BIO 141 - CLASS - CHPT 2: CHEMISTRY COMES ALIVE

Foods contain chemical energy

Electrical energy is the energy used by nerve cells to transmit messages in the body

Potential Energy (PE) is available when we are still.
Kinetic Energy (KE) when we are exercising

the "stuff" of the universe

anything that has mass and takes up space

matter exists in solid, liquid and gaseous states.
Solid - like bones and teeth, have definite shape and volume.
Liquids - blood plasma have a definite volume
Gases - have neither a definite shape or volume. (air we breathe)

Kinetic Energy (KE) - Energy in action

Potential Energy (PE) - stored energy

Chemical Energy
Electrical Energy
Mechanical Energy
Radiant Energy

Form of Energy

pertain to the way atoms interact with one another (bonding behavior)

Form of Energy

movement of charged particles

Form of Energy

Energy directly involved in moving matter. When you ride a bike, your legs provide the mechanical energy that moves the pedals

Form of Energy

Energy that travel in waves
(visible light, infrared waves, radio waves, ultraviolet waves and x-rays)

more or less identical building blocks for each element

unique substances that cannot be broken down into simpler substances by ordinary chemical methods

one or two letter chemical shorthand for each element

1. nucleus
a. protons
b. neutrons
2. electrons

Atomic Structure

have no charge (neutral) and a mass of one atomic mass unit (amu/atomic mass unit)

Atomic Structure

(p+) positive electrical charge and a mass of 1 amu

Atomic Structure

(n0) neutral charge and a mass of 1 amu

neutrons and protons have the same mass

Atomic Structure

negative chage and 1/2000 the mass of a proton (0 amu)

electrons are found orbing the nucleus

Carbon and Oxygen help to make up the bulk of living matter

82 protons in its nucleus and 82 electrons in its orbitals

Atomic mass indicates the sum of the protons and nuetrons in a given atom's nucleus. Atomic weight indicates the average mass of all the isotopes of a given element

A molecule is 2 or more atoms held together by chemical bonds

a compound is formed when two or more different kinds of atoms chemically bond together, as in NaCl. Oxygen gas is 2 oxygen atoms bonded together

Blood is a misture b/c its components are not changed by their combination and they can be separated by physical means

equal to the number of protons

equal to the mass of the protons and neutrons

number of protons + number of neutrons

atoms with same number of protons but different number of neutrons

average of the mass number of all isotopes

(decimal in box, round off to nears whole #)

atoms that under spontaneous decay called radioactivity/nucleus is unstable

(half-life) time required for half of a given amount of the isotope to decay (lose radiation)

range = fractions of a second to billions of years of half-life
element X - half-life = 50 years

0 yrs 100g --> 50yrs 50g --> 50yrs 25g --> etc.

alpha particles
beta particles
gamma rays

Type of Radioactive emissions

emitted by the nucleus of large radioactive atoms (ex: uranium)

least dangerous

Type of Radioactive emissions

released by radioisotopes

Type of Radioactive emissions

very high energy electromagnetic waves, comparable to x-rays

most dangerous

When you use radioactive, they are called tracers.
weakly radioactive isotopes with short half-lives used to check the structural and function state of an organ.

Can be incorporated into specific compounds normally found within the body

Molecule - two or more attoms held together by chemical bonds (H2O, NaCl, O2)

Compounds - Two or more different kinds of atoms chemically bonded together (H2O, NaCl, C6H12O6)

*All compounds are molecules but not all molecules are compounds

2 or more components physically intermixed/mingled (not chemically bonded)
3 basic types:
solutions
colloids
suspensions

Basic Type of Mixture

Solutions - homogeneous mixtures of components that may be gases, liquids or solids

3 types of solutions:
Solvent
Solute
Expressing the concentration of solutions

Basic type of Solutions

substances present in greatest amount. Substance DOING the dissolving (water)

Basic type of Solutions

Substance(s) present in smaller amount
Substance BEING dissolved

Type of mixture

(emulsions) heterogeneous mixtures. Whose solutes do not settle out

All liquids inside a cell is a colloid

Type of mixture

heterogeneous mixtures with visible solutes that tend to settle out
Ex: Blood

no chemical bonding occurs between the components of a mixture. The properties of atoms and molecules are not changed when they become part of a mixture

1. Electron Shells
2. Energy Levels
3. Filling of electron shells
a. valence
b. rule of eight
4. chemically inert elements
5. chemically active elements

Role of electrons in chemical bonding
terms used interchangeably

Electrons forming the electron cloud around the nucleus of an atom occupy regions of space

each electron shell represents a different energy level because this prompts you to think of electrons as particles with a certain amount of PE

Role of electrons in chemical bonding

Each electron shell can hold a specific number of electrons.
Shell 1 - the shell immediately surrounding the nucleus, accomodates only 2 electrons.
Shell 2 - Holds maximum of 8 electrons
Shell 3 - holds maximum of 18 electrons

