Ch 2 Anatomy

8/3/2019 Ch 2 Anatomy

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Fundamentals of

Anatomy & Physiology Frederic H. Martini

Unit

1Levels of Organization

Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings

PowerPoint ® Lecture Slides prepared by

Professor Albia Dugger, Miami –Dade College, Miami, FLProfessor Robert R. Speed, Ph.D., Wallace Community College, Dothan, AL



Chapter 2: The ChemicalLevel of Organization



KEY CONCEPT

• Matter is made up of atoms

• Atoms join together to form chemicals

with different characteristics

• Chemical characteristics determine

physiology at the molecular and

cellular level



Atoms

• Atoms are divided into 2

basic regions:

– the central nucleus,

contains heavy particles

– the electron cloud,contains very light,

moving particles

•Atoms are the smallest units of matter with their

own chemical characteristics.



Atomic Particles

• Proton:

– positive, 1 mass unit

• Neutron:– neutral, 1 mass unit

• Electron:

– negative, low mass



Particles and Mass

• Atomic number:

– number of protons

• Mass number:

– number of protons plus neutrons

• Atomic weight:

– exact mass of all particles (daltons)



Isotopes

• 2 or more elements with equal numbers of

protons but different numbers of neutrons

http://www.gravitywarpdrive.com/NGFT_Images/Hydrogen_Isotopes.gif



Elements

• Are determined by the atomicnumber of an atom:

– are the most basic

chemicals

– The atomic number is thenumber of protons

– The number of electrons in

an element equals the

number of protons



Elements in the Human Body

Table 2–1



Chemical Bonds

• Ionic bonds:

– attraction between cations and anions

• Covalent bonds:

– strong electron bonds

• Hydrogen bonds:

– weak polar bonds



Molecules and Compounds

• Molecules:

– atoms joined by strong bonds

• Compounds:

– atoms joined by strong or weak bonds



Ionic Bonds

Figure 2–3a

(1) Ionic bonds form between atoms with opposite electrical

charges (ions).

•An atom that loses electrons (electron donor) has a net positive

charge, and is called a cation.

•An atom that gains electrons (electron acceptor) has a net negative

charge, and is an anion



Ionic Bonds

• Are attractions

between atoms with

positive or negativecharge

Figure 2–3b



Covalent Bonds

Covalent bonds occur when atoms share, rather than gain or lose electrons, forming molecules



Hydrogen Bonds

• Hydrogen bonds between

H2O molecules cause

surface tension

Figure 2–6

(3) Hydrogen bonds are weak attractions between the

positive, hydrogen side of one polar molecule and the

negative side of another polar molecule. Hydrogen bonds

influence the shape of larger molecules, which is important

to molecules such as proteins and DNA



States of Matter

• Solid:

– constant volume and shape

• Liquid:

– constant volume but change shape

• Gas:

– change volume and shape



Why are chemical reactionsimportant to physiology?



Energy

• Energy:

– the power to do work

• Work:

– a change in mass or distance



Forms of Energy

• Kinetic energy:

– energy of motion

• Potential energy:

– stored energy

• Chemical energy:

– potential energy stored in chemical bonds



KEY CONCEPT

• When energy is exchanged, heat is

produced, but cells cannot capture it

or use it for work



Break Down, Build Up

• Decomposition reaction (catabolism):

AB A + B• Synthesis reaction (anabolism):

A + B AB

• Exchange reaction (reversible):AB + C AC + B

AB + CD AC + BD



Water In, Water Out

• Hydrolysis:

A—B—C—D—E + H2O A—B—C—H + HO—D—E

• Dehydration synthesis (condensation):

A—B—C—H + HO—D—E A—B—C—D—E + H2O



KEY CONCEPT

• Reversible reactions seek equilibrium,

balancing opposing reaction rates

• Add or remove reactants:

– reaction rates adjust to reach a new

equilibrium



Materials in Reactions

• Reactants:

– materials going into a reaction

• Products:

– materials coming out of a reaction

• Enzymes:– proteins that lower the activation energy of a

reaction



Figure 2–7

Activation Energy

• Chemical reactions in cells cannot startwithout help

• Activation energy gets a reaction

started



Enzymes

Enzymes are proteins that act as catalysts they arejust facilitators speeding up the chemical reaction

One specific enzyme reduces the activation energyfor one specific reaction.

Enzymes are not used up in a reaction



Energy In, Energy Out

• Exergonic reactions:

A chemical reaction which releases more energy than it usesto get started is an exergonic reaction (exo = outside).

• Endergonic reactions:

When the activation energy of a reaction is greater than the

energy it produces, it is an endergonic reaction (endo =inside).



