Test 1 Flashcards
(131 cards)
1
Q
What is a diastereomer?
A
Stereoisomers that have more than one asymmetric carbon. (There are 8 diastereomeric pairs).
2
Q
What is the general formula of carbohydrates?
A
(CH20)n
3
Q
What do carbohydrate names usually end in?
A
-ose, -an, and -in.
4
Q
What are the functions of carbohydrates?
A
Energy storage and utilization.
Structure (cell wall of plants. GAG’s -glycosyl amino glycans.)
Components of other compounds (nucleic acids and glycoproteins).
5
Q
What’s the structure of carbs?
A
They are organized by levels of complexity:
Monosaccharides, disaccharides, and polysaccharides.
6
Q
What are also simple sugars?
A
Monosaccharides and disaccharides.
7
Q
What is also a complex carb?
A
Polysaccharides.
8
Q
Describe monosaccharides:
A
Lowest complexity.
Single units.
The most common are D-glucose (6 C’s), D-fructose (6 C’s), D-ribose (5 C’s), and D-galactose (6 C’s).
9
Q
What kind of anomers have the OH group facing up?
A
Beta
10
Q
What kind of anomers have the OH group facing down?
A
Alpha.
11
Q
What is the anomeric carbon?
A
The carbon located where the ring closes.
pg. 2
12
Q
Are cyclic or chair structures more stable?
A
Cyclic.
13
Q
What is needed for mutarotation?
A
Free anomeric -OH group.
The sugar must be able to switch back and forth b/w beta and alpha.
(3)
14
Q
What is a disaccharide?
A
Two monosaccharides linked by a glycosidic bond.
(Maltose, sucrose, lactose).
(4)
15
Q
What makes maltose?
A
2 Glucose.
4
16
Q
What makes sucrose?
A
Disaccharide of glucose and fructose.
4
17
Q
What makes lactose?
A
Disaccharide of glucose and galactose.
18
Q
How do polysaccharides differ from disaccharides?
A
The type of monosaccharides.
Type of glycosidic bonds.
Amount of branching.
(5)
19
Q
What is the overwhelming bulk of carbs in nature?
A
Polysaccharides.
5
20
Q
What is predominantly the fundamental unit of polysaccharides?
A
Glucose.
5
21
Q
Describe amylose:
A
Linear polymer.
Glucose units are linked together in alpha-1,4 glycosidic bonds.
(5)
22
Q
Describe amylopectin:
A
Has more of a branching effect (more efficient than linear).
Has alpha-1,4 bonds with alpha-1,6 bonds.
(5)
23
Q
Describe glycogen:
A
“Animal starch”.
Storage form of glucose –primarily in muscle (1%) and liver (5%).
Similar to amylopectin, but has more branching (b/c of the alpha-1, 4 and alpha-1,6 bonds).
24
Q
What are glycosaminoglycans (GAG’s)?
A
Polymers of repeating disaccharide units containing an amino sugar and usually glucuronic acid and/or sulfated sugars.
(GAG’s are important components in connective tissue and present in all interstitium).
(6)
25
What are 3 types of GAG's?
Chondroitin sulfate.
Hyaluronic acid.
Keratan sulfates.
(6-7)
26
What is the larger GAG?
Hyaluronic acid (~50,000 repeats).
| 7
27
What are GAG's components of?
Proteoglycans.
(GAG's are often found associated with proteins).
(7)
28
What is the nature of GAG's that makes them good for binding H2O?
They're hydrophilic.
| This makes them like a big molecular sponge
29
What are the 2 functions of proteoglycans in the interstitium?
Act as cusions: Protect against mechanical shock (The bond water molecules to provide some give in the structure).
Serve as molecular sieves: The proteoglycans let smaller molecules pass, but not larger structures like bacteria.
30
In cartilage, what are the additional roles of proteoglycans?
B/c of their hydrophilic nature, cartilage is made stiff by being swollen w/H2O bound to PG's. These structures play a key role in joint movement (compliance).
Movement of H2O helps deliver nutrients to the chondrocytes which is indirectly controlled by the proteoglycans (GAG's).
(8)
31
How is water critical in the binding in cartilage?
When there is compression (incr. pressure), water leaves.
When pressure is decr., water enters -> relaxed tissue.
