Question

This are organic chemistry assignments, sorry if it's long but i appreciate any help i can get

7. What is the name for the enantiomer of D-fructose?

	A. D-glucose
	B. L-glucose
	C. L-galactose
	D. L-fructose 10.Which monosaccharide is not a reducing sugar? A. glucose B. galactose C. fructose D. all the monosaccharides are reducing sugars. 11. Which disaccharide is not a reducing sugar? A. maltose B. lactose C. sucrose D. all the disaccharides are reducing sugars.

12.Is this reaction an oxidation or reduction?

	A. oxidation
	B. reduction 13. Sucrose is a disaccharide formed from which monosaccharides? A. glucose and glucose B. glucose and fructose C. fructose and galactose D. glucose and galactose 14. All monosaccharides can undergo hydrolysis. A. True B. False 15. All disaccharides can undergo hydrolysis. A. True B. False

17. Polysaccharides consist of repeating galactose units joined by glycosidic bonds.

	A. True
	B. False 20. When starch is converted to glucose, this is an example of a hydrolysis reaction. A. True B. False

Answer 1

Q7) The enantiomer of D- glucose is L - glucose.

For all D - sugars the enantiomers are their L- counterparts.

Q10) All monosaccharides are reducing sugars, as thir cyclic structures are only hemiacetals, which are in equilibrium with the open aldehyde or ketone that tautomerizes to aldehydeic group in solution. thus all monosccharides are reducing sugars.

Q11) All disaccharides are reducing sugars except sucrose.

In sucrose a glucose and fructose are bonded the the glycosidic linkage at the anomeric carbon of both. Thus sucrose is a non-reduing sugar.

Q12) The given reaction is reduction as the keto group of reactant is reduced to alcohol in the product.

Q13) Sucrose is formed form one molecule of glucose and one molecule of fructose.

Q14) False. MOnosccharides are the ones which do not undergo any hydrolysis.

Q15) True. all disaccharides undergo hydrolysis to give two units of monosaccharides (same or different)

17) False.

Polysaccharides may contain varius monosaccharides. like glucose , fructose or galactose.

20) True. Starch hydrolysed to give glucose as the monosaccharide unit.