• Endergonic reactions:

– use more energy than they produce

• Exergonic reactions:

– produce more energy than they use



KEY CONCEPT

• Most chemical reactions that sustain

life cannot occur unless the right

enzymes are present



Organic and Inorganic Molecules

• Organic:

– molecules based on carbon and hydrogen

• Inorganic:– molecules not based on carbon and

hydrogen



Essential Molecules

• Nutrients:

– essential molecules obtained from food

• Metabolites:– molecules made or broken down in the

body



Why is water so important to life?

Properties of Water (1 of 2)• Solubility:

– water’s ability to dissolve a solute in a

solvent to make a solution

• Reactivity:

– most body chemistry uses or occurs inwater



Properties of Water (2 of 2)

• High heat capacity:

– water’s ability to absorb and retain heat

• Lubrication:

– to moisten and reduce friction



KEY CONCEPT

• Most of our body weight is water

• Water is the key structural and

functional component of cells and theircontrol mechanisms, the nucleic acids



Aqueous Solutions

Figure 2–8

•Polar water molecules form hydration spheres

around ions and small polar molecules to keep

them in solution



Electrolytes • Inorganic ions which conduct electricity in solution

• Electrolyte imbalance seriously disturbs vital body

functions



Molecules and Water

• Hydrophilic:

– hydro = water, philos = loving

– reacts with water

Hydrophobic:

– phobos = fear

– does not react with water



Solutions

• Colloid:– a solution of very large organic molecules

• Suspension:– a solution in which particles settle

(sediment)

• Concentration:– the amount of solute in a solvent (mol/L,

mg/mL)



pH

• pH:

– the concentration of hydrogen ions (H+) in

a solution • Neutral pH:

– a balance of H+ and OH—

– pure water = 7.0



Acids and Bases• Acid (acidic): pH lower than 7.0

– high H+ concentration,

low OH— concentration

• Base (basic): pH higher than 7.0

– low H+ concentration,

high OH— concentration



pH Scale

Figure 2–9

• Has an inverse relationship with H+

concentration:– more H+ ions mean lower pH, less H+ ions mean

higher pH



KEY CONCEPT

• pH of body fluids measures free H+ ions in

solution

• Excess H+

ions (low pH):– damages cells and tissues

– alters proteins

– interferes with normal physiological functions

• Excess OH— ions (high pH) also causeproblems, but rarely



Acid and Alkaline

• Acidosis:

– excess H+ in body fluid (low pH)

• Alkalosis:– excess OH— in body fluid (high pH)



Controlling pH

• Salts:

– positive or negative ions in solution

– contain no H+ or OH— (NaCl)

• Buffers:

– weak acid/salt compounds

– neutralizes either strong acid or strongbase



What kinds of organic

compounds are there,and how do they work?



Functional Groups

Table 2–4

• Molecular groups which allow molecules to

interact with other molecules



Simple Sugars

• Monosaccharides:

– simple sugars with 3

to 7 carbon atoms

(glucose)

• Disaccharides:

– 2 simple sugars

condensed bydehydration

synthesis (sucrose)



Polysaccharides

• Chains of many

simple sugars

(glycogen)

Figure 2–12



Carbohydrate Functions

Table 2–5



KEY CONCEPT

• Carbohydrates are quick energy

sources and components of membranes

• Lipids have many functions, includingmembrane structure and energy

storage



Classes of Lipids

• Fatty acids

• Eicosanoids

• Glycerides

• Steroids

• Phospholipids and glycolipids

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Saturated and Unsaturated

• Fatty acids may be:

– saturated with

hydrogen (no

covalent bonds)

– unsaturated (1 or

more double bonds)

















Types of Eicosanoids

• Leukotrienes:– active in immune system

• Prostaglandins:

– local hormones, short-chain fatty acids
















Figure 2–15

Glycerides

• Glycerides: are

the fatty acids

attached to aglycerol molecule

• Triglyceride: are

the 3 fatty-acidtails, fat storage

molecule



















Figure 2–16

Steroids

• 4 carbon rings










Types of Steroids

• Cholesterol:– component of cell membranes

• Estrogens and testosterone:– sex hormones

• Corticosteroids and calcitrol:

– metabolic regulation• Bile salts:

– derived from steroids





























Combination Lipids

Figure 2–17a, b








Phospholipids and Glycolipids • Have hydrophilic heads and hydrophobic tails

• Are structural lipids, components of cellmembranes










Protein Structure

• Proteins are the most abundant andimportant organic molecules

• Basic elements:– carbon (C), hydrogen (H), oxygen (O), and

nitrogen (N)

• Basic building blocks:– 20 amino acids

Proteins PLAY

Protein Functions




















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Protein Functions

• 7 major protein functions:

1. support:

• structural proteins

2. movement:

• contractile proteins

3. transport:

• transport proteins

4. buffering:

