CHAPTER 2 The Chemical Level of Organization

Question 1

atoms and molecules

Answer 1

release or store energy in processes known
as chemical reactions.

Question 2

Chemistry

Answer 2

the science of the structure and interactions of matter

Question 3

MATTER

Answer 3

All living and nonliving things consist of matter
Anything that occupies space and has a mass

exists in 3 states

SOLID - compact and have a definite shape and volume
LIQUID - have a definite volume and assume the shape of their container
GAS - have neither a definite shape nor volume

all forms of matter are made up of a limited number of building blocks call chemical elements

Question 4

mass

Answer 4

The AMOUNT of matter in any object
Which does not change

Question 5

Weight

Answer 5

The force of gravity acting on matter
weight changes

ex. When objects are farther from
Earth, the pull of gravity is weaker; this is why the weight of an astronaut
is close to zero in outer space.

Question 6

chemical elements

Answer 6

All forms of matter are made up of a limited number of building blocks and cannot be split into simpler substances by ordinary chemical means.

(ex different apples but still an apple)

each element is made up of atoms (only one)
(118 elements)
(26 elements in the body)

Question 7

chemical symbol

Answer 7

Each named element is
designated by a chemical symbol they have their name (symbol) which are letters.

Question 8

Major elements

Answer 8

96% of the body’s mass:

Oxygen – Part of water and many organic (carbon-containing) molecules; used to generate ATP, a molecule used by cells to temporarily store chemical energy

Carbon – Forms backbone chains and rings of all organic molecules carbohydrates, lipids (fats), proteins, and nucleic acids (DNA and RNA).

Hydrogen (H) - Constituent of water and most organic molecules; ionized form (H+) makes body fluids more acidic

Nitrogen (N) - Component of all proteins and nucleic acids.

Question 9

Lesser elements

Answer 9

3.6% to the body’s mass:

Calcium (Ca) - Contributes to the hardness of bones and teeth; ionized form (Ca2+) needed for blood clotting, release of some hormones, contraction of muscle

Phosphorus (P) - Component of nucleic acids and ATP; required for normal bone and tooth structure

Potassium (K) - Ionized form (K+) is the most plentiful cation (positively charged particle) in intracellular fluid needed to generate action potential

Sulfur (S) - Component of some vitamins and many proteins.

Sodium (Na) - Ionized form (Na+) is the most plentiful cation in extracellular fluid; essential for maintaining water balance; needed to generate action potentials

Chlorine (Cl) - Ionized form (Cl−) is the most plentiful anion (negatively charged particle) in extracellular fluid essential for maintaining water balance

Magnesium (Mg) - Ionized form (Mg2+) needed for action of many enzymes (molecules that increase the rate of chemical reactions in organisms)

Iron (Fe) 0.005 Ionized forms (Fe2+ and part of hemoglobin (oxygen-carrying protein in red blood cells) and some enzymes.

Question 10

Trace elements—are present in tiny amounts. Together, they account
for the remaining body mass, about 0.4%. Several trace elements have
important functions in the body.

Answer 10

Are present in tiny amounts 0.4%.
Several trace elements have important functions in the body.

• iodine is needed to make thyroid hormones and its the most massive element present
  in the human body (53 electrons)

Question 11

Atoms

Answer 11

The smallest units of matter that RETAIN the properties and characteristics of the element.

Question 12

subatomic particles

Answer 12

protons, neutrons, and electrons

Question 13

electron shells

Answer 13

may be depicted as simple circles around the nucleus.

The first electron shell (nearest the nucleus) never holds more
than 2 electrons. The second shell holds a maximum of 8 electrons,
and the third can hold up to 18 electrons.

The electron shells fill with
electrons in a specific order, beginning with the first shell

The number of electrons in an atom of an element always equals
the number of protons. Because each electron and proton carries one
charge, the negatively charged electrons and the positively charged
protons balance each other. Thus, each atom is electrically neutral; its
total charge is zero.

the number of electrons of an
atom determines its chemical properties.

