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Chp

VIEWS: 23 PAGES: 29

									Chp. 2: “Essential Chemistry for Biology”

Life: Macro to Micro
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Biosphere Ecosystem Community Population Organism Organ system Organ Tissue Cell Molecule Atom

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Matter  Has mass & takes up space  Composed of chemical elements

Some Basic Chemistry

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Living things are made of matter (chemicals) 25 essential for life 4 make up ≈ 96% of human body

Some Basic Chemistry

Humans: What Are We Made Of?

Compounds
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Substance containing 2 or more elements in a fixed ratio Combine elements NaCl H2O

Atoms
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Smallest amount of carbon = 1 atom Structure  Subatomic particles  Proton: in nucleus  Neutron: in nucleus  Electron: orbit nucleus

Structure of Atoms

That Darn Periodic Table
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What do all those numbers mean anyway? Atomic number  Number of what?  Unique to each element Mass number  Sum of what?

I

The Periodic Table!!!

There’s Different Kinds of Carbon?
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Isotopes  When an element can have different numbers of what?  Carbon = very good example

More On Electrons
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Electrons determine how atoms behave Location, location, location Energy shells  First shell can hold up to  Second shell can hold up to  Third shell can hold up to Number of electrons in outer energy shell determines chemical properties Goal: have outer energy shell full

Filling The Energy Shells

(Empty circle = no electron present)

Chemical Bonds
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Ionic bond  Transfer of electrons  NaCl  Ions: electrically charged atoms  Na+1  Cl-1  Attraction between oppositely charged ions

Ionic Bonding

Chemical Bonds
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Covalent bond  Electrons are shared  H2O  Formation of molecules

Covalent Bonding

Representing Molecules

Ionic vs. Covalent

Chemical Reactions

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Must be balanced! Reactants vs. products

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Life began in water 3/4 of Earth is water All living things need water Your cells ≈ 70-95% water

Water & Life

Structure of Water
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Polar  Unequal sharing of electrons  Opposite charges on opposite ends  Appears bent

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Hydrogen bonds  Weak attractions of neighboring water molecules  H of one molecule attracted to O of another molecule

Structure of Water

Water’s Life-Supporting Properties
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Cohesive  Much stronger for water than most other liquids  Trees: transport water  High surface tension

Water’s Life-Supporting Properties
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Moderates temperature  Heats & cools slowly  Earth’s water supply keeps temperatures within limits that support life  Evaporative cooling

Water’s Life-Supporting Properties
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Ice  As water cools, molecules move farther apart  Ice floats  Why is this important?

Water’s Life-Supporting Properties
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Solvent  Water can dissolve many things  The medium for chemical reactions

Acids, Bases & pH
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pH scale  Measurement of H+ ions Acid: pH less than  Greater H+ conc. Neutral: pH of Base: pH greater than  Lower H+ conc.

www.cartoonstock.com

Now, that wasn’t so bad, was it?

iatric DT used through age 6 years. Adult Td for persons 7 years and older. Tdap for persons 10-18 years (Boostrix) or 11-64 years (Adacel)

Tetanus Toxoid

• Formalin-inactivated tetanus toxin • Schedule Three or four doses + booster
Booster every 10 years

• Efficacy Approximately 100% • Duration Approximately 10 years • Should be administered with diphtheria
toxoid as DTaP, DT, Td, or Tdap

Routine DTaP Primary Vaccination Schedule
Dose Age Interval
--4 wks 4 wks 6 mos

Primary 1 2 months Primary 2 4 months Primary 3 6 months Primary 4 15-18 months

Children Who Receive DT

• The number of doses of DT
needed to complete the series depends on the child’s age at the first dose:

–if first dose given at <12 months
of age, 4 doses are recommended –if first dose given at ≥12 months, 3 doses complete the primary series

Routine DTaP Schedule Children <7 years of age
Booster Doses
school

• 4-6 years of age, before entering

• 11-12 years of age if 5 years
since last dose (Tdap)

• Every 10 years thereafter (Td)

Routine Td Schedule Unvaccinated Persons ≥7 Years of Age

Dose* Primary 1 Primary 2 Primary 3

Interval --4 wks 6-12 mos

Booster dose every 10 years
*ACIP recommends that one of these doses (preferably the first) be administered as Tdap

Diphtheria and Tetanus Toxoids Adverse Reactions

• Local reactions (erythema,
induration)

• Exaggerated local reactions
(Arthus-type)

• Fever and systemic symptoms
not common

• Severe systemic reactions rare

Diphtheria and Tetanus Toxoids Contraindications and Precautions

• Severe allergic reaction to
vaccine component or following a prior dose

• Moderate or severe acute illness

National Immunization Program
Contact Information

• Telephone

800.CDC.INFO nipinfo@cdc.gov www.cdc.gov/nip

• Email
• Website


								
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