Anatomy chapter 2 section 5

Biochemistry is "wet" chemistry. What does this statement mean?

All chemical reactions in the body take place in a watery environment.

Salts, acids, and bases are electrolytes. What is an electrolyte?

An electrolyte is a substance that produce ion(s) when they dissolve in water.

Which of the following formulas indicates an acid?

H2SO4

Distinguish inorganic from organic compounds, and list the major categories of each in the body.

Inorganic compounds with few exceptions are non-carbon containing. The major categories are water, salts, acids, and bases. Organic compounds contain carbon. The major categories are carbohydrates, lipids, proteins, and nucleic acids

LOOK AT PICTURES IN BOOK

LOOK AT PICTURES IN BOOK

LOOK AT SLIDESHOW

LOOK AT SLIDESHOW

Which of the following is classified as an inorganic compound:

water

most abundant inorganic compound in the body

water

What component of a buffer would provide negative feedback control of a person whose blood pH was 7.3?

weak base

A pH of 3.3 is (1 / 10 / 100 / 1000) times more acidic than a pH of 4.3

The answer is 10.

Define pH. The pH range of blood is from 7.35 to 7.45. Circle the correct answer to complete the sentence. This is slightly (acidic/basic)

The answer is basic. pH is the symbol for hydrogen ion concentration, a measure of the relative acidity or alkalinity of a solution.

What property of water prevents rapid changes in body temperature?

The high heat capacity of water prevents rapid changes in body temperature.

Which of these occurs when acid is added to a solution with a pH of 7?

The pH drops below 7.

Salts are electrolytes. What does that mean?

They conduct an electrical current when dissolved in water.

The lower the pH, the greater the number of hydrogen ions.

True

Organic Compound

a compound containing carbon; examples include proteins, carbohydrates, and fats.

inorganic compound

a compound that lacks carbon; for example, water

polymer

a long, chainlike molecule consisting of many similar or repeated units

Which of the following solutions is the weakest acid:

a solution with a pH of 6.4

buffer

a substance or substances that help to stabilize the ph of a solution

electrolyte

a substance that breaks down into ions when in solution and is capable of conductioniing an electric current

In which of these does a hydrogen atom form an ionic bond?

acid

substance that is a proton donor

acid

substance that releases hydrogen ions

acid

Which is a proton donor—an acid or a base?

acids

Carbon is found in all inorganic compounds.

false

On the pH scale, zero is considered to be neutral because hydrogen ions and hydroxyl ions are equal.

false

Which of the properties of water is most closely associated with the body's ability to maintain homeostasis in terms of temperature?

high heat capacity

What substance on the pH scale is a strong acid?

hydrochloric acid

Which of the following is an example of an inorganic molecule:

hydrochloric acid

which ion is responsible for increased acidity

hydrogen ion

salt

ionic compound that dissociates into charge particles (other than hydrogen or hydroxyl ions) when dissolved in water

A solution with a pH of 7:

is neutral

polysaccharide

literally, many sugars, a polymer of linked monosaccharides; examples include starch and glycogen

substance that releases equal amounts of hydrogen and hydroxyl ions

neutral

Fill in the blank or provide a short answer: Compounds that contain carbon-hydrogen bonding are collectively termed __________ compounds.

organic

carbohydrate

organic com-pound composed of carbon, hydrogen, and oxygen , includes sugars, starches, cellulose

dehydration synthesis

process by which a larger molecule is synthesized from smaller ones by removal of a water molecule at each site of bond formation

An acid is a molecule that releases (donates) __________. State the answer in two ways.

protons, hydrogen ions

neutralization

(1) a chemical reaction that occurs between an acid and a base (2) blockage of the harmful effects of bacterial exotoxins or viruses by the binding of antibodies to their functional sites

Base

(1) a substance that accepts hydrogen ions; proton acceptor; compare with acid; (2) the broad, posterosuperior aspect of the heart where large vessels enter or leave the heart; (3) the broad inferior area of each lung resting on the diaphragm

