Exam 3 Phase 3 Flashcards
(180 cards)
1
Q
What are carbohydrates?
A
Alcohols that have aldehyde or ketone function
2
Q
What are monosaccharides?
A
Simple sugars and derivatives with 3 to 9 carbons
3
Q
What are oligosaccharides?
A
Compound formed by linking several monosaccharides together
4
Q
What are polysaccharides?
A
Polymer formed from multiple saccharide units; may be homopolysaccharide or heteropolysaccharide
5
Q
What is a homopolysaccharide?
A
Composed of a single type of monosaccharide
6
Q
What is a hetersaccharide?
A
Composed of multiple types of monosaccharides
7
Q
What is the general formula of a carbohydrate?
A
(CH2O)n
n=1 is formaldehyde
8
Q
What are the diverse functions of carbohydrates?
A
Metabolism, storage, and generation of energy Molecular Recognition Cellular Protection Cell Adhesion Biological Lubrication Maintenance of Biological Structure
9
Q
What are examples of how carbohydrates are used for metabolism, storage, and generation of energy?
A
Glucose, glycogen, and starch
10
Q
What is cellulose?
A
A polymer of glucose; 2 beta linked 1->4 D-glucose units
11
Q
Where is molecular recognition used?
A
In the immune system
12
Q
Where is cellular protection used?
A
Bacterial and plant cell walls
13
Q
Where is cell adhesion used?
A
Glycoproteins
14
Q
Where is biological lubrication used?
A
Glycosaminoglycans
15
Q
Where is maintenance of biological structure used?
A
Cellulose, chitin
16
Q
Monosaccharides can be ______ or _______
A
Ketoses or aldoses
17
Q
What sugar is used in DNA?
A
2-Deoxy-D-Ribose
18
Q
What does reduction of dihodroxyacetone by NADH produce?
A
A sugar alcohol
19
Q
What are the simplest monosaccharides?
A
They are derivatives of glycerol
20
Q
What is an epimer?
A
Any sugar in which one location of -OH has been altered, both will be L-L or D-D
21
Q
What is the orientation of most amino acids?
A
L
22
Q
What is the orientation of most sugars and what is the exception?
A
Most sugars are D but some glycoconjugates have L isomers
23
Q
Give an example of epimers?
A
D-Erythrose and D-threose
24
Q
What are the epimers of glucose?
A
Mannose (at C2)
Galactose (at C4)
25
What is a furanose and how is it made?
A 5 membered ring, made when OH of C4 attacks C1
26
What is a pyranose and how is it made?
A 6 membered ring, made when OH of C5 attacks C1
27
What does creating furanose do?
It makes 1 more stereocenter
28
What does cyclization do?
It creates a new asymmetric center
29
What is the new center created in cyclization called?
It is called an anomeric center and is designated as alpha or beta
30
What is the alpha orientation?
OH of anomeric carbon faces down
31
What is the beta orientation?
OH of anomeric carbon faces up
32
How do anomers interconvert?
Spontaneously in solution by mutarotation
33
What are the anomers of glucose?
1/3 alpha
| 2/3 beta
34
What does the reduction of a sugar carbonyl yield?
An alditol
35
What does the reduction of glucose yield?
D-glucitol, also called sorbitol
36
What does oxidation of C1 form?
An aldonic acid
37
What does oxidation of C6 form?
A uronic acid
38
What is the aldonic acid in equilibrium with?
The lactone
39
What types of sugars can be oxidized?
Reducing sugars
40
How can monosaccharides be oxidized?
Only in the linear form
41
What is an oxidase?
Introduces O2 but not in the final compound
42
What is an oxygenase?
Introduces O2 in the final compound
43
What amino acids does glucose react with?
Valine or epsilon Lys in hemoglobin
44
What is the extent of glycation proportional to?
The concentration of glucose
45
What occurs after glycation?
A series of reactions that may give damaging products
46
Why is too much glucose bad?
It can cause it to react with hemoglobin and it will continue reacting to form a stable product called glycylated hemoglobin that can cause damage to the body
47
What yields an O-glycoside?
