Carbohydrates

Question 1

____________ are the most abundant biomolecule on earth.

Answer 1

Carbohydrates

Question 2

Which biomolecule is often abbreviated to ‘CHO’?

Answer 2

Carbohydrate

Question 3

Name two carbohydrates that are staples of the human diet.

Answer 3

Sugar and starch

Question 4

___________ of carbohydrates is the central energy-yielding pathway in most non-photosynthetic cells.

Answer 4

Oxidation

Question 5

Which type of carbohydrates are found in the cell coats of animals?

Answer 5

Insoluble

Question 6

Name two classes of simple sugars.

Answer 6

Aldehyde sugars (aldoses) and ketone sugars (ketoses)

Question 7

How many R-groups does an aldose have?

Answer 7

One

Question 8

How many R-groups does a ketose have?

Answer 8

Two

Question 9

Define ‘stereoisomers’.

Answer 9

Molecules that are non-superimposable, mirror images of each other

Question 10

Glyceraldehyde has a single _______ carbon atom.

Answer 10

Asymmetric

Question 11

Name the stereoisomers of glyceraldehyde.

Answer 11

D- and L-glyceraldehyde

Question 12

What do ‘D and L’ refer to, in the context of stereoisomers?

Answer 12

D and L refer to the configuration of the asymmetric carbon atom, furthest from the aldehyde or ketone group

Question 13

L-sugars rotate polarised light to the _____.

Answer 13

Left

Question 14

D-sugars rotate polarised light to the _____.

Answer 14

Right

Question 15

True or false: most hexose sugars are found naturally in the D-sugar form.

Answer 15

True

Question 16

Name a sugar that naturally occurs in the L-sugar form.

Answer 16

L-arabinose

Question 17

What is an epimer?

Answer 17

A D-sugar that differs in configuration at only a single asymmetric carbon atom

Question 18

What are the two crystalline forms of D-glucose?

Answer 18

Downward-pointing alpha-D-glucose and upward-pointing beta-D-glucose

Question 19

Glucose undergoes a reversible reaction between -OH group of C5, and the anomeric carbon (C1) forms a _______ _______ structure

Answer 19

Pyranose ring

Question 20

Fructose undergoes a common reaction between the -OH group of ___ and the anomeric carbon (C2), forming a furanose ring structure.

Answer 20

C5

Question 21

Six-membered sugar rings are called ________.

Answer 21

Pyranoses

Question 22

Five-membered sugar rings are called ________.

Answer 22

Furanoses

Question 23

What type of sugar will the following reaction for maltose yield?
A condensation reaction takes place. A bond is formed that is termed ‘glycosidic linkage’. Maltose involves the linking of two glucose molecules, 1-4 glycosidic linkage between the C1 and C4 positions of two D-glucose molecules.
The D-glucose containing C1 atom is in its alpha form, therefore the bond is termed an alpha (1-4) glycosidic bond.

Answer 23

Disaccharide

Question 24

A ______ glycosidic bond is seen in the glycosidic linkage of sucrose

Answer 24

1 - 2

Question 25

True or false: Multiple reactions in a sugar create smaller polysaccharides.

Answer 25

False

Question 26

Carbohydrates may be _________ or branched.

Answer 26

Linear

Question 27

Name two functions of carbohydrates.

Answer 27

Storage and structure

Question 28

Excess glucose is stored as ________.

Answer 28

Glycogen

Question 29

Plants store excess glucose as _______.

Answer 29

Starch

Question 30

What is the exoskeleton of some animals called?

Answer 30

Chitin

Question 31

Cellulose is a plant storage __________.

Answer 31

Polysaccharide

Question 32

Bacteria and yeasts store excess glucose as _______.

Answer 32

Dextran

Question 33

What is amylose?

Answer 33

Unbranched polymers of glucose units, joined by α1-4 glycosidic bonds

Question 34

What is amylopectin?

Answer 34

Similar to amylose, but additional α1-6 bonds occur every 25-30 units, creating branchpoints

Question 35

_________ consists entirely of glucose units, mostly linked by α1-4 bonds

Answer 35

Glycogen

Question 36

Every ___ sugar units, glycogen's chains are branched by the formation of an α1-6 bond

Answer 36

10

Question 37

Where is glycogen primarily made and stored?

Answer 37

The liver and the muscles

Question 38

Cellulose strands are held together by which type of bond?

Answer 38

Hydrogen

Question 39

Name two animals that are capable of degrading cellulose in their gut.

Answer 39

Cow and horse

Question 40

Cellulose is made up of unbranched ___________ of glucose units, linked by β1-4 glycosidic bonds

Answer 40

Polysaccharides

Question 41

α and β forms exist for all cyclic _______________.

Answer 41

Monosaccharides