A & P Exam 1: Chemical Foundations for Cells (set 2)

Radiant Energy

(electromagnetic radiation) energy that travels in waves & vary in length called the electromagnetic spectrum. Include visible light (sight), X- rays, infared waves, radio waves & ultra-violet waves (causes sunburn & allows our body to make Vit D)

high heat of vaporization

(it takes a lot of energy to evaporate a molecule of water or to change phase; leaving the remaining water cooler, or your body cooler when sweat evaporates)

high specific heat

(it takes a lot of energy to raise the temperature of water) As water absorbs heat energy, some of the energy is used to break H bonds, leaving less energy left over to inc the motion of water mol which would increase the water's temperature. Important as it lessens the impact of environmental temp changes. The amount of energy needed to raise 1 gram of water 1°C = 586 calorie Water can absorb or radiate large amounts of heat w/o changing its own temperature (cools and heats up slowly)

high heat of fusion

(much energy is removed from water as it forms ice, thus heating up surroundings)

Radioactive isotopes

(radioisotopes) are unstable a & undergo nuclei decay...which may have deleterious effects or they can be used to help mankind. They can produce tissue damage or cause certain types of cancer

Some radioisotopes can be used as tracers to follow the movement of certain substance through the body:

- A PET scan uses radioactive glucose to detect cancerous tumors - Thallium 201 monitors blood through the heart during a stress test - Iodine 131 is used to detect cancer of the thyroid gland & to asses its size & activity & may also be used to destroy part of an overactive thyroid gland - Cesium-137 is used to treat advance cervical cancer while - Iridium-192 is used to treat prostrate cancer.

Electron Configuration

--Electrons are arranged around the nucleus in electron shells (distances from the nucleus) that correspond to different energy levels --1, 2, 3, 4, 5, etc (primary quantum number) --BUTREMEMBER: #ofe=#ofp

Kinds of Chemical Bonds

1. Covalent Bond 2. Ionic Bond 3. Hydrogen Bond 4. Van der Waals Forces

Writing formulas

1. Letter is called the symbol; it represents one atom of that element 2. First letter must be capitalized 3. If second letter, it must be lower case (not smaller) 4. # in front of symbol is called the coefficient and represents un-joined repeating numbers of that atom (4H) 5. # behind the symbol is called the subscript and represents repeating number of atoms that are joined by chemical bonds (CH4)

Types of Mixtures

1. Solution - solvent dissolves another substance called the solute. Solutions usually have more solvent than solute. Solutes remain evenly dispersed among the solvent molecules & because solute particles are very small, they give a clear and transparent color. Solutes that are charged or contain polar covalent bonds are hydrophilic, dissolving easily in water whereas molecules containing mainly nonpolar covalent bonds are hydrophobic and not very soluble in water. 2. Colloid - Size of particles are larger which scatter light making them translucent or opaque. Particles do not settle out (ex. Milk) 3. Suspension - Particles size is very large and will eventually settle out forming a precipitate (ex. Blood)

Types of Chemical Reactions

1. Synthesis Reactions...Anabolism • These reactions will combine molecules to form new & larger molecules; the new molecule will have more bonds and therefore more stored energy or potential energy. •A+B >>AB 2. Decomposition Reactions...Catabolism • Reactions that break up large molecules into smaller atoms, ion, molecules that have fewer bonds and therefore less energy. • AB >> A + B 3. Exchange Reactions • Reactions consisting of both synthesis reactions and decomposition reactions • AB + CD>> AD + BC 4. Reversible Reactions • Reactions in which the product can revert to the original reactants • AB >>><<<A + B

unique properties of water

1. high specific heat (# of H bonds) 2. high latent heat: common forms of latent heat (energies) encountered are latent heat of fusion (melting or freezing) & latent heat of vaporization (boiling or condensing). These names describe the direction of energy flow when changing from one phase to the next: from solid to liquid to gas. The large value of the energy of condensation of water vapor is the reason that steam is a far more effective heating medium than boiling water, making it more hazardous . 3. high surface tension (many H bonds exert a great deal of strength giving water unusual properties)

Atoms & molecules are in continuous motion

A collision can disrupt the movement of valence electrons causing an existing chemical bond to break or a new one to form. The collision energy needed to break the chemical bonds or the reactants is called the activation energy of the reaction. Both concentration of particles & temperature influence chance that collisions will occur; a catalyst can speed up chemical reactions by lowering amt. of energy needed, like enzymes

Salt

A compound that dissociates in water into cations and anions that are not H+ or OH- NaCl >> Na+ + Cl-

Base

A substance that disassociates into one or more positive ions (cations) and one or more negatively charged hydroxide ions (OH-) NaOH >> Na+ + OH- A base can also be defined as a Proton (H+) acceptor, removing H+ from a solution

Acid

A substance that dissociates into one or more hydrogen ions (H+) and one or more negative ions (anions). HCl>>H+ +Cl- An acid can also be defined as a Proton (H+) donor.

inhalation

A thin film of watery fluid coats the air sacs of the lungs. So, each inhalation must have enough force to overcome the opposing effect of surface tension as the air sacs stretch and enlarge when inhaling.

