(Unit 1) Chapter 5: The Structure and Function of Large Biological Molecules Flashcards
1
Q
The critically important large molecules of all living things fall into just ___ main classes:
A
Four
Carbohydrates, lipids, proteins, and nucleic acids
2
Q
What are called macromolecules? Why?
A
Carbohydrates, proteins, nucleic acids
On molecular scale, they are huge (e.x. 1 protein may have a mass of well over 100,000 daltons)
3
Q
Define:
Polymer
A
A long molecule consisting of many similar or identical building blocks linked by covalent bonds
4
Q
Define:
Monomers
A
The smaller molecules and repeating units that serve as the building blocks of a polymer
5
Q
How are monomers connected?
A
Through condensation reaction, specifically a dehydration reaction
6
Q
How does a dehydration reaction work?
A
A type of condensation reaction where two molecules are covalently bonded to each other through loss of a water molecule (thus dehydration)
7
Q
Define:
Enzymes
A
Specialized macromolecules that speed up chemical reactions in cells
8
Q
How are polymers disassembled to monomers?
A
Hydrolysis
9
Q
Define:
Hydrolysis
A
A process that is essentially the reverse of dehydration reaction, thus bonds are broken b the addition of water
10
Q
Where does the word polymer come from?
A
Greek polys (many) and meris (part)
11
Q
Where does the word hydrolysis come from?
A
Greek hydro (water) and lysis (break)
12
Q
Carbohydrates include both ______ and ________ of ______
A
Sugar
Polymers
Sugars
13
Q
What are simple sugars known as?
A
Monosaccharides
14
Q
What are disaccharides?
A
Double sugars, consisting of two monosaccharides joined by a covalent bond
15
Q
Define:
Polysaccharides
A
Polymers composed of many sugar building blocks
16
Q
Where does the word monosaccharides come from?
A
Greek mono (single) and sacchar (sugar)
17
Q
What is general formula for a monosaccharide?
A
Some multiple of the unit CH2O
18
Q
List the sources of diversity for simple sugars (3)
A
The location of the carbonyl group (ketoses or aldoses)
The size of the carbon skeleton
The spatial arrangement of their parts around asymmetric carbons
19
Q
Define:
Asymmetric carbon
A
A carbon attached to four different atoms or groups of atoms
20
Q
For sugars, how long do the carbon skeleton range from? What are they called?
A
3 to 7 carbons
Trioses (3-carbon), pentoses (5-carbon), hexoses (6-carbon)
21
Q
Glyceraldehyde and Dihydroxyacetone are:
A
Trioses, glyceraldehyde is an aldose while dihydroxyacetone is a ketone
22
Q
Ribose and Ribulose are:
A
Pentoses, ribose is an aldose while ribulose is a ketone
23
Q
Glucose and Fructose are:
A
Hexoses, glucose is an aldose while fructose is a ketone
24
Q
What is the difference between glucose and galactose?
A
Only differ in the placement of parts (hydroxyl group and hydrogen) around asymmetric carbons
25
Monosaccharides are major _________ for cells; How do cells extract energy from glucose?
Nutrients
| Through cellular respiration
26
Define:
| Disaccharide
Consists of two monosaccharides joined by a glycosidic linkage
27
Define:
| Glycosidic linkage
A covalent bond formed between two monosaccharides by a dehydration reaction
28
What are examples of disaccharides? (List the monosaccharides in their formation in brackets) (3)
Maltose (glucose and glucose), sucrose (glucose and fructose), lactose (glucose and galactose)
29
Where is maltose present?
Where is sucrose present?
Where is lactose present?
Known as malt sugar, used in brewing beer
Known as table sugar
Present in milk
30
In aqueous solutions, glucose molecules, as well as most other sugars form what?
Rings
31
In abbreviated ring structure, what do the corners of the ring represent?
Carbons
32
Define:
| Polysaccharide
A macromolecule, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages
33
What type of linkage is between the two glucose molecules in maltose?
1-4 glycosidic linkage
34
What type of linkage is between the glucose and fructose molecules in sucrose?
1-2 glycosidic linkage
35
Even though fructose is a hexose, it forms a ____-sided ring
Five
36
Plants and animals store ______ for later use in the form of:
Sugars
| Storage polysaccharides
37
What storage polysaccharides do plants use?
Starch, a polymer of glucose monomers
38
Where do plants store starch?
As granules within cellular structures known as plastids, which include chloroplasts
39
How are glucose monomers in starch joined?
1-4 glycosidic linkage
40
What storage polysaccharides do animals use?
