MIT Biology Flashcards
1
Q
What is the valency of sulfur?
A
2
2
Q
Which five molecule types make up most of the human body (in order)?
A
Water, proteins, carbohydrates, lipids/fats, nucleic acids
3
Q
What do you get if you combine a glycerol molecule with three fatty acids?
A
Triacylglycerol (triglyceride)
4
Q
What is this functional group? -SH
A
Sulfhydryl (aka thiol) group
5
Q
Which field of biological science seeks to purify and fractionate?
A
Biochemistry
6
Q
What do you call an organic compound which contains a carboxyl group?
A
A carboxylic acid
7
Q
How much of the human body is composed of carbon (by atom count)?
A
10%
8
Q
A
9
Q
What is the technical term for fats?
A
Triglycerides
10
Q
Amino group - acid or basic?
A
Basic - the nitrogen has a lone pair that can accept hydrogen protons
11
Q
What molecule is this?
A
Adenosine diphosphate
12
Q
How much of the human body is composed of phosphorus (by atom count)?
A
0.2%
13
Q
How long ago did the first human-like creatures emerge on Earth?
A
5 million years ago
14
Q
What kind of bond is this?
A
Hydrogen bond
15
Q
What is an unsaturated fat?
A
A triglyceride in which at least one double bond is present between carbons
16
Q
Is a sulfhydryl group polar?
A
Yes, weakly.
17
Q
What kind of molecule does this represent?
A
A hydrocarbon
18
Q
What is a saturated fat?
A
A triglyceride in which there are no double-bonds between carbons, meaning all possible bonds with hydrogen are made.
19
Q
What are the three stages of cell respiration?
A
Glycolysis, the Krebs cycle, electron transport chain
20
Q
Is a water molecule polar or non-polar?
A
Polar
21
Q
How long was it between the emergence of life on Earth, and the emergence of the first eukaryotic cells?
A
About 2 billion years
22
Q
How long ago did the Earth cool?
A
4 billion years
23
Q
How are oxygen and hydrogen bonded in a water molecule?
A
Covalent bonds
24
Q
Which type of fats do not occur in nature?
A
Trans fats
25
What is the name of the functional group -OH?
Hydroxyl group
26
What is in a phosphate group?
A phosphorus bonded to four oxygens
27
What is a triglyceride with multiple double-bonds between carbons called?
A polyunsaturated fat
28
What was the first form of life on Earth?
Prokaryotic cells
29
What is the other technical name for triglycerides?
Triacylglycerol
30
What kind of molecule does this represent?
A fatty acid
31
What is this configuration of phospholipids called?
A micelle
32
What is an amino group?
-NH2
33
Why are most polyunsaturated fats liquid at room temperature?
They have multiple double-bonds between carbons, meaning those bonds are rigid so they can be less densely packed. Multiple cis-configured double bonds also cause kinks in the carbon chains which make them even harder to pack densely.
34
What kind of molecule is this?
Triglyceride
35
Which molecule is often thought of as the currency of energy in biological systems?
ATP - adenosine triphosphate
36
Which functional group is this?
Carboxyl group
37
38
When a hydroxyl group is present, what kind of organic compound do we have?
An alcohol
39
Which 6 elements account for most of the human body, in order of proportion?
Hydrogen, oxygen, carbon, nitrogen, phosphorus, sulfur
40
What is this configuration of phospholipids called?
A lipid bilayer
41
What determines how electronegative an element is?
How many protons it has, and how far away they are
42
Define trans fats
These are triglycerides in which there are trans-configured double bonds in the carbon chain. They were created artificially when hydrogen was added to polyunsaturated fats.
43
What are the four macromolecules in organic chemistry?
Proteins, lipids, carbohydrates, and nucleic acids
44
How many hydrogen atoms are in this molecule?
Ten. Assume carbons are at any corner or end of line where another atom is not indicated. Assume hydrogens are bonded to any carbons not already showing four covalent bonds.
45
How much of the human body is composed of sulfur (by atom count)?
\<0.1%
46
Describe how ionic bonding works
One atom "gives" one or more of its valence electrons to another. The resulting positive charge in the giver attracts to the resulting negative charge in the receiver, and they bond together.
47
How many carbon atoms are in this molecule?
Eight - carbon should be assumed at end corner or at the end of any line where no other element is indicated
48
What is in a sulfhydryl group?
-SH
49
What is the valency of nitrogen?
5
50
What is a carbonyl group?
An oxygen double-bonded to a carbon
51
How long ago did the first eukaryotic cells evolve on Earth?
1.5 billion years
52
What is this?
Methyl group
53
What is produced during fermentation?
Carbon dioxide and alcohol
54
Which type of fat is most prone to rancidity?
Polyunsaturated fat
55
What configuration is this isomer in?
Cis
56
What is this?
Amino group
57
Archaea, eukaryote and bacteria are at what level of classification?
Domain
58
What kinds of molecules are hydrophobic?