Question 14

atomic number

Answer 14

The number of PROTONS in the nucleus of an atom

Question 15

mass number

Answer 15

Is the sum of its protons and neutrons

Because sodium has 11 protons and 12 neutrons, it’s mass
number is 23

Question 16

isotopes

Answer 16

atoms of an element that have different numbers of neutrons and therefore different
mass numbers

Although the isotopes of an element have different numbers of neutrons, they have identical chemical properties because they have the same number of electrons.

Question 17

Stable isotopes

Answer 17

their nuclear structure does not change over time

Question 18

Radioactive isotopes (radioisotopes)

Answer 18

are unstable; their NUCLEI decay (spontaneously changes) into a stable configuration.

As they decay, these atoms emit radiation—either subatomic particles or packets of
energy—and in the process, often transform into a different element.

Question 19

Half-life

Answer 19

is the time required for half of the radioactive atoms in a sample of that isotope to
decay into a more stable form.

Question 20

Atomic mass

Answer 20

The atomic mass (also called the atomic weight) of an element is the average mass of all
its naturally occurring isotopes.

Typically, the atomic mass of an element is close to the mass number of its most abundant isotope.

dalton

Question 21

ION

Answer 21

is an atom that has a positive or negative charge because it has
unequal numbers of protons and electrons

If an atom either gives up or gains electrons, it becomes an ion,

Question 22

Ionization

Answer 22

is the process of giving up or gaining electrons.

Question 23

molecule

Answer 23

When two or more atoms share electrons, the resulting combination

A molecule may consist of two atoms of the same kind

Question 24

compound

Answer 24

a substance that contains atoms of two or
more different elements.

However, a molecule of oxygen (O2) is
not a compound because it consists of atoms of only one element.

Question 25

free radical

Answer 25

A free radical is an atom or group of atoms with an unpaired electron in the outermost shell Free radicals become stable by either giving up their unpaired electron to, or taking on an electron from, another molecule. In so doing, free radicals may break apart important body molecules.

Question 26

chemical bonds

Answer 26

The forces that hold together the atoms of a molecule or a compound are chemical bonds.

Question 27

valence shell

Answer 27

The likelihood that an atom will form a chemical bond with another atom depends on the number of electrons in its outermost shell, also called the valence shell.

Question 28

IONC bond

Answer 28

The force of attraction that holds together ions with opposite charges is an ionic bonds are found mainly in teeth and bones, where they give great strength to these important structural tissues. In general, ionic compounds exist as solids, ex When an atom of sodium donates its sole valence electron to an atom of chlorine, the resulting positive and negative charges pull both ions tightly together, forming an ionic bond

Question 29

CATION

Answer 29

positively charged

Question 30

anion

Answer 30

a negatively charged ion

Question 31

electrolyte

Answer 31

An ionic compound that breaks apart into positive and negative ions in solution are called an electrolyte Most ions in the body are dissolved in body fluids as electrolytes, so named because their solutions can conduct an electric current.

Question 32

Covalent Bonds

Answer 32

two or more atoms share electrons rather than gaining or losing them. The larger the number of electron pairs shared between two atoms, the stronger the covalent bond.

Question 33

Single covalent bond

Answer 33

two atoms share one electron pair.

Question 34

double covalent bond

Answer 34

results when two atoms share two pairs of electrons, as happens in an oxygen molecule

Question 35

triple covalent bond

Answer 35

A triple covalent bond occurs when two atoms share three pairs of electrons, as in a molecule of nitrogen

Question 36

nonpolar covalent bond.

Answer 36

In some covalent bonds, two atoms share the electrons equally— one atom does not attract the shared electrons more strongly than the other atom.

