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SPE 3510Basic Anatomy and Physiology

Roxana Dev Omar Dev

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CONTENTS IN BRIEF

FOR SEMESTER

How the body is organized

Protection, Support, and Movement

Control, Communication and Coordination

Transport and Maintenance

Reproduction and development

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Chapter 2

The Chemical Basis of LifeThe Chemical Basis of Life

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Basic Chemistry

Matter, Mass, and WeightMatter: anything that occupies space and has mass

Mass: the amount of matter in an object

Weight: the gravitational force acting on an object ofa given mass

Elements and Atoms

Element: the simplest type of matter with unique

chemical properties; composed of atoms of only one

kind

Atom: smallest particle of an element that has

chemical characteristics of that element

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Atomic Structure

Atoms: composed ofsubatomic particles

Neutrons: no electrical

charge

Protons: one positive charge

Electrons: one negative

charge

Nucleus: formed by protons

and neutrons

Most of the volume of an

atom occupied by electrons

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Atomic Number and Mass

Number

Atomic Number: equal

to number of protons in

each atom which is equalto the number of electrons

Mass Number: number

of protons plus number of

neutrons

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Isotopes and Atomic Mass

Isotopes: two or more forms of same element with samenumber of protons and electrons but different neutronnumber

For example; there are three types of hydrogen Denoted by using symbol of element preceded by mass number as

1H, 2H, 3H

Atomic Mass: average mass of naturally occurringisotopes

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Radioactive Isotopes

Forms of atoms that emit radioactivity such

as gamma rays, which can then be measured

Used clinically and in research

Examples of uses

Tracking hormone uptake

Treating cancer

Sterilization of materials to be used in surgery

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Electrons and Chemical Bonding Intramolecular bonding occurs

when outermost electrons are eithershared with or transferred toanother atom

Ionic Bonding: atomsexchange electrons

Covalent Bonding: two ormore atoms share electron pairs

Ion: an atom loses or gainselectrons and becomes charged

Cation: positively charged ion Anion: negatively charged ion

In an ionic bond, cations andanions are attracted to each otherand remain close to each other

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Covalent Bonding

Atomsshare one or morepairs of electrons Single covalent: two

atoms share one pair ofelectrons

Double covalent: Twoatoms share 4 electrons

Nonpolar covalent:Electrons shared equally

because nuclei attract theelectrons equally

Polarcovalent: Electronsnot shared equally

because one nucleusattracts the electrons morethan the other does

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Molecules and Compounds

Molecules: two or more atoms chemicallycombine to form an independent unit

Example: a hydrogen molecule (H2)

Compounds: a substance composed of twoor more different types of atoms chemically

combined

Example: water (H2O)

Molecular Mass: determined by adding up

atomic masses of its atoms or ions

Example: NaCl (22.99 + 35.45)

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Intermolecular Forces

Forces between molecules

Result from weak electrostatic attractions

between oppositely charged parts or

molecules, or between ions and molecules

Weaker than forces producing chemical

bonding

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Intermolecular Forces: Hydrogen Bonds

Occur when the positivelycharged H of one molecule isattracted to the negativelycharged O, N or F of anothermolecule For example, in water the

positively charged hydrogenatoms of one water molecule

bond with the negativelycharged oxygen atoms of other

water molecules Hydrogen bonds play animportant role in determiningthe shape of complexmolecules

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Intermolecular Forces:

Solubility and Dissociation Solubility: ability of one

substance to dissolve in another

For example, sugar or saltdissolves in water

DissociationorSeparation: inionic compounds, cations areattracted to negative end andanions attracted to positive endof water molecules; the ions

separate and each becomessurrounded by water molecules

Electrolyte: dissociation of anionic compound in water

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Electrolytes and Nonelectrolytes

Electrolytes: solutions made by the

dissociation of cations (+) and anions (-) in

water

Have the capacity to conduct an electric currentCurrents can be detected by electrodes

Nonelectrolytes: solutions made by

molecules that dissolve in water, but do notdissociate; do not conduct electricity

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Chemical Reactions Atoms, ions, molecules or compounds interact

to form or break chemical bondsReactants: substances that enter into a chemical

reaction.