Glycogen, a polymer of glucose that is like amylopectin but more extensively branched
41
Where do humans and other vertebrates store glycogen?
Mainly in liver and muscle cells
42
True or False:
| Glycogen stores are depleted in about a day
True, unless they are replenished by consumption of food
43
Organisms build strong materials from:
Structural polysaccharides
44
The polysaccharide _________ is a major component of the tough walls that enclose plant cells. On a global scale, plants produce almost __^__ kg (___ _______ tons) per year
Cellulose
10^14
100 billion
45
What is the difference between starch and cellulose? (2)
In starch, glucose monomers are in alpha formation (they are in beta formation in cellulose)
Starch molecule is mostly helical while cellulose molecules are straight
46
What is the difference between alpha and beta glucose?
In alpha glucose, the hydroxyl group on carbon 1 is positioned below the plane of the ring
In beta glucose, the hydroxyl group on carbon 1 is positioned above the plane of the ring
47
True or False:
| Cellulose is sometimes branched
False, cellulose is never branched
48
The hydrogen bonding between some hydroxyl groups of cellulose, parallel cellulose molecules held together this way are grouped into units called:
Microfibrils
49
Enzymes that digest starch by ___________its alpha linkages are unable to hydrolyze the beta linkages of _________ because of the distinctly different shapes of these two molecules
Hydrolyzing
| Cellulose
50
On food packages, what does "insoluble fiber" mainly refer to?
Cellulose
51
Some ___________ can digest cellulose
Prokaryotes
52
Cows harbour cellulose-digesting prokaryotes in its _____, the first compartment in its _______
Rumen
| Stomach
53
Define:
| Chitin
The carbohydrate used by arthropods (insects, spiders, crustaceans, and related animals) to build their exoskeleton)
54
Define:
| Exoskeleton
A hard case the surrounds the soft parts of an animal
55
True of False:
| Pure chitin is hard
False, pure chitin is leathery but becomes hardened when encrusted with calcium carbonate (a salt)
56
True or False:
| Chitin is found in fungi, who use it instead of cellulose
True
57
Describe the structure of chitin monomer
Similar to glucose monomer of cellulose except that it also has nitrogen containing appendage
58
Compounds called Lipids are group together due to one important trait:
They mix poorly, if at all, with water
59
What is fat constructed from?
Two kinds of smaller molecules: glycerol and fatty acids
60
Define:
| Glycerol
An alcohol with three carbons, each bearing a hydroxyl group
61
Describe the structure of a fatty acid
Has a long carbon skeleton, usually 16 or 18 in length
| The carbon at one end of the chain is part of a carboxyl group
62
In making a fat, ______ fatty acid molecules each join to glycerol by an ____________. The resulting fat is called a _______________
Three
Ester linkage
Triacylglycerol
63
Define:
| Ester linkage
A bond between a hydroxyl group and a carboxyl group
64
What is a triacylglycerol also called?
Triglyceride
65
True or False:
| Fatty acids vary in length and in the number and locations of double bonds
True
66
If there are no double bonds between carbon atoms in the chain of a fatty acid, what is it known as?
Saturated fatty acid (as it is saturated with hydrogen)
67
If there is one or more double bonds in the chain of a fatty acid, what is it known as?
Unsaturated fatty acid
68
The fatty acid will have a kink in the chain wherever:
There is a cis double bond
69
Fat made from saturated fatty acids is called:
Saturated fat
70
The lack of double bonds in saturated fats and flexibility allow the fat molecules to pack tightly in an _________ ___,
Saturated fat
71
Saturated animal fats are _____ at room temperature
Solid
72
Why are unsaturated fats (e.x. fish and plant fats) liquid at room temperature?
The kinks due to cis double bonds prevent molecules from packing together closely
73
Hydrogenating unsaturated fats can also produce fats with _____ double bonds
Trans
74
True or False:
Diet rich in saturated fats is one of several factors that may contribute to cardiovascular disease known as atherosclerosis
True
75
Why are fats useful? (3)
Fats can store more than twice as much energy as starch
Can cushion vital organs such as kidneys
Can also insulate the body
76
Describe the structure of a phospholipid (3)
Only two fatty acids attached to glycerol
The third hydroxyl group of glycerol is joined to a phosphate group (has negative charge)
Additional small molecules (usually charged or polar) can be linked to the phosphate group to form a variety of phospholipids
77
True of False:
| The two ends of phospholipids are both hydrophobic
False, hydrocarbon tails are hydrophobic while phosphate group and attachments form a hydrophilic head
78
When phospholipids are added to water, what happens?