Role of electrons in chemical bonding (Filling of electron shell)

outermost energy level containing chemically active electrons

Role of electrons in chemical bonding (Filling of electron shell)

except for the first shell which is full with 2 electrons, atoms interact in a manner to have 8 electrons in their valence shell

Role of electrons in chemical bonding

When the outermost energy level of an atom is filled to capacity or contains 8 electrons, the atom is stable. Such atoms are chemically inert, unreactive.
Helium (He)
Neon (Ne)

1. Ionic Bonds
a. Ions
b. Anions
c. Cations
2. Covalent Bonds
a. Sharing of electrons
b. Multiple covalent bonds
c. Nonpolar covalent bonds
Polar covalent molecules
3. Hydrogen bonds
a. surface tension
b. intramolecular bonds

Types of chemical bonds

chemical bond between atoms formed by the transfer of one or more electrons form one atom to the other

Types of chemical bonds - Ionic bond

charged atoms resulting from the gain or loss of electons

Types of chemical bonds - Ionic bond

gained one or more electrons

Types of chemical bonds - Ionic bond

lost one or more electron
(think of the "t" in "cation" as a + sign)

Table salt, sodium chloride (NaCl)

Types of chemical bonds

Formed by sharing of 2 or more electrons

Types of chemical bonds - covalent bonds

Produces Molecules.
The shared electron pair orbits around the molecule as a whole, satisfying the stability needs of each atom.

Types of chemical bonds - covanet bond

When 2 atoms share one pair of electrons, a single covalent bond is formed
Double - atoms share 2 electrons
Triple - atoms share 3 electrons

Types of chemical bonds - covanet bond

electrons shared equally between atoms

Types of chemical bonds - covanet bond


unequal sharing of electrons
Electronegativity - (gain electrons) atoms with 6 or 7 valence shell electrons

Types of chemical bonds

Too weak to bind atoms together. Common in dipole, such as water

a. surface tension
b. intramolecular bonds

Types of chemical bonds - hydrogen bond

Surface tension - responsible for surface tension in water

intramolecular bonds - important between molecules

reactive elements do not have their outermost energy level fully occupied by 8 electrons.

Hydrogren only needs 2 to be stable

Chemical Reactions

1. Reactants - The number and kinds of reacting substances
2. Products - chemical compsition of the product and in balanced equations, the relative proportion of each reactant and product.
3. Molecular Formula - indicates the number of atoms in a molecule of a substances

Chemical Reactions

Write chemical reactions in symbolic form.
Ex: indicate the joining of 2 hydrogen atoms to form hydrogen gas a H + H --> H2 (hydrogen gas)
H + H (reactant)
H2 (product)

adenosine triphosphate

adenosine diphosphate

1. Synthesis (Combination) Reaction - Always involves bond formation A + B --> AB
2. Decomposition Reaction - molecules are broken down into smaller molecules AB --> A + B
3. Exchange (Displacement) Reaction - bonds are both made and broken AB + C --> AC + B
4. Oxidation Reduction Reaction - Reactants losing electrons are electron donors and are oxidized. Reactants taking up electrons are electron acceptors and become reduced

Patterns of Chemical Reactions

endergonic reactions - products of energy absorbing, reactions whose products contain more PE than did its reactants.
Exergonic reactions - reactions that release energy

Patterns of Chemical Reactions

All chemical reactions are theoretically reversible
A + B --> AB
AB --> A + B

if neither a forward nor reverse reaction is dominant

1. Temperature - Chemical reactions proceed quicker at higher temps.
2. Particle Size - The smaller the particle, the faster the chemical reaction
3. Concentration - higher reacting particle
4. catalysts - Increase the rate of a reaction without being chemically changed

1. Water
2. salts
3. acids and bases

Inorganic Compound

Most important in living material. Makes up 60-80% of the volume of most living cells.
High Heat Capacity
2. High heat of vaporization (sweat)
3. Poloarity/Solvent Properties - important consequences, electrolytes, hydrophobic molecules
4. Reactivity - water is an important reactant in chemical reactions (digestion)
5. Cushioning - forming a resistent cushion around certain body organs

Inorganic Compound

Ionic compound (all ions are electrolytes). The most plentiful salts are the calcium phosphates that make bones and teeth hard

Inorganic Compound

Electrolytes. They ionize and dissociate in water and can conduct an electrical current.
1. Acid - when acides dissovr in water, they release hydrogen ions (protons) and anions
2. Base - take up hydrogen ions in detectable amounts
3. pH: acid-base concentration - The more hydrogen ions in a solution, the more acidic the solution is.
4. Neutralization - when acids and bases mix - they react with each other to form water and salt
5. Buffers - homeostatis of acid-base balance is carefully regulated by the kidneys and lungs

relative concentration of hydrogen ions in various body fluids is measured in concentration units

group of molecules that includes surgars and starches, represent 1-2% of cell mass.

