Transcript Chapter 2 Chemical Basis of Life

Human
Anatomy and Physiology I
CHAPTER 2
Chemical Basis of Life
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Chapter 2
Chemical Basis of Life
Why study chemistry in an Anatomy and Physiology class?
- ________________________________________
- cellular functions result from chemical changes
- ______________________________________________
processes, and develop new drugs and methods for
treating diseases
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Structure of Matter
Matter – anything that takes up ___________________;
composed of elements
Elements – composed of chemically identical atoms
• bulk elements – ____________________________
amounts
• ________________ – required by the body in
small amounts
Atoms – ___________________________
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Atomic Structure
Atoms - composed of
_________________
• protons – carry a
_____________
• ________ – carry no
electrical charge
• electrons – carry a
__________ charge
Nucleus
• __________________
• composed of _______ and
_________
• ___________ move around
the nucleus
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Atomic Number and
Atomic Weight
Atomic Number
• number of ________ in the
________ of one atom
• each element has a unique
_______________
• equals the number of
electrons in the atom
Atomic Weight
• the number of ________
plus the number of
__________ in one atom
• __________ do not
contribute to the weight of
the atom
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Isotopes
Isotopes
• atoms with the same _____________ but
with different atomic weights
• atoms with the same number of ________
and __________ but a different number of
neutrons
• oxygen often forms isotopes (O16, O17,
O18)
• unstable isotopes are ____________; they
emit subatomic particles
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Molecules and Compounds
___________ – particle formed when two or more
atoms chemically combine
Compound – particle formed when two or more
___________________ elements chemically combine
Molecular formulas – depict the elements present
and the number of each atom present in the molecule
H2
C6H12O6
H2O
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Electrons
• found in regions of space called ________________ (energy shells)
• each shell can hold a _____________________________
• for atoms with atomic numbers of ________, the following rules apply:
• the first shell can hold up to _________
• the second shell can hold up to __________
• the third shell can hold up to ______________
• lower shells are filled first
• _____________________________________
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Ions
Ion
• an atom that has ______________________(s)
• an electrically charged atom
• _________________________ become stable
Cation
• a ________ charged
ion
• formed when an atom
_______________
Anion
• a ________________ charged ion
• formed when an atom gains an
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electron(s)
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Ionic Bond
Ionic Bond
• an attraction between a ___________________
• formed when electrons are transferred from one atom
to another atom
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Covalent Bond
________________________________
•____________ atoms form ____________
•_________ atoms form ____ bonds
•Nitrogen atoms form three bonds
•______________ form _____ bonds
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H―H
O=O
N≡N
O=C=O
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Structural Formula
Structural formulas ________________________ arranged
in various molecules
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Polar Molecules
Polar Molecule
• molecule with a _____________ end and a slightly positive
end
• results when electrons are ___________ equally in covalent
bonds
• water is an important polar molecule
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Hydrogen Bonds
Hydrogen Bond
• a ________________ between the positive end of one
__________________ and the negative end of another
polar molecule
• formed between _______________
• important for ________ and nucleic acid structure
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Chemical Reactions
Chemical reactions occur when ________________ form
or break among atoms, ions, or molecules
Reactants are _______________________ by the
chemical reaction
Products are _____________ formed at the end of the
chemical reaction
NaCl  Na+ + ClReactant
Products
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Types of Chemical Reactions
Synthesis Reaction – ________________ are formed
A + B  AB
Decomposition Reaction – chemical bonds are __________
AB  A + B
Exchange Reaction – chemical bonds are _________ and ______
AB + CD  AD + CB
Reversible Reaction – the products can __________ to
the reactants
A + B n AB
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Acids, Bases, and Salts
Electrolytes – substances that release __________
NaCl  Na+ + Cl-
Acids – __________ that release hydrogen ions in water
HCl  H+ + Cl-
Bases – substances that ____________ that can combine
with ________________
NaOH  Na+ + OH-
Salts – ____________ formed by the reaction between an
_____________
HCl + NaOH
 H2O + NaCl
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Acid and Base Concentrations
_________ - indicates the
concentration of hydrogen ions in
solution
Neutral – ____; indicates
equal concentrations of H+
and OH-
Acidic – pH less than 7;
_________________
concentration of ___
Basic or alkaline – pH
______________;
indicates a greater concentration
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of ___
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Organic Versus Inorganic
Organic molecules
• contain __________
• usually larger than __________ molecules
• dissolve in ______ and ____________
• ____________, proteins, lipids, and nucleic acids
Inorganic molecules
• generally __________________
• usually _________ than organic molecules
• usually ______________ or react with water
to release ions
• water, _______, ___________, and inorganic
salts
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Inorganic Substances
Water
• most abundant compound in living material
• _____________ of the weight of an adult human
• major component of all body fluids
• ___________________________________
• important role in transporting chemicals in the body
• can absorb and transport heat
Oxygen (O2)
• used by _____________ to release energy from nutrients
• necessary for survival
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Inorganic Substances
Carbon dioxide (CO2)
• __________________ released during metabolic reactions
• must be removed from the body
Inorganic salts
• ___________________
• sources of necessary ions (___, ___, ___, Ca2+, etc.)
• play important roles in _________________
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Organic Substances
Carbohydrates
• provide _______________ to cells
• supply materials to build cell structures
• water-soluble
• contain ____________
• ratio of H to O close to 2:1 (C6H12O6)
• __________________ – glucose, fructose
• disaccharides – _______, _______
• ________________ – glycogen, cellulose
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Organic Substances
Carbohydrates
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Organic Substances
Lipids
• soluble in organic solvents
• fats (_______________)
• used primarily for ______
• contain C, H, and O but less O than carbohydrates (C57H110O6)
• building blocks are __________ and __________ per molecule
• saturated and unsaturated
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Organic Substances
Lipids
• phospholipids
• building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per
molecule
• ___________________________
• ______________________________
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Organic Substances
Lipids
• steroids
• connected _______________
• component of _________________
• used to ___________________
• cholesterol
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Organic Substances
Proteins
• structural material
• ________________
• ___________
• ___________
• __________
• ___________
• building blocks are __________
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• amino acids held
together with
_________ bonds
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Organic Substances
Proteins
Four Levels of Structure
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Organic Substances
Nucleic Acids
• constitute genes
• play role in _________________
• building blocks are _____________
• DNA (deoxyribonucleic acid) – double polynucleotide
• RNA (ribonucleic acid)chapt2student
– single polynucleotide
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Organic Substances
Nucleic Acids
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Clinical Applications
Radioactive Isotopes Reveal Physiology
• injected into the body
• different types taken up by different organs
• can be detected in the body using a scintillation
counter
• can be used to destroy specific tissues
• commonly used
• _______-131 for thyroid function
• thallium-201 for heart function
• gallium-67 and cobalt-60 for cancer
• others used to assess kidney functions, measure hormone
levels and bone density changes
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