Quiz time …..Carbohydrates

man-thinking

Hey guys, here is a short relatively easy quiz on Carbohydrates. Please attempt and have fun!

  1. 1. Monosaccharaides, such as ribose, fructose, glucose, and mannose differ significantly in

    1. Their sweetness.
    2. The positions of their carbonyl groups.
    3. Their diastereomeric configurations.
    4. Their number of carbon atoms.
     

    a. 1, 2
    b. 1, 3, 4
    c. 1, 2, 4,
    d. 2, 3, 4
    e. All of the above
     

2. Boat and chair conformations are found

a. In pyranose sugars.

b. In furanose sugars.

c. In any sugar without axial -OH groups.

d. In any sugar without equatorial -OH groups.

e. Only in a-D-glucopyranose.

3. Which polysaccharise is used as storage in animals?

a. Amylose

b. Glycogen.

c. Keratin.

d. Cellulose

e. Starch.

4. Cellulose, a b(1->4)-linked glucose polysaccharide, differs from starch in that starch is

a. a b(1->6)-linked mannose polysaccharide

b. a b(1->6)-linked glucose polysaccharide.

c. An a(1->6)-linked glucose polysaccharide.

d. An a(1->4)-linked glucose polysaccharide.

e. An a(1->4)-linked mannose polysaccharide.

5. The glycosidic bond

1. Joins glucose and fructose to form sucrose.

2. In sucrose is hydrolyzed by bees to make honey from nectar.

3. In maltose is not hydrolyzed in “lactose intolerant” humans.

4. In lactose is hydrolyzed by human infants to make two galactose monosaccharaides.

a. 1 only
b. 1, 2
c. 1. 2, 3
d. 2, 3, 4
e. All of the above

.

6. Cellulose fibers resemble ___ in proteins; whereas a-amylose is similar to ___.

a. a-helices; b-sheets.

b. b-sheets; a-helices.

c. b-sheets; the hydrophobic core.

d. a-helices; b-turns.

e. b-turns; coiled-coils.

7. All of the following are carbohydrates EXCEPT:

a. starch

b. glycogen

c. chitin

d. cholesterol

e. glyceraldehyde

8. Which of the following is a simple sugar or monosaccharide?

a. Sucrose

b. Galactose

c. Maltose

d. Lactose

e. Cellulose

9. Carbon can form ___ separate bonds with other elements?

a. 1

b. 2

c. 3

d. 4

e. 5

10. Sucrose is made from two monosacchrides whose name are…..

a. Fructose and Galactose

b. Two Glucose Units

c. Glucose and Fructose

d. Dextrose and Galactose

e. Mannose and Dextrose

11. . How is glucose stored in animals?

a. As dextrose in pancreas

b. As glycogen in liver & muscles

c. As cellulose in thighs & abdominal cavity

d. As protein & cellulite in adipose tissue

e. As starch in starch granules

12. When digesting a complex carbohydrate, water is added and simple sugars are obtained through which process?

a. Photosynthesis

b. Condensation

c. Hydrolysis

d. Dehydration

e. Esterification

Liquid Center Chololates…. yumm yummm :D

Manufacture of Liquid-Filled Chocolates

The manufacture of chocolates containing a liquid center is an interesting application of enzyme engineering. The flavored liquid center consists largely of an aqueous solution of sugars rich in fructose to provide sweetness. The technical dilemma is the following: the chocolate coating must be prepared by pouring hot melted chocolate over a solid (or almost solid) core, yet the final product must have a liquid, fructose-rich center. Suggest a way to solve this problem. (Hint: Sucrose is much less soluble than a mixture of glucose and fructose.)
Answer:

Prepare the core as a semisolid slurry of sucrose and water. Add a small amount of sucrase (invertase) [enzyme], and quickly coat the semisolid mixture with chocolate. After the chocolate coat has cooled and hardened, the sucrase hydrolyzes enough of the sucrose to form a more liquid center: a mixture of fructose, glucose, and sucrose.