Salts

- a salt is an ionic compound containing cations other than the hydrogen ion (H+) and anions other than the hydroxide ion (OH-) - salts of many metals are commonly found in body, but most plentiful salts are those containing calcium and phosphorus, found chiefly in bones and teeth - when dissolved in body fluids, salts easily separate into their ions - this process called dissociation occurs rather easily because the ions have already been formed - all that remains is for the ions to "spread out" - this is accomplished by the polar water molecules which orient themselves with their slightly negative ends toward the cations and their slightly positive ends toward the anions, thereby overcoming the attraction between them. - salts both in their ionic forms and in combination with other elements are vital to body functioning. - example: sodium and potassium ions are essential for nerve impulses, and iron forms part of the hemoglobin molecules that transport oxygen within red blood cells. - because ions are charged particles all salts are electrolytes - substances that conduct an electrical current in solution - when electrolyte balance is severally disturbed, virtually nothing in the body works - (the functions of the elements found in body salts are summarized in table 2.1)

Characteristic of acids

- acids have sour taste and can dissolve many metals or "burn" a hole in your rug - acids can have devastating effect; for example, consider the damage to sea life, trees, and famous historical monuments caused by the vinegar-like acid rain - most useful definition of an acid is that it is a substance that can release hydrogen ions (h+) in detectable amounts - because a hydrogen ion is a hydrogen nucleus (a "naked proton" ) acids are also defined as proton (H+) donors - you may find it useful to think of acids as putting protons "in the game" - as free protons, hydrogen ions can influence the acidity of body fluids - when acids dissolved in water they release hydrogen ions and some anions. - the anions are unimportant; it is the release of protons that determines an acid's effects on the environment - ionization of hydrochloric acid (an acid produced by stomach cells that aid digestion) is shown in following equation -HCl (hydrochloric acid) = H+ (proton) + Cl- (anion) - other acids found or produced in body include acetic acid (the acidic component of vinegar ) and carbonic acid. - acids that ionize completely and liberate all of their protons are called strong acids; for example, hydrochloric acid - acids that ionize incompletely, as do acetic and carbonic acid, are called weak acids - ex: when carbonic acid dissolves in water, only some of its molecules ionize to liberate h+ 2H2CO3 (carbonic acid) = H+ (proton) + HCO3- (anion) + H2CO3 (carbonic acid)

Biochemistry: The chemical composition of living matter

- all chemicals found in body fall into one of two major classes of molecules: inorganic or organic compounds - class of compound is determined solely by the presence or absence of carbon - Except for a few so far unexplainable exceptions such as carbon dioxide gas (CO2 ) and carbon monoxide (CO) , inorganic compounds lack carbon and tend to be small, simple molecules - Ex: of inorganic compounds found in the body are water, salts, and many (but not all) acids and bases - Organic compounds contain carbon - The important organic compounds in the body are carbohydrates, lipids, proteins, and nucleic acids. - All organic compounds are fairly (or very) large covalent molecules - inorganic and organic compounds are equally essential for life - Trying to determine which is more valuable can be compared to trying to decide whether the ignition system or the engine is more essential to the operation of a car

Characteristics of bases

- bases have bitter taste, feel slippery, and are proton (H+) acceptors - (you can also think of them as taking protons "out of the game" ; when protons are bound to a molecule, they are unable to affect the acidity of body fluids) - hydroxides are common inorganic bases - likes acids, the hydroxides ionize and dissociate in water; but in this case, the hydroxide ion (OH-) and some cations are released - ionization of sodium hydroxide (NaOH) commonly known as lye, is shown as NaOH (sodium hydroxide) = Na + (cation) + OH- (hydroxide ion) - hydroxide ion is an avid proton (H+) seeker, and any base containing this ion is considered a strong base. - By contrast, bicarbonate ion (HCO3-), an important base in blood, is a fairly weak base

Carbohydrates

- carbohydrates, which include sugars and starches, contain carbon, hydrogen, and oxygen. - with slight variations , the hydrogen and oxygen atoms appear in the same ratio as in water; that is, two hydrogen atoms to one oxygen atom. - this is reflected in the word carbohydrate, which means "hydrated carbon" and in the molecular formulas of sugars. - example: glucose is C6H12O6 and ribose is C5H10O5 - usually classified according to size and solubility in water as monosaccharides, dissaccharides, or polysaccharides -because monosaccharides are joined to form the molecules of the other 2 groups, they are structural units, or building blocks, of carbohydrates.

