Anatomy and Physiology
Chapter #2
2.1 Introduction
 Chemistry is the branch of science
that considers the composition of
matter and how this composition
changes.
 Chemistry is essential for
understanding anatomy and
physiology because body structures
and functions result from chemical
changes within cells.
2.2 Structure of Matter
 Matter is anything that has mass
(weight) and takes up space. Matter
is found in various forms, gases,
liquids, and solids
 Elements make up all matter.
 Elements are composed of tiny
particles called atoms.
 The smallest complete units of
elements are atoms.
Atomic Structure
 Nucleus is the central portion of the
atom which contains neutrons
(neutral) and protons (positive).
 Electrons, which are extremely small,
found outside the nucleus in energy
shells or levels or rings have a
negative charge.
 What are the components of an atom
that determine its electrical charge?
 Protons and electrons
Drawing atoms
 Atomic number is the number of
protons in an element.
 The number of protons in the nucleus
of an atom equal the number of
electrons in its shells.
 Energy levels or shells:
1. 1st shell can hold a max of 2
electrons
2. 2nd – 6th shells can hold a max of 8
electrons
Drawing atoms continued…
 Atomic weight is the number of
protons plus neutrons.
 SO…. Atomic weight – atomic number
= the number of neutrons.
 Draw Lithium?
 The defining characteristic of stable
elements is the maximum number of
electrons in its outer shell. Noble
gases.
 Unstable elements achieve stable
structures by gaining, losing, or
sharing electrons in their energy
levels or shells.
Bond Types 3 Main Types
1) Ionic bond between a metal and
nonmetal they transfer electrons
forming ions.
 Ion atoms that gain or lose electrons () become electrically charged.
2) Covalent bond between two nonmetals
they share electrons.
 When atoms combine with other
atoms, they can share an electron with
another atom, lose an electron or gain
an electron.
3. Hydrogen Bonds
Molecules and Compounds
 A molecule is formed when two or more
atoms combine.
 If atoms of different elements combine, the
resulting structure can also be called a
compound. Examples: Baking soda, sugar
 Molecular formula represents the numbers
and types of atoms in a molecule.
Examples… H2O & C6H12O6
 Structural formulas show what molecules
look like.
You do Not need
in your notes
Structural Formation
Chemical Reactions 4 Types
1) Synthesis when two or more atoms
or reactants bond to form a new,
more complex structure. Synthesis
requires energy and is important to
the growth of body parts.
2) Decomposition the opposite of
synthesis
3) Single Replacement
4) Double Replacement
 Catalysts affect the speed of a
reaction but is not consumed by the
reaction.
 Electrolytes contains electrically
charged particles (ions), it will
conduct an electric current. When
electrically charged ions disassociate
in water, the solution will conduct
electricity. Example: Salt water
Acids and Bases
 pH scale ranges from 0 to 14. It
indicates how acidic something is.
 Acids have pH less than 7
 Neutral pH equal to 7
 Bases have pH greater than 7
2.3 Chemical Constituents of
Cells
 2 types of chemicals
1. Organic must contain carbon and
hydrogen but may contain other
elements as well. (C6H12O6) Living
things or once living things.
2. Inorganic all the other compounds
(H20) do NOT contain C.
Inorganic Compounds
1.
2.
3.
4.
Water
Oxygen
Carbon Dioxide
Salts
Water
 In the human body, water plays an
important role in dissolving solid
substances, moving chemicals around the
body, and absorbing and moving heat
 Is the most abundant compound in cells
and is a solvent in which chemical reactions
occur.
 Transports chemicals and heat.
Oxygen
 Releases energy from glucose and
other nutrients.
 This energy drives metabolism.
Carbon Dioxide
 Is an inorganic substances that is a
metabolic waste product, exhaled
from the lungs.
Salts
 Provide a variety of ions that
metabolic processes require.
Organic Compounds
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic acids
Carbohydrates
Supply most of the energy needed by cells
Composed of what 3 elements? C,H,O
Monosaccharides (simple sugars)
Disaccharides are two sugars joined
together
3) Polysaccharides, such as starch, are built
of many sugars.
 Humans synthesize the complex
carbohydrate called glycogen.


1)
2)
Lipids
Lipids made of C,H,O but in different amounts
 Lipids include fats (most common),
steroids, and phospholipids.
 A fat that has all of its carbon atoms joined
by single carbon to carbon bonds is said to
be saturated. (solid at room temp, bad for
you)
 Unsaturated fats (liquid at room temp,
good for you, double bonds)
 Cholesterol, estrogens, and testosterone
are all steroids.
 A phospholipid typically has two fatty acid
chains and a phosphate group.
Proteins
 Proteins have a great variety of functions in the
body---as structural materials, as energy
sources, as certain hormones, as receptors on
cell membranes, as antibodies, and as enzymes
to catalyze metabolic reactions.
 Proteins contain what 4 elements? C,H,O,N
Sometimes S
 Building blocks of proteins are the amino acids
(20)
 Proteins have complex shapes held together by
hydrogen bonds. (their many shapes changes
their functions)
 Protein shapes, which determine how proteins
function, can be altered by pH, temperature,
radiation, or chemicals. H bonds break this is
called denatured.
You do NOT need in
your notes
Amino Acids
1. Alanine
2. Glutamic acid
3. Leucine
4. Serine
5. Arginine
6. Glutamine
7. Lysine
8. Threonine
9. Asparagine
10.Glycine
11.Methionine
12. Tryptophan
13. Aspartic acid
14. Histidine
15. Phenylalanine
16. Tyrosine
17. Cysteine
18. Isoleucine
19. Proline
20. Valine
(NOTE: the 8 essential amino
acids are in red. These
cannot be synthesized by
the human body and must
be obtained from food.
Arginine and histidine are
essential only for
children.)
Nucleic Acids
 Nucleic acids form genes and take
part in protein synthesis.
 They contain the elements C,H,O,N,P
 The building blocks are called
nucleotides.
 Nucleic acids are of two major types:
DNA (with deoxyribose) and RNA
(with ribose).
DNA & RNA
Deoxyribonucleic acid: DNA
(deoxyribonucleic acid) stores the
molecular code in genes.
 How many strands does it have? 2
 Deoxy means without Oxygen
Ribonucleic acid: RNA (ribonucleic acid)
functions in protein synthesis.
 How many strands does it have? 1
Clinical Connection
 Prion protein can assume up to 12 different
shapes before prion was discovered it was
believed protein shape was always 3-D
 Some prions are infectious “mad cow disease”
 Some prions are not infectious “Alzheimer
disease” which cause gummy plaques in the
brain and disrupt functioning.
 Some forms of Alzheimer disease may be
caused by protein misfolding
Work cited
 Chemistry Image.
www.aperfectworld.org/healthcare_medicine.ht
ml
 DNA image.
www.pbs.org/wgbh/nova/origins/knoll.html
 Structural formula image.
 www.chemistry.mtu.edu/pages/courses/course
s/ch4412