They assemble into a bilayer that shield the hydrophobic sections away from water
79
True or False:
| At the surface of the cell, phospholipids are arranged in a similar bilayer
True
80
Is it true that cells could not exist without phospholipids?
True
81
Define:
| Steroid
Lipids that are characterized by a carbon skeleton consisting of four fused rings
82
What is cholesterol?
A common component of animal cell membranes, also the precursor from which other steroids are synthesized in vertebrates
83
Where is cholesterol synthesized in vertebrates?
In the liver
84
Where does the word protein come from?
Greek proteios (first place)
85
Name the types of proteins (8)
```
Enzymatic proteins
Structural proteins
Storage proteins
Transport proteins
Hormonal proteins
Receptor proteins
Contractile and motor proteins
Defensive proteins
```
86
State the function and example of:
| Enzymatic proteins
```
Selective acceleration of chemical reactions
Digestive enzymes (catalyse hydrolysis of polymers in food)
```
87
State the function and example (3) of:
| Structural proteins
Support
Collagen and elastin provide fibrous framework in animal connective tissues
Keratin is protein of hair, horns, feathers and other skin appendages
88
State the function and example (2) of:
| Storage proteins
Storage of amino acids
Ovalalbumin is the protein of egg white (used as amino acid source for developing embryos)
Casein, protein in milk, is major source of amino acids for baby mammals
89
State the function and example of:
| Transport proteins
Transport of other substances
| Hemoglobin transports oxygen from lungs to other parts of other body
90
State the function and example of:
| Hormonal proteins
Coordination of an organism's activities
| Insulin (hormone secreted by pancreas) helps regulate the concentration of sugar in the blood of vertebrates
91
State the function and example (2) of:
| Contractile and motor proteins
Movement
| Actin and myosin are responsible for contraction of muscles
92
State the function and example of:
| Receptor proteins
Response of cell to chemical stimuli
| Receptors built into nerve cells detect chemical signals released by other nerve cells
93
State the function and example of:
| Defensive proteins
Protection against disease
| Antibodies combat bacteria and viruses
94
Life would not be possible without _______, most of which are ________
Enzymes
| Proteins
95
Define:
| Catalysts
Chemical agents that selectively speed up chemical reactions without being consumed by the reaction
96
What are polymers of amino acids known as?
Polypeptides
97
A protein consists of ___ or ____ ____________, each ______ and ______ into a specific three-dimensional structure
One
More polypeptides
Folded
Coiled
98
What are amino acids?
Organic molecules possessing both carboxyl and amino groups
99
What is the asymmetric carbon in the middle of an amino acid known as?
Alpha-carbon
100
How many types of amino acids are there?
20
101
What are the three types of amino acids?
Nonpolar, polar, and electrically charged
102
Which amino acids are nonpolar? (9)
Glycine, Alanine, Valine, Leucine, Isoleucine, Methionine, Phenylalanine, Tryptophan, Proline
103
Which amino acids are polar? (6)
Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine
104
What are the types of electrically charged amino acids? (2)
Acidic and Basic
105
Which amino acids are electrically charged? (5)
Aspartic acid, Glutamic acid, Lysine, Arginine, Histidine
106
Which electrically charged amino acids are acidic?
Aspartic acid and Glutamic acid
107
Which electrically charged amino acids are basic?