Review Acids and Bases- pH

Acids release protons (hydrogens) in water • Hydrogen ions: H+ • Cause low pH # = Sour taste Bases combine with H+ ions • Usually hydroxide ions OH- • Opposite of acids • Cause high pH # = Bitter taste

Transition Elements, Lanthanides, and Actinides

All metals. Many of them have varying valences because they can trade around electrons from the outer shell to the inner d or f subshells that are not filled. For this reason they sometimes appear to violate the electron addition scheme.

Electrolytes

Aqueous solutions of soluble inorganic molecules containing cations (+) and anions (-); charged particles will conduct an electrical current = electrolytes Changes in the concentrations of electrolytes in body fluids will disturb almost every vital function, which may cause death if not balanced

Atomic Structure

Atom = basic unit of matter Bohr Mode nucleus = protons + neutrons electron clouds = (shells, orbits, rings) electrons

Atomic mass vs atomic #

Atomic number = # p + Atomicmass = #p+ & #n # p+ = # e -Atoms are neutral Atomic mass is relative to the mass of a hydrogen atom as seen in periodic table Expressed as daltons or amu

Valence #

Atoms are most stable when the arrangement of e- fill the orbits Electrons of an atom fill the shells in a specific order; when shells are not filled, it causes the atom to be highly reactive interacting with other atoms so as to gain or lose enough e- to achieve a completed outer shell creating a bond Valence # = of e- atoms must gain or lose; it will equal # of bonds created

Isotopes

Atoms with the same atomic number (protons) but differing in number of neutrons are called isotopes; ie Variations in # of neutrons yields different isotopes; Multiple isotopes of all elements exist in nature, including some that are unstable; the more neutrons, the greater the instability.

EX of Buffer

Blood is buffered with bicarbonate ion (HCO3-) CO2 + H2O H2CO3 HCO3- + H+ • CO2 adds protons to blood..... inc acidity • Bicarbonate ion compensates

Types of Bonds

Bond = when e- exchange transferring e- = ionic bond sharing e- = covalent bond; shared electrons can be shared equally, resulting electrically balanced product sometimes e- are shared unevenly = polar covalent (water) non polar covalent: shared equally (hydrocarbon chains)

Buffers

Buffers control acid/base balance; They help to maintain pH by accepting or releasing protons H+ EX: The bicarbonate ion is also a very an important buffering system in body Buffers = accept or donate protons & minimize changes in pH natural buffers = proteins, carbohydrates, phosphates

Chemical Reactions = Metabolism

Chemical reactions occur when new bonds form or old bonds break between atoms...it requires energy. Chemical reactions are the foundation of all life processes. •Starting substances are know as reactants. •Ending substances are known as products. •The arrow indicates the direction in which the reaction proceeds. •The number of atoms of each element is the same before & after the reaction. •Because the atoms are rearranged , what you start with is not what you end up with (law of conservation of matter) , having very different chemical properties than what you started with.

High Surface Tension

Cohesion = much greater attraction of like molecules Water > water When air & water meet water molecules have greater attraction to other water molecules than to air molecules; causes rain to form droplets Adhesion = attraction of unlike molecules

Energy

Compared w/ matter, energy is less tangible. It has no mass, does not take up space, & we can only measure its effects on matter. Energy is definded as the capacity to do work, or to put matter into motion. The greater the work done, the more energy is used doing it.

Water is ------ & --------

Covalent & dipolar Electron pair forms covalent bond Each spends some time w/one, then the other atom Less time w/ H, more time w/ O which has greater electonegativity Hydrogen bonds result from an attraction of oppositely charged parts of molecules rather than sharing or loss/gain of e-. Causes polarity of H2O molecule

Summary: Covalent vs. Ionic Bonds

Covalent bond — electrons shared • Shared unequally — polar • Shared equally— non polar Ionic bond — total electron transfer • Both atoms ionized • May dissociate in water

Polar vs. Nonpolar in Covalent Bonds

Distribution of charge on molecule Polar — charged surface •Prefer to be mixed with other charged molecules • Soluble in water; hydrophilic Nonpolar — no residual charge • Prefer to be mixed with other uncharged molecules; interact little w/ polar molecules. •Attracted to one another by very weak bonds called vander waals forces • Soluble in oils;hydrophobic