(8)
32
Describe cellulose:
B-1,4 polymer of glucose.
Most abundant organic compound in nature.
Linear polymer (forms sheets).
Part of good fiber (roughage).
(9)
33
Describe glycoproteins:
Largely a protein str.
Contains a limited # of saccharide units.
Often linked to serine and threonine.
(Protein that has a carb attached).
(9)
34
What is hydrolysis?
Addition of h2o to break glycosidic bonds.
| 11
35
What are 2 of the main products of amylase?
Maltose and dextrins.
(Found in saliva).
(Usually breaks A-1, 4 glycosidic bonds at alternating sites).
(11)
36
Describe the breakdown of high fructose corn syrup:
Starch (add amylase) --> maltose and dextrins (add glucoamylase) --> glucose (add glucose isomerase) --> fructose.
(glucoamylase breaks the A-1,4 and A-1,6 glycosidic bonds).
(11)
37
What is a lipid?
Molecules that are soluble in nonpolar solvents.
| Main lipids include f.a., trigly., phosphates, terpenes, and steroids
38
Describe fatty acids:
Long chain carboxylic acids.
| Usually have even # of carbons, no branching, and cic C=C bonds.
39
What are the 2 short chain f.a.'s that are digested in the stomach?
(12)
Butyric and caproic.
40
What are the 2 most common saturated f.a.'s?
| 12
Palmitic.
| Stearic.
41
What are the 2 monounsaturated f.a.'s?
| 12
Palmitoleic.
Oleic.
(12)
42
What are the 3 polyunsaturated f.a.'s?
| 12
Linoleic.
Linolenic.
Arachidonic.
43
What are 2 essential f.a.'s?
| 12
Linoleic.
| Linolenic.
44
What causes a bend in the str. of lipids?
CIS C=C bond.
45
Describe a trans-f.a.:
The trans bond gives a straight-chain str.
The trans bond forms during processing.
Behaves more like a solid.
More stable and not naturally occurring.
46
What is the most common short hand notation for A-linolenic acid?
(13)
18:3 W3
| 18 C's, 3 dbl. bonds
47
What is a main physical property of f.a.'s?
| 13
They're amphipathic.
| Have both polar and nonpolar sections
48
What is the str. of a micelle?
Spherical with the - section on the outside and + section on the inside.
49
What is the difference b/w saturated and unsaturated f.a.'s?
| 14
Unsat. f.a.'s have CIS C=C bonds that cause a bend in the str. which makes the molecule more liquid-like (fewer forces).
50
Describe triglycerides:
| 15
Neutral fats; storage molecule of fatty acids.
Esters of glycerol and fatty acids.
NONPOLAR.
51
What are the differences b/c fats and oils?
| 15
Fat: Solids at room temp; has relatively more saturated f.a.'s. (Has a bend in their structure).
Oil: Liquids at room temp; has relatively more unsaturated f.a.'s.
52
What is hydrolysis?
Addition of H2O to break ester bonds.
53
What does a lipase do?
| 17
Breaks ester bond in triglyceride.
| Acts as an esterase.
54
What is hydrogenation?
| 17
Hardening.
| eg., oil --> fat
55
What are the 2 types of degradative reactions?
| 18
Oxidation (directly involves C=C; more volatile).
| Peroxidation (involves single e-; preferably with unsat; creates free radicals; more stable).
56
What is the role of anti-oxidants?
| 19
Prevents peroxidation, or reverses it.
57
What is the phospholipid structure?
| 20
```
Phosphate head (polar).
Fatty acid tail (nonpolar).
```
58
What is phosphatidic acid composed of?
| 20
3 C backbone w/ 2 lipids.
| Used to make phosphoglycerides.
59
What characteristic does phosphatidylcholine have?
| 21
It's amphipathic.
| Be able to draw it
60
What does the PIP2 (2nd messenger system) yield?
| 22
Diglyceride + Inositol-1,4,5-triphosphate
| DG + IP3
61
What is intermediary metabolism?
| 23
Reactions and processes involving generation, transfer, and utilization of energy-- energy catalyzed reactions.
62
What are the 2 phases of intermediary metabolism?
| 23
Catabolism: degradative; conserved in ATP, etc.
Anabolism: synthetic.
63
Describe catabolism:
| 24
Degradative (larger molecules are degraded to smaller low E molecules).
