Advanced Bio test 2

ions

charged particles

acids

substances that increase the H+ concentration of a solution -proton donor - "low" numbers on pH scale

bases

substances that reduce the H+ concentration of a solution -proton acceptor - "high" numbers on pH scale -Some work by creating water by combining the H+ and their OH- -Som work by accepting the H+ AKA: alkaline

Most cleansers are highly acidic. True or False

False. The cleaners were basic according to the litmus tests.

hydroxyl group

*OH -"Alcohols" -Names end in -ol usually -Polar *Do not confuse this with the OH- for the hydroxide ion!!!

Importance of Benzene in Organic Chemistry / Biology

-Alternating double bonds -Extraordinary molecular stability -Puts any substance possessing it into a very broad organic family known as the aromatic compounds -The number of chemical structures which include the benzene ring are almost immeasurable -Common products...besides oil derivatives --wood preservatives --Aspirin --oil of wintergreen

Buffers

-Biological fluids resist changes to their own pH with these. -Substances that minimize the changes in the concentrations of H+ and OH- ions in a solution. -accepts H+ from the solution when they are in excess and donates H+ to the solution when they have been depleted. -Most can do this because they are weak acids or weak bases. -Most are acid-base pairs.

methyl group

-Carbon bonded to 3 hydrogen atoms and something else -Can affect the expression of genes and/or hormones

pH scale

-Defined as the negative logarithm of the hydrogen ion concentration. -Each pH unit represents a tenfold difference in H+ and OH- concentrations -When the pH of a solution changes SLIGHTLY, the actual concentration of H+ and OH- in the solution change SUBSTANTIALLY! -The pH of a neutral solution is 7, with most biological fluids falling between 6-8- -In any solution, the product of the H+ and the OH- concentrations is constant at 10-14 M2. -Because the H+ and OH- concentrations of solutions can vary by a factor of 100 trillion or more, scientists developed the pH scale.

the 7 functional groups

-Hydroxyl -Carbonyl -Carboxyl -Amino -Sulfhydryl -Phosphate -Methyl

Simple Organic Molecules

-Methane = CH4 -Ethane = C2H6 -Ethene = C2H4 -Propane = C3H8 -Benzene = C6H6

Amino group

-Nitrogen bonded to 2 hydrogens -N-H l H -"Amines" -Acts as a base by picking up a proton

Buffer example in body

-Normally blood pH is very near 7.4 and a person cannot survive for more than a few minutes if the blood pH is <7 or >7.8 -Carbonic acid is a main blood buffer (H2CO3) -It dissociates to yield bicarbonate ion and a hydrogen ion H2CO3 HCO3− + H+ Acid / <--- Base/Hydrogen Ion H+ donor ---> H+ acceptor *The reaction proceeds from L to R when blood pH rises (H+ falls) so that H2CO3 can release a H+ and turn into HCO3 *The reaction proceeds from R to L when blood pH decreases (H+ rises) so HCO3 can accept a H+ and turn into H2CO3

carbonyl group

-O double bonded to C -O=C -Called an ALDEHYDE if the carbonyl group is at the end of the C skeleton -Called a KETONE if the carbonyl group is elsewhere

dissociation of water molecules

-Occasionally a hydrogen atom shared between 2 water molecules in a hydrogen bond shifts from one water molecule to the other -This is statistically rare: only 1 water molecule in every 554,000,000 is dissociated.

carboxyl group

-Oxygen double bonded to a C that is single bonded to a hydroxyl group -O=C-OH -Hybrid of carbonyl and hydroxyl groups -"Carboxylic acids" or "organic acids" -Has its acidic properties due to 2 close oxygen atoms being so electronegative

phosphate group

-Phosphate attached to 4 oxygen molecules -One O is double-bonded -One O attaches the group to the C skeleton -"Organic phosphates" -Work in energy transfer...ATP, ADP

Why do some acid/base equations use single arrows?

