1.1 Biological Molecules: Carbohydrates

Question 1

What is a monomer?

Answer 1

Small subunits that join together to form a polymer.

Question 2

Give examples of monomers.

Answer 2

Monosaccharides, amino acids, nucleotides

Question 3

What is a polymer?

Answer 3

Long chain molecules formed when many monomers join together.

Question 4

Give examples of polymers.

Answer 4

Polysaccharides, proteins, DNA/RNA

Question 5

What are the monomers of a carbohydrate?

Answer 5

Saccharides

Question 6

What happens in a condensation reaction?

Answer 6

A chemical bond forms between two molecules and a molecule of water is produced

Question 7

What happens in a hydrolysis reaction?

Answer 7

A water molecule is used to break a chemical bond between two molecules

Question 8

Name the 3 hexose monosaccharides.

Answer 8

Glucose, fructose, galactose

Question 9

What bonds are formed between monosaccharides?

Answer 9

Glycosidic bonds

Question 10

What reaction forms glycosidic bonds?

Answer 10

Condensation

Question 11

What is released in a condensation reaction?

Answer 11

Water molecule

Question 12

Name 3 disaccharides.

Answer 12

Maltose, sucrose, lactose

Question 13

What forms maltose?

Answer 13

a glucose + a glucose

Question 14

What forms sucrose?

Answer 14

Glucose + fructose

Question 15

What forms lactose?

Answer 15

Glucose + galactose

Question 16

What is the molecular formula of maltose, sucrose and lactose?

Answer 16

C₁₂H₂₂O₁₁

Question 17

How do disaccharides form?

Answer 17

Condensation reactions form glycosidic bonds between 2 monosaccharides

Question 18

Describe the difference between alpha glucose and beta glucose.

Answer 18

The H and OH on carbon 1 are rinverted, the OH below on alpha glucose and above on beta glucose

Question 19

What is a polysaccharide?

Answer 19

Many monosaccharides joined by condensation reactions to form glycosidic bonds

Question 20

Name 3 polysaccharides.

Answer 20

Starch, cellulose, glycogen

Question 21

What is the function of starch?

Answer 21

Glucose storage molecules in plants for respiration

Question 22

What is the function of glycogen?

Answer 22

Glucose storage molecules in animals for respiration

Question 23

What is the function of cellulose?

Answer 23

Strong plant cell walls

Question 24

Describe the structure of starch.

Answer 24

Insoluble so there is no osmotic effect on cells
Large so it doesnt diffuse out of cells

Question 25

What is the monosaccharide for starch?

Answer 25

Alpha glucose

Question 26

What is the monosaccharide for glycogen?

Answer 26

Alpha glucose

Question 27

What is the monosaccharide for cellulose?

Answer 27

Beta glucose

Question 28

What kind of bonding is found in starch?

Answer 28

1,4 and 1,6 glycosidic bonds

Question 29

What kind of bonding is found in glycogen?

Answer 29

1,4 and 1,6 glycosidic bonds

Question 30

How do the bonds in starch impact the structure?

Answer 30

Makes it highly branched

Question 31

How do the bonds in glycogen impact the structure?

Answer 31

Makes it highly branched

Question 32

What are the adaptations of starch?

Answer 32

Highly branched Helical Insoluble Large

Question 33

What are the adaptations of glycogen?

Answer 33

Highly branched Helical Insoluble Large

Question 34

Why is having a highly branched structure an adaptation for starch?

Answer 34

Many ends Greater surface area for faster hydrolysis Removal of glucose for respiration

Question 35

Why is having a highly branched structure an adaptation for glycogen?

Answer 35

Many ends Greater surface area for faster hydrolysis Removal of glucose for respiration

Question 36

Why is being helical an adaptation for starch?

Answer 36

Compact so lots can be stored in cell

Question 37

Why is being helical an adaptation for glycogen?

Answer 37

Compact so lots can be stored in cell

Question 38

Why is being insoluble an adaptation for starch?

Answer 38

Doesn't effect the osmotic potential of the cell

Question 39

Why is being insoluble an adaptation for glycogen?

Answer 39

Doesn't effect the osmotic potential of the cell

Question 40

Why is being large an adaptation for starch?

Answer 40

Cannot leave the cell

Question 41

Why is being large an adaptation for glycogen?

Answer 41

Cannot leave the cell

Question 42

What two types of bonds are found in cellulose?

Answer 42

1,4 glycosidic bonds H bonding between seperate strands

Question 43

How does the glycosidic bonding in cellulose affect its structure?

Answer 43

Only straight strands without branching

Question 44

Why is being in straight chains an adaptation for cellulose?

Answer 44

Allows H bonds to form between strands

Question 45

What does the hydrogen bonding in cellulose form?

Answer 45

Microfibrils

Question 46

What property do microfibrils give cellulose?

Answer 46

Rigidity strength

Question 47

What reagent is used to test for sugars?

Answer 47

Benedicts

Question 48

What condition is needed for Benedicts to work?

Answer 48

Heat (80degrees+)

Question 49

How is a positive result shown with Benedicts?

Answer 49

Colour change from blue to brick red due to the precipitate formed

Question 50

Name the reducing sugars.

Answer 50

Glucose, galactose, fructose, lactose, maltosez

Question 51

Name the non-reducing sugars.

Answer 51

Sucrose

Question 52

How can a quantitive results be shown on the amount of sugar present in a solution?

Answer 52

1. Filter to remove precipitate from solution 2. Dry and weigh precipitate 3. The greater the mass, the more sugar present

Question 53

How can a colourimeter be used to give quantitive results on the presence of sugar?

Answer 53

1. Make up solutions of known sugar concentration using serial dilution and place in colourimeter 2. Create a calibration curve from the absorbance of each known concentration 3. Compare unknown solution absorbancy and read off the concentration of sugar

Question 54

Describe the Benedicts test for reducing sugars.

Answer 54

1. Add an equal volume of Benedicts reagent to a sample 2. Heat the mixture in a hot water bath for 5 minutes 3. Positive result = colour change from blue to brick-red

Question 55

Describe the Benedicts test for non-reducing sugars.

Answer 55

1. Control - negative result remaining blue 2. Hydrolyse non-reducing sugars by adding hydrochloric acid 3. Heat in hot water bath for 5 minutes 4. Neutralise the mixture using sodium carbonate solution 5. Benedicts test

Question 56

Describe the test for starch.

Answer 56

1. Add iodine solution 2. Positive result = colour change from orange to blue-black