Carbohydrates

Question 1

A single sugar unit is known as a…

Answer 1

Monosaccharide (a monomer of sugar)

Question 2

What is the chemical composition of a carbohydrate?

Answer 2

Carbon, oxygen, & hydrogen

Question 3

When two or more monosaccharides are linked they form…

Answer 3

A polymer called a polysaccharide.

Question 4

Glucose is a monosaccharide composed of six carbons and is therefore a…

Answer 4

Hexose monosaccharide

Question 5

Name the two structural variation of the glucose molecule

Answer 5

Alpha (α) glucose
Beta (β) glucose

Question 6

Draw what the alpha glucose molecule looks like

Answer 6

Alpha (α) glucose

Question 7

Draw what the beta glucose molecule looks like

Answer 7

Beta (β) glucose

Question 8

How does alpha glucose differ from beta glucose?

Answer 8

The hydroxyl group (OH) on carbon 1 is in opposite positions

This affects the structure and properties of the polysaccharides when it bonds

Question 9

How is a disaccharide formed? From what? What is released as well?

HINT: Two Hands Bond and Release

Answer 9

Two Hands Bond and Release

T - Two Monosaccharides (join together in the reaction)
H - Hydroxyl Groups (the OH groups from each monosaccharide interact)
B - Bond Formation (a new glycosidic bond forms between the monosaccharides)
R - Release Water (water is released as a byproduct)

Question 10

From what is the disaccharide lactose made of?

Answer 10

Glucose + galactose = Lactose

Question 11

From what is the disaccharide maltose made of?

Answer 11

Glucose + glucose = Maltose

Question 12

From what is the disaccharide sucrose made of?

Answer 12

Glucose + fructose = Sucrose

Question 13

What is a pentose sugar?

Answer 13

Sugars that contain five carbon atoms

Question 14

Which two pentose sugars are important components of biological molecules?

Answer 14

Ribose (sugar found in RNA) and Deoxyribose (sugar found in DNA)

Question 15

What does ribose look like?

Answer 15

Ribose

Question 16

What is the structure of starch?

Answer 16

Made of amylose (mainly, 1-4 glycosidic bonds) and amylopectin (1-4 and some 1-6 glycosidic bonds)

Question 17

What are the properties of starch?

HINT: Curvy Cheerleader Easily Interact

Answer 17

C - Compact (starch molecules are packed tightly for efficient storage)
C - Chemical Energy Store (starch stores chemical energy for the plant)
E - Easily Digestible (starch can be broken down quickly for energy)
I - Insoluble (doesn’t dissolve in water, so it avoids creating a water potential gradient that could cause cells to swell from osmosis)

Question 18

Describe the structure of amylose.

HINT: Alpha Glue Helps Hold

Answer 18

Alpha Glue Helps Hold

A - Alpha glucose (long chains of alpha glucose)
G - Glycosidic Bonds (1-4 glycosidic bonds join glucose molecules)
H - Helix (the chain twists into a helix shape, making it compact for storage)
H - Hydrogen Bonds (the helix shape is stabilized by hydrogen bonds)

Question 19

What are the properties of amylose?

Answer 19

Insoluble (does not create water potential gradient)
Long chain of glucose that twists into a helix (compact for storage)

Question 20

Describe the structure of amylopectin.

HINT: Long Branches Grow Slowly

Answer 20

Long Branches Grow Slowly

L - Long chains of alpha glucose
B - Branches (1-6 glycosidic bonds form branching points)
G - Glycosidic Bonds (1-4 bonds in chains; 1-6 bonds for branches)
S - Spacing of branches (approximately every 25 glucose units)

Question 21

What are the properties of amylopectin?

Answer 21

Compact and idealy for storage
Insoluable (do not affect water potential)
Branches gives ‘free ends’ so glucose can be added or released quickly

Question 22

Describe the structure of glycogen.

Answer 22

Short, branched chains of alpha glucose
Joined by 1-4 glycosidic bonds (chains) and 1-6 glycosidic bonds (branches)

Question 23

What are the properties of glycogen?

Answer 23

Compact and insoluble so good for storage
Branching means many ‘free ends so glucose can be released (or stored) quickly

Question 24

What is the function of glycogen?

Answer 24

Main energy store in animals
Stores soluble glucose that affects water potential as insoluble polysaccharide until needed

Question 25

Describe the structure and properties of cellulose.

HINT: Bad Cats Bite My Fingers

Answer 25

Big Cellulose Builds Mighty Fibers:

B - Beta glucose chain
C - Chains that are Compact (1-4 glycosidic bonds link glucose molecules to form long, unbranched chains)
B - Bonded by hydrogen bonds (between chains for strength)
M - Microfibrils form (hydrogen bonds create strong, straight microfibrils)
F - Fibers are formed (microfibrils combine into macrofibrils and then into larger fibers)

Question 26

Describe the function of cellulose?

Answer 26

Cellulose provides structural support for cells

Question 27

How is a disaccharide broken down?

HINT: Hungry Hippos Eat Carefully

Answer 27

Hungry Hippos Eat Carefully

H - Hydrolysis: The reaction process that breaks down larger molecules.
H - H₂O Added: Water is added to split the disaccharide into monomers.
E - Enzyme-Catalyzed: Enzymes facilitate and speed up the hydrolysis reaction.
C - Condensation Opposite: This reaction is the opposite of condensation, which forms glycosidic bonds instead of breaking them.