The elimination of water between the hydroxyl group of the anomeric carbon of a cyclic saccharide and the hydroxyl group of another compound
48
What is the bond that is formed in a glycoside called?
A glycosidic bond
49
What is the activated sugar in lactose biosynthesis?
UDP galactose
50
What do you use anytime you make a polymer?
UDP
51
How do you know if the sugar is a reducing sugar?
If you can make the anomeric carbon an aldehyde. AKA if it is a hemiacetal
52
What is a glycosidic bond (technically)?
An acetal
53
Where is a glycosidic bond present?
Present in polysaccharides
54
What is the activated sugar in lactose biosynthesis?
UDP-Galactose
55
What is UDP?
A nucleotide diphosphate that you use any time you want to make a polymer
56
How do you know if a sugar is a reducing sugar?
If you can open up the anomeric carbon to make an aldehyde
57
What is a glycosidic bond, technically, and where is it present?
It is technically an acetal and is present in polysaccharides
58
What is a souped aldehyde?
A hemiacetal (present in sugar rings)
59
What does sucrose do?
Protects glucose from oxidation
60
What is an example of a reducing sugar?
K=Lactose
61
What are examples of non-reducing sugars?
Sucrose and trehalose
62
What are the two components of starch?
Linear amylose and branched amylopectin
63
Where does amylopectin branch?
alpha 1 and 6
64
Compare glycogen and amylopectin
Glycogen is the animal version of amylopectin and it is more branched than amylopectin
65
Where is the linear connection in amylose?
alpha 1-4
66
What is the secondary structure of amylose?
The orientation of successive glucose residues favors the formation of a helix with a large interior core and stabilized by hydrogen bonds
67
What are the linkages of cellulose?
Beta 1->4 linkages
68
Compare chitin and cellulose
Chitin has the linkage of cellulose but between N-acetyl glucosamine units
69
Why is chitin so hard to break?
Because of the N-groups in it
70
What is agarose?
It has charged groups of sulfate and pyruvate. It can trap a large amount of water forming a gel which is the base for electrophoresis
71
What are glycoconjugates?
Large and present and present in the cell surface or extracellular matrix
72
What do glycoconjugates serve as?
Serve as sites for recognition, affinity binding for lectins, signal transduction, etc.
73
What are the 3 amino acids used in glycoconjugates?
Asn, Ser, Thr
74
Compare glycoproteins and proteoglycans
Glycoproteins are smaller
75
Where does the anomeric carbon of a glycoprotein attach?
To Ser, Thr, or Asn
76
What percentage of proteins are glycosylated?
About half
77
Where does trehalose come from?
Mushrooms
78
What are the two types of glycoprotein linkages?
O linked and N linked
79
What enzyme does Type A blood have?
GalNAc glycosyltransferase
80
What enzyme does type B blood have?
Gal Glycosyltransferase
81
What enzyme does type AB blood have?
Both GalNAc glycosyltransferse and Gal glycosyltransferase
82
What enzyme does type O blood have?`
Neither GalNAc glycosyltransferase nor Gal glycosyltransferase
83
What is the ABO?
ABO is one of 14 genetically characterized blood group systems with more than 100 different antigens, many found in tissues other than blood
84
What is Erythropoetin A (EPO)?
A glycoprotein with both O and N linked oligosaccharides; a hormone synthesized in the kidney that stimulates production of red blood cells
85
Where are linkages of O and N oligosaccharides present in EPO>
164 amino acid residues with N linked oligosaccharides at Asn-24, 38, and 83. and O linked oligosaccharide at Sea-136
86
When is EPO administered?
During chemotherapy to counteract anemia
87
What do oligos do?
Help stabilize the protein in the blood
88
How is EPO misused?
Recombinant EPO misused by some athletes to improve performance; presumably nonglycosylated
89
What is glucose converted to for storage purposes?
Glycogen, starch, sucrose
90
What is glucose converted to in glycolysis?
Pyruvate
91
What is glucose converted to via oxidation in the pentose phosphate pathway?
Ribose-5-phosphate
92
What are the structural polymers of glucose?
Extracellular matrix and cell wall polysaccharides
93
What brings glucose into the muscle?
