1st midterm Flashcards by Andrew McKen

How many asymmetric carbons are in a D-glucose molecule? D-fructose? D-ribose?

D-glucose = 4 asymmetric carbons 
D-fructose = 4 asymmetric carbons
D-ribose = 3 asymmetric carbons (5 total carbons)

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T or F: D-ribose forms a hexose?

False; D-ribose (5 carbons) forms a pentose

Glucose, galactose, fructose form hexose

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T or F: Disaccharides and polysaccharides are examples of complex sugars?

False; mono- and disaccharides are simple sugars

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Where are the anomeric -OH and anomeric -C found?

Where the ring closes;

The -OH group connected to the last asymmetric carbon attaches w/ the C originally connected to C=O (aldose, keytose…)

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Is the anomeric -OH group up or down in the Alpha configuration?
What about the Beta configuration?

Alpha = down
Beta = up

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Is D-fructose an aldose, a ketose, or a pentose?

Keytose

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Which carbon is the anomeric carbon on D-fructose?

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What type of bond links two monosaccharides together to form a disaccharide?

Glycosidic bond (requires at least one anomeric carbon)

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What monosaccharides makes up Sucrose?

What is the bond arrangement?

Glucose and Fructose

alpha,beta-1,2 glycosidic bond

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What monosaccharides makes Lactose?

What is the bond arrangement?

Glucose and Galactose

beta-1,4 glycosidic bond

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What monosaccharides make Maltose?

What is the bond arrangement?

2 Glucose molecules

alpha-1,4 glycosidic bond

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Is Amylose a mono, di, or polysaccharide?

What types of glycosidic bonds does amylose have?

Polysaccharide

alpha-1,4 glycosidic bonds

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Is Amylopectin a mono, di, or polysaccharide?

What types of glycosidic bonds does amylopectin have?

Polysaccharide
alpha-1,4 glycosidic bonds, but also has alpha-1,6 glycosidic bonds (every 25-30 glucose units) for branching = more efficient packaging

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Which polysaccharide has more branching, glycogen or amylopectin?

Glycogen

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What are the requirements for a structure to be GAG (glycosaminoglycan)?
(6)

An amine group (NH2) &

Carboxyl group &/or Sulfate sugar (OSO3)

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GAGs are important structural compounds in connective tissue and …. ? (6)

Cartilage

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Because of their hydrophilic nature, proteoglycans serve what two functions in the interstitium?

1) act as cushions

2) serve as molecular sieves (barrier to larger molecules such as bacteria)

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Which GAG is at the center of a proteoglycan?

Hyaluronic Acid

Huge. 50,000 repeats

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Which GAG(s) are on the outside of proteoglycans? (look like mascara brushes?)

Chondroitin Sulfates (beta-1,3 bond)
Keratan Sulfates (alpha-1,4 bond)

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What is cellulose made our of?

Beta-1,4 polymers of glucose

=most abundant organic compound in nature

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Is cellulose digestible?

Is cellulose a linear polymer? What structure does it form?

Non-digestible (part of food fiber)
Linear Polymer
Forms Sheets

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Do saturated or unsaturated fatty acids contain C=C double bonds?

Unsaturated

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In unsaturated fatty acids, are the H+ in the C=C double bonds in the cis or trans conformation?

Cis

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Which has a higher melting point, saturated or unsaturated fatty acids?

Saturated

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Are triglycerides amphipathic? (have a non-polar and a polar end) Are fatty acids amphipathic?

Triglycerides are non-polar and NOT amphipathic (15) | Fatty acids ARE amphipathic (13)

Do trans-fatty acids behave like a solid or a liquid?

Solid (13)

What is the formula for Palmitic fatty acid? | Is it saturated or unsaturated?

CH3 (CH2)14 COOH

What is the formula for Stearic fatty acid? | Is it saturated or unsaturated?

CH3 (CH2)16 COOH | saturated

What is the formula for Palmitoleic acid? | Is it saturated or unsaturated?

CH3 (CH2)5 CH=CH (CH2)7 COOH | monounsaturated

What is the formula for Oleic acid? | Is it saturated or unsaturated?

CH3 (CH2)7 CH=CH (CH2)7 COOH | monounsaturated

What is the formula for Linoleic fatty acid? | Is it saturated or unsaturated?

CH3(CH2)4 CH=CHCH2CH=CH (CH2)7COOH | polyunsaturated *essential

What is the formula for Linolenic fatty acid? | Is it saturated or unsaturated?

CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH | polyunsaturated *essential

Which 2 fatty acids are considered essential?

Linoleic and Linolenic

What do fatty acids placed in water form?

Micelles

What is the product when you hydrolize a triglyceride?

Glycerol and 3 fatty acids

What is it called when you hydrolize a triglyceride with a base?

