chemistry comes alive

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Human Anatomy & PhysiologySEVENTH EDITION

Elaine N. MariebKatja Hoehn

PowerPoint® Lecture Slides prepared by Vince Austin, Bluegrass Technical and Community College

C H

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2Chemistry Comes Alive

P A R T A


Blood is collected from your patient and treated so it will not clot. This blood is placed in a long narrow tube that is placed vertically on a laboratory bench. In an hour, all the blood cells have settled to the bottom of the tube, leaving the rest of the tube filled with a clear, yellowish liquid called plasma. Why did the blood cells settle out of the blood?

A. blood is an acidic solution of cells and plasma that sticks to the tube

B. blood is a mixture of solids and gases that react with the air C. blood is a solution of Na+ and CL– ions that react to form a

precipitate D. blood is a suspension of cells in plasma that settles by gravity

Human Blood Collection Bellringer – NOT to turn in


Human Blood Collection Bellringer – NOT to turn in Blood is collected from your patient and treated so it will not clot.

This blood is placed in a long narrow tube that is placed vertically on a laboratory bench. In an hour, all the blood cells have settled to the bottom of the tube, leaving the rest of the tube filled with a clear, yellowish liquid called plasma. Why did the blood cells settle out of the blood?

A. blood is an acidic solution of cells and plasma that sticks to the tube

B. blood is a mixture of solids and gases that react with the air C. blood is a solution of Na+ and CL– ions that react to form a

precipitate D. blood is a suspension of cells in plasma that settles by gravity


Matter Anything that has mass and takes up space States of matter

Solid – has definite shape and volume Liquid – has definite volume, changeable shape Gas – has changeable shape and volume

All are important in Anatomy & Physiology


Composition of Matter Elements – unique substances that cannot be

broken down by ordinary chemical means Atoms –building blocks for each element


Major Elements of the Human Body Oxygen (O) Carbon (C) Hydrogen (H) Nitrogen (N)


Lesser and Trace Elements of the Human Body Lesser elements make up 3.9% of the body and

include: Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)

Trace elements make up less than 0.01% of the body


If given an element, identify if it is…

A major element of the body A lesser element of the body A trace element of the body

Vitamin Labels


Molecules and Compounds Molecule – two or more atoms held together by

chemical bonds Compound – two or more different kinds of atoms

chemically bonded together (water or H2O is an example)


Mixtures and Solutions Mixtures – two or more components physically

intermixed (not chemically bonded) Example: blood cells in blood

Most mixtures can be separated by physical means Solutions – homogeneous mixtures of components

Example: electrolytes such as Na+Cl-, K+CL-, etc. Solvent – substance present in greatest amount Solute – substance(s) present in smaller amounts


Types of Chemical Bonds

Ionic Covalent Hydrogen Importance of polar and nonpolar molecules


Factors Influencing Rate of Chemical Reactions

Catalysts – increase the rate of a reaction without being chemically changed

Enzymes = biological catalysts


Biochemistry

Organic compounds Contain carbon, are covalently bonded, and are

often large Inorganic compounds

Do not contain carbon Water, salts, and many acids and bases


Salts (NaCL, KCL, Na2SO4, etc.)

Inorganic compounds Contain cations other than H+ and anions other

than OH–

Are electrolytes; they conduct electrical currents


Acids and Bases

Acids release H+ and are therefore proton donors

HCl H+ + Cl –

Bases release OH– and are proton acceptors

NaOH Na+ + OH–


Acid-Base Concentration (pH)

Acidic solutions have higher H+ concentration and therefore a lower pH

Alkaline solutions have lower H+ concentration and therefore a higher pH

Neutral solutions have equal H+ and OH– concentrations


Acid-Base Concentration (pH)

Acidic: pH 0–6.99 Basic: pH 7.01–14 Neutral: pH 7.00

Blood has pH ~ 7.4 Most body fluids pH 7.2 – 7.6


Buffers

Chemical systems that resist abrupt and large swings in the pH of body fluids

Example: Carbonic acid-bicarbonate system in blood

Carbonic acid dissociates, reversibly releasing bicarbonate ions and protons

The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood


Bicarbonate Buffer System Removes Acid If blood is too acidic: HLac(aq) + HCO3

-(aq) ↔ Lac-(aq) + H2CO3(aq) Lactic Acid + Bicarbonate Lactate + Carbonic Acid

If blood is too basic (alkaline): H2CO3(aq) ↔ H+(aq) + HCO3

-(aq)Carbonic Acid Protons + Bicarbonate


Organic Compounds

Molecules unique to living systems contain carbon and hence are organic compounds

They include 4 important macromolecular biochemical polymers:

Carbohydrates Lipids Be able to identify from Proteins descriptions or pictures Nucleic Acids}


Carbohydrates Contain carbon, hydrogen, and oxygen Their major function is to supply a source of

cellular food Examples:

Monosaccharides or simple sugars

Figure 2.14a


Carbohydrates Polysaccharides or polymers of simple sugars

Figure 2.14c


Lipids Contain C, H, and O, but the proportion of oxygen

in lipids is less than in carbohydrates Examples:

Neutral fats or triglycerides Phospholipids Steroids Eicosanoids


Neutral Fats (Triglycerides)

Composed of three fatty acids bonded to a glycerol molecule

Figure 2.15a


Other Lipids Steroids – flat molecules with four interlocking

hydrocarbon rings

Figure 2.15c


Representative Lipids Found in the Body

Neutral fats – found in subcutaneous tissue and around organs

Phospholipids – chief component of cell membranes

Steroids – cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones

Fat-soluble vitamins – vitamins A, E, and K


Amino Acids

Building blocks of protein, containing an amino group and a carboxyl group

Amino group NH2

Carboxyl groups COOH


Amino Acids

Figure 2.16a–c


Examples of proteins


Protein Macromolecules composed of combinations of 20

types of amino acids bound together with peptide bonds

Figure 2.17

Amino acid Amino acid

Dehydrationsynthesis

HydrolysisDipeptide

Peptide bond

+N

H

H

C

R

H

O

N

H

H

C

R

CC

H

O H2O

H2O

N

H

H

C

R

C

H

O

N

H

C

R

C

H

O

OH OH OH


Fibrous and Globular Proteins Fibrous proteins

Extended and strand-like proteins Examples: keratin, elastin, collagen, and certain

contractile fibers


Fibrous and Globular Proteins Globular proteins

Compact, spherical proteins with tertiary and quaternary structures

Examples: antibodies, hormones, and enzymes


Characteristics of Enzymes Frequently named for the type of reaction they

catalyze Enzyme names usually end in -ase Lower activation energy of a reaction


Nucleic Acids Composed of carbon, oxygen, hydrogen, nitrogen,

and phosphorus Their structural unit, the nucleotide, is composed

of N-containing base, a pentose sugar, and a phosphate group


Nucleic Acids Five nitrogen bases contribute to nucleotide

structure – adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)

Two major classes – DNA and RNA


Deoxyribonucleic Acid (DNA) Double-stranded helical molecule found in the

nucleus of the cell Replicates itself before the cell divides, ensuring

genetic continuity Provides instructions for protein synthesis


Structure of DNA

Figure 2.22b


Adenosine Triphosphate (ATP) Source of immediately usable energy for the cell Adenine-containing RNA nucleotide with three

phosphate groups


Adenosine Triphosphate (ATP)

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