All Questions
Tagged with biochemistry carbohydrates
47
questions
29
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2
answers
82k
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Why does fructose reduce Tollen's reagent and Fehling's solution?
Even though fructose is a ketohexose (ketone-containing hexose, a six-carbon monosaccharide), it reduces Tollen's reagent and Fehling's solution. Generally, a ketone does not reduces Tollen's reagent ...
- 26.3k
14
votes
2
answers
5k
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Why starch (amylose) and cotton (cellulose) are so different?
Both amylose and cellulose have the same "monomer" structure (glucose), so what makes them look/form so differently?
- 4,265
14
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1
answer
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How do you identify reducing / non-reducing sugar by looking at structure?
Identifying reducing / non-reducing sugar been confusing me for a while now , I know that reducing sugar contain aldehyde or ketone group . It's easy to identify them in monosaccharides but this ...
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10
votes
1
answer
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Can sugars dissolve in liquid ammonia?
Can monosaccharides and disaccharides dissolve in liquid ammonia due to hydrogen bond formation?
My rationale is that these sugars may be able to form hydrogen bond with ammonia ($\ce{NH3}$).
- 109
10
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2
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Is formaldehyde a carbohydrate?
Formaldehyde has the formula $\ce{CH2O}$, and the ratio of atoms in a simple carb is $\ce{1C:2H:1O}$. This fits the formula of carbohydrates. When I researched this, I found some sources saying that ...
- 435
10
votes
1
answer
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What is the correct way to notate conformation preferences of polysaccharides?
In some webpages (1 or 2) are found the way to notate the conformational preferences of monosaccharides such as furanose and pyranose.
But, it lacks to give a brief description on how to do it with ...
- 2,600
9
votes
3
answers
27k
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How do you recognize a carbohydrate molecule?
I am studying carbohydrates in organic chemistry and I am confused a bit on what they are and how you recognize whether a molecule is a carbohydrate or not. For example, will a carbohydrate always ...
- 1,096
9
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1
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Why do polysaccharides consisting of alpha-glucose have helical structures?
Why do the polysaccharides consisting of alpha-glucose such as starch and glycogen have helical structure, while the one such as cellulose consisting of beta glucose don't display such structures?
The ...
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8
votes
1
answer
2k
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Does cooling a potato change the nature of its carbohydrates?
A talk-show guest of Joe Rogan claimed that cooling a potato after cooking creates "resistant starch" that's better for human consumption
https://www.youtube.com/watch?v=niwqfwA2Lb8
The ...
- 519
7
votes
2
answers
4k
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Can I break starch down into glucose units?
I was wondering if starch can be broken up into individual glucose units. Because on a site I saw, it said that through acid hydrolysis starch can be broken up into amylose and amylopectin. However, ...
- 71
7
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2
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Oxidation of hydroxyl groups of glucose
In all oxidation reactions of glucose, it seems that the aldehyde group alone gets oxidised and none of the hydroxyl groups. In one reaction with nitric acid, the aldehyde group and the terminal ...
- 103
6
votes
4
answers
4k
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Why is fermentation of cellulose to produce biofuel and nutrients so difficult?
The formula for glucose is $\ce{C6H12O6}$ and that of cellulose is very similar $\ce{C6H10O5}$. Glucose can be readily fermented by yeast and other micro-organisms to produce carbon dioxide and ...
- 357
6
votes
1
answer
564
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How is it that fructose has a different metabolic pathway than glucose but yet glucose is converted to fructose?
Fructose is described to have a different metabolic pathway (a more fat-inducing one) than glucose (see: http://healthyeating.sfgate.com/difference-between-sucrose-glucose-fructose-8704.html) as it ...
- 703
6
votes
2
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What does ‘D’ in GADP (glyceraldehyde 3-phosphate) stand for?
Wikipedia says glyceraldehyde-3-phosphate can be abbreviated as G3P, GA3P, GADP, GAP, TP, GALP or PGAL, and many resources seem to use GADP as its abbreviation.
I have no idea where ‘D’ came from. ...
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5
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2
answers
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How does existence of alpha and beta form of glucose prove that it exists as a cyclic structure
My book says that
Glucose is found to exist in two different crystalline forms which are
named as $\alpha$ and $\beta$.
Next it says that
This behaviour could not be explained by the open ...
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