Question 37

polar covalent bond

Answer 37

In a polar covalent bond, the sharing of electrons between two atoms are unequal—the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom. A very important example of a polar covalent bond in living systems is the bond between oxygen and hydrogen in a molecule of water

Question 38

electronegativity,

Answer 38

When polar covalent bonds form, the resulting molecule has a partial negative charge near the atom that attracts electrons more strongly. This atom has greater electronegativity electronegativity - the power to attract electrons to itself.

Question 39

Hydrogen Bonds

Answer 39

The polar covalent bonds that form between hydrogen atoms A hydrogen bond forms when a hydrogen atom with a partial positive charge (δ+) attracts the partial negative charge (δ−) of neighboring electronegative atoms, Thus, hydrogen bonds result from the attraction of oppositely charged parts of molecules rather than from sharing of electrons as in covalent bonds, or the loss or gain of electrons as in ionic bonds. The hydrogen bonds that link neighboring water molecules give water considerable cohesion, the tendency of like particles to stay together.

Question 40

surface tension

Answer 40

The cohesion of water molecules creates a very high surface tension, a measure of the difficulty of stretching or breaking the surface of a liquid.

Question 41

chemical reaction

Answer 41

A chemical reaction occurs when new bonds form or old bonds break between atoms. foundation of all life processes, and as we have seen, the interactions of valence electrons are the basis of all chemical reactions

Question 42

are potential energy

Answer 42

are potential energy, energy stored by matter due to its position (potential to jump but didn't jump)

Question 43

kinetic energy

Answer 43

and kinetic energy, the energy associated with matter in motion. (movement)

Question 44

Chemical energy

Answer 44

form of potential energy that is stored in the bonds of compounds and molecules. The total amount of energy present at the beginning and end of a chemical reaction is the same.

Question 45

law of conservation of energy

Answer 45

Although energy can be neither created nor destroyed, it may be converted from one form to another. This principle is known as the law of conservation of energy. Conversion of energy from one form to another generally releases heat, some of which is used to maintain normal body temperature.

Question 46

Exergonic reactions

Answer 46

Exergonic reactions (ex- = out) release more energy than they absorb.

Question 47

endergonic reactions

Answer 47

endergonic reactions (end- = within) absorb more energy than they release.

Question 48

Activation Energy

Answer 48

the collision energy needed to break the chemical bonds of the reactants is called the activation energy of the reaction This initial energy “investment” is needed to start a reaction.

Question 49

Concentration.

Answer 49

Concentration. The more particles of matter present in a confined space, the greater the chance that they will collide

Question 50

Temperature

Answer 50

As temperature rises, particles of matter move about more rapidly. Thus, the higher the temperature of matter, the more forcefully particles will collide, and the greater the chance that a collision will produce a reaction.

Question 51

Catalysts

Answer 51

chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur catalyst helps to properly orient the colliding particles. Thus, they interact at the spots that make the reaction happen. "enzymes"

Question 52

synthesis reactions. (anabolism)

Answer 52

When two or more atoms, ions, or molecules combine to form new and larger molecules, combine anabolism

Question 53

anabolism

Answer 53

All of the synthesis reactions that occur in your body are collectively referred to as anabolism they are endergonic because they absorb more energy than they release.

Question 54

Decomposition Reactions (catabolism)

Answer 54

split up large molecules into smaller atoms, ions, or molecules. Catabolism

Question 55

catabolism

Answer 55

catabolic reactions are usually exergonic because they release more energy than they absorb. ex the series of reactions that break down glucose to pyruvic acid, with the net production of two molecules of ATP,

Question 56

exchange reactions;

Answer 56

they consist of both synthesis and decomposition reactions.

Question 57

Reversible Reactions

Answer 57

the products can revert to the original reactants.

Question 58

Oxidation–Reduction Reactions

Answer 58

they are the reactions that break down food molecules to produce energy

Question 59

Oxidation

Answer 59

Oxidation refers to the loss of electrons; in the process the oxidized substance releases energy.