Three Subatomic Particles

Electron: • Light • Negative charge • Electron cloud Proton: • Heavy • Positive charge • Nucleus Neutron: • Heaviest • Neutral • Nucleus

Energy is transferred when chemical reactions occur; the overall reaction may either release energy or absorb energy:

Exergonic reactions release more energy than they absorb Endergonic reactions absorb more energy than they release • Usually the body couples exergonic reactions w/ endergonic reactions. Exergonic reactions occur as nutrients(glucose is broken down),releasing ATP. Approximately 32 + ATPs are exergonically released on the complete oxidation of one molecule of glucose

Matter

Fancy word for "stuff"; things that you can feel, see and has mass mass: equal to the amount of matter weight: the gravitational pull on that matter

HONC

H (1 bond) O (2 bonds) N (3 bonds) C (4 bonds)

Acid - Base Balance

Higher amount of [H+] in solution = more acidic Higher amount of [OH-] in solution = more basic (alkaline) The amount of H+ in a solution is expressed as pH (potential of hydrogen) on a logarithmic scale from 0 - 14. (measures protons and equal up to pH of 7)

Role of Water in the body

Human Body is 70% water; Most abundant chemical compound in living organisms Water content varies with tissue type --Blood & muscle - more --Fat & Bone - less Protoplasm is generally 95% water --Free --Bound to other components

Some Elements Molecular

In oxygen gas, two oxygen atoms share four electrons, forming a double bond (O = O or O2). In hydrogen gas, one electron from each hydrogen atom is shared, forming a single covalent bond. The resulting molecule of hydrogen gas is represented as H-H or H2

In pure water...

In pure water, only 1 mol in 10 million molecules (107) ionizes spontaneously

Matter and energy are

Inseparable. Matter is the substance, energy is the mover of that substance. All living things are composed of matter & they all require energy to grow & function. The release & use of energy by livings systems allows us the elusive quality we call life!

Intracellular water vs. extracellular fluid

Intracellular water = 50% of total body weight Extracellular fluid bathes cells = 15% of total body weight --holds many anabolic materials & end products of catabolism (breaking down) --provides a firm substance (interstitial substances = ground substances or matrix) that embeds cells

NaCl Formation

Ionic Bond As a result, sodium becomes a positive ion (11 p+ & 10 e-), while chlorine becomes a negative ion (17 p+ & 18 e-). Opposites attract. Sodiums nestle between chlorines. Perfectly cubicle crystals.

Chemical Energy

Is the energy stored in chemical bonds of chemical com- pounds. Chemical reactions allow the rearrangement of atoms, in a particular way that releases potential energy which then becomes kinetic energy (energy in action). Food is eventually converted to kinetic energy, temporarily captured in bonds of ATP which we can use).

Energy exists in two states:

Kinetic energy: energy in action; will move atoms as well as large objects Potential energy: energy that is stored. It is inactive energy that has the potential or capability to do work but is not presently doing so..batteries, water behind a dam, inactive leg muscles. (our energy is ATP)

Lakes are going to freeze... how?

Lakes remain liquid on bottom in winter, allowing aquatic organisms to continue: high heat of fusion

sub-orbitals

Major shells contain a sub-structure called sub-orbitals (flight patterns) within the major shell. The number of the subshells is the same as the quantum number of the major shell

Properties of Aqueous Solutions

Many inorganic compounds are held together by ionic bonds. When in water: •Ions & polar compounds under go ionization, or dissociation in water •Polar water molecules form hydration spheres around ions & other small polar molecules to keep them in solution

Molecule vs. Compound

Molecule = when two or more atoms share e- Compound = substance containing atoms of two different elements A shorthand way of showing the kinds and proportions of different atoms in a molecule 1. Molecular Formula Water = H2O Oxygen = O2 Carbon Dioxide = CO2 If two atoms of the same element join = molecule ex. N2, H2, O2 If atoms of two different element join = compound ex. NaCl

Energy Conversions

Most energy conversions are easily converted from one form to another. However they are quite inefficient, as they lose energy in the process which is usually given off as heat, and un-usable

