Life on This Rock: Section 2 Flashcards
(138 cards)
1
Q
What is the best way to begin to understand complex things?
A
To understand the parts.
2
Q
What is the smallest part of any living thing?
A
An atom or molecule.
3
Q
What is the power supply for the planet?
A
The sun.
4
Q
All life is based on chemistry. What is chemistry based on?
A
The interactions of atoms.
5
Q
True or false? An electron microscope has the ability to examine small molecules and atoms.
A
False. The smallest things most electron microscopes can see are proteins and viruses.
6
Q
What are the building block of chemicals and therefore, life?
A
Atoms.
7
Q
What is the difference between protons and electrons?
A
Protons are positively charged particles that carry mass. Electrons carry no mass and are negatively charged.
8
Q
What is a neutron?
A
Particles that have the same mass as protons, but carry no charge.
9
Q
What kinds of particles are in the nucleus of the atom?
A
Protons and neutrons.
10
Q
What kinds of particles orbit the nucleus?
A
Electrons.
11
Q
How do you find the atomic mass of an atom?
A
Adding the sum of the protons and neutrons.
12
Q
What are elements?
A
Substances that consist of one type of atom.
13
Q
How many naturally occurring elements are there in the world?
A
92
14
Q
Name the top six elements that make up the bodies of living creatures in order.
A
Oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorous.
15
Q
True or false? The atoms of non-living things follow the same basic rules as those of living things.
A
True.
16
Q
What particles have behavior that dictates the interactions of atoms?
A
Electrons.
17
Q
True or false? The charge of a proton can occasionally attract or repulse another atom.
A
True.
18
Q
What kind of state do atoms try to achieve?
A
A stable one.
19
Q
What is the orbit of an electron around a nucleus called?
A
The shell.
20
Q
What is the combination of all shells around a nucleus called?
A
The electron cloud.
21
Q
How many electrons can the first shell of an atom contain?
A
2
22
Q
How many electrons can every shell of an atom hold outside of the first?
A
8
23
Q
When is an atom stable?
A
When its outermost shell is filled.
24
Q
How will atoms attempt to balance their outer shell?
A
They will shed electrons or take electrons form other atoms.
25
What is the official term for the outermost shell of an atom?
The valence shell.
26
How do you find the charge of an atom?
You subtract the number of electrons from the number of protons.
27
What is matter?
Anything that has mass and takes up space.
28
What is an isotope?
Atoms of the same element that differ only in the number of neutrons.
29
Are isotopes stable? What do many isotopes emit?
They are not stable. They may emit radiation.
30
What is the name for a charged particle?
Ion.
31
True or false? The interior of the atom does not participate in bond formation.
True.
32
What does an atom no longer do if its valence shell is filled?
React.
33
What is the atomic number?
The number of electrons and protons in an element.
34
What are the rows on the periodic table called?
Periods.
35
What are the columns on the periodic table called?
Groups.
36
What is an ionic bond?
When two atoms are attracted to each other because they have a positive and negative charge.
37
Do metals form cations or anions?
Cations.
38
Do non-metals form anions or cations?
Anions.
39
What is a covalent bond?
When atoms share electrons to fill each other's valence shell.
40
How does carbon gain a full outer shell?
By sharing electrons.
41
What does a subscript (small letter) after an atomic symbol denote?
How many atoms of that element are in that molecule.
42
What is a molecule?
A combination of atoms via ionic or covalent bonds.
43
What is the chemical symbol for methane?
CH4
44
True or false? An atom will always go for the easiest way to fill its valence shell.
True.
45
Can molecules form from the same types of atoms?
Yes.
46
Complete the phrase. Atoms with similar valence numbers will behave similarly regardless of the number of ______.
Inner shells.
47
Elements in the same ____ will behave similarly.
Group.
48
The interactions atoms will have with other atoms can be predicted by looking at their ______.
Valence electrons.
49
Why are chemical reactions often depicted as equations?
Reactants come in, and products go out. An equation shows how this occurs.