Acids and Bases

- like salts, acids and bases are electrolytes -that is they ionize, dissociate in water, and can then conduct an electrical current

lipids

- lipids or fats are a large and diverse group of organic compounds - they enter the body in the form of meats, egg yolks, dairy products, and oil -the most abundant lipids in the body are trigylcerides, phospholipids, and steroids. - like carbohydrates, all lipids contain carbon, hydrogen, and oxygen atoms, but in lipids, carbon and hydrogen atoms far outnumber oxygen atoms, as illustrated by the formula for a typical fat named tristearin, which is C57H110O6 - lipids are insoluble in water but readily dissolve in other lipids and in organic solvents such as alcohol and acetone

Polysaccharides

- long, branching chains of linked simple sugars are called polysaccharides (literally, "many sugars") -because they are large, insoluble molecules, they are ideal storage products -another consequence of their large size is that they lack the sweetness of simple and double sugars -only 2 polysaccharides, starch and glycogen, are of major importance to the body -starch is the storage polysaccharide formed by plants - we ingest it in the form of "starchy" foods such as grain products (corn, rice) and root vegetables (potatoes and carrots for ex) -glycogen is slightly smaller but similar, polysaccharide found in animal tissues (largely in the muscles and liver) - like starch, it is a polymer of linked glucose units -carbohydrates provide a ready, easily used source of fuel for cells, and glucose is at the top of the "cellular menu" -when glucose is oxidized ("burned" by combining with oxygen) in a complex set of chemical reactions, it is broken down into carbon dioxide and water -some of the energy released as the glucose bonds are broken is trapped in the bonds of high-energy ATP molecules, the energy "currency" of all body cells - if not immediately needed for ATP synthesis , dietary carbohydrates are converted to glycogen or fat and stored - those of us who have gained weight from eating to many carbohydrate - rich snacks have firsthand experience of this conversion process - small amounts of carbohydrates are used for structural purposes and represent 1 and 2 percent of cell mass. Some sugars are found in our genes and others are attached to outer surfaces of cell membranes (boundaries) where they act as road signs to guide cellular interactions

Monosaccharides

- monosaccharide means one (mono) sugar (saccharide) and thus monosaccharides are also referred to as simple sugars - they are single-chain or single-ring structures (meaning the carbon backbone forms either a line or circle) containing from 3-7 carbon atoms - most important monosaccharides in the body are glucose, fructose, galactose, ribose, and deoxyribose - glucose, also called blood sugar, is the universal cellular fuel -fructuose and galactose are converted to glucose for use by body cells -ribose and deoxyribose form part of the structure of nucelic acids, another group of organic molecules responsible for genetic info

Organic compounds

- most organic compounds are large molecules, but their interactions with other molecules typically involve only small, reactive parts of their structure called functional groups (acid groups, amines, and others) - many organic compounds (carbohydrates and proteins for example) are polymers - polymers are chainlike molecules made of many similar or repeating units (monomers), which are joined together by dehydration synthesis -during dehydration synthesis, a hydrogen atom is removed from 1 monomer and a hydroxyl group (OH) is removed from the monomer it is to be joined with - covalent bond then forms, uniting monomers, and water molecule is released. - this removal of a water molecule (dehyrdation) at the bond site occurs each time a monomer is added to the growing polymer chain - when polymers must be broken down or digested to their monomers, the reverse process, called hydrolysis occurs - as a water molecule is added to each bond, the bond is broken, releasing the monomers. - all organic molecules covered in this chapter - carbohydrates, lipids, proteins, and nucleic acids - are formed by dehydration synthesis and broken down by hydrolysis

pH: Acid-base concentrations

- the relative concentration of hydrogen (and hydroxide) ions in various body fluids is measured in concentration units called pH units. - pH scale which was devised in 1909 by a danish biochemist (and part time beer brewer) name Sorenson, is based on the # of protons in solution - pH scales runs from 0-14 and each successive change of 1 pH unit represents a tenfold change in hydrogen ion concentration - at pH of 7 the # of hydrogen ions exactly equals the number of hydroxide ions, and the solution is neutral; that is neither acidic or basic - solutions with ph lower than 7 are acidic: the hydrogen ions outnumber the hydroxide ions - a solution with a ph of 6 has 10 times as many hydrogen ions as a solution with a Ph of 7 and a ph of 3 indicates a 10,000 fold (10 times 10 times 10 times 10) increase in hydrogen ion concentration from ph 7 - solutions with ph numbers higher than 7 are basic, or alkaline, and solutions with ph of 8 and 12 have 1/10 and 1/1000000 (respectively ) the number of hydrogen ions present in a solution with ph of 7 - living cells are extraordinarily sensitive to even slight changes in ph - acid - base balance is carefully regulated by the kidneys, lungs, and a number of chemicals called buffers that are present in body fluids - weak acids and weak bases are important components of the body's buffer system, which act to maintain pH stability by taking excess hydrogen or hydroxide ions - because blood comes into close contact with nearly every blood cell, regulation of blood ph is especially critical - normally blood ph varies in a narrow range, from 7.34-7.45 - when blood ph changes more than a few tenths of a pH unit from these limits, death becomes a distinct possibility - although we could give 100s of examples to illustrate this point, we will provide just 1 very important one - when blood ph begins to dip into the acid range, the amount of life-sustaining oxygen that the hemoglobin in blood can carry to body cells decreases rapidly to dangerously low levels

