3: The Chemistry of Life Flashcards

Module 1, Lesson 3

1
Q

Life depends on the ____ of the molecules that make up cells.

A

Chemical properties

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2
Q

The smallest stable component of cells are…

A

Atoms

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3
Q

Atoms are made up of smaller, unstable particles called…

(three items)

A

Protons, neutrons, and electrons

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4
Q

What is the charge of a proton?

A

Positive

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5
Q

What is the charge of a neutron?

A

Neutral / no charge

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6
Q

What is the charge of an electron?

A

Negative

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7
Q

Protons and neutrons are located in an atom’s…

A

Nucleus

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8
Q

True or false:

Most of the volume of an atom is empty space.

A

True

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9
Q

An atom’s interactions with other atoms are influenced by its…

A

Electrons

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10
Q

The ____ represents atoms as a nucleus surrounded by rings representing orbitals.

A

Bohr model

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11
Q

A substance that can’t be broken down into another substance by chemical means is called an…

A

Element

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12
Q

The number of protons in an element is its…

A

Atomic number

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13
Q

The amount of a substance is its…

A

Mass

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14
Q

The force exerted by gravity on an object is its…

A

Weight

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15
Q

The sum of the masses of an atom’s protons and neutrons is its…

A

Atomic mass

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16
Q

Atomic mass is measured in…

A

Daltons

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17
Q

1 Dalton equals…

A

The mass of a proton or a neutron

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18
Q

Only ____ elements are regularly found in living systems.

A

12

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19
Q

Most of an organism’s mass is made up of…

(four items)

A

Carbon, oxygen, hydrogen, and nitrogen

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20
Q

Carbon-containing molecules are known as…

A

Organic molecules

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21
Q

Atoms of the same element that have different numbers of neutrons are called…

A

Isotopes

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22
Q

An electron’s energy level is related to its distance from the…

A

Nucleus

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23
Q

Energy is required to move an electron ____ the nucleus.

A

Away from

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24
Q

Moving an electron towards the nucleus ____ energy.

A

Releases

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25
Q

Electrons occupy discrete energy levels called…

A

Quanta

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26
Q

Chemical properties repeat every ____ elements.

A

Eight

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27
Q

Most elements necessary for life have no more than ____ valence electrons.

A

Eight

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28
Q

An atom’s chemical behavior is determined by…

A

How many of its valence positions are filled

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29
Q

Elements with all eight valence electrons tend to be…

A

Unreactive

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30
Q

The octet rule states that…

A

Atoms tend to want to establish completely full outer energy levels

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31
Q

Atoms with an electrical charge are called…

A

Ions

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32
Q

An ion that is positively charged (has more protons than electrons) is called a…

A

Cation

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33
Q

An ion that is negatively charged (has more electrons than protons) is called an…

A

Anion

34
Q

In biological systems, reactive elements usally exist as…

A

Ions

35
Q

A group of atoms held together in a stable association is called a…

A

Molecule

36
Q

A molecule that contains atoms of two or more elements is called a…

A

Compound

37
Q

Models that we can use to visualize molecules include…

(three items)

A

Bohr model, ball-and-stick model, space-filling model

38
Q

A strong, stable interaction formed through the sharing of electron pairs is called a…

A

Covalent bond

39
Q

True or false:

Electrons in covalent compounds are always shared equally.

A

False

40
Q

When charge distribution is not equal in a covalently-bonded molecule…

A

The molecule has regions of partial positive and negative charge

41
Q

A covalent bond or molecule where electrons are not shared equally is considered…

A

Polar

42
Q

When atoms share more than one pair of electrons, a ____ forms.

A

Multiple bond

43
Q

The strength of a covalent bond depends on…

A

The number of shared electrons

44
Q

List the three main types of chemical bonds

A
  1. Covalent
  2. Ionic
  3. Hydrogen bonding
45
Q

Which type of chemical bond is the strongest in living cells?

A

Covalent

46
Q

Which type of chemical bond depends on attractions between positively and negatively charged ions?

A

Ionic

47
Q

In ionic bonds, atoms form a ____ structure.

A

Crystal

48
Q

Which type of chemical bond can be described as the “sharing” of a hydrogen atom?

A

Hydrogen bonding
(H-bonding)

49
Q

Water molecules can form hydrogen bonds with which two kinds of molecules?

A
  1. Other water molecules
  2. Polar organic molecules
50
Q

Water is able to form hydrogen bonds with other polar molecules because…

A

The charge distribution in these molecules in unequal.

51
Q

Life functions around the properties of…

A

Water

52
Q

List the properties of water that are critical for life on Earth.

(six items)

A
  1. Cohesion
  2. Adhesion
  3. High specifc heat
  4. High heat of vaporization
  5. Less dense in its sold form
  6. Acts as a solvent
53
Q

Water is able to exist as a liquid on Earth because of the effects of…

A

Cohesion

54
Q

Water molecules are attracted to ____ molecules.

A

Other polar

55
Q

True or False:

Water will adhere to any material it can form hydrogen bonds with.

A

True

56
Q

Adhesion can enable molecules to overcome…

A

Gravity

57
Q

Because water has a high specific heat…

A

It heats slowly and loses heat slowly.

58
Q

The heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius is the…

A

Specific heat

59
Q

Organisms can maintain a constant internal temperature because…

A

Water has a high specific heat

60
Q

The energy needed to change 1 gram of a substance from a liquid to a gas is the…

A

Heat of vaporization

61
Q

The heat of vaporization reflects the energy needed to break ____ bonds

A

Hydrogen

62
Q

Organisms are able to stay cool in high temperatures because…

A

Water has a high heat of vaporization

63
Q

Aquatic organisms are able to survive beneath ice in winter because…

A

Ice is less dense than water

64
Q

If a molecule can interact with water, it will also be ____ in water.

A

Soluble

65
Q

The molecule being dissolved in water is called the…

A

Solute

66
Q

True or false:

Nonpolar molecules cannot form hydrogen bonds with water.

A

True

67
Q

Molecules that cannot form hydrogen bonds with water are called…

A

Hydrophobic

68
Q

Hydrophobic molecules ____ in water.

A

Cluster

69
Q

Molecules that have both hydrophobic and hydrophilic regions are considered…

A

Amphipathic

70
Q

True or false:

Water rarely forms ions spontaneously.

A

True

71
Q

The pH scale measures the concentration of ____ in solution.

A

Hydrogen ions

72
Q

A difference of 1 on the pH scale represents a ____ change in hydrogen ion concentration.

A

Tenfold

73
Q

Solutions with a higher pH value have ____ hydrogen ion concentration.

A

Less

74
Q

Solutions with a lower pH value have ____ hydrogen ion concentration.

A

Greater

75
Q

The pH of pure water is…

A

7

76
Q

A substance that dissociates in water to increase the concentration of hydrogen ions is called a(n)…

A

Acid

77
Q

A substance that dissociates in water to decrease the hydrogen ion concentration is called a(n)…

A

Base

78
Q

A substance that resists changes in pH is called a…

A

Buffer

79
Q

Human blood is a…

A

Buffer system

80
Q

In human blood, the acid component is…

A

Carbonic acid

81
Q

In human blood, the base component is…

A

Bicarbonate