Non-polar molecules
59
What is the term for the metabolic process that occurs within cells to convert biochemical energy from nutrients into adenosine triphosphate molecules and release waste products.
Cellular respiration
60
61
What does -ose usually indicate?
A sugar
62
How long after creation of the Earth was the first life present?
800 million years
63
Which functional group turns an organic compound into an alcohol?
Hydroxyl group
64
What kind of molecules do you need to make a triacylglycerol?
A glycerol and three fatty acids
65
How long ago was the first life present on earth?
3.7 billion years
66
What are the domains of life?
Archaea, Eukaryote, Bacteria
67
What is Eduard Buchner best known for?
Designing a way to produce fermentation without live yeast cells
68
Which is polar - a hydroxyl group or a sulfhydryl group?
Both are polar, the hydroxyl group more strongly so
69
Which are the two most electronegative types of atoms among the six which make up most of the human body?
Oxygen and nitrogen
70
What is a methyl group?
-CH3
71
Draw a carboxyl group
72
What is the valency of oxygen?
2
73
Carboxyl group - acid or basic?
Acid - the hydroxyl group can easily 'donate' an electron
74
What is in a carboxyl group?
A carbon, double-bonded to an oxygen (carbonyl group) and single-bonded to a hydroxyl group -COOH
75
What word means of a molecule having both hydrophilic and hydrophobic portions?
Amphipathic
76
How much of the human body is composed of nitrogen (by atom count)?
1.4%
77
Which molecule is this?
Adenosine triphosphate (ATP)
78
What is the valency of carbon?
4
79
What is the valency of hydrogen?
1
80
What is the valency of phosphorus?
3
81
How many carbons do most fatty acids have in animals?
16, 18, or 20
82
Most naturally occurring unsaturated fats are in which configuration?
Cis
83
What do we call an oxygen double-bonded to a carbon?
A carbonyl group
84
When a phosphate group breaks from ATP, does it go into a higher or lower energy state?
Lower
85
What is a hydroxy group?
-OH
86
What living substance causes fermentation?
Yeast
87
Which type of macromolecule is not a polymer?
Lipids
88
Why is adenosine triphosphate able to store so much energy?
The phosphate groups in ATP are joined with high energy bonds - because each phosphate group has a negative charge, they repel each other. Bonded in the ATP molecule, they are in a high energy state, and "want" to break out of this bond to achieve a lower energy state.
89
How long did it take for the Earth to cool after its creation?
500 million years
90
What is -NH2?
An amino group
91
What is the name of this molecule?
Glycerol
92
How much of the human body is composed of hydrogen (by atom count)?
63%
93
What do you call a triglyceride in which there are no double bonds between carbons?
A saturated fat
94
What is adenosine triphosphate commonly shortened to?
ATP
95
What configuration is this isomer in?
Trans
96
Is a methyl group hydrophobic or hydrophilic?
Hydrophobic
97
By which process is a triglyceride formed?
Dehydration synthesis
98
How long ago did multicellular life emerge on Earth?
500 million years ago
99
What does ATP stand for?
Adenosine triphosphate
100
What is biochemistry?
The study of chemical processes within and related to living organisms
101
How do phospholipids form cell membranes?
In solution, the hydrophobic hydrocarbon tails align together, between two layers of hydrophilic phosphate heads on either side, forming a phospholipid layer which forms the cell membrane.
102
How are sulfur and oxygen similar and different in terms of bonding?
They both have a valency of 2, and are both electronegative, however sulfur is less electronegative than oxygen.
103
How long ago did homo sapiens first emerge?
About 1 million years ago
104
True or false - proteins account for about 50% of human molecular composition
False - water accounts for about 80% of human molecular composition. Protein accounts for about 50% of dry weight.
105
Describe how hydrogen bonds work
Water is a polar molecule. The oxygen is more electronegative than the hydrogen. The shared electrons from each covalently bonded hydrogen atom therefore spend more time close to the oxygen atom, giving it a partial negative charge and the hydrogen atoms a partial positive charge. The positively charged hydrogen atoms are attracted to the negatively charged oxygen atoms of adjacent water molecules.
106
What is another name for a sulfhydryl group?
Thiol
107
What is -CH3?
A methyl group
108
109
What is cell respiration?
The metabolic process that occurs within cells to convert biochemical energy from nutrients into adenosine triphosphate molecules and release waste products.
110
Which type of fat is usual solid at room temperature?
Saturated fats
111
How much of the human body is composed of oxygen (by atom count)?
24%
112
By which process is energy released from ATP?
Hydrolysis
113
What is a phosphorus bonded to four oxygens?
A phosphate group
114
What is this?
A phosphate group
115
Is a hydroxyl group polar?
Yes (-OH)
116
What is a hexose?
A sugar with six carbons
117
Define amphipathic
Describes a molecule which has both hydrophilic and hydrophobic parts
118
How long ago was the earth formed?
4.5 billion years
119
What does ADP stand for?
Adenosine diphosphate