Water

- water most abundant inorganic compound in body - accounts for 2/3 of body weight - among the properties that make water so vital are the following: High heat capacity - water has high heat capacity , that is, it absorbs and releases large amounts of heat before it changes temp. - Thus, prevents the sudden changes in body temp that might otherwise result from intense sun exposure, chilling winter winds, or internal events (such as vigorous muscle activity) that literature large amounts of heat Polarity/Solvent properties - water excellent solvent because of its polarity; indeed, often called the "universal solvent" - solvent is a liquid or gas in which smaller amounts of other substances, called solutes (which may be gases, liquids, or solids) can be dissolved or suspended. - resulting mixture is called a solution when the solute particles are exceedingly tiny, and a suspension when the solute particles are fairly large. - translucent mixtures with solute particles of intermediate size are called colloids - small reactive chemicals - such as salts, acids, and bases - dissolved easily in water and become evenly distributed - molecules can't react chemically unless they are in solution, so virtually all chemical reactions that occur in the body depend on water's solvents properties - because nutrients, respiratory gases (oxygen and carbon dioxide) and wastes can dissolve in water, water can act as a transport and exchange medium in the body. - Ex: all theses substances are carried around the body in blood plasma (the liquid part of blood that is mostly made up of water) and are exchanged between the blood and body cells by passing through the water-based interstitial fluid that baths cells - specialized molecules that lubricate the body, such as mucus and synovial fluid, also use water as their solvent - synovial fluid "oils" the ends of bones as they move within joint cavities Chemical reactivity - water important reactant in some types of chemical reactions -ex: to digest foods or break down biological molecules , water molecules are added to the bonds of the larger molecules in order to break them -such reactions called hydrolysis reactions, a term that specifically recognizes this role of water ( hydro = water; lys= splitting) Cushioning - water also serves as protective function -in cerebrospinal fluid, water forms a cushion around the brain that helps to protect it from physical trauma - amniotic fluid , which surrounds a developing fetus within the mother's body, plays a similar role in protecting the fetus.

Acids, Bases, and neutralizations

- when acids and bases are mixed they react with each other (in an exchange reaction) to form a water and a salt - HCl (acid) + NaOH (base) = H2O (water) + NaCl (salt) - this type of exchange reaction, in which an acid and a base interact, is more specifically called a neutralization reaction

Dissaccharides

-dissaccharides or double sugars are formed when 2 simple sugars are joined by dehydration synthesis -in this reaction, as notes earlier, a water molecule is lost as the bond forms - some of the important disaccharides in the diet are sucrose (glucose-fructose) which is cane sugar; lactose (glucose-galactose) found in milk; and maltose (glucose-glucose), or malt sugar. -because the double sugars are too large to pass though cell membranes, they must be broken down (digested) to their monosaccharide units to be absorbed from the digestive tract into the blood; this is accomplished by hydrolysis

A solution with a pH of 11.7 is __________ times more basic (alkaline) than a solution with a pH of 8.7.

1000

Is a pH of 11 acidic or basic? What is the difference in pH between a solution at pH 11 and a solution at pH 5?

A pH of 11 is basic. A pH of 5 is 1,000,000-fold more acidic than pH 11.

Which of these is aided by water's high heat capacity?

basking in the sun

ionic compound containing cations other than hydrogens and anions other than hydroxyls

salt

Hydrogen bonding between water molecules is responsible for:

surface tension

glucose

the principle sugar in the blood; a monosaccharide

hydrolysis

the process in which water is used to split a substance into smaller particles

pH

the symbol for hydrogen ion concentration; a measure of the relative acidity or alkalinity of a solution

Acids are defined as proton donors since they release hydrogen ions.

true

Water is the single most abundant inorganic compound in the human body.

true

When a solution produces equal numbers of hydrogen and hydroxyl ions, it is said to be neutral.

true