Glut 1 and 4 (4 if [glucose]>4)
94
When is glucose committed to the cell?
When it reacts with ATP to form glucose-6-phosphate
95
What is glucose uptake triggered by?
Insulin that commands the movement of glucose transporters
96
What does the absence of insulin cause?
It forces the release of fatty acids as energy sources for ATP production by oxidative phosphorylation
97
What are the ketone body byproducts used for?
They are used by the brain for energy but cause acidosis in blood
98
Why does glucose-6-phosphate turn into fructose-6-phosphate?
Because forming a 5 membered ring is more stable and makes the molecule more symmetrical
99
What happens when the level of glucose-6-phosphate is too high?
The cell recognizes that is does not need anymore and the glucose remains outside of the cell
100
What is hexokinase regulated by?
By the level of glucose-6-phosphate
101
What kind of enzyme is PFK-1?
An allosteric enzyme (binds away from site)
102
What regulated PKF-1?
High [ATP] stops PFK-1
| High [AMP] starts PFK-1
103
What is the committed step determined by?
By the intermediate step
104
What enzyme do we use during exercise and why?
Creatine kinase to produce more ATP
105
What is the oxidation step in glycolysis? (which enzyme)
Glyceraldehyde 3-PO4 dehydrogenase
106
How does hexokinase function in glycolysis?
It covers the whole molecule of glucose except where we want the reaction to happen
107
What are the critical amino acids in the process from glucose-6-phosphate to fructose-6-phosphate?
Glutamate and histidine
108
What is different about allosteric enzymes?
They do not follow the Michaelis Menten equation. It is lower than the normal curve and is sinusoidal
109
What amino acid is found in the formation of Schiff bases?
Lysine
110
What needs to be consumed immediately in glycolysis?
Glyceraldehyde-3-phosphate
111
Describe triode phosphate isomerase?
8 alpha helices, then 8 parallel beta sheets with His and Glu inside
112
What happens once the substrate enters the triode phosphate isomerase?
The enzyme covers the active site to prevent the substrate from leaving
113
Why does the reaction of glyceraldehyde-3-PO4 to 1,3 bisphosphoglycerate go forward?
Because of 2 processes:
1) Oxidation of aldehyde
2) Addition of inorganic phosphate
114
How to thioesters aid a reaction?
They are the critical points that make the reaction favorable because they are so high energy
115
What is in the Rossman fold?
NAD+ (sits close to Cys)
116
What makes the inorganic phosphate attack?
NADH has to leave and NAD+ has to enter
117
What is a mutase?
An isomerase that changes the arrangement of molecules
118
What does phosphoglyerate mutase do?
Uses 2 histones. His PO4 attacks position 1 then the electrons on the N of the His that just attacked take the PO4 to switch the two positions
119
What is the last step in glycolysis?
An irreversible substrate phosphorylation
120
What does amylase do?
It takes everything and breaks it down completely
121
What is the function of alpha amylase in saliva?
It cleaves alpha (1->4) linkages from the nonreducing ends but cannot cleave alpha (1->6) linkage
122
How does digestion continue after amylase?
alpha(1->6) glucosidase is required to remove the limit dextrin which exposes more alpha(1->4) linked saccharides
123
Why does glycogen have so many branches?
Because you want to produce as much glucose as quickly as possible
124
Compare isomerization of glucose phosphate from 1 to 6 to phosphoglycerate from 3 to 2
Isomerization of glucose PO4 uses His while isomerization of phosphoglycerate uses Ser as PO4 carrier
125
What is pyruvate?
A multipurpose material that can be used in catabolic and anabolic processes
126
When does pyruvate turn to lactate?
It reduces to lactate when tissues are insufficiently aerobic to oxidize the NADH from glycolysis
127
What is pyruvate the vehicle for?
For transporting ammonia from muscles to liver via alanine formation
128
What does high pH do?
Activates ATP
129
How do RBC make ATP?
Glucose to pyruvate makes 2 ATP then pyruvate to lactate
130
What does pyruvate make under anaerobic conditions?