Contain carbon, hydrogen and oxygen and generally the hydrogen and oxygen atom occur in the same 2:1 ratio as in water

1. Monosaccharides
2. Disaccharide
3. Plysaccharides

Type of carbohydrate

"one sugar" or "simple sugars" - monomers or building blocks.
Single-chain or single-ring structures containing from 3 to 7 ccarbon atoms

Type of carbohydrate

"Two sugars" or "double sugar" - is formed when 2 monosaccharides are joined by deydration synthesis.
Disaccharide are too large to pass through cell membranes, so they must be digested to their simple sugar units to be absorbed from the digestive tract into the blood

Type of carbohydrate

"Many sugars" are polymers of simple sugars linked together by dehydration synthesis. Storage products. Lack the sweetness of the simple and double sugars

storage carbohydrates of animal tissues, is stored primarily in skeletal muscle and liver cells

major functions in the body is to provide a ready, easily used source of cellular fuel, only small amounts of carbohydrates are used for structural purposes. Others are attached to external surfaces of cells where they act as "road signs" to guide cellular interactions

Insoluble in water but dissolve readily in other lipids and in organic solvents (alcohol)

Like carbohydrates, lipids contain carbon, hydrogen and oxygen. Phosphorus is found in some of the complex lipids.

Neutral Fats
Phospholipids
Steroids

Types of lipids

Fats when solid
Oil when liquid

composed of 2 types of building blocks: fatty acids and glycerol, in a 3:1 ratio of fatty acids to glycerol. Fatty acids are linear chains of carbon and hydrogen atoms with an organic acid ground at one end.

Found mainly beneath the skin, insulating the deep body tissue from heat loss

Types of lipids

modified triglycerides. Diglycerides with a phosphorus-containing group & 2, fatty acid chains.
Chief material for building cellular membranes

Types of lipids

Flat molecules made of four interlocking hydrocarbon rings.
Like triglycerides, steroids are fat soluble and contain little oxygen.
Single most important molecule in our steroid chemistry is cholesterol

Carbohydrates
Lipids
Proteins

Organic Compound

composed 10-30% of cell mass and is the basic structure material of the body.

Not all proteins are construction materials. Many play roles in cell function.
Contains carbon, oxygen, hydrogen and nitrogen and many contain sulfur and phosphorus as well

Type of protein

Peptide bonds - arrangement of linked atoms

Primary Level
Secondary Level
Tertiary Level
Quaternary level

Structural levels of proteins

Linear sequence of amino acids, composed of polypeptide chain. Resembles a strand of amino acid "beads", is the backbone of the protein molecule

Structural levels of proteins

Proteins twist or bend upon themselves to form a complex structure.
Alpha -helix resembles a slinky toy or the coils of the telephone cord.

Beta -pleated - do not coil, but are linked side by side to form ribbonlike structures

Structural levels of proteins

Achieved when alpha -helix or beta -pleasted regions of the polypeptide chain fold upon one another to form a compact ball-like molecule

Structural levels of proteins

When 2 or more polypeptide chains aggregate in a regular manner to form a complex protein

Fibrous - (structural proteins) extended and strandlike. Insoluble in water - qualities for providing mechanical support and strength to the body tissue

Globular - (Functional proteins) compact, spherical proteins. Water soluble, chemically active molecules and they play crucial roles in all biological processes (immunities, growth and development)

Fibrous proteins are stable, globular is not.
Hydrogen bonds begin to break when the pH drops or the temperature rises above normal levels, causing proteins to unfold and lose their shape call denatured.
Disruption is reversible

Enzymes are globular proteins that act as biological catalysts.
Can be thought of as a chemical traffic cops that keep our metabolic pathways flowing.
Enzymes incrase the speed of chemical reactions to occur between molecules

Enzymes and Enzyme activity

depending on the enzyme, the cofactor may be an ion of a metal element such as copper or iron or an organic molecule needed to assist the reaction in some way

Enzymes and Enzyme activity

every chemical reaction requires that a certain amount of energy be absorbed to prime the reaction. Its the amount of energy needed to break bonds of the reactants so they can rearrange themselves and become the product

CHON

Carbon (C)
Hydrogren (H)
Oxygen (O)
Nitrogen (N)

- Lesser elements make up 3.9% of the body and include:
Calcium (Ca)
Phosphorus (P)
Potassium (K)
Sulfer (S)
Sodium (Na)
Chlorine (Cl)
Magnesium (Mg)
Iodine (I)
Iron (Fe)

Energy levels, surround the nucleus of an atom

-Bonds are formed using the electrons in the outermost energy level

- Valnce shell - outermost energy level containing chemically active electrons

Octet rule - 8 electrons in outter layer to make it stable. They all want 8