Question 60

Reduction

Answer 60

Reduction refers to the gain of electrons; in the process the reduced substance gains energy. are always parallel; when one substance is oxidized, another is reduced at the same time.

Question 61

Inorganic compound

Answer 61

Inorganic compounds usually lack carbon and are structurally simple. cannot be used by cells They include water and many salts, acids, and bases. Inorganic compounds - carbon dioxide (CO2), - bicarbonate ion (HCO3) - carbonic acid (H2CO3).

Question 62

Organic compounds

Answer 62

- always contain carbon, - usually contain hydrogen, - always have covalent bonds.

Question 63

water

Answer 63

We have already mentioned the most important property of water, its polarity The versatility of water as a solvent for ionized or polar substances is due to its polar covalent bonds and its bent shape, which allows each water molecule to interact with several neighboring ions or molecules its inorganic

Question 64

solution

Answer 64

a substance called the solvent dissolves another substance called the solute.

Question 65

hydrophilic

Answer 65

hydrophilic (hydro- = water; -philic = loving), which means they dissolve easily in water. Solutes that are charged or contain polar covalent bonds sugar and salt.

Question 66

hydrophobic

Answer 66

Molecules that contain mainly nonpolar covalent bonds, by contrast, are hydrophobic (-phobic = fearing animal fats and vegetable oils.

Question 67

hydrolysis

Answer 67

break down of molecules into smaller molecules by the ADDITION of water molecules (to loosen or brake apart )

Question 68

dehydration synthesis reaction

Answer 68

dehydration synthesis reaction (de- = from, down, or out; hydra- = water), a water molecule is one of the products formed.

Question 69

mixture

Answer 69

A mixture is a combination of elements or compounds that are physically blended together but not bound by chemical bonds.

Question 70

liquid mixtures

Answer 70

colloid suspension solutions

Question 71

colloid

Answer 71

differsj from a solution mainly because of the size of its particles. milk

Question 72

suspension

Answer 72

suspension, by con-trast, the suspended material may mix with the liquid or suspending medium for some time, but eventually, it will settle out. blood

Question 73

solutions

Answer 73

solutes in a solution remain evenly dis-persed among the solvent molecules. Because solute particles in a solution are very small, a solution looks transparent

Question 74

acid

Answer 74

An acid is a substance that dissociates into one or more hydrogen ions (H+) and one or more anions. Because H+ is a single proton with one positive charge, an acid is also referred to as a proton donor. (below 7ph)

Question 75

base

Answer 75

removes H+ from a solution and is therefore a proton acceptor. Many bases dissociate into one or more hydroxide ions (OH−) and one or more cations. Acids and bases react with one another to form salts. (above 7 ph)

Question 76

buffer systems

Answer 76

functions to convert strong acids or bases into weak acids or bases. buffers. - The chemical compounds that can convert strong acids or bases into weak ones are called buffers.

Question 77

polymers

Answer 77

polymers (poly- = many; -mers = parts).

Question 78

isomers

Answer 78

Molecules that have the same molecular formula but different structures

Question 79

carbohydrates

Answer 79

In humans and animals, carbohydrates function mainly as a source of chemical energy for generating ATP needed to drive metabolic reactions

Question 80

Monosaccharides

Answer 80

contain from three to seven carbon atoms. They are designated by names ending in “-ose” with a prefix that indicates the number of carbon atoms.

Question 81

disaccharide

Answer 81

is a molecule formed from the combination of two monosaccharides by dehydration synthesis.

Question 82

Polysaccharides

Answer 82

tens or hundreds of monosaccharides joined through dehydration synthesis reactions Unlike simple sugars, polysaccharides usually are insoluble in water and do not taste sweet. The main polysaccharide in the human body is glycogen, which is made entirely of glucose monomers linked to one another in branching chains.

Answer 83

Unlike simple sugars, polysaccharides usually are insoluble in water and do not taste sweet. The main polysaccharide in the human body is glycogen, which is made entirely of glucose monomers linked to one another in branching chains.