Transcript A&P Chapter 2

Chemistry Of the
Human Being
Part 1: Organization of the
Human Body
Types of Chemistry

Inorganic Chemistry: Deals with
substances that aren’t based upon carbon
molecules.
 Also

known as General Chemistry
Organic Chemistry: Deals with
substances produced naturally by plants
and animals and contain carbon.
Organic Molecules
Basis of human structure and function.
 4 Primary Categories:

 Carbohydrates
 Lipids
 Proteins
 Nucleic
Acid
Chemical Elements


Chemical Element: The simplest form of matter
with its own unique chemical properties that
cannot be broken down by ordinary chemical
means.
112 known elements
 92

occurring naturally
Each element is made up of atoms (which are
combinations of protons, neutrons, and
electrons).
Chemical Element Structures

Central Nucleus
 Protons
(+ charge)
 Neutrons (no charge)
 Ps & Ns in equal numbers

Electrons: (- charge)
 Electron
Shells
1st Shell: 2 Electrons
 2nd Shell: 8 Electrons
 3rd Shell & Beyond: 18 Electrons

Periodic Table Information
Atomic Number: The number of protons
(same as neutrons).
 Atomic Mass: The number of protons
plus the number of neutrons in the atom.
 Isotopes: Contain a different number of
neutrons than protons. This doesn’t
change the charge of the atom.

Chemical Elements in the Human
Body

24 elements important for human physiology
6
of these account of 98.5% of the human body’s
total weight.






Oxygen
Carbon
Hydrogen
Nitrogen
Calcium
Phosphorus
Ions




Ion: Charged particle with unequal numbers of
protons and electrons.
Gains or loses electrons & develop an electronic
charge.
Cation: A particle that looses electrons and has
a net positive charge. Ex. Na+ (sodium)
Anion: A particle that gains an electron to
develop a net negative charge. Ex. Cl- (chloride)
Ions in the Human Body

4 Ions essential to human physiology
 Sodium:
Na+
 Chloride: CL
 Potassium: K+
 Calcium: Ca++
Combinations

Molecules: Chemical particles composed of two
or more atoms.
 Atoms
united by covalent bonding (sharing an
electron pair).
 Atoms can be the same (O2) or different (CO2).

Compounds: Composed of atoms of two or
more different elements.
 Examples:
Water (H2O), Sodium Chloride (NaCL)
Free Radicals


Charged groups of atoms with an odd number of
electrons.
Unstable and quick to combine with fats,
proteins and DNA.
 Converts
these into more free radicals which trigger
chain reactions that destroy nearby molecules.

Produced by…
 Some
normal metabolic reactions of the body
 Radiation (including ultraviolet light and x-rays)
 Harmful chemicals (tetrachloride cleaning solvent)
Antioxidants
Antioxidants combat the chemical
damage of free radicals by neutralizing
their chemical reactions.
 Examples:

 Vitamin

E, Selenium, Vitamin C
Free Radicals have been linked to cancer,
diabetes, arthritis, Alzheimer’s, and more.
Bonding

Bonds: How atoms are held together to
form compounds and molecules.
 Chance
of bonding depends on number of
electrons in the valence (outer) shell. Atoms
prefer to have 8 electrons in the valence shell.
 Octet Rule: Atoms that have 8 electrons in
the valence shell are les likely to bond.
3 Basic Types of Bonds


Ionic Bond: Relatively weak attraction between
an Anion and Cation.
Covalent Bond: Much stronger bond consisting
of one or more shared electron pairs.
 Nonpolar
Bond: Shares the electrons equally.
 Polar Bond: Shares the electrons uneqyally.

Hydrogen Bond: A weak attraction between a
hydrogen atom with a partial positive charge and
a neighboring atom with a partial negative
charge. Best example is water.
Inorganic & Organic Compounds

Inorganic Compounds: A compound that
does not contain carbon.
 The
most important compound (essential for
life) is H20!

Organic Compounds: A compound that
contains carbon.
Inorganic Compounds

H20 is an important Inorganic compound
due to it’s…
 Solvency:
The ability to dissolve solutes
(other chemicals).

H20 known as a universal solvent because of its
high number of dissolvable solutes.
 Cohesion:
The tendency of molecules of the
same substance to cling to each other.

This causes the surface film of water known as
surface tension.
Inorganic Compounds

H20 is an important Inorganic compound due to
it’s…
 Chemical
Reactivity: The ability of water to
participate in a wide variety of chemical reactions.


Hydrolysis reactions add water molecules to decompose
compounds.
Dehydration removes water molecules to add small
molecules together.
 Thermal
Stability: Water helps stabilize the internal
temperature of the body.