Release of chemical energy (saved in ATP, etc.).
Oxidative (loss of e-).
Convergent (converge on kreb's cycle).
64
Describe anabolism:
| 24
Biosynthetic (making larger molecules from smaller molecules).
Requires an input of energy (need coupled rxns. using ATP, etc.).
Reductive (usually involves H ions added to e-'s).
Divergent (diverge from the kreb's cycle).
65
What happens in stage 1 of metabolism?
| 25
Polymers Monomers.
| Protein - amino acids; polysaccharides - glucose; lipids - fatty acids
66
What happens in stage 2 of metabolism?
| 25
Monomers Acetyl-CoA (pyruvate).
| Separate pathways involved- catabolic, anabolic
67
What happens in stage 3 of metabolism?
| 25
Kreb's cycle.
68
What are the 3 general characteristics of the basic design of metabolic pathways?
(26)
Limitations of enzyme reactions: complicated reactions need more than one step (glycolysis).
Economical: requires regulation, often multiple regulatory enzymes (feedback mechanisms). More energy conservation (needs multiple coupling steps- multiple ATP's require multiple sites).
Flexibility: More interconversions, regulation. Different inputs, multiple by-products, interconversions (by-product used in another pathway), and more control/regulation needed.
69
How does a decrease in ATP affect metabolic regulation?
| 27
Favors catabolic pathways (will produce more ATP).
| Catabolism: Inhibited by ATP; activated by AMP and ADP.
70
How does an increase in ATP affect metabolic regulation?
| 27
Favors anabolic pathways.
| Anabolism: Activated by ATP; inhibited by AMP and ADP.
71
What are the ways that a metabolic pathway can be regulated?
(27)
Enzyme effects: [S], [P], cofactors, Km, Vmax, pH.
Regulatory enzymes: Allosteric enzymes (heterotropic --> regulatory site); Near beginning of pathway, non-equilibrium step (- change in G), and committed step (can be).
Genetic control: Transcriptional control, gene activation- incr. mRNA (e.g, incr. CH2O...incr. glucokinase activity in liver).
Hormonal: Works at different levels. Insulin (incr. glucose uptake --> more [S]); Epinephrine (cAMP --> enzyme activation- turns on/off enzymes); Cortisol/steroids (gene activation).
72
What are the characteristics of metabolism?
| 28
Gives off heat, conserves energy, uses energy, does chemical work, etc.
73
What is the study of energy exchanges in terms of heat, work, and energy?
(28)
Thermodynamics.
(Gibbs free energy, change in G, is a key variable). /_\ G
```
/_\H = Enthalpy (heat).
/_\S = Entropy (randomness, disorder).
```
74
What is Gibbs free energy, /_\G?
| 28
Essentially dictates whether a process will occur on its own or requires an input of energy.
75
What are the 2 main issues with Gibbs free energy and the 2nd law of thermodynamics?
(28)
Magnitude and sign dictate equilibrium positioning.
Useful in explaining energy exchange (i.e, coupling).
(reacts until reaches keq).
76
Describe the 3 main values for /_\G :
| 28
```
/_\G = 0 --> At equilibrium (no net rxn).
/_\G = (+) --> Endergonic (uphill rxn; keq --> R>P).
/_\G = (-) --> Exergonic (Downhill/spontaneous; @ keq --> P>R)
```
(/_\G => energy lost to satisfy the 2nd law of thermodynamics).
77
How can energy lost be retrieved?
| 28
It can be coupled to an uphill process --> /_\G = useful work.
78
T/F: The entropy (S) of the universe is always changing.
| 29
True.
79
What is the formula for entropy (/_\S)?
| 29
/_\S universe = /_\S system + /_\S surr
--> (+), less ordered
(high entropy- coin flips; low entropy- poker hands).
80
What are the 2 trends in the entropy of chemical compounds?
| 29
S increases with temperature.
| S s < S1 < S g.
81
If keq is >1, then what is /_\G and the direction of the chem. rxn.?
(30)
Negative.
Direction of the chemical rxn is downhill.
(P>R)
82
If keq = 1, then what is /_\G' and the direction of the chem. rxn.?
(30)
Zero.
| No direction.
83
If keq < 1, then what is /_\G' and the direction of the chem. rxn.?