 

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credits: [http://www2.fiu.edu/~bch3033/probsolns/solutionsch07.pdf ]

A Taste of Honey!!!!!

sweet-as-honey

The fructose in honey is mainly in the beta-D-pyranose form. This is one of the sweetest carbohydrates known, about twice as sweet as glucose; the beta-D-furanose form of fructose is much less sweet. The sweetness of honey gradually decreases at a high temperature. What chemical property of fructose could account for this observation?

Answer:

Straight-chain fructose can cyclize to yield either the pyranose or the furanose structure. Increasing the temperature shifts the equilibrium in the direction of the furanose form, reducing the sweetness of the solution. The higher the temperature, the less sweet is the fructose solution.

i think i got it!! 😀

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[credits: http://www2.fiu.edu/~bch3033/probsolns/solutionsch07.pdf

http://25.media.tumblr.com/tumblr_lq825gOZcW1qfw3mwo6_250.gif ]

Another Theodor?? :S

We met Robert Hooke, Matthias Schleiden, Theodor Schwaann and Rudolf Virchow.

So who is Theodore Selliwanoff?? :S

Image

Theodore Seliwanoff (1817 -1895) was a German chemist who invented the Seliwanoff’s test in 1887.

Seliwanoff’s test is a chemical test which distinguishes between aldose and ketose sugars. Ketoses are distinguished from aldoses.

Ketoses Reactions:

The test reagent dehydrates ketohexoses to form 5-hydroxymethylfurfural. 5-hydroxymethylfurfural further reacts with resorcinol present in the test reagent to produce a red product within two minutes. Aldohexoses react to form the same product, but do so more slowly.

Seliwanoff’s Test

½ mL of a sample solution is placed in a test tube. 2 mL of Seliwanoff’s reagent (a solution of resorcinol and HCl) is added. The solution is then heated in a boiling water bath for two minutes.

Carbohydrate Word Search

Find the names of ten carbohydrates:

C C E M R S E O B O C E A O R G E S O T C A L T
L E R A E T U C C E S F R F S Y O E A Y L U O L
B B S L L F E C S Y B T O R G U L O R S C G O U
Y D S T E R S S R E D Y H E D L A R E C Y L G L
S O E O C S O S E O C A A Y L U R L G T E Y Y L
C C R S T R T T D E S E I O E U T L E R N O E Y
T R D E I D C R G O U E E L G T Y Y G Y C T C O
G U T R H G U R L D O S G R O C T G R E U L O R
S E R Y T H R O S E E S G A O C D A Y E R T R S
S R T E H E F E S E R O E G E R S T O S B G C Y
E G O O G G L S C C Y O E G H C L S E Y T G T O
E D C H D E O O L U U N L T R E E S O C U L G Y
C E O T A C E B B Y M Y G S C G T G L T O L C S
U U G O O A H I L E U E T O T N Y R N C O L S E
E O C T G E O R D L C A L I G A L A C T O S E G
E O T O L E T A S O C O O R A E T U G S A G E E

 

[credit: The Biochemistry Questions Site]

Carbohydrate Crossword

ImageAcross

 3. Minor disaccharide that can be obtained from starch hydrolysis

 5. The main kind of carbohydrate in foods. Also the way in which glucose is stored in plants.

7. The way in which glucose is stored in animals

12. The ketotriose

14. A ketohexose

15. Milk sugar

16. Pentose forming DNA

17. A polyalcohol related to the formation of cataracts in diabetic patients

18. An amino sugar

19. A tetrose

20. A polyalcohol related to the formation of cataracts in patients with galactosemia

21. C-2 epimer of glucose  

Down  

1. The lineal molecule found in starch granules

2. A heteropolysaccharide with anticoagulant effects.

4. A heptose

5. Table sugar

6. An aldohexose found in lactose

8. “Blood sugar”

9. An aldotriose

10. The branched molecule forming starch granules

11. Pentose forming RNA

13. Polysaccharide with a structural role in plants

21. Main disaccharide obtained from starch hydrolysis

[credits : The Biochemistry Questions Site]