Lysine, Arginine, and Histidine
108
Name the amino acid:
| Gly or G
Glycine
109
Name the amino acid:
| Ala or A
Alanine
110
Name the amino acid:
| Val or V
Valine
111
Name the amino acid:
| Leu or L
Leucine
112
Name the amino acid:
| Ile or I
Isoleucine
113
Name the amino acid:
| Met or M
Methionine
114
Name the amino acid:
| Phe or F
Phenylalanine
115
Name the amino acid:
| Trp or W
Tryptophan
116
Name the amino acid:
| Pro or P
Proline
117
Name the amino acid:
| Ser or S
Serine
118
Name the amino acid:
| Thr or T
Theonine
119
Name the amino acid:
| Cys or C
Cysteine
120
Name the amino acid:
| Tyr or Y
Tyrosine
121
Name the amino acid:
| Asn or N
Asparagine
122
Name the amino acid:
| Gln or Q
Glutamine
123
Name the amino acid:
| Asp or D
Aspartic acid
124
Name the amino acid:
| Glu or E
Glutamic acid
125
Name the amino acid:
| Lys or K
Lysine
126
Name the amino acid:
| Arg or R
Arginine
127
Name the amino acid:
| His or H
Histidine
128
Name the abbreviations of amino acid:
| Glycine
Gly or G
129
Name the abbreviations of amino acid:
| Alanine
Ala or A
130
Name the abbreviations of amino acid:
| Valine
Val or V
131
Name the abbreviations of amino acid:
| Leucine
Leu or L
132
Name the abbreviations of amino acid:
| Isoleucine
Ile or I
133
Name the abbreviations of amino acid:
| Methionine
Met or M
134
Name the abbreviations of amino acid:
| Phenylalanine
Phe or F
135
Name the abbreviations of amino acid:
| Tryptophan
Trp or W
136
Name the abbreviations of amino acid:
| Proline
Pro or P
137
Name the abbreviations of amino acid:
| Serine
Ser or S
138
Name the abbreviations of amino acid:
| Threonine
Thr or T
139
Name the abbreviations of amino acid:
| Cysteine
Cys or C
140
Name the abbreviations of amino acid:
| Tyrosine
Tyr or Y
141
Name the abbreviations of amino acid:
| Asparagine
Asn or N
142
Name the abbreviations of amino acid:
| Glutamine
Gln or Q
143
Name the abbreviations of amino acid:
| Aspartic acid
Asp or D
144
Name the abbreviations of amino acid:
| Glutamic acid
Glu or E
145
Name the abbreviations of amino acid:
| Lysine
Lys or K
146
Name the abbreviations of amino acid:
| Arginine
Arg or R
147
Name the abbreviations of amino acid:
| Histidine
His or H
148
Name the amino acid with R group of:
| H-
Glycine
149
Name the amino acid with R group of:
| CH3-
Alanine
150
Name the amino acid with R group of:
| (CH3)2CH-
Valine
151
Name the amino acid with R group of:
| (CH3)2CHCH2-
Leucine
152
Name the amino acid with R group of:
| CH3CH2CH(CH3)-
Isoleucine
153
Name the amino acid with R group of:
| CH3SCH2CH2-
Methionine
154
Name the amino acid with R group of:
| C6H5CH2-
Phenylalanine
155
Name the amino acid with R group of:
| C8H8NHCH2-
Tryptophan
156
Name the amino acid with R group of:
| -CH2CH2CH2
Proline
157
Name the amino acid with R group of:
| HOCH2-
Serine
158
Name the amino acid with R group of:
| (OHCH3)CH-
Threonine
159
Name the amino acid with R group of:
| HSCH2-
Cysteine
160
Name the amino acid with R group of:
| HOC6H4CH2-
Tyrosine
161
Name the amino acid with R group of:
| H2NC(O)CH2-
Asparagine
162
Name the amino acid with R group of:
| H2NC(O)CH2CH2-
Glutamine
163
Name the amino acid with R group of:
| O(-)C(O)CH2-
Aspartic acid
164
Name the amino acid with R group of:
| O(-)C(O)CH2CH2-
Glutamic acid
165
Name the amino acid with R group of:
| H3N(+)CH2CH2CH2CH2-
Lysine
166
Name the amino acid with R group of:
| H2NC(NH2(+))NHCH2CH2CH2-
Arginine
167
Name the amino acid with R group of:
| C3H2NHNH(+)CH2-
Histidine
168
The group that differs on an amino acid is known as:
R group
169
When two amino acids join by a dehydration reaction, what is the resulting covalent bond called?
Peptide bond
170
What are the two ends of a polypeptide chain known as?
```
Amino end (N-terminus)
Carboxyl end (C-terminus)
```
171
True or False:
| A polypeptide is a protein
False, the term polypeptide is not synonymous with the term protein
172
A functional protein is ___ or more ____________ precisely _______, ______, and ______ into a ________ of unique shape
```
One
Polypeptides
Twisted
Folded
Coiled
Molecule
```
173
Describe:
| Globular proteins
Roughly spherical proteins
174
Describe:
| Fibrous proteins
Proteins shaped like long fibers
175
What does a ribbon model show?
Shows how the single polypeptide chain folds and coils to form the functional protein
176
What do the yellow lines in a ribbon model represent?
Cross-linking bonds between the protein peptides that stabilizes its shape
177
What does a space-filling model show?
Shows more clearly the globular shape seen in many proteins, as well as the specific three-dimensional structure unique to certain proteins
178
What can mimic endorphins? Why?
Heroin, morphine, and other opiate drugs
| They share a similar shape with endorphins
179
What are the four levels of protein structure?
Primary, secondary, tertiary, quaternary
180
Define:
| Protein's Primary Structure
The unique sequence of amino acids
181
Define:
| Protein's Secondary Structure
The coils or folds that contribute to the protein's overall shape
182
What are the coils and folds in secondary structure of a protein a result of?
