Types Of Carbs Flashcards

1
Q

What kind of color, solubility, and taste to monosaccharides have?

A

Colorless
Solubility
Sweet tasting

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2
Q

Sucrose is composed of

A

Alpha glucose-1 and beta fructose-2

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3
Q

Lactose is composed of

A

Glucose and galactose: Beta 1,4

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4
Q

Maltose is composed of:

A

Glucose and Glucose: alpha 1,4

- Less sweet

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5
Q

What are the characteristics of glycosidic bond?

A

Type of covalent bond

  • formed by dehydration reactions
  • anomeric carbon attack OH of another
  • reversible by acid catalyze hydrolysis
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6
Q

What does a glycosyltransferase vs glycosidase do?

A

Glycosyltransferase > form new glycosidic bonds

Glycosidase > break bonds

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7
Q

Starch

A

About 1/4 amylose: alpha 1,4 glucose

About 3/4 amylopectin: alpha 1,4 with alpha 1,6 at branch points

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8
Q

Glycogen and is it more branched than amylopectin?

A

Stored in liver and muscle: breaks down with energy shortage

  • Glycogen: 1-4 alpha glucose linear, 1-6 alpha glucose branched
  • more branched
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9
Q

Cellulose

A
  • beta 1,4 glucose

- humans can’t break down, source of dietary fiber

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10
Q

Chitin, Chitin, Peptidoglycan

A

Cellulose: plants
Chitin: fungi
Peptidoglycan: bacteria capsule

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11
Q

What is a way to think of hemiacetal vs hemiketal in terms of drawing?

A

Draw cyclic glucose and fructose respectively and look at the anomeric carbon

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12
Q

What does the attacking in cyclyzing of carbs?

A

OH nucleophile attacks carbonyl carbon

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13
Q

What would make a carbonyl carbon of sugar more electrophlic?

A

Protonation that adds on a positive charge to the oxygen

- this would make the carbonyl carbon more electrophilic as the electrons are pulled more towards the positive oxygen

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14
Q

What carbon OH causes the formation of a furanose vs pyranose?

A

Carbon 4 OH vs 5 OH intramolecular attack

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15
Q

What is a good LG in glycosidic bond hydrolysis?

A

Protonating the R group of bond, makes it a good LG

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16
Q

Where does the brown food color from?

A

Mallard reaction: 140-165 C

  • faster in basic (coating pretzels with alkaline solution)
  • high temp can create acrylamide
17
Q

What are the substrates in Maillard reaction?

A

Reducing sugars

  • Reducing agents that become oxidized (aldehydes to COOH)
  • Fructose > keto-enol taut
18
Q

How do disaccharides and polysaccharide work as reducing sugars?
Example?

A
  • if they have free end anomeric carbon

- Ex: maltose and lactose

19
Q

What carries out redox reactions with reducing sugars? What kind of agent and some examples?

A

Oxidizing agents: Cu, Ag, Fe

20
Q

What is the tollen’s test? What color and oxidizing agent is used?

A

Silver aq > Silver solid, forms silver color film

21
Q

What is Benedict’s test?

A

Uses copper sulfate as oxidizing agent

- bright blue (Cu2+) > Cu+ aq > brick red

22
Q

What is Fehling’s test? Which other test is it similar to?

A
  • similar to Benedict’s Reagant

- Copper oxidizing agent, looks for reduced sugars in the urine to detect high blood glucose levels