Transcript Human Body - Geneva High School

Human Body
Chapter 2
Basic Chemistry
Chemistry in the Human Body
• The food that we eat is composed of
chemicals
• The medicines that we take are composed of
chemicals
• The entire body is composed of chemicals
• Chemical rxns underlie all body processes
Concepts of Matter and Energy
• Matter= the “stuff” of the universe
• Anything that occupies space and has mass
• Matter exists in solid, liquid, and gaseous state
– Ex. Solids= bones and teeth
– Ex. Liquids= blood plasma and interstitial fluid
– Ex. Gases= air that we breathe
Changes in Matter
• Physical Changes- do not alter the basic
nature of a substance.
– Ice melting to become water, cutting food into
smaller pieces
Changes in Matter
• Chemical Changes- do alter the composition
of a substance
– Fermenting grapes to make wine, digestion of
food
Energy
• No mass and does not take up space
• It can only be measured by its effects on
matter
• The ability to do work or to put matter into
motion
Types of Energy
• Kinetic Energy-when energy is actually doing
work
• Potential Energy- inactive or stored energy
• All forms of energy exhibit both kinetic and
potential work capacites.
Forms of Energy
1. Chemical Energy- energy that is stored in the
bonds of chemical substances
**All body activities are “run” by the chemical
energy harvested from the foods we eat.
Forms of Energy
2. Electrical Energy-energy that results from the
movement of charged particles.
-An electrical current is generated when charged
particles (ions) move across cell membranes
Forms of Energy
3. Mechanical Energy- is directly involved in
moving matter.
-As the muscles in your legs shorten, they pull
on your bones, causing your limbs to move.
Forms of Energy
4. Radiant Energy- energy that travels in waves,
energy of the electromagnetic spectrum.
-includes x-rays, ultraviolet waves
-Ultraviolent waves are responsible for the
suntan we get at the beach but also stimulate
our bodies to make vitamin D.
Energy Form Conversions
• Ex. The chemical of foods is trapped in the
bonds of high energy molecules called ATPs.
• ATPs energy can be transformed into the
electrical energy of a nerve impulse or
mechanical energy of shortening muscles.
Energy Form Conversions
• Energy conversions are very inefficient.
• Some initial energy is lost as heat(ex. Light
bulb is losing some energy as heat and not all
of it is used as light energy.
• Humans have a high body temp. that
influences the rxns in the body
Composition of Matter
• All matter is composed of a limited number of
fundamental substances called ELEMENTS.
• Element-a unique substance that cannot be
broken down or decomposed into simpler
substances by ordinary chemical methods.
Composition of Matter
• A complete listing of elements appears in the
Periodic Table.
• The most abundant elements in the Human
Body are listed in Table 2.1.
• The building block of matter=ATOM
• Atoms of each element will differ from those
of all the other atoms.
Composition of Matter
• Atomic Symbol=a one or two letter chemical
shorthand that is used to identify each
element.
– Ex. O=oxygen, Ca=Calcium, Ag=Silver
(sometimes the symbol is taken from the Latin
name of the elements)
Atomic Structure
Subatomic Particles
1) Protons-are found in the nucleus of the atom
and carry a positive charge.
2) Neutrons- are found in the nucleus of the
atom and carry a neutral charge.
3) Electrons- are found in the energy shells
orbiting the nucleus and carry a negative
charge.
Atomic Structure
• Atomic Number= the number of protons
• Atomic Mass Number= the number of the
protons + the number of neutrons
Isotopes
• Almost all elements have at least two or more
structural variations.
• Isotopes have the same number of protons
and electrons but different numbers of
neutrons.
• Isotopes of the same element will have the
same atomic number but different mass
numbers.
Molecules
• A molecule is formed when two or more
atoms are combined chemically.
– Ex. O+O=O2
• When two or more atoms of different
elements join together a Compound is
formed.
– Ex. H+ O= H2O
Chemical Rxns
• Occur whenever atoms combine with or
dissociate from other atoms.
• A chemical bond is not a physical structure but
an energy relationship that involves the
interactions between the electrons of the
reacting elements.
Chemical Bonds
• Ionic Bonds-form when electrons are
completely transferred from one atom to
another.
• Atoms are neutral but when they gain or lose
electrons they become charged.
• Ions=charged particles
Chemical Bonds
• Covalent Bonds- when electrons are shared
between atoms.
**The point of bonds is for atoms to become
stable***
Hydrogen Bonds
• Extremely weak bonds formed when a
Hydrogen atom gives an electron to another
element.
Patterns of Chemical Rxns
• Chemical rxns involve the making or breaking
of bonds between atoms.
Three Types of Rxns
1) Synthesis Rxns
2) Decomposition Rxns
3) Exchange Rxns
Synthesis Rxns
• Occur when two or more atoms or molecules
combine to form a larger, more complex
molecule.
• Always involve bond formation
• Energy absorbing rxns
• Underlie all anabolic activities that occur in body
cells. Really important for growth and repair of
worn out and damaged cells.
Decomposition Rxns.
• Occur when a molecule is broken down into
smaller molecules, atoms, or ions.
• Synthesis rxns in reverse
• As bonds are broken energy is released
• Underlie all catabolic processes that occur in the
body.
Exchange Rxns