(30)
Positive.
The direction is uphill.
(R>P)
84
How many kcal/g is fat?
| 32
9 kcal/g.
85
How many kcal/g is CH2O?
| 32
4 kcal/g.
86
How many kcal/g is protein?
| 32
4 kcal/g.
87
How does the transfer of chemical energy happen in living organisms?
(32)
Chemical energy is obtained in living organisms from the catabolism of food. This chemical energy is converted to usable energy by way of ATP.
88
Is cellular work catabolic or anabolic?
| 32
Anabolic.
89
What is the cycle for the transfer of chemical energy?
| 32
Food is catabolized into chemical energy and stored/converted to ATP. The ATP is then used through anabolic pathways to do cellular work (coupled to uphill rxns) such as biosynthesis, contraction, motility, active transport, and replication. This breaks down ATP into ADP + Pi.
90
What kind of bonds bind the phosphate groups together in ATP?
(33)
Phosphoanhydride bonds.
| a phosphate ester bond binds the 3 phosphates to the rest of the ATP molecule
91
In ATP chemistry where does the equilibrium lie?
| 33
Far to the right, in favor of the products.
It's a down-hill reaction that can be coupled with an uphill reaction.
The breakdown of ATP rxn has a -7.3 kcal/m /_\G'.
92
What are the 2 contributions to /_\G'?
| 33
```
Electrostatic strain (~pH 7): Negative charged phosphate groups are sitting next to each other; they prefer to be separated in solution.
Resonance stabilization: More delocalized electrons in P and ADP than ATP.
```
93
What are the 3 factors affecting /_\G for ATP hydrolysis?
| 34
pH: At lower pH's, phosphates are protonated.
Mg++, Mn++: Phosphates are often chelated.
Non-standard conditions.
94
What is an example of a molecule with a thiol ester bond?
| 34
Acetyl-CoA.
| refers to the S
95
Why is ATP omnipresent?
| 35
Intermediate /_\G: part of a shuttle system.
Single control: Regulatory tissue; makes regulating pathways easier to have one metabolite that signals high energy or low energy conditions.
Phosphoanhydride bonds are kinetically stable: Since it's kinetically stable it won't breakdown immediately so it requires an enzyme to break.
96
ATP hydrolysis is coupled to an uphill process so that the overall rxn is downhill. What are the 3 major types of cellular work?
(35)
Biosynthesis: anabolic pathways.
Active transport: Na/K pumps.
Muscle contraction: x-bridge mechanism.
(All need coupling mechanisms).
97
T/F: AMP will always involve pyrophosphate.
| 38
True.
| P-P --> 2P
98
What are the functions of carbohydrate metabolism?
| 39
Fuel: Catabolic pathways
Precursor to amino acids (non-essential) and fatty acids (long term fuel storage).
Structural components: glycoproteins, nucleic acids, GAGs.
99
Describe the glucose tolerance test (glucose tolerance curve):
(40)
Involves intake of 75 g of carbs.
Just under an hour after intake the blood glucose levels stop rising and begin to drop.
At about 2 hours it gets back to pre-meal level. (A slight dip is typical; not hypoglycemia).
100
Where does most of the glucose go to?
| 40
Liver (~2/3).
| Adipose, muscle: Use an insulin-dependent carrier in membrane (GLUT-4).
101
What are the typical conditions for hypoglycemia?
| 41
2-5 hours after a meal blood glucose levels are <50 mg/dL. (Due to epinephrine/sympathetic response).
Symptoms include incr. h.r., exhaustion, anxiety, irritability, etc.
102
What can be used for treatment of hypoglycemia?
| 41
Increase protein, complex carbs, small meals (more frequent), no simple sugars, decrease ethanol and caffeine intake.
103
What are the 2 forms of hyperglycemia?
| 41
Diabetes Mellitus: Not an effective insulin response to carb intake. (Family of diseases).
Other endocrine disorders, major disease states, drugs.
104
How does glucose mainly come into the cells?
| 42
```
Facilitated diffusion (via membrane carrier).
This diffusion is made possible b/c of the high glucose concentration of the blood.
```
105
What is GLUT-4?
| 42
```
It's a glucose transporter protein/carrier found in muscle and fat.
Insulin dependent (#'s increase with insulin).