Radioactivity

Neutrons contribute to the structural stability of the nucleus; If there are too many or too few, it will cause instability & nucleus will disintegrate = (spontaneously change) called radioactive decay EX: Co^60 when decaying it gives off particles

free radicals

Normal cellular processes (metabolism) produce molecules containing oxygen atoms with unfilled outer electron shells = free radicals A common example is superoxide which is formed by the addition of an e- to an oxygen molecule. Having this unpaired e- makes a free radical unstable, highly reactive & very destructive to nearby molecules & only becomes stable by giving up their unpaired e- to or taking an e- from another molecule which causes a breakup of potentially important molecules Since these oxygen atoms are very reactive, they cause damage = oxidative stress to other cellular molecules & structures (sort of like rusting; biological rusting)

Acid-Base reactions

Often very vigorous reactions NaOH => Na+ + OH- HCl => Cl- + H+ bases & acids combine to neutralize each other forming a salt NaOH + HCl => NaCl + H2O

Bonding Involves Outer Electrons

One pair electrons per bond Outer electrons form bonds Usually behave using "octet rule" • If more than four in outer shell - Desires more electrons - Oxidizer • If less than four in outer shell - Desires fewer electrons - Reducer

Organic vs. Inorganic

Organic: Carbon based; always contain hydrogen & carbon; usually complex Inorganic: Not carbon based polymeric (normally pretty large); usually small & simple (oxygen, carbon dioxide, salts, acids, bases)

H2O Formation

Oxygen has 6 outer electrons and wants 8; therefore it has two "vacancies. Each hydrogen has one "excess" electron and/or one "vacancy. So two hydrogens combine with one oxygen to make H2O

Strong Acids and Weak Acids

Range of 0 - 14 Pure water = pH 7 (H+ = OH-) Strong acids give up their protons (release hydrogen ions) quickly (HCl); Weak acids like carboxyl groups are reluctant to give up protons All life exists pH 3.5 - 8 7.35 to 7.45

Structural Formula

Show not only the kinds & numbers of atoms in a chemical compound, but also their arrangement

Atom

Smallest pieces of all "stuff" occurring atoms or "stuff" that make 92 different elements; 26 have been created atoms cannot be simplified; Matter is composed of elements ( Iron, Oxygen, Carbon, etc.)

pH Scale Examples

Stomach very acidic: 3 pH

Solutions

The ability of water to form solutions is essential to health & survival. It can dissolve many different substances, making an ideal medium for metabolic reactions. Water enables dissolved reactants to collide & form products. Water also dissolves wastes products, allowing them to be flushed out of the body.

Concentrations

The concentration of a solution may be expressed in several different ways: 1. Concentration the amount of a substance in a specified volume of solvent; used by physiologists to monitor inorganic & organic solute concentrations in body fluids because concentrations in chemical reactions directly affect reaction rates a. May be expressed as mass per volume percentage which gives the relative mass of a solute found in a given volume of solution b. Solute concentrations are also reported in moles per liter (mol/L or M/L) or millimoles per liter (mmol/L) = molarity of the solution. Can only be expressed this way when you know the molecular wt of the ion or molecules in question (mass in g equal to the sum of the atomic mass of all its atoms) Mole = is a quantity of any substance having a weight in grams equal to the atomic or molecular weight of that substance 2. In complex mixtures of materials, conc is expressed in terms of wt. of material dissolved in unit volume of solution; mg or g per 100mL

valence electrons

The electrons in the outermost shell (energy level) are called valence electrons; the only electrons that are important. Atoms like to have their outermost shell full;Atoms w/ a full outer shell are not chemically reactive The octet rule states that atoms are most stable when they have a full shell of electrons in the outside electron ring The valence shell refers to an atom's outermost energy level or that portion of it containing the electrons that are chemically reactive Atoms w/ an unfilled outer shell are chemically unstable (they react with other atoms) forming compounds

Electrons determine...

The number of e- on the outer shell determines the chemical nature (reactivity) of that atom = chemical profile

Why chemistry in biology?

The science of chemistry isstudies the nature of matter, especially how its building blocks are put toghether & interact Can't understand bio w/o chem; Chemical reactions underlie all physiological proceses ! Essence of life is chemical ! Living vs.. dead is chemical ! Organization of cells is chemical ! Energy of life is in chemical bonds !

Water

Universal solvent 60-70% of body Needed for almost all of life processes Reproduction Respiration Digestion Makes up 75% of the earth Many different phases - Solid Liquid - Gas

ions

Variations in # of electrons

Ionization of Water

Water molecules are continuously exchanging protons with each other to form hydronium ions = H+ hydroxyl ions = OH- When polar covalent molecules come in contact with water, the Hydrogen (proton) is attracted to larger negative Oxygen forming hydronium ion = H3O Substances that release protons when dissolved in water make H3O = acids A molecule capable of accepting proton = base (alkaline)

Hydrogen Bonds in Water

Water molecules tend to stick together through hydrogen bonds = cohesion, producing surface tension. Hydrogen bonds are weak bonds when there are few & break easily, however, they are strong when there are many! They tend to make special shapes causing a spiral or folding in DNA & proteins.

