BIO-2 EXAM 1 Carbohydrates

Question 1

Defining Carbohydrates…

Answer 1

“hydrates of carbon” = lots of carbon and water

Sugars are very hydrophilic

often use “-ose” suffix

Question 2

Defining D-Glucose…

Answer 2

Hexose: Six Carbons

Has Aldehyde group: Aldose

Non-superimposable: carbons 2-5 are chiral

Chirality is indicated by which side the OH is on (on the second or fourth carbon)

C4 change makes Galactose, C2 change makes Mamose. The way the C5 chiral carbon is set up, makes it D-Glucose (last chiral atom)

if the aqueous solution they freely interconnect

Question 3

If glucose takes on a ring form, how do you determine alpha and beta groups…

Answer 3

in a ring form the hydroxyl group attached to the end will determine

as if the OH group is down, it is alpha; if it is up, it is beta.

Question 4

Defining D-Galactose…

Answer 4

Hexose: 6 Carbon

Aldose

differs in the chirality of carbon 4

can form rings with differing beta and alpha carbons

Question 5

Defining D-Ribose…

Answer 5

Pentose: 5 Carbons

Aldose

Three Chiral Atoms (last makes it D)

Question 6

Defining D-Fructose…

Answer 6

Hexose: 6 carbons

Ketone: Ketose

Forms a ring through C5-0-C2

Question 7

Combining Carbohydrates…

Answer 7

All of these are monosaccharides

We can combine these units together to make disaccharides (two) and polysaccharides (many)

Maltose is two units of D-glucose. Maltose is D-glucose a beta1→4 D-glucose (Condensation reaction)

Lactose is D-galactose beta1→4 D-glucose

Question 8

Defining Polysaccharides…

Answer 8

Starch: Mostly found in plantsGlucose monomers joined with beta 1→4 linkages

Few branches

Cellulose: Found in plant cell wallsGlucose monomers joined with beta 1→4 linkages

No branches

Glycogen: Animal storage form of glucoseMostly glucose monomers joined with beta 1→4 linkages

Some branches of beta 1→6 linkages