ch. 2 chem of life Flashcards
chemical elements
element
simplest form of matter to have unique chemical properties
chemical elements
atomic number
number of protons in its nucleus
chemical elements
periodic table
elements arranged by atomic number
24 elements have biological rule
6 elements=98.5% of body weight (oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus)
chemical elements
minerals
inorganic elements extracted from soil by plants and passed up food chain to humans
Ca, P, Cl, Mg, K, Na, S
about 4% body weight
important for enzymes
electolytes: mineral salts needed for nerve and muscle function
atomic structure
nucleus
center of atom
atomic structure
proton
single + charge
atomic structure
neutron
no charge
atomic structure
atomic mass
equal to total number of protons and neutrons
atomic structure
electron
in concentric clouds surrounding nucleus
single - charge
atomic structure
an atom is electronically neutral as number of electrons equals number of
protons
atomic structure
valence electrons orbit in the
outermost shell and determine chemical bonding properties of an atom
isotopes and radioactivity
isotopes
varities of an element that differ only in the number of neutrons
extra neutrons increase atomic weight
isotopes and radioactivity
istoper of an element are chemically similar because they
have the same number of valence electrons
ions, electrolytes, free radicals
ion
charged particle with UNEQUAL number of protons and electron
ions, electrolytes, free radicals
ionization
transfer of electrons from one atom to another
ions, electrolytes, free radicals
anion
particle that GAINS electron
net negative
ions, electrolytes, free radicals
cation
particle that LOSES electron
net positive charge
ions, electrolytes, free radicals
ions with opposite charges are
attracted to each other
ions, electrolytes, free radicals
electrolytes
substances that ionize in water and form solutions capable of conducting electric current
ions, electrolytes, free radicals
Electrolyte importance
-Chemical reactivity, osmotic effects, electrical excitability
of nerve and muscle
– Electrolyte balance is one of the most important
considerations in patient care (imbalances can lead to
coma or cardiac arrest)
ions, electrolytes, free radicals
Free radicals
- short-lived particles with an unusual
number of electrons
– Produced by normal metabolic reactions, radiation, certain
chemicals
– Trigger reactions that destroy molecules, and can cause
cancer, death of heart tissue, and aging
Ions, Electrolytes, and Free Radicals
Antioxidants
– Chemicals that neutralize free radicals
– Superoxide dismutase (SOD) is an antioxidant enzyme in
the body
– Selenium, vitamin E, vitamin C, and carotenoids are
antioxidants obtained through the diet
Molecules and Chemical Bonds
Molecule
chemical particle composed of two or more atoms
united by a chemical bond
Molecules and Chemical Bonds
Compound
molecule composed of two or more different
elements
Molecules and Chemical Bonds
Molecular formula
identifies constituent elements and how many
atoms of each are present
Molecules and Chemical Bonds
Structural formula
identifies location of each atom
Molecules and Chemical Bonds
Isomers
- molecules with identical molecular formulae but
different arrangement of their atoms
Molecules and Chemical Bonds
molecular weight (MW
of a compound is the
sum of the atomic weights of its atoms
Molecules and Chemical Bonds
Chemical bonds
hold atoms together within a
molecule or attract one molecule to another
Most important types of chemical bonds: ionic
bonds, covalent bonds, hydrogen bonds, van der
Walls forces
Molecules and Chemical Bonds
Ionic bonds
- Attractions between anions and cations (example, NaCl)
- Electrons donated from one atom to another
- Easily broken by water
Molecules and Chemical Bonds
Nonpolar bond
electrons shared equally
(strongest bond
Molecules and Chemical Bonds
Polar bond:
electrons shared unequally (spend
more time near oxygen)
Molecules and Chemical Bonds
Hydrogen bond
a weak attraction between a
slightly positive hydrogen atom in one molecule and
a slightly negative oxygen or nitrogen atom in
another
– Water molecules are attracted to each other by hydrogen
bonds
– Large molecules (DNA and proteins) shaped by hydrogen
bonds within them
– Important to physiology
Molecules and Chemical Bonds
Van der Waals forces
weak, brief attractions
between neutral atoms
– Fluctuation in electron density within an atom creates
polarity for a moment, and attracts adjacent atom for
a very short time
– Only 1% as strong as a covalent bond, but important
in physiology (example, protein folding)
Acids, Bases, and pH
acid
proton donor
releases ions in water
acids bases and pH
base
proton donor
accepts ions
acids bases pH
pH
measure derived from the molarity of
ph 7.0 neutral pH
less than 7 is acidic
more than 7 is basic
acids bases pH
pH is a measurement of molarity on a
logarithmic scale
a change of one number on the pH scale represents a 10-fold change in concentration
ph 4.0 is 10x more acidic than ph 5.0
acids bases pH
buffers
chemical solutions that resist changes in pH
maintaining normal ph of blood is crucial for physiological functions
metabolism oxidation reduction
metabolism
all chemical reactions of the body
metabolism oxidation reduction
catabolism
energy-releasing decomposition reactions
breaks covalent bonds
produces smaller molecules
metabolism oxidation reduction
anabolism
energy-storing synthesis reactions
requires energy input
production of protein or fat
metabolism oxidation reduction
catabolism and anabolism are
inseparably linked
anabolism is driven by energy released by catabolism
metabolism oxidation reduction
Oxidation
– A chemical reaction in which a molecule gives up electrons
and releases energy
– Molecule oxidized in this process
– Electron acceptor molecule is the oxidizing agent
* Oxygen is often involved as the electron acceptor
metabolism oxidation reduction
Reduction
– Any chemical reaction in which a molecule gains electrons
and energy
– Molecule is reduced when it accepts electrons
– Molecule that donates electrons is the reducing agent
Metabolism, Oxidation, and Reduction
Oxidation-reduction (redox) reactions
– Oxidation of one molecule is always accompanied by
reduction of another
– Electrons are often transferred as hydrogen atoms
carbon compunds and functional groups
carbon has 4 valence
electrons
binds with other atoms that can provide it with 4 more electrons to fill its valence shell
carbon compunds and functional groups
carbon atoms bind readily with
each other to form carbon backbones
form long chains branched molecules and rings
form covalent bonds with H, O, N, S
carbon backbones carry a variety of functional groups
carbohydrates
hydrophilic organic molecule
ex sugars and starches
“saccar-“ and “-ose” both meaning sugar and sweet
carbohydrates
3 important monosaccarides
glucose
galactose
fructose
all isomers of each other
produced by digestion of complex carbs
carbohydrates
3 important disaccharides
sucrose-table sugar
lactose-sugar in milk
maltose-grain products
carbohydrates
3 important ex of polysaccharides
glycogen- energy storage in cells of liver, muscle, brain, uterus, vagina
starch- energy storage in plants that are DIGESTABLE
cellulose- energy storage in plants that is important for human dietary fiber (INDIGESTABLE)
Carbs are a quickly mobilized source of energy
All digested carbs converted to glucose
Oxidized to make ATP
Conjugated carb
Covalently bound to lipid or protein
Ex glycolipids
Glycoproteins
Proteoglycans
Glycolipids
External surface of cell membrane
Glycoproteins
External surface of cell membrane
Mucus of respiratory and digestive tracts
Proteoglycans
More carb than protein
Gels that hold cells and tissues together
Gelatinous filler in umbilical cord and eye
Joint lubrication and cartilage texture
Lipids are
Hydrophobic organic molecules with a high ratio of hydrogen to oxygen
Have more calories per gram than carbs
5 primary lipids
Fatty acids
Triglycerides
Phospholipids
Eicosanoids
Steroids
Fatty acids
Chains of 4-24 carbon atoms with carboxyl group on one end and methyl group on the other
–Saturated fatty acids have a lot of hydrogen
–Unsaturated fatty acids contain some double bonds between carbons in chain (potential to add hydrogen)
•Polyunsaturated fatty acids have multiple double bonds between carbons in chain
–Essential fatty acids must be obtained from food
Triglycerides
Three fatty acids linked to glycerol
–Each bond formed by dehydration synthesis
–Broken down by hydrolysis
Triglycerides at room temperature
–When liquid, called oils
•Often polyunsaturated fats from plants
–When solid, called fat
•Saturated fats from animals
Triglycerides primary function
energy storage
–Also help with insulation and shock absorption (adipose tissue)