Products: substances that result from the reaction

Chemical bonds are made (synthesis;anabolism) and broken (decomposition;catabolism) during chemical reactions

Metabolism: collective term used for the sumof all of the anabolic and catabolic reactions inthe body

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Synthetic Reactions Two or more reactants chemically combine to form a new

and larger product. Anabolism. Chemical bonds made; energy stored in the bonds.

Responsible for growth, maintenance and repair

Hydrolysis: synthetic reaction where water is a product

Produce chemicals characteristic of life: carbohydrates, proteins,lipids, and nucleic acids

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Decomposition Reactions A large reactant is broken down to form smaller products.

Catabolism. Chemical bonds broken; energy released.

Hydrolysis: water is split into two parts that contribute to the formation ofthe products

Example: the breakdown of ATP to form ADP and inorganic phosphatewith a concomitant release of free energy

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Reversible Reactions

Chemical reactions in which the reaction

can proceed either from reactants to

products or from products to reactants. Equilibrium: rate of product formation is

equal to rate of reactant formation

Example: CO2 and H+ formation in plasma

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Oxidation-Reduction Reactions

Oxidation: lossof an electron by an atom

Reduction:gainof an electron by an atom

Oxidation-Reduction Reactions: the

complete or partial loss of an electron byone atom is accompanied by the gain of thatelectron by another atom

Synthetic/decomposition reactions can beoxidative reduction reactions

Reactions can be described in more than oneway

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Energy: the capacity to do work

Potential Energy: energy stored in chemical bonds;energy that could do work if it were released.

Breaking chemical bonds releases energy.

Kinetic Energy: does work and moves matter Mechanical Energy: energy resulting from the

position or movement of objects

Chemical Energy: form of potential energy in the

chemical bonds of a substance

Heat Energy: energy that flows between objects of

different temperatures

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ATP and Potential Energy

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Heat Energy

When a chemical bond is broken and

energy is released, only some of that energy

is used to manufacture ATP. Energy that is released but not captured is

released as heat.

The heat used by humans to maintain bodytemperature.

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Speed of Chemical Reactions

Temperature affects rate of reaction. Increase in temperature means increase of kinetic energy.

Molecules move faster, collide harder and more frequently.

Concentration of reactants. As concentration of reactants increases, rate of reaction increases.

A decrease of O2 in cells can cause death as rate of aerobic

chemical reactions decreases.

Catalysts: substances that increase the rate of chemical

reactions without being permanently changed or depleted Enzymes: proteinaceous catalysts that increase the rate of chemical

reactions by lowering the activation energy necessary for reactionto begin

Activation Energy: minimum energy reactants must have to start achemical reaction

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Activation Energy and Enzymes

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Chemistry

Inorganic Chemistry: generally,

substances that do not contain carbon

Water, oxygen

Exceptions: CO, CO2, and HCO3-

Organic Chemistry: study of carbon-

containing substances. Those that arebiologically active are called biochemicals.

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Water

High specific heat: large amount of heatrequired to raise temperature of waterStabilizes body temperature

ProtectionLubricant, cushion

Participates in chemical reactions

Many reactions take place in waterDehydration and hydrolysis

Serves as a mixing medium

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Mixtures, Solutions and Measures of Concentration

Mixture: substances physically but not chemically

combined Suspension: materials separate unless stirred. Sand and

water.

Colloid: dispersal of tiny particles through a medium. Milk.

Solution: mixture of liquids, gasses, or solids that areuniformly distributed and chemically combined Solvent: that which dissolves the solute

Solute: that which dissolves in the solvent

Concentration: measure of number of particles of

solute per volume of solution Unit used by physiologists is osmolality

Concentration of body fluids influences movement of fluidinto and out of cells.

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Acids and Bases; Salts and Buffers

Acid: a proton donor or any substance thatreleases hydrogen ions

Base: a proton acceptor or any substance

that binds to or accepts hydrogen ions Salt: a compound consisting of a cation

other than a hydrogen ion and an anion

other than a hydroxide ion. Example: NaCl Buffer: a solution of a conjugate acid-base

pair in which acid and base components

occur in similar concentrations

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The pH Scale

Refers to the Hydrogenion concentration in a

solution

Neutral: pH of 7 or equal

hydrogen and hydroxideions

Acidic: a greater

concentration of hydrogen

ions Alkaline or basic: a

greater concentration of

hydroxide ions

O d C b Di id

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Oxygen and Carbon Dioxide:

Important Inorganic Compounds

Oxygen (O2): required in the final step in

the series of reactions used to extract energy

from food.