– regulation of pH

5. metabolic regulation:

• enzymes

6. coordination and

control:

• hormones

7. defense:

• antibodies

































KEY CONCEPT

• Proteins:

– control anatomical structure and

physiological function– determine cell shape and tissue properties

– perform almost all cell functions















Amino Acid Structure

1. central carbon

2. hydrogen

3. amino group (—NH2)

4. carboxylic acid

group (—COOH)

5. variable side chain

or R group

Peptide Bond


























Peptide Bond

• A dehydration synthesis

between:– the amino group of 1

amino acid

– and the carboxylic acid

group of another aminoacid

– producing a peptide

Protein structure
























Protein structure

• For the polypeptide chain to become a protein, it

must be folded into a unique shape.

• Proteins have 4 levels of shape:

(1) primary structure: the order of amino acids (2) secondary structure: hydrogen bonds form

(3) tertiary structure: folds the secondary structure

(4) quaternary structure: several tertiary structurestogether

















Figure 2–20a

Primary Structure

• Polypeptide:

– a long chain of amino acids













Secondary Structure

Figure 2–20b

• Hydrogen bonds form spirals or pleats










Figure 2–20c

Tertiary Structure

• Secondary structure folds into a unique

shape











Shape and Function

• Protein function is based on shape

• Shape is based on sequence of amino

acids• Denaturation:

– loss of shape and function due to heat or

pH




















Protein Shapes

• Fibrous proteins:

– structural sheets or strands

• Globular proteins:– soluble spheres with active functions














Enzymes

• Enzymes are catalysts:

– proteins that lower the activation energy

of a chemical reaction – are not changed or used up in the reaction

Enzymes PLAY

















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How Enzymes Work

Figure 2–21








How Enzymes Work

• Substrates:

– reactants in enzymatic reactions

• Active site:– a location on an enzyme that fits a

particular substrate
















Enzyme Helpers

• Cofactor:– an ion or molecule that binds to an

enzyme before substrates can bind

• Coenzyme:– nonprotein organic cofactors (vitamins)

• Isozymes:– 2 enzymes that can catalyze the same

reaction
























Enzyme Characteristics

• Specificity:

– one enzyme catalyzes one reaction

• Saturation limits:– an enzyme’s maximum work rate

• Regulation:

– the ability to turn off and on




















Protein Combinations

• Glycoproteins:

– large protein + small carbohydrate

• includes enzymes, antibodies, hormones, andmucus production

• Proteoglycans:

– large polysaccharides + polypeptides

• promote viscosity























Nucleic Acids

• Large organic molecules, found in the

nucleus, which store and process

information at the molecular level• DNA and RNA













Deoxyribonucleic Acid (DNA)

• Determines inherited characteristics

• Directs protein synthesis

• Controls enzyme production

• Controls metabolism













Ribonucleic Acid (RNA)

• Codes intermediate steps in protein

synthesis










KEY CONCEPT

• DNA in the cell nucleus contains the

information needed to construct all of

the proteins in the body









Nucleotides

• Are the building blocks of DNA

• Have 3 molecular parts:

– sugar (deoxyribose)– phosphate group

– nitrogenous base (A, G, T, C)

Nucleotides PLAY













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The Bases

Figure 2–22b, c







Complementary Bases

• Complementary base pairs:

– purines pair with pyrimidines:

• DNA:– adenine (A) and thymine (T)

– cytosine (C) and guanine (G)

• RNA:

– uracil (U) replaces thymine (T)






























Nucleic Acids

• Long chains of

nucleotides form

RNA and DNA

Figure 2–23















RNA and DNA

Table 2–8








RNA and DNA

• RNA:

– a single strand

• DNA:– a double helix joined at bases by hydrogen

bonds




















ADP and ATP

• adenosine diphosphate (ADP):

– 2 phosphate groups

• di = 2• adenosine triphosphate (ATP):

– 3 phosphate groups

•tri = 3

























Phosphorylation

• Adding a phosphate group to ADP with

a high-energy bond to form the high-

energy compound ATP• ATPase:

– the enzyme that catalyzes phophorylation




















Figure 2–24

The Energy Molecule

• Chemical energy stored in phosphate

bonds

C d I t t











Compounds Important

to Physiology

Table 2–8








Recycling Old Molecules

Table 2–9








SUMMARY (1 of 2)

• Atoms, molecules, and chemical bonds

control cellular physiology

• Metabolism and energy work within thecell

• Importance of organic and inorganic

nutrients and metabolites














SUMMARY (2 of 2)

• Role of water and solubility in

metabolism and cell structure

• Chemistry of acids and bases, pH andbuffers

• Structure and function of

carbohydrates, lipids, proteins, andnucleic acids













Ch 2 Anatomy

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