proteins have lost their shape and therefore their
function (Figure 2-22) Proteins can be denatured by changes in pH, temperature,
radiation, and other chemicals If the chemical environment is restored, proteins may be renatured
and function normally
Slide 67
Nucleotides and related molecules, nucleic acids, ATP, et alREAD ABOUT IT.
Slide 68
NUCLEOTIDES
NUCLEOTIDES are the building blocks of:
a. The Nucleic acids: DNA, RNA, and b. ATP (Adenosine Tri-
Phosphate)
Mosby items and derived items © 2007, 2003 by Mosby, Inc.
Importance of DNA, RNA The Nucleic Acids are POLYMERS of
thousands of smaller molecules called NUCLEOTIDES
a DEOXYRIBONUCLEOTIDE consists of:
1. the pentose sugar: Deoxyribose, 2. a PHOSPHATE group, and 3. a nitrogenous base (one of
four; Adenine, Thymine, Cytosine, or Guanine)
DNA MOLECULES ARE THE LARGEST MOLECULES IN THE BODY
Slide 70
Slide 71
Nucleic acids and related molecules
DNA (deoxyribonucleic acid) Composed of deoxyribonucleotides; that is,
structural units composed of the pentose sugar (deoxyribose), phosphate group, and nitrogenous base (cytosine, thymine, guanine, or adenine)
DNA molecule consists of two long chains of deoxyribonucleotides coiled into double-helix shape
Alternating deoxyribose and phosphate units form backbone of the chains
Slide 72
DNABase pairs hold the two chains of DNA molecule
together (HYDROGEN BONDS)
Specific sequence of more than 100 million base pairs constitute one human DNA molecule;
all DNA molecules in one individual are identical (to each other) and,
they are different from those of ALL other individuals
DNA functions as the molecule of heredity
Slide 73
DNA - THE MOLECULE OF HEREDITY, THE GENETIC LIBRARY Within the DNA molecule is the enormous bank of genetic information which passes traits from one generatin to the next.
DNA acts as the information molecule storing the MASTER CODE , or the Recipes (called GENES) for the formation of RNA, and the thousands of differing protein molecules of the body.
Slide 74
Nucleic acids and related molecules (cont.)
RNA (ribonucleic acid) a single stranded molecule Composed of the pentose sugar (ribose),
phosphate group, and a nitrogenous base
Nitrogenous bases for RNA are adenine, uracil, guanine, or cytosine (uracil replaces thymine compared to DNA)
Some RNA molecules are temporary copies of segments (genes) of the DNA code and are involved in synthesizing proteins (later : mRNA, tRNA, rRNA)
Slide 75
OTHER NUCLEOTIDES - ATP Nucleotides have other important roles in
the body
ATP Adenosine triphosphateComposed of
(A) Adenosine: A. Ribose—a pentose sugar , and B. Adenine—a nitrogen-containing molecule
C. ( TP) Three phosphate subunits
ATP
Slide 77
IMPORTANCE OF ATP High-energy bonds present between phosphate
groups
Cleavage of high-energy bonds releases energy during catabolic reactions
Energy stored in ATP is used to do the body’s work
ATP often called the ENERGY CURRENCY of cells
ATP is split into adenosine diphosphate (ADP) and an inorganic phosphate group by a special enzyme
Slide 78
OTHER NUCLEOTIDESNAD and FAD (Figure 2-31)
Used as coenzymes to transfer energy-carrying molecules from one chemical pathway to another
cAMP (cyclic AMP) Made from ATP by removing two
phosphate groups to form a monophosphate
Used as an intracellular signal
Slide 79
Combined formsExamples:
Adenosine triphosphate (ATP)—two extra phosphate groups to a nucleotide, important ‘energy’ molecule
Lipoproteins—lipid and protein groups combined into a single molecule (important ones are HDL and LDL -- the way CHOLESTEROL is carried in the bloodstream
Glycoproteins—carbohydrate (glyco, “sweet”) and protein (cellular markers