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Chapter 2 – Martini; Anatomy and Physiology
Chemistry
Elements and atoms
• Element – a substance that has certain chemical properties
• Can’t be easily broken apart
• Carbon, hydrogen, oxygen
• Atoms are the smallest unit of a certain element
• 1 atom of hydrogen
• 1 atom of oxygen
• Water (H2O) 2 atoms of hydrogen + 1 atom of oxygen
Atomic structure – subatomic particles
• Nucleus of atom – protons & neutrons
• Protons
• Weight of 1 AMU
• Positive electrical charge
• Atomic number is number of protons
• An atom of certain type of element always has the same number of protons
• Neutrons
• No charge
• Weight of 1 AMU
• Atomic weight = Protons + neutrons
• Electrons
• No weight
• Negative charge
• Electron cloud or orbits around nucleus
Isotopes
• Different number of neutrons
• Some are radioactive
Ions
• For an atom to be neutral
• The number of protons equals the number of electrons
• Lose or gain electrons = ION
• Positively charged ions – lost electrons
• Na+
• Negatively charged ions – gained electrons
• ClMolecules
• Atoms held together by chemical bonds
• NaCL (salt)
• Ionic bonds (weak)
• Covalent bonds
• H2O and C6H12O6
• Strong bonds
• Hydrogen bonds
• Hold molecules or parts of molecules together (weak)
BIO 1121; Ch 2

Page 1

Types of Chemical Bonds
• Ionic bonds
o Attraction between oppositely charged ions
o NaCl
o Weak bonds, easily dissociate
o NaCl  Na+ and Cl- in water
• Covalent bonds
o Strong bonds – atoms share electrons
 Single bond – share one pair of electrons
 Double bond- share two pairs of electrons
o Nonpolar covalent bonds – electrons are shared equally
o Polar covalent bonds – electrons are shared unequally
 Results in:
 polar molecules such as water
 polar regions of large molecules (proteins)
• Hydrogen bond
o Attraction between polar molecules (water) or polar regions (intramolecular bonds in proteins)
o Weak bond which is easily broken
Inorganic molecules - don’t contain C and H
• Water
• oxygen
• Carbon dioxide
• Acids and bases (inorganic)
Water
• Solubility – solvent
• Solution = solvent + solute
• Reactivity – involved in chemical reactions
• High heat capacity – absorb and retain heat
• Lubrication – serous fluid
Water
• Aqueous solutions
• Water is the solvent in living organisms
• Many substances dissolve easily in water
• Water is a polar molecule
• Dissociates molecules to form electrolytes:
• NaCL  Na+ + Cl• Hydrophilic
• “water loving”
• Mix with water
• Hydrophobic
• “water fearing”
• Don’t mix with water (fats)
Acids and bases
ACIDS
• Molecules can dissociate to form ions
BIO 1121; Ch 2

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If the ion is a H+
Molecule is an acid
Proton donor

• H+ are very reactive
• Break chemical bonds
• Change shapes of complex molecules
• Disrupt cell and tissue functions
BASES
• Bases are proton acceptors
• Removes H+ from solutions
• Many bases release a hydroxide ions
• OH• H+ + OH-  H2O
• Because acids and bases are reactive it is important to manage the concentration is solutions
• Do this with the pH scale
pH scale
• Measures the concentration of H+ and OH• pH of blood ranges from 7
...
45
• Acidosis or alkalosis
0

ACID

7

BASE

14

Organic molecules (compounds)
• Always contain:
• Carbon
• Hydrogen
• Sometimes oxygen
• Often carbon is hooked together in chains or rings
Organic Molecules
• 4 types important to life
• Carbohydrates
• Lipids
• Proteins
• Nucleic acid and energy molecules
Carbohydrates
• C, H and O
• Carbon + water
• H:O = 2:1
• Includes sugars and starches
• Serve mainly as fuel
• Supplying energy to the cells
• Monosaccharides
• One sugar units
BIO 1121; Ch 2

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Includes
• Glucose (blood sugar)
• Fructose (plant sugar)
• Disaccharides
• 2 sugar units hooked together
• Sucrose (table sugar)
• Polysaccharides
• Many sugar units
Monosaccharide
• Glucose
• Cells oxidize to produce energy
• Aerobic cellular respiration
C6H12O6 + 6O2  6CO2 + 6H2O + energy (heat and ATP)
Disaccharide
• Dehydration synthesis (remove water, make a bond)
• Hydrolysis (add water, break a bond)
Polysaccharide –Many sugar units hooked together
• Glycogen
• Stored in liver and muscle
• Other polysaccharides
• Starch
• cellulose
Lipids
• Carbon, hydrogen
• Small amounts of P, N
• C:H = 1:2
• Very little oxygen
• Insoluble in H2O
• Different types in body
• Triglycerides
• Stored energy – adipose tissue
• Phospholipids
• Major component of cell membranes
• Steroids
• Cholesterol – cell membranes
• Hormones
• Triglycerides - subunits
o 1 glycerol molecule
o 3 fatty acids
• Fatty acids
 Chains of carbons and hydrogen
 Acid group at the end
• Saturated Fatty Acids
 Filled with Hs
 No double bonds
BIO 1121; Ch 2

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Unsaturated Fatty Acids
 Some double bonds between Cs
 Don’t hold as many Hs as possible
 Plants
 healthy
Phospholipids
• Cell membranes
• Glycerol
• 2 fatty acids
 Nonpolar
 Hydrophobic
• 1 phosphate group
 Polar
 hydrophilic
Eicosanoids
• modified fatty acids
• Prostagladins
• Direct local cellular activities

Steroids
• 4 hydrocarbon rings
• Cholesterol
• hormones
Proteins
• Most complex molecules in the body
• Building units are amino acids
• Amino acids
• Amino part – contains nitrogen
• Acid part – acts as an acid
• 20 different amino acids
Protein functions
1
...
Movement – contractile proteins
3
...
Buffering – act as acid or base to maintain pH in body
5
...
Coordination and control – hormones
7
...
DNA
• Deoxyribonucleic acid
2

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