Water has a high heat capacity so can absorb or release
large amounts of heat without changing its own temperature
a whole lot.
Organic Compounds










Carbohydrates
Monosaccharides
Disaccharides
Polysaccharides
Triglycerides
Fatty Acids
Phospholypids
Eicosanoid
Steroids
Proteins
Carbohydrates
Hydrophilic (water-loving)
 Organic (contain carbon)
 Main source of energy production for
cellular chemical reactions

 ATP
Typically have sacchar root word or ose as
a suffix.
 Composed of 2:1 ratio of hydrogen to
oxygen with carbon added in

Monosaccharides
Simple sugars composed of a single
carbon containing molecule.
 Includes:

 Glucose
(main blood sugar)
 Fructose (fruit)
 Galactose (milk)
Disaccharides
Simple sugars composed of 2
monosaccharide molecules.
 Includes:

 Sucrose
(glucose + fructose; table sugar)
 Lactose (glucose + galactose; milk)
 Maltose (two glucose chains)
Polysaccharides
Complex sugars made of many
monosaccharide molecules.
 Glycogen: Energy-storage polysaccharide
in animals, stored in muscles and liver.

 Produced
by the liver after a meal and when
blood glucose is high.
 Liver breaks it down when blood glucose is
low to maintain homeostasis.
Polysaccharides

Lipids: Organic, hydrophobic (won’t dissolve in
polar solvents like water); composed of carbon,
hydrogen, and oxygen.
 Function
as a source of stored energy & components
of cell structures.
 Much more variable in structure than other
macromolecules.
 Primary function to store energy.
 Provide thermal insulation
 Act as a shock-absorbing cushion for organs
 4 Primary Lipids in humans: Triglycerides,
phospholipids, eicosanoids, & steroids.
Lipids Important to the Human
Body

Triglycerides: Most common lipid in the body &
the diet; stored as adipose tissue.
 Consists
of 3 fatty acids attached to glycerol.
 Fatty Acids:






Saturated: Full of hydrogen with a single bond between
carbon atoms; sold at room temperature.
Unsaturated: Room for hydrogen with double bonds
between carbon atoms; liquid at room temperature
Polyunsaturated: More than one double covalent bond
between carbon atoms.
Monounsaturated: One double bond between atoms.
Nonessential Fatty Acids: Can be synthesized by the
human body
Essential Fatty Acids: Must be obtained from the diet.
Lipids Important to the Human
Body

Phospholipids: Any lipid containing
phosphorus, including those with a backbone
(base) or glycerol or sphingosine.
 The

major lipid in cell membranes.
Eicosanoids: Any physiologically active
substance derived from arachidonic acid.
 Includes
Eprostaglandins.
 Along with prostaglandins, plays an important role in
inflammation, blood clotting, hormone action, labor
contractions, and control of blood pressure.
Lipids Important to the Human
Body

Steroids: Lipids composed of 4 rings of
carbon atoms and include cholesterol.
 Cholesterol
is necessary for human life & is a
building block molecule for all sex hormones,
adrenalin, and is an essential cell membrane
component.
Proteins

Proteins: “Proteios” is Greek for “of first
importance.”
 Most
versatile molecules in the body
 Structural component of cells and tissue
 Are polymers (large molecules) of building blocks
called amino acids joined by peptide bonds.

Composed of carbon, hydrogen, oxygen, nitrogen
 Proteins
have complex coiled and folded structures
critically important to their function. Even slight
changes can destroy or change protein function.
Proteins

4 Basic structural Formations:
 Primary:
Sequence of amino acids in polypeptide
chain (10-2000 amino acids joined together)
 Secondary: Two neighboring polypeptide chains held
together by hydrogen bonds.
 Tertiary: 3-dimensional shape of a polypeptide chain
 Quaternary: Arrangement of 2 or more polypeptide
chains in relation to each other.
Proteins

Proteins have more diverse functions than other
macromolecules, including…
 Structural:
Keratin, elastin, and collagen provide
structural support
 Regulatory: Many hormones and neurotransmitters
regulate important body functions
 Catalysis: Most metabolic pathways of the body are
controlled by enzymes that function as catalysts
 Immunity: I.e., antibodies
 Contractile: Allow muscle to shorten and produce
movement (actin & myosin)
Mixtures

Mixtures: Consists of substances that are
physically blended together but NOT
chemically combined.
 The
chemicals mixed retain their own
chemical properties.

