Carbohydrates

Question 1

finish the sentence

Organic molecules are ones that contain …….

Answer 1

• Carbon

Question 2

What are monosaccharides?

Answer 2

• Monosaccharides are the monomers from which larger carbohydrates are made
• The single monomer (of sugar) ie. 1 sugar unit.

Monosacchardies = particular sugars

Question 3

Give 3 examples of monosaccharides?

Answer 3

1.) Glucose
2.) Galactose
3.) Fructose.

Question 4

How many isomers does glucose have, what are they?

Answer 4

• 2 isomers
• Alpha glucose
• Beta glucose.

Question 5

What is an isomer?

Answer 5

• Isomer: same molecular formula but different structures.
• Ie. alpha and beta glucose are both isomers of glucose.

Question 6

What are disaccharides?

Answer 6

• A pair of monosaccharides (ie. two sugar units.)

Question 7

What are polysaccarides?

Answer 7

• Many monosaccharides joined together.

Question 8

3 examples of disaccharides.

Answer 8

1.) Sucrose.
2.) Maltose
3.) Lactose.

Question 9

3 examples of polysaccharides.

Answer 9

1.) Starch.
2.) Cellulose.
3.) Glycogen.

Question 10

What actually forms a glycosidic bond?

Answer 10

• Condensation reaction between two monosaccharides forms a glycosidic bond.

Question 11

How are disaccharides formed?

Answer 11

• Disaccharides are formed by the condensation of two
  monosaccharides

Question 12

What are maltose, sucrose and lactose examples of?

Answer 12

• Maltose, sucrose and lactose are examples of dissacharides.

Question 13

Give the word equation for the condensation reaction of maltose.

Answer 13

glucose + glucose —> maltose+ water

formed by the condesation of two glucose molecules.

Question 14

Give the word equation for the condensation reaction of sucrose.

Answer 14

glucose + fructose –> sucrose + water

Question 15

Give the word equation for the condensation reaction of lactose.

Answer 15

glucose + galactose –> lactose + water

Question 16

How are polysaccharides formed?

Answer 16

• Monosaccharides (ie. glucose units) joined together by glycosidic bonds that were formed from condensation reactions.

Question 17

What monomer is starch made up of? How are the monomers joined together?

Answer 17

• Many alpha glucose monosacharides join together by glycosidic bonds formed by condensation reactions.

Question 18

What type of glycosidic bonds are between the alpha glucose monosacharides/ monomers in amylose?

Answer 18

1-4 glycosidic bonds in amylose

Numbers show what part of molecule is bonded to other molecule (labelled numbers - sticky note on wall.)

Question 19

What type of glycosidic bonds are between the alpha glucose monosacharides/ monomers in amylopectin?

Answer 19

**1-4 and 1-6 **glycosidic bonds in amylopectin.

Numbers show what part of molecule is bonded to other molecule (labelled numbers - sticky note on wall.)

Question 20

What monomer is cellulose made up of?

Answer 20

• Beta glucose

Question 21

What type of glycosidic bond is between beta glucose monomers in cellulose?

Answer 21

1-4 glycosidic bonds.

Question 22

What type of glycosidic bond is between alpha glucose monomers in glycogen?

Answer 22

1-4 and 1-6 glycosidic bonds.

Question 23

Explain the hydrolysis of a disaccharide?

Answer 23

• Water added to disaccharide.
• Breaks/ hydrolyses glycosidic bond
• Releases monosachrides

Question 24

Give the function of starch, glycogen and cellulose.

Answer 24

• Starch: store of glucose
• Glycogen: store of glucose.
• Cellulose: Provides structural strength for the cell wall.

Question 25

What organs is glycogen mainly found in?

Answer 25

- Muscle and liver cells.

Question 26

Where is starch found?

Answer 26

- Plant cells.

Question 27

# Finish the sentence Glycogen and starch are formed by the .......... of ........ ..........

Answer 27

- Condensation - alpha glucose

Question 28

# Finish the sentence Cellulose is formed by the ........... of ....... ........

Answer 28

- Condensation. - Beta glucose.

Question 29

What is the structure of starch?

Answer 29

- Mixture of two polysaccharides (bonded together) amylopectin and amylose. - Amylose: an unbranched helix (1-4 glycosidic bonds.) - Amylopectin: a branched molecule (1-4 glycosidic bonds AND 1-6 glycosidic bonds.) ## Footnote () - extra info for clarification

Question 30

Explain how amylose's (polysaccharide in starch) structure allows it to carry out its function.

Answer 30

- Helix structure (helical) can compact to store a lot of glucose in a smaller place (ie. allowing for storage of glucose = function of starch.)

Question 31

Explain how amylopectin's (component of starch) structure allows it to carry out its function.

Answer 31

- Branched molecule. - Increases surface area for enzymes to hydrolyse the glycosidic bond - allowing glucose to be released quickly FOR RESPIRATION!

Question 32

How is starch's structure specially suited for its function of glucose storage?

Answer 32

- It is insoluble (does not affect water potential) so water is not drawn into cells by osmosis. - Compact. - The branches: large surface area: so enzymes can attach and hydrolyse the glycosidic bond (ie. for fast enzyme action.)

Question 33

What is the structure of cellulose?

Answer 33

- Long, straight, unbranched chains - Chains are held in parallel by hydrogen bonds. - Hydrogen bonds between the chains form thick fibres called microfibrils (many cellulose chains .)

Question 34

How is cellulose's structure specially suited for its function of providing structural strength to cell wall?

Answer 34

- Many hydrogen bonds provide collective strength. - Cellulose --> insoluble (won't affect water potential.)

Question 35

What is the structure of glycogen?

Answer 35

- A highly- branched molecule

Question 36

How is glycogen's structure specially suited for its function of glucose storage?

Answer 36

- Branched structure, more ends for faster hydrolysis/ enzyme action. - Branched so is compact. - Insoluble: won't affect water potential (water won't be drawn into cell --> cell won't burst ALONG WITH the glycogen.) - Glucose polymer so provides respiratory substrate for energy release. | () - extra info in own words for clarification

Question 37

What makes a polysaccharide branched?

Answer 37

- Its 1-6 glycosidic bonds.

Question 38

What is the -OH group on monosaccharides known as?

Answer 38

- Hydroxyl group.

Question 39

What is it called in cellulose when every other glucose is rotated 180 degrees?

Answer 39

- They are **inverted. **

Question 40

What is the advantage of glycogen, starch and cellulose being insoluble/ not affecting water potential?

Answer 40

- Water won't be drawn into cells that contain these molecules. - So the cells won't burst (along with the starch, cellulose and glycogen.)