Carbon dioxide (CO2): produced during the

catabolism of organic compounds.

Metabolic waste product.

Combines with water in plasma and forms H+

thus affecting acid/base balance

O i Ch i t Bi h i l

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Organic Chemistry: Biochemicals

Carbohydrates: composed of carbon, hydrogen, oxygen. Divided into monosaccharides, disaccharides, polysaccharides

Example: glucose

Energy sources and structure

Lipids: composed mostly of carbon, hydrogen, oxygen. Relatively insoluble in water.

Example: anabolic steroids Functions: protection, insulation, physiological regulation, component ofcell membranes, energy source

Proteins: composed of carbon, hydrogen, oxygen, nitrogen,sometimes iodine.

Example: insulin Functions: regulate processes, aid transport, protection, muscle contraction,

structure, energy

Nucleic Acids: composed of carbon, hydrogen, oxygen, nitrogen,phosphorus.

Examples: ATP, DNA, RNA

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Carbohydrates: Monosaccharides

Simple sugars.

Six-carbon sugars like

glucose, fructose, andgalactose are important

in the diet as energy

sources.

Five-carbon sugars are

components of ATP,

DNA and RNA

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Carbohydrates: Disaccharides

Two simple sugars

bound together by

dehydration Examples: sucrose,

lactose, maltose

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Carbohydrates: Polysaccharides

Long chains of manymonosaccharides.

Storage molecules formonosaccharides and form

part of cell surface markers

Glycogen formed byanimals.

Starch and celluloseformed by plants Starch in food is used as a

source of monosaccharides

Cellulose in food acts asfiber (bulk) in the diet

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Lipids: Fats

Ingested and broken

down by hydrolysis Triglycerides:

composed of glycerol

and fatty acids

Functions: protection,insulation, energy

source

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Lipids: Phospholipids

Polar (hydrophilic) at

one end; nonpolar

(hydrophobic) at the

other.

Function: important

structural component of

cell membranes

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Lipids: Steroids

Cholesterol, bile

salts, estrogen,

testosterone. Carbon atomsarranged in four rings

Functions:

physiologicalregulators and

component of cell

membranes

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Lipids: Eicosanoids and

Fat-soluble Vitamins

Eicosanoids: Derived from fatty acids.

Function: Important regulatory molecules

Fat-soluble Vitamins: nonpolar molecules

essential for normal functioning.

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Proteins

Amino acids: buildingblocks of protein

Peptide bonds:covalent bonds formed

between amino acidsduring protein

synthesis

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Protein Structure Primary: sequence of

amino acids in thepolypeptide chain

Secondary: folding andbending of chain caused byhydrogen bonding

Tertiary: formation ofhelices or of pleatedsheets; caused in part by S-S bonds between amino

acids Quaternary: two or more

proteins associate as afunctional unit

E P t i C t l t

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Enzymes: Protein Catalysts Lower the activation energy necessary

for a reaction to occur; bring reactants

into close proximity Three-dimensional shape contains an

active site where reactants attach.

Induced Fit Hypothesis: enzymeschange shape to accommodate the shapeof specific reactants

Enzyme names usually end in ase andoften have the same word stem as thereactant; for example a lipid is a reactant

for lipase. Cofactors: combine with active site and

make nonfunctional enzymes functional

Organic cofactors called coenzymes

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DNA: Deoxyribonucleic acid

Genetic material ofcells copied from onegeneration to next

Composed of 2 strandsof nucleotides Each nucleotide

contains one of theorganic bases ofadenine or guanine(which are purines) andthymine or cystosine(which are

pyrimidines).

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RNA: Ribonucleic acid

Similar to a single strand of DNA

Four different nucleotides make up organic

bases except thymine is replaced with uracil(pyrimidine)

Responsible for interpreting the code within

DNA into the primary structure of proteins.

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Adenosine Triphosphate (ATP)

Energy currency of the body

Provides energy for other chemical reactions as anabolismor drive cell processes as muscle contraction

All energy-requiring chemical reactions stop when there isinadequate ATP