2 lactate or 2 ethanol + CO2
131
What does pyruvate make in aerobic conditions?
Acetyl-CoA
132
What is the critical part of vitamin B1 and why?
The thiazolium ring because it can be deprotonated
133
What does TPP do?
Aids in the transformation of pyruvate to lactate because it acts as a nucleophile. This is why Vitamin B1 is so important
134
How much glucose does the entire body need and how much does the brain need?
Whole body requires 160 grams, brain requires 120
135
How much glucose do glycogen reserves provide?
190 g
136
How much glucose is in body fluids?
20 g
137
What is gluconeogenesis?
Synthesis of new glucose
138
How many oz of protein should we consume in one day?
2 oz
139
What is masonic acid?
3 C dicarboxylic acid
140
What is succincic acid?
4 C dicarboxylic acid
141
What is Glutamic acid?
5 C dicarboxylic acid
142
When does gluconeogenesis occur?
When we have low glucose concentration
143
What are the gluconeogenic starting materials?
Lactate, glycerol, amino acids
144
Which organs do gluconeogenesis?
The liver and kidney
145
What are the two main functions of the pentose phosphate pathway?
1) Provide NADPH for general biosynthesis
| 2) Provide ribose-5-PO4 for nucleotide and nucleic acid synthesis
146
What amino acids make glutathione?
Cysteine
Glutamate
Glycine
147
Where do glycolysis and gluconeogenesis occur?
In the cytosol
148
How do we form aspartate?
Oxaloacetate forms it using a transaminase
149
What kind of group is CoA?
A thiol group
150
What amino acid is in CoA?
Adenine
151
Why is lipoic acid critical?
It is a dithiol attached to lysine and it is critical for movement
152
What is important about citrate synthase?
It uses 2 His and an Asp
153
What does aconitase use?
Uses iron sulfur protein (metaloprotein) but the iron is not heme. Has 3 organic S and 4 inorganic S. Organic S comes from cysteine. Used for dehydration rehydration
154
Where do most amino acids come from?
From the krebs cycle
155
What are the two sources of NADPH?
Pentose phosphate pathway and malic enzyme
156
What is the fatty acid transporter?
Carnitine
157
When do we need a transporter?
When the compound has 12 or more carbon
158
What does propynyl-CoA result from?
An odd numbered FA
159
What coenzyme is needed for methyl malonyl mutase?
Coenzyme B12
160
What are the main ketone bodies?
Acetoacetate and D-beta-hydroxybutyrate
161
What are exported as energy for the heart, skeletal muscle, kidney, and brain?
Acetoacetate and D-beta-hydrocybutyrate
162
What does PEP make?
Glucose and the following amino acids:
Ser, Gly, Cys, Phenylalanine, Tyrosine, Tryptophan
It is in equilibrium with oxaloacetate
163
What do you need for the krebs cycle to occur?
Oxaloacetate
164
Why is citrate the carrier for acetyl CoA?
Because it can move in and out of the mitochondria
165
Synthesis of fatty acids occurs where?
The cytosol
166
Catabolism of fatty acids occurs where?
The mitochondria
167
What does succinyl Co-A make?
Pyrophins and heme
168
What does pyruvate make and how?
Acetyl CoA
Oxaloacetate via pyruvate carboxylase
Malata via malic enzyme
169
What does citrate make?
Fatty acids, sterols
170
What does alpha ketoglutarate make?
Glutamate
171
What does glutamate make?
Purines and the following amino acids:
Glu
Pro
Arg
172
What does oxaloacetate make?
Equilibrium with PEP
| Makes aspartate and Asparagine
173
What does asparagine make?
Pyrimidines
174
Where does the glyoxylate cycle occur?
In the glyoxysome
175
apo-C function?
Activates lipase because they have receptors
176
What are chylomicrons?
They are like a cell but they have a single layer and are filled with fats
177
How many electrons do we produce thru beta oxidation for palmitic acid?
28
178
How many acetyl coA do we produce for palmitic acid?
8 acetyl coA
179
How many electrons do 8 acetyl co A produce?
64
180
General steps of beta oxidation?
Oxidation, dehydration, oxidation, fermentation