Hydrogen bonds
183
What are the two main types of secondary structures?
Alpha helix and Beta pleated sheet
184
Describe:
| Alpha helix
A delicate coil held together by hydrogen bonding between every fourth amino acid
185
Describe:
| Beta pleated sheet
Two or more regions of the polypeptide chain lying side by side are connected by hydrogen bonds between parts of the two parallel polypeptide backbones
186
Define:
| Protein's Tertiary Structure
The overall shape of a polypeptide resulting from interactions between the side chains (R groups) of the various amino acids
187
What is one interaction that contributes to tertiary structure?
Hydrophobic interaction
188
Describe:
| Hydrophobic interaction
Amino acids with hydrophobic side chains end up in clusters at the core of the protein, out of contact with water
189
In tertiary structure, the shape of a protein may be reinforce further by covalent bonds called:
Disulfide bridges
190
Where do disulfide bridges form?
Form where two cysteine monomers (amino acids with sulfhydryl groups on side chains) are brought close together by the folding of the protein; the sulfur of the two cysteine bond together
191
Define:
| Protein's Quaternary Structure
The overall protein structure that results from the aggression of these polypeptide subunits (some proteins consist of two or more polypeptide chains aggregated into one functional macromolecule)
192
True or False:
| Even a change in the primary structure can affect a protein's shape and ability to function
True
193
What is an example of the effects of the change in primary structure?
Sickle-cell disease; The substitution of valine for glutamic acid causes an exposed hydrophobic region in the secondary/tertiary structure or hemoglobin, which in turn causes crystallization into a fibre (causes the abnormal sickle shape)
194
Define:
| Denaturation
Protein unravelling and losing its native shape
195
Define:
| Chaperonins
Protein molecules that assist in the proper folding of other proteins
196
What are chaperonins also known as?
Chaperone proteins
197
When were the first 3-D structure for proteins worked out? For what?
1959
| Hemoglobin and related protein
198
What first made working out 3-D structures for proteins possible?
X-ray crystallography
199
What is a newer method now used for working out the 3-D structure of proteins? What is different about it?
Nuclear magnetic resonance (NMR) spectroscope
| Does not require protein crystallization
200
What is the newest approach of figuring out the 3-D structure of proteins?
Bioinformatics
201
Define:
| Gene
A unit of inheritance that programs the amino acid sequence of a polypeptide
202
DNA belongs to which group of compounds?
Nucleic Acids
203
What are the two types of nucleic acids in living organisms? What is their function?
```
Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)
Enable living organisms to reproduce their complex components from one generation to the next
```
204
State the flow of DNA to proteins (3)
DNA directs the synthesis of a type of RNA known as messenger RNA (mRNA)
The mRNA moves into the cytoplasm via the nuclear pore
The mRNA interacts with the cell's protein-synthesizing machinery to direct production of a polypeptide, which folds into all or part of a protein
205
Nucleic acids are macromolecules that exist as polymers called:
Polynucleotides
206
What are the monomers of polynucleotides called?
Nucleotide
207
Describe the structure of a nucleotide
Composed of three parts:
A nitrogenous base
A five-carbon sugar (pentose)
A phosphate group
208
What is the portion of a nucleotide without the phosphate group called?
Nucleoside
209
There are ___ families of nitrogenous bases:
Two
| Pyrimidines and Purines
210
Describe:
| Pyrimidines
Have six-membered ring of carbon and nitrogen atoms
211
Describe:
| Purines
Larger, with a six membered ring fused to a five membered ring
212
State the pyrimidines (3)
Cytosine (C)
Thymine (T)
Uracil (U)
213
State the purines (2)
Adenine (A)
| Guanine (G)
214
What sugar is connected to the nitrogenous base in the nucleotides of RNA? DNA?
RNA: Ribose
DNA: Deoxyribose
215
What is the difference between ribose and deoxyribose?
In deoxyribose, the second carbon in the ring lacks an oxygen atom
216
True or False:
| RNA is composed of two polypeptide chains
False, RNA is composed of one polypeptide chain while DNA is composed of two polypeptide chains
217
What is the structure of DNA?
Double helix
218
What are the two ends of nucleotide polymers known as? Why?
5' and 3' ends
| One end has a phosphate attached to a 5' carbon, while the other end has a hydroxyl group on a 3' carbon
219
The two sugar phosphate backbones of DNA run in ________ 5' to 3' directions from each other, referred to as:
Opposite
| Antiparallel