How can we rid ourselves of free radicals?

We can rid ourselves of free radicals by eating antioxidants rendering free radicals harmless. (Dietary anti-oxidants include selenium, zinc, beta- carotene, vitamins C & E) EAT LOTS OF orange, yellow, blue and red fruits and vegetables (even chocolate contains antioxidants called flavenoids).

Radon - 222

a colorless & odorless gas that is naturally occurring radioactive breakdown product of uranium that accumulates in buildings; it is associated w/ lung cancer

Atomic structure determines

behavior of elements

Element

cannot be broken down into other kinds of substances & still retain its properties 118 total elements; 92 different kinds of naturally

Mixture

combination of elements or compounds that are physically blended together but not bonded together

Electrons are in ___ motion around the nucleus.

continuous motion around nucleus. But laws dictate that e- in an atom can exist only in certain regions of movement and only in limited numbers Where they exist = "probability cloud"

Atomic Models

e- do not follow a fixed orbit, form a negative cloud but move in predictable regions

beta particles

easy to stop (paper); appear in fallout > Radiation Sickness

Mechanical Energy

energy directly moving matter like your leg muscles

gamma ray

fast; causes burns (vaporize); difficult to stop (lead shield)

Water expands when

frozen; Ice is less dense than water therefore, floats

alpha particles

heavy; easy to stop (paper) but causes a lot of damage = hemorrhage (hitting damaged vessels, uncontrolled bleeding)

In our body, the heat we generate is used to...

help maintain your body temperature which influences body functioning; the higher the temperature, the faster the body's chemical reactions occur. Gasoline is a good example. We can put a match to it and it wil explode all at one, releasing its energy in the form of light, sound & heat. If we put it in your car, it will be used a little at a time & be used by the pistons as mechanical energy.

Organisms are composed of

matter % all matter exists in solid, liquid & gaseous states

Water is a major component of....

mucus & other lubricating fluids throughout the body. Lubrication is necessary in: chest (pleural & pericardial cavities) & abdomen (peritoneal cavity) where internal organs touch & slide over one another, joints, where ligaments and tendons rub against one another, in gastrointestinal tract, mucus & other watery secretions moisten foods to allow smooth passage through digestive system

pH Scale

pH = power or potential of hydrogen H+Concentration A change in one pH unit is a tenfold increase or decrease in hydrogen ion concentration = Log scale 0 -14 (the negative logarithm of its hydrogen ion concentration)

Elements may vary in electrons & neutrons, but not

protons; every kind of atom has a specific atomic number = # of protons The element carbon is made of atoms with 6 protons Therefore, All atoms w/6 protons = carbon

Electrical Energy

results in movement of charged particles. In your body, electrical currents are generated when charged particals called ions move across cell membranes as nerve impulses (electrical currents) to transmit messages from one part of the body to another or to generate a heart beat. However, too strong an electrical shock can interfere w/ normal currents & cause death.

Electrons

spin & orbit around nucleus • Atomic nucleus≈sun, • Electrons sort of like planets # of electrons - = # of protons + (so charge of nucleus is neutral) Travel at speed of light

H2 Formation

the innermost energy level of each hydrogen "wants" two electrons, but only has one. Thus, it can be said to have a "vacancy." But if they move close together, they can mutually satisfy each other's "vacancy."

The more modern orbital model

the more useful in predicting the chemical behavior of atoms...it depicts probable regions of greatest electron density

Beneficial effects of certain radioisotopes include

their use in medical imaging & treatment certain disorders

half life

time required for half of the radioactive atoms of a sample to decay into a more stable element (uranium > lead) = 4.5 x 10^7 years

Solvent vs. solute

water exhibits a unique combination of properties important to living things → dipolarity which allows dissolving many substances → good solvent In a solution, the solvent dissolves another substance called the solute. Solutes that are charged b/c made of polar covalent bonds are hydrophilic (dissolve easily in water) Solutes that are not charged b/c made of nonpolar covalent bonds are hydrophobic

Protons & neutrons

• Packed into atomic center • Form the dense "nucleus" or core •Makes up the mass of the atom=atomic mass (amt of matter)

Chemical Bonds

•Atoms often come together to become more stable •Different types of atoms bond together chemically to form molecules/compounds that have completely different properties. •The likelihood that an atom will form a chemical bond w/ another atom depends on the # of e- in its outermost shell or valence shell (chemical profile) The Inert elements have completely filled outer shells; therefore, stable so do not react. ie Noble gases