```
106
What are the 2 things phosphorylation does?
| 43
Traps glucose in cells.
| Maintains concentration gradient for facilitated diffusion.
107
What does hexokinase do?
| 43
G-6-phosphate acts as a non-competitive inhibitor (presumably to prevent depletion of blood glucose).
It is found in all cells.
108
What does glucokinase do?
| 43
Induced by insulin in the liver (larger Vmax, Larger Km);
Works at higher glucose levels.
Also no G-6-phosphate inhibition (allows to process more glucose).
Incr. carbs --> Incr. insulin --> incr. GK
109
In the cell, where does glycolysis occur?
| 44
Cytosol.
110
What is the major importance of glycolysis?
| 44
Catabolic pathway that sets up carbs (mainly glucose) for further oxidation in the KREBS CYCLE (requires O2).
111
How many ATP does glycolysis yield?
| 44
2 ATP/glucose.
112
What are the 4 major events in glycolysis?
| 44
Priming: Use of 2 ATP high energy bonds.
Cleavage: Aldolase rxn-cleavage of C6 sugar to 2 C3 sugars.
ATP formation: 2 net ATP's produced.
Lactate formation: LDH rxn (under anaerobic conditions).
113
What is NAD+?
| 49
Nicotinamide Adenine Dinucleotide.
| This is a coenzyme which acts as a hydrogen, electron carrier in oxidation-reduction rxns.
114
When NAD+ is reduced, what does it yield?
| 50
NADH.
115
When NADH is oxidized, what does it yeld?
| 50
NAD+
116
What is know as the pacemaker of glycolysis?
| 50
PFK.
| Down-hill, allosteric enzyme w/reg. site
117
What are the inhibitors (-) of PFK?
| 50
ATP; citrate.
118
What are the activators (+) of PFK?
| 50
ADP; AMP; Fructose-2, 6-bis phosphate (if there's an increase in glucose); Increase glucose
119
Describe the Priming stage of glycolysis:
| 47
One step uses HK, and the other uses PFK.
| Both steps have negative free energy changes (down-hill) due to ATP hydrolysis.
120
What does the cleavage stage entail?
| 48
It's an aldolase rxn.
| Up-hill rxn, which requires a build-up of reactants/removal of products.
121
Describe the ATP formation stage:
| 48
Event for making ATP involving substrate level phosphorylation.
Nets 2 ATP's.
122
What is substrate level phosphorylation?
| 48
ATP formation via phosphate transfer from a metabolic intermediate (versus oxidative phosphorylation).
123
When is ATP produced?
| 48
During the 2nd half of glycolysis.
| Put in 2 ATP to get 4. --> 2 ATP/G net
124
What is responsible for regulation during glycolysis?
| 51
PFK.
HK.
NAD+ availability (NAD+ s needed at step 6 of glycolysis, therefore, somewhere in the cell we need to oxidize NADH + H+ back to NAD+.
125
Describe anaerobic glycolylsis:
| 51
25x faster and gives about 2x faster production of ATP than aerobic glyxolysis.
But, Glucose is used faster. (NOT efficient).
Yields 2 ATP/G.
126
Describe aerobic glycolysis:
| 51
Occurs in the mitochondria.
Produces ~30 ATP/G.
Much slower than anaerobic glycolysis.
127
How are NAD/NADH levels affected in fatigued muscle?
| 52
Levels are lower in fatigued muscle b/c you lose NAD+.
128
Describe the stages illustrated in the anaerobic threshold graph as related to energy expenditure:
(52)
Aerobic exercise: Slower ATP production.
Anaerobic threshold: Healthy untrained = 55-65% of max; trained endurance athlete = >80%.
Intense activity: Faster ATP production.
129
What gets regenerated during alcoholic fermentations?
| 53
NAD+.
| Fermentation = anaerobic glycolysis
130
T/F: DOMS and trigger points are related to lactic acid buildup/formation.
(54)
F. Not related.
131
What are the effects of lactic acid in the muscle?
| 54
Production allows for optimal ATP output (faster) during intense exercise.
But, it lowers pH and may cause muscle fatigue; could cause muscle pain triggered by H+ buildup.
(Lactate levels go back to normal about 30 minutes after exercise; most goes to the liver to be converted to glucose).
