A&P Intro to chemistry (1) Flashcards
chemistry is
the science of the structure and interactions of matter
Atoms are
the smallest fundamental unit of life
subatomic particles are protons+ neutrons= electrons-
atoms are and individual unit of an element
h2o two elements, in a glass of water many atoms but still only two elements present
protons and neutrons are found in
the nucleus
electrons found in
shells
valence shell
aka “outermost shell” – this shell contains electrons that contribute to the reactive properties of the atom b/c they are either:
Donated
Received
Shared
the Octet rule
electrons with the atomic number under 20 strive to achieve 8 electrons in the valence shell
an isotope is
a variation of the same element due to a difference in its atomic mass (PROTON numbers are always the SAME, it’s the NEUTRONS that DIFFER.)
E.g. Hydrogen (H) has 1 proton & 1 electron in its most stable form. However if it has 1 neutron, it is now called deuterium, 2 neutrons => tritium. Some isotopes are highly unstable and therefore are prone to decaying which causes radioactivity (these are then called radioactive isotopes)
some substances such as uranium & plutonium are like this, and are often used in making WMD
free radicals are
atoms / molecules with an unpaired electron in its outermost shell.
E.g. Superoxide, hydrogen peroxide. These compounds are highly reactive and unstable and possess the capability to cause cellular damage.
free radicals2
Free radicals “steal” electrons from other cells by a process called “oxidation” thus causing cellular damage (in medical literature, this is termed OXIDATIVE STRESS)
ANTIOXIDANTS, such as vitamin E, carotene, lycopene, etc… help prevent this type of biochemical process.
FYI – many chronic diseases are the direct result or correlated with oxidative stress. E.g. macular degeneration, arthritis, Alzheimers, cancer…..to name a few.
ionic bonds
Ionic bonds- attraction between elements of OPPOSITE CHARGES when elements have lost or gained an electron. These are relatively strong when NOT in solution, but VERY weak when placed in solution.
tends to form between a metal and a non-metal
There are 2 categories of ions:
anion – negative charge (-‘ve) – elements that have gained electron (s)
cation – positive charge (+’ve) .. think cats make you feel positive….. prrrrrrrrrr. – elements that have lost electron (s)
The process of gaining or losing electrons is called ionization (as in ionizing radiation
when IONIC bonds are in water they become
electrolytes
covalent bonds are
when atoms SHARE electrons.
Very strong bonds. Also the most common type of bond that occurs in the body naturally.
Single = 1 pair, double = 2 pairs, triple = 3 pairs.
Covalent bonds have a tendency for POLARITY, (when 1 atom has a stronger attraction for the shared electrons than the other.
most common type of bond in the body
polar covalent bonds
polarity examples: the earth, batteries
when 2 atoms share the electrons un-equally (one atom has a stronger pull on the electrons therefore attracting it more than the other)
this property allows certain atoms greater ELECTRO-NEGATIVITY – the power to attract electrons to itself, more than the other element/atom within the same molecule
having polar bonds allows a molecule to have “POLARITY” (the property of one end being more negatively charged, and the other more positively charged) .. like a battery with opposite ends.
non polar covalent bonds
when 2 atoms share electrons equally (thus the electrons are found exactly in the middle between the 2 atoms)
hydrogen bonds
weakest of 3 bonds – results from the attraction of opposites parts of molecules, NOT from the sharing of electrons.
E.g. H2O (water)
1 Oxygen + 2 Hydrogen; the +ve charge of the H is attracted more to the –ve charge of O.
this type of bonding, although very weak, allows for interaction b/w H & other parts of larger molecules. (ie. proteins & nucleic acids)
Hydrogen bonds occur mostly with Oxygen & Nitrogen
This bonding allows for the formation of surface tension of water, (that’s why very light insects can “walk” on water) as well as contributes to water’s amazing heat capacity property (more on this later)
hydrophilic
POLAR COVALENT BONDS (salt sugar alcohol)
hydrophobic
NON-POLAR COVALENT BONDS (fats oils)
chemical reactions
General Terminology:
Reactions - defined as the formation of new products due to the breakdown or creation of bonds.
Energy – the capacity to do work
1. potential energy – energy stored by matter due to its position 2. kinetic energy – energy associated with motion or movement of matter
Reactants (Starting) Products (End)
*ATP = adenosine triphosphate
This is how energy is measured/quantified in biochemical processes (like using currency to measure economics)
exergonic reaction
more energy released than absorbed = positive release of energy E.g. cellular respiration in the body yields high levels of ATP (energy for living cells). These reactions tend to break larger molecules into smaller ones.
*ATP = adenosine triphosphate
endorgenc reaction
less energy released than absorbed = negative release of energy (or NET loss of energy or energy is converted). In other words, they require energy to start.
Note: All chemical reactions require an initial amount of energy to occur (Activation energy). Coupling of these reactions allow the body to utilize the energy released in the most efficient way possible. Ie. Energy released from 1 reaction is used to fuel another. (Energy is never lost or destroyed but simply converted to another form - law of conservation of energy)
anabolism
aka “synthesis reactions” –
- builds new larger/more complex molecules (think: anabolic steroids)
A + B = AB
- these reactions tend to be ENDERGONIC (requires energy) – there is a negative release of energy
- very important in growth and healing processes. E.g.Muscle growth or DNA formation.
- when we eat, our bodies undergo anabolism, which takes the nutrients from our diet and both processes and packages them into forms to be stored into the cells/tissues, therefore causing us to grow.
catabolism
Decomposition reactions –
- breaks down or destroys larger molecules into smaller molecules.
AB A + B
- these reactions tend to be EXERGONIC. (releases energy) – there is a positive release of energy.
E.g. Breakdown of nutrients for absorption into cells and tissues for immediate body use
exchange reactions
involves the exchange of chemicals & molecules to compensate for changes to physiological state and metabolism. (too acidic, too basic? The body will initiate exchange reactions to create BUFFERS to restore homeostasis)
AB + CD AD + BC
many of body’s natural chemical reactions use this method.
E.g.
HCL + NaHCO3 H2CO3 + NaCl
reversible reactions
AB A + B AB
Ex Glycogen breaks down to glucose + ATP during catabolism (when you’re hungry need energy). But in anabolism (at rest of after eating), glucose is converted to glycogen for energy stores to be used another day. Glycogen, as we’ll learn later is the bodies’ naturally stored form of sugar.
reactions are
defined as the formation of new products due to the breakdown or creation of bonds.
energy is
Energy – (the capacity to do work)
- POTENTIAL energy – energy stored by matter due to its position
- KINETIC energy – energy associated with motion or movement of matter