-Single arrows show that the reaction is unidirectional as the compounds dissociate completely when mixed with water. -These acids and bases are termed STRONG.

C Skeletons may be:

-Straight -Branched -Closed rings

sulfydryl group

-Sulfur bonded to hydrogen -SH -"Thiols" -Sulfur has 6 valence electrons like oxygen does Stabilizes proteins

What bearing does the process of dissociation of water have on living systems?

-The process is exceedingly important to the chemistry of life. -H+ and OH- are highly reactive. --Changes in their concentrations can drastically alter a cell's proteins and other complex molecules.

hydronium ion

-The water molecule that the proton bonded to (H3O+) -gain proton=positive

Describe this reaction of dissociation of water at its state of dynamic equilibrium.

-This reaction is reversible and reaches a state of dynamic equilibrium when water dissociates at the same rate it is being reformed from H+ and OH-. -At equilibrium, the concentration of water molecules greatly exceeds the concentration of H+ and OH-

acid precipitation

-Uncontaminated rain: pH about 5.6 -Acid precipitation: pH more acidic than 5.6 -Mainly due to sulfur dioxides and nitrogen oxides in the air as byproducts of fossil fuel burning. -Particularly noticeable when spring thaw drains into areas where aquatic life are producing eggs and young. -Can also affect abiotic portions of environment such as soil.

The Nitrogenous Bases ☺

-Uracil - C4H4N2O2 -Thymine - C5H6N2O2 -Guanine - C5H5N5O -Cytosine - C4H5N3O -Adenine - C5H5N5

what does dissociation have to do with ions?

-When dissociation happens, the hydrogen atom leaves its electron behind and what is actually transferred is a hydrogen ion. -A hydrogen ion is actually a single proton with a charge of +1. -The water molecule lost a proton and is now an ion too.

Isomers

-compounds that have the same molecular formula, but different structures and therefore, different properties --Structural isomers --Geometric isomers --Enantiomers

Hydrocarbons

-organic molecules consisting of only C and H -Not prevalent in organisms, but don't forget about portions of fats and cell membranes... -Non-polar...hydrophobic

functional groups

-parts of organic molecules most commonly involved in chemical reactions -"Kind of" can be considered attachments that replace an H in the C skeleton -Each functional group behaves consistently from one organic molecule to another

hydroxide ion

-water molecule that lost a proton (OH-) -lose proton=negative

organic

Compounds that contain carbon -C counts for the endless diversity of biological molecules. -Due to its 4 valence electrons, C usually doesn't gain or lose electrons to form ionic bonds, but rather makes 4 covalent bonds instead...TETRAVALANCE!

structural isomers

Different covalent arrangement of atoms

geometric isomers

Different spatial arrangements

pH can be used to tell if a product is edible or not. True or False

False. A good amount of the substances tested had a close to neutral pH, but the substances ranged from drinks to cleaning products, and the latter is not edible despite having the same pH as the drinks.

chemical equation for dissociation of water

H2O --> H+ + OH- -But, we actually get OH- and H30+

What ion or part of a water molecule is associated with an acid? What is its chemical formula?

Hydronium ion. H3O+

What ion or part of a water molecule is associated with a base? What is its chemical formula?

Hydroxide ion. OH-

Enantiomers

Mirror Images...Can be dangerous in drugs

When some acids and bases are mixed, the amount of liquid is often more than that of the combined amounts of acid and base. Why might that be?

The H+ ions in acid join with the OH- ions in base and become H2O, so there is more water.

How can the concentrations of H+ and OH- in pure water be disrupted?

The addition of acids or bases in solution will disrupt the H+ and OH- balance in pure water.

Humans tolerate fairly strong acids well internally. True or False

True. Fruit juices, hot sauce, and vinegar were fairly acidic according to the pH meter.

Personal hygiene products are neither highly acidic nor highly basic. True or False

True. The pH meters stayed a yellow/orange color, which is hardly acidic or basic.