Saponification | 16

What is the term when you go from a liquid form triglyceride to a solid form triglyceride? Are you going from saturated to unsaturated, or unsaturated to saturated?

Hydrogenation-hardening Unsaturated to saturated (17)

Where do oxidation of triglyceride reactions occur on the triglyceride?

At or near the C=C bond | 18

True or False: When triglycerides are oxidized and short chain fatty acids are formed, they are considered more stable?

False; short chains are more volatile | 18

Does peroxidation involve saturated or unsaturated fatty acids?

UNsaturated b/c C=C bond | 18

What happens when peroxidation occurs?

A single H+ (electron) is lost next to C=C by oxidizers, and a free radical is formed The remaining electron becomes delocalized over all 3 carbons to become more stable (18)

What is the role of anti-oxidants?

Prevent peroxidation or reverse it | 19

Which vitamin is a common anti-oxidant found in a cell membrane?

Vitamin E | 19

Are phosphoglycerides amphipathic?

Yes | 21

True or False: Phosphoglycerides are the predominant component of the lipid by layer?

True | 21

Is increasing the number of bonds to Oxygen a characteristic describing oxidation or reduction?

Oxidation | 24

Is loosing electrons a characteristic describing oxidation or reduction?

Oxidation | 24

In anabolism, do molecules converge on the Kreb's cycle, or diverge from the Kreb's cycle?

Diverge from the Kreb's cycle | 24

Once you pass the "committed step" in a metabolic pathway, is the reaction described as having a (+) or (-) delta G?

Negative | 26

In general, does a decrease of ATP favor anabolic or catabolic pathways?

Catabolic (decreased ATP means will produce more ATP which is done by catabolism) (27)

True or False: Catabolism is activated by ATP and anabolism is activated by AMP, ADP

False: catabolism is inhibited by ATP and anabolism is inhibited by AMP, ADP (27)

Does entropy increase or decrease with increased temperature?

Entropy increases | 29

If products are greater than reactants, is delta G positive or negative? Is this a downhill or uphill reaction?

P>R (Keq>1) means delta G is negative = downhill reaction = exergonic = spontaneous (30)

If reactants are greater than products, is delta G positive or negative? Is this a downhill or uphill reaction?

If R>P, (Keq<1), delta G is positive = uphill reaction | 30

What are the two requirements for a bond to be considered a "high energy bond"?

1) involves reactions with negative delta G | 2) can be coupled to uphill process

Does a lower pH give a more negative or less negative delta G?

Less negative delta G. Phosphates are protonated at lower pH = less electrostatic strain (34)

What affect does Mg(+2) or Mn(+2) have on delta G?

Gives a less negative delta G b/c has less electrostatic strain b/c phosphates are often chelated (ionically attracted) (34)

Are phosphoanhydride bonds kinetically stable? Do they need an enzyme to break these bonds?

Yes, they are chemically stable and need an enzyme to break this bond (35)

True or False: The conversion of ATP to AMP always involves pyrophosphate?

Ture | 38

Where is the majority (2/3) of glucose we consume found?

Stored in the liver as glycogen

True or False: glucose mainly comes into cells via active transport through the cell membrane?

False; glucose enters cells via Facilitated Diffusion due to concentration gradient (42)

What are the 4 major events in glycolosis?

``` Priming Cleavage ATP formation Lactate formation (44) ```

What are the two enzymes involved in the priming step of glycolysis?

Hexokinase (ATP to ADP) PFK (ATP to ADP) Both are downhill reactions (45)

What is the enzyme involved with the cleavage step in glycolysis? Does this step have a negative delta G?

Aldolase This step has a positive delta G = unfavorable = uphill (45)

Ture or False: Formation of lactate from pyruvate marks the end of aerobic glycolysis?

False; formation of pyruvate marks the end of aerobic glycolysis. Making lactate = anaerobic (46)

Which enzyme, hexokinase or glucokinase, has a larger Km value?

Glucokinase | 43

Where does glucokinase enzyme found/work?

In the liver. Has no G-6-phosphate inhibition (like hexokinase) so it can process more glucose (43)

Which enzyme converts a 6-carbon sugar into two 3-carbon sugars in glycolysis?

Aldolase (cleavage) | 48

True or False: Glycerate-1,3-bisphosphate and Phosphoenolpyruvate are high energy phosphate donors?

True | 48

How many ATP's are formed in the first half of glycolysis? the second half?

0 made in the first half, 2 used 4 made in the second half (0 used) Total NET of +2

True or False: The H isozyme of LDH favors lactate formation while the M isozyme favors aerobic metabolism and is inhibited by pyruvate?

False: The M (muscle, liver) isozyme of LDH favors lactate formation while the H (heart, brain) isozyme favors aerobic metabolism and is inhibited by pyruvate, favors aerobic metabolism (49)

1st midterm Flashcards

(71 cards)