Carbohdrates Flashcards
1
Q
What are the elements that carbohydrates are composed of?
A
Carbon
Hydrogen
Oxygen
2
Q
What are sugars?
A
Small, water-soluble molecules that taste sweet.
3
Q
What are the two groups of sugars?
A
Monosaccharides
Disaccharides
4
Q
What are monosaccharides?
A
The single units which all other carbohydrates are built with.
5
Q
What are glucose and fructose both examples of?
A
Monosaccharides
6
Q
What is the common formula of a carbohydrate?
A
Cx (H20)y
7
Q
What does carbohydrate actually mean?
A
Hydrated carbon - C and Water - C(H20)
8
Q
What is the general formula of a monosaccharide?
A
(CH2O)n
9
Q
Monosccharides are grouped based on what?
A
The number of carbons they have (n).
10
Q
What is a triose?
A
A monosaccharide with an n value of 3, (3 carbons).
Tri = 3
11
Q
What is a tetrose?
A
A monosaccharide with an n value of 4, (4 carbons).
tetro = 4
12
Q
What is a pentose?
A
A monosaccharide with an n value of 5, (5 carbons).
Pent = 5
13
Q
What is a hexose?
A
A monosaccharide with an n value of 6, (6 carbons).
Hex = 6
14
Q
What is a heptose?
A
A monosaccharide with an n value of 7, (7 carbons).
Hept = 7
15
Q
State the formula of glucose:
A
C6H1206
16
Q
Which category of monosaccharides does glucose fall into?
A
Hexoses - C6H1206
17
Q
What are isomers?
A
Isomers have the same chemical formula, but have different structural formula.
18
Q
State two glucose isomers.
A
alpha - glucose
beta - glucose
19
Q
What is a disaccharide?
A
Two monosaccharides that are chemically joined through a condensation reaction.
20
Q
What type of reaction can be used to split a disaccharide into two monosaccharides?
A
A hydrolysis reaction.
21
Q
What are the monosaccharides that make up the disaccharide of Maltose?
A
Maltose = Glucose + Glucose
22
Q
What are the monosaccharides that make up the disaccharide of Sucrose?
A
Sucrose = Glucose + Fructose
23
Q
What are the monosaccharides that make up the disaccharide of Lactose?
A
Lactose = Glucose + Galactose
24
Q
What is the disaccharide known commonly as table sugar?
A
Sucrose
25
What is the disaccharide known commonly as milk sugar?
Lacotse
26
What is the disaccharide known commonly as malt sugar?
Maltose
27
What do Maltose, Sucrose and Lactose all have in common?
They are all disaccharides, furthermore they all contain at least one glucose monosaccharide.
28
In the formation of a disaccharide from two monosaccharides, what two products are created?
The disaccharide and a water molecule.
29
How can you tell the difference between alpha and beta glucose?
Alpha glucose has an OH group below the first carbon, whereas in the beta glucose, the OH group is above the fist carbon.
30
Two monosaccharides can be chemically joined in a condensation reaction to create a disaccharide. What is formed when two glucose monomers are joined?
Glucose + Glucose = Maltose
31
Two monosaccharides can be chemically joined in a condensation reaction to create a disaccharide. What is formed when a glucose and fructose monomer are joined?
Glucose + Fructose = Sucrose
32
Two monosaccharides can be chemically joined in a condensation reaction to create a disaccharide. What is formed when a glucose and galactose monomer are joined?
