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biology 255 > CHAPTER 2 The Chemical Level of Organization > Flashcards

CHAPTER 2 The Chemical Level of Organization Flashcards

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1
Q

atoms and molecules

A

release or store energy in processes known
as chemical reactions.

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2
Q

Chemistry

A

the science of the structure and interactions of matter

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3
Q

MATTER

A

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

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4
Q

mass

A

The AMOUNT of matter in any object
Which does not change

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5
Q

Weight

A

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.

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6
Q

chemical elements

A

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)

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7
Q

chemical symbol

A

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

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8
Q

Major elements

A

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.

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9
Q

Lesser elements

A

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.

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10
Q

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.

A

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)
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11
Q

Atoms

A

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

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12
Q

subatomic particles

A

protons, neutrons, and electrons

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13
Q

electron shells

A

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.

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14
Q

atomic number

A

The number of PROTONS in the nucleus of an atom

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15
Q

mass number

A

Is the sum of its protons and neutrons

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

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16
Q

isotopes

A

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.

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17
Q

Stable isotopes

A

their nuclear structure does not change over time

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18
Q

Radioactive isotopes (radioisotopes)

A

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.

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19
Q

Half-life

A

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

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20
Q

Atomic mass

A

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

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21
Q

ION

A

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,

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22
Q

Ionization

A

is the process of giving up or gaining electrons.

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23
Q

molecule

A

When two or more atoms share electrons, the resulting combination

A molecule may consist of two atoms of the same kind

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24
Q

compound

A

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.

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25
Q

free radical

A

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.

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26
Q

chemical bonds

A

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

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27
Q

valence shell

A

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.

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28
Q

IONC bond

A

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

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29
Q

CATION

A

positively charged

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30
Q

anion

A

a negatively charged ion

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31
Q

electrolyte

A

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.

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32
Q

Covalent Bonds

A

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.

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33
Q

Single covalent bond

A

two atoms share one electron
pair.

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34
Q

double covalent bond

A

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

35
Q

triple
covalent bond

A

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

36
Q

nonpolar covalent bond.

A

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

37
Q

polar covalent bond

A

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

38
Q

electronegativity,

A

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.

39
Q

Hydrogen Bonds

A

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.

40
Q

surface tension

A

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.

41
Q

chemical reaction

A

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

42
Q

are potential energy

A

are potential energy, energy stored by matter due to its position

(potential to jump but didn’t jump)

43
Q

kinetic energy

A

and kinetic energy, the energy associated with matter in motion.

(movement)

44
Q

Chemical energy

A

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.

45
Q

law of conservation of energy

A

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.

46
Q

Exergonic reactions

A

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

47
Q

endergonic reactions

A

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

48
Q

Activation Energy

A

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.

49
Q

Concentration.

A

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

50
Q

Temperature

A

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.

51
Q

Catalysts

A

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”

52
Q

synthesis reactions. (anabolism)

A

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

combine

anabolism

53
Q

anabolism

A

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.

54
Q

Decomposition Reactions (catabolism)

A

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

Catabolism

55
Q

catabolism

A

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,

56
Q

exchange
reactions;

A

they consist of both synthesis and decomposition reactions.

57
Q

Reversible Reactions

A

the products can revert to the original reactants.

58
Q

Oxidation–Reduction Reactions

A

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

59
Q

Oxidation

A

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

60
Q

Reduction

A

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.

61
Q

Inorganic compound

A

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).

62
Q

Organic
compounds

A
  • always contain carbon,
  • usually contain hydrogen,
  • always have covalent bonds.
63
Q

water

A

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

64
Q

solution

A

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

65
Q

hydrophilic

A

hydrophilic (hydro- = water; -philic = loving), which means
they dissolve easily in water.

Solutes that are charged or contain polar covalent
bonds

sugar and salt.

66
Q

hydrophobic

A

Molecules that contain mainly nonpolar covalent
bonds, by contrast, are hydrophobic (-phobic = fearing

animal fats and vegetable oils.

67
Q

hydrolysis

A

break down of molecules into
smaller molecules by the ADDITION of water molecules

(to loosen or brake apart )

68
Q

dehydration synthesis reaction

A

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

69
Q

mixture

A

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

70
Q

liquid mixtures

A

colloid
suspension
solutions

71
Q

colloid

A

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

milk

72
Q

suspension

A

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

73
Q

solutions

A

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

74
Q

acid

A

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)

75
Q

base

A

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)

76
Q

buffer systems

A

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.

77
Q

polymers

A

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

78
Q

isomers

A

Molecules that have the same molecular formula but different
structures

79
Q

carbohydrates

A

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

80
Q

Monosaccharides

A

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.

81
Q

disaccharide

A

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

82
Q

Polysaccharides

A

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.

83
Q
A

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.

biology 255 (3 decks)

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