Can be Solutions, Colloids, or
Suspensions
Characteristics of Solutions
Dissolved solutes
 Mixed with an abundant solvent (such as
water)
 Solvent is transparent
 Small particle size
 Solute evenly dispersed within solvent

Characteristics of Colloids
Mixture typically cloudy (opaque)
 Particles less than 100 nm
 Particles suspended but not dissolved

 Particles
typically small enough to remain
permanently mixed with the solvent so they
don’t settle

Most common colloid in the body is protein
 Examples
albumin in blood
 Milk is a colloid due to large proteins
Characteristics of Suspension
Suspended particles larger than 100 nm
 Particle size causes suspension to be
cloudy
 Particles too heavy to remain permanently
suspended (will separate on standing)
 Example: Blood is a suspension of plasma
and blood cells

Acids & Bases: pH

pH scale:
 Ranges
from 0 to 14
 Denotes the level of Hydrogen ions (H+) &
Hydroxide ions (OH-) in a solution.
 An equal number of H+ and OH- particles is a
neutral pH level of “7”.
 Acidic: More H+ than OH- (pH less than 7)
 Alkaline: More OH- than H+ (pH more than 7)
pH in the Human Body
Blood has a normal pH of 7.35 to 7.45
 Acidosis: pH below 7.35
 Alkalosis: pH above 7.45

Work & Energy

Energy & Work are the process of
breaking old bonds (releasing energy) and
forming new bonds (requiring energy).
 All

activities by the body require energy!
Four main types of energy are…
 Potential
energy
 Kinetic Energy
 Chemical Energy
 Activation Energy
Potential Energy

Potential energy: Energy stored by
matter because of its position or internal
state.
 Is
NOT doing work at this point in time.
Kinetic Energy
Kinetic energy: Energy of motion.
 Example: Heat!

 Heat
occurs because of molecular
activity/motion.
 The more activity/motion occurs, the more
heat is generated.
Chemical Energy
Chemical Energy: Potential energy
stored in the chemical bonds of molecules.
 Found in all molecules sharing a bond.

Activation Energy
Activation Energy: The amount of energy
needed to allow an atom or molecule to
collide with another and cause a
disturbance of their valence electrons.
 Is influenced by amount of particles and
the environmental temperature.

 The
more particles & the higher the
temperature, the more likely a collision &
resulting chemical reaction is.
Activation Energy


The amount of particles in the body and the
normal temperature are not high enough to
trigger a life-sustaining rate of chemical
reactions.
Catalysts: Substances that speed up the rate of
chemical reactions in the body by lowering the
amount of activation energy needed to start the
reactions.
 Do
not alter the reactants or the products of the
chemical reaction.

Enzymes used as a catalyst in the human body.
Enzymes

Enzymes: Function as biological catalysts to
permit the biochemical reactions to occur rapidly
at normal temperatures.
 Substrate:
A reactant molecule onto which the
enzyme acts; each enzyme only binds to a specific
substrate.
 Active Site: Part of the enzyme that catalyzes the
reaction,
 Apoenzyme: Protein portion of an enzyme.
 Cofactor: Nonprotein portion of an enzyme.
Metabolism

Metabolism: The sum of all chemical
reactions in the body. Has 2 divisions:
 Anabolism:
Energy requiring reactions where
small molecules are bonded to form larger
ones.

AKA Synthesis or Endergonic Reactions
 Catabolism:
Energy releasing reactions
where large molecules are broken down into
smaller ones.

AKA Decomposition or Exergonic Reactions
Adenosine Triphosphate (ATP)
The body’s most important energy-transfer
molecule!
 Much of the energy used to synthesize
ATP comes from glucose oxidation.
 First stage of glucose oxidation is
glycolysis (meaning “sugar splitting”)

Glycolysis
1.
Glucose split into 2 Pyruvic acid molecules
1.
2.
If oxygen is not available than anaerobic metabolism
takes place (fermentation)
1.
2.
3.
Produces lactic acid (toxic end product responsible for
muscle soreness & converted back to pyruvic acid by the liver)
Enables glycolysis to continue without oxygen
If oxygen is available, than aerobic metabolism takes
place
1.
2.

2 molecules of ATP produced, but most energy retained in the
pyruvic acid
Break pyruvic acid down into Carbon dioxide (CO2) and water
(H2O)
Generates a total of 38 ATP
Glycolysis Anamation
Nucleic Acid

Nucleic Acid: polymers of nucleotides or
chains of repeating monomers
 HUGE
organic molecules containing carbon,
hydrogen, oxygen, nitrogen, and
phosphorous.

Includes…
 Deoxyribonucleic Acid
(DNA)
 Ribonucleic Acid (RNA)
DNA

Largest nucleic acid is Deoxyribonucleic acid
(DNA) that constitutes the human genome
(genes)
 Provides
genetic code (instructions) for the
manufacture of all proteins
 Transfers genetic information from cell to cell when
cell division take place & from generation to
generation in reproduction
 Composed of a double-stranded helix containing 4
nitrogenous bases in set pairs:


Adenine (A) bonds to Guanine (G) in larger double-ring
bases known as purines.
Thymine (T) bonds to Cytosine (C) in smaller single-ring
bases known as pyramidines.
RNA

RNA translates the genetic information
from DNA into specific proteins.
 Single-stranded
molecules