50
Is H2O two covalent or ionic bonds?
Covalent.
51
Why don't noble gases often interact with other atoms?
Because their valence shell is already full.
52
Why do water molecules cling together and bead up on a dry surface?
Because it is a polar molecule with a positive end and a negative end.
53
What is an adhesive molecule?
A polar molecule that clings to other surfaces that are polar.
54
How do plants use the properties of water to survive?
Water evaporates on their leaves and as that happens, they pull water up through the stem. This in turn pulls water from the ground and through the roots.
55
What kind of bond is the attractive forces between water molecules?
Hydrogen bond.
56
Whether a substance is liquid, solid, or gaseous depends on the substance's ______ and _______.
Molecular properties; the local temperature.
57
What happens to water as it freezes?
It expands.
58
Why would lake ecosystems be dramatically different if water did not expand when it froze?
Lakes would freeze from the bottom up, killing plants.
59
How does ice on the surface help organisms in a lake or pond?
It provides insulation and keeps the water below warmer.
60
Why do deserts get extremely cold at night?
Because there is no water in the air to retain the days heat and release it slowly during the night.
61
How does sweating keep us cool?
The water absorbs heat from our bodies.
62
Why does salt dissolve very fast in water?
The positive sodium ion is attracted to the negative side of water, whereas the negative chlorine ion is attracted to the positive side of water.
63
Why does salt cause water to heat faster?
Due to the unique attraction, the ions disrupt hydrogen bonds that would usually require more heating to be disrupted.
64
What does evaporation require in regards to hydrogen bonds?
All the hydrogen bonds to be broken simultaneously.
65
Water is constantly ______ and ______ hydrogen bonds.
Forming; breaking.
66
While constantly forming and breaking hydrogen bonds, what does some of the water continuously split into?
Free hydrogen ions (H+) and hydroxyl ions (OH-)
67
What happens when the free hydrogen ions in water encounter another water molecule?
They can displace one of the hydrogen ions. (Think changing partners in a square dance)
68
What are all the elements in the middle of the periodic table called?
Transition metals.
69
Why is ion displacement of little consequence in pure water?
There are equivalent numbers of each ion.
70
What happens to the balance of H+ and OH- ions when other molecules are dissolved in water?
An excess of one or the other can occur.
71
An excess of H+ ions generates what kind of conditions?
Acidic.
72
An excess of OH- ions generates what kind of conditions?
Basic.
73
What happens if hydrogen chloride is added to water?
It splits into H+ and Cl-, creating a higher concentration of H+ and making acidic conditions.
74
What happens if sodium hydroxide is added to water?
It splits onto Na+ and OH- ions, creating a higher concentration of OH- and basic conditions.
75
Any ion will try to interact with molecules of _____.
An opposing charge.
76
Why do H+ ions have such a great ability to interact with other molecules?
Because they have no electrons and are essentially just a naked proton.
77
What are organic molecules?
Molecules that make up living things.
78
What do many organic molecules have?
Exposed regions with a negative or partially negative charge.
79
Why do many organic molecules have the property of being able to easily attract?
So they can form cells and tissues.
80
What kind of acid is stomach acid?
Hydrochloric acid.
81
How do ulcers form?
When the mucus lining of the stomach is too weak, the hydrochloric acid begins to burn it.
82
True or false? Hydrochloric acid causes heartburn.
True.
83
What is the chemical name for Tums?
Calcium chloride.
84
How does Tums stop heartburn?
It dissolves in your stomach into Ca+ and Cl- ions and the Cl- ions combine with the H+ in your stomach.
85
Why do acids burn?
They deplete the OH- ions within our cells.
86
How do bases injure cells?
They deplete the H+ ions in our cells.
87
What is the amount of acidity in a solution called?
pH (Power of hydrogen ions)
88
What does pure water have a pH of?
7
89
What is the pH of human blood?
7.4
90
What causes blood to be a basic solution?
Dissolved substances taken from cells and tissues.
91
True or false? Blood contains buffers.
True.
92
What are buffers?
Compounds that can absorb OH- or H+ to keep a stable pH.
93
Why are we not as affected by acid rain as marine animals?
Their gills and tissues are directly exposed to the water.
94
True or false? All aquatic organisms are fairly resistant to changes in water pH.
False. Only larger fish are. Aquatic plants, smaller fish, and invertebrates are not.
95
How does acid rain happen?
Sulfur dioxide and nitrogen oxide ions combine with vapor and oxygen to form acids. These acids then come back down as rain.
96
What is the pH of normal rainwater?
5.3
97
Does acid rain raise or lower the pH of rivers and lakes?
Lower.
98
True or false? Extreme acid rain can destroy land plants.
True.
99
The unique properties of _______ make it a central element in life.
Carbon.
100
How many valence electrons does carbon have?
Four.
101
Why does carbon usually form covalent bonds rather than ionic?
It is hard to take on or shed four electrons, but sharing is easy.
102
Can carbon form covalent bonds with itself?
Yes.
103
Why is carbon unique compared to oxygen, nitrogen, and hydrogen?
It can form long chains.
104
Why is carbon such a stable structure?
It forms rings.
105
Chemistry can be seperated into ______ and ______ chemistry.
Inorganic; organic.
106
Organic chemistry refers to the study of molecules primarily composed of ______ and _______.
Carbon; hydrogen.
107
What element do inorganic molecules not contain?
Carbon.
108
What does "organic" refer to when applied to crops, rather than chemistry?
It indicates crops that wee grown without synthetic fertilizers, pesticides, or herbicides.
109
Besides the carbon base, what are the interactions of organic molecules based on?
Their functional groups.
110
What are function groups?
Regions of organic molecules that contain atoms besides carbon.
111
What is a hydrocarbon chain?
A carbon skeleton surrounded by hydrogens with no functional groups.
112
Is a hydrocarbon chain a polar molecule?
No.
113
Why are pure hydrocarbon chains insoluble in water?
The presence of polar functional groups is what allows molecules to dissolve in water.
114
What are the four groups of biological molecules?
Carbohydrates, lipids, proteins, and nucleic acids.
115
What do nucleic acids make up?
Our genetic material.
116
What are monomers?
Molecules that can join with other similar molecules to form chains.
117
What are polymers?
Long chains/assemblies of monomers.
118
How are polymers both formed and broken down?
Water interacts with their functional groups.
119
What is a dehydration reaction?
Formation of a polymer via the removal of a water molecule.
120
What is hydrolysis?
Dissociation of a polymer by adding water molecules.
121
What is the single most important molecule on earth?
Water.
122
What is the percentage range for how much of an organism is comprised of water?
70 - 90%
123
What are some properties of water that support life?
Solvency, cohesion and adhesion, high surface tension, high heat capacity, high heat of vaporization, and varying density.
124
Do water molecules cling more tightly to each other, or the air above?
Each other.
125
Why do water molecules cling so tightly together?
Hydrogen bonds.
126
What is the difference between a solvent and a solute?
A solute gets dissolved, a solvent does the dissolving.
127
Why don't oil and water mix?
Oil is not polar.
128
What are carbohydrates comprised of?
Carbon, hydrogen, and oxygen.
129
Carbohydrate monomers are ______, which we metabolize for quick energy.
Simple sugars.
130
True or false? Carbohydrate monomers can be assembled into polymers for long-term energy storage.
True.
131
Why do simple sugars easily dissolve?
They have numerous OH- groups.
132
How is the energy released from carbohydrates?
By breaking them down.
133
How do complex sugars release energy?
By breaking them down into monomers.
134
What is glycogen?
A short-term storage form for glucose.
135
What is the scientific term for sugar molecules?
Saccharides.
136
What are single-saccharides called?
Monosaccharides.
137
What are polymer saccharides called?
Polysaccharides.
138
What is the storage molecule within plants called?
Starch.
