Chapter 3.3.1 (Exam 1) Carbohydrates

Question 1

What are some functions of carbohydrates?

Answer 1

Sources of stored energy

Used to transport stored energy

Carbon skeletons for many other molecules

Form extracellular structures such as cell walls

Question 2

What are the 4 types of carbohydrates?

Answer 2

Monosaccharides: Simple sugars

Disaccharides: Two monosaccharides linked by covalent bonds

Oligosaccharides: 3 to 20 monosaccharides

Polysaccharides: Hundreds or thousands of monosaccharides

Question 3

All cells use ________ as an energy source.

Answer 3

glucose

Question 4

What are the two forms of glucose?

Answer 4

Straight chain

Ring form

Question 5

What are the two configurations of ring form glucose?

Answer 5

α-glucose

β-glucose

Question 6

What is the difference between α-glucose and β-glucose?

Answer 6

In α-glucose the hydrogen is on top of the hydroxide attached to the first carbon

In β-glucose the hydroxide is on top of the hydrogen attached to the first carbon

Question 7

Describe how the intermediate form of glucose converts to the α form or β form.

Answer 7

Aldehyde group (-CHO) made from the first carbon can be oriented with the H or the O on top

If the O is on top, it bonds with the loose H after the first C bonds with the O from the other hydroxide to close the ring, forming a β-glucose

If the H is on top, the loose H goes to the bottom to bind with the O, forming an α-glucose

Question 8

What are the two types of monosaccharides (simple sugars)?

Answer 8

Pentoses and Hexoses

Question 9

What are pentoses?

Answer 9

Five-carbon sugars; includes ribose and deoxyribose in RNA and DNA

Question 10

What are hexoses?

Answer 10

Six-carbon sugars; some are structural isomers

Question 11

What is the bond that binds monosaccharides?

Answer 11

Monosaccharides bind together in condensation reactions to form glycosidic bonds to form disaccharides

Question 12

What does disaccharide formation depend on? (i.e. whether something forms sucrose or lactose)

Answer 12

The two monosaccharides involved

Site of bonding (i.e. which C atoms are involved)

Form of bond (i.e. α or β)

Question 13

What disaccharide is made when α-glucose is combined with β-glucose?

Answer 13

Maltose

Question 14

What disaccharide is made when β-glucose is combined with another β-glucose?

Answer 14

Cellobiose

Question 15

What disaccharide is formed when glucose is combined with fructose?

Answer 15

Sucrose

Question 16

What disaccharide is formed when glucose is combined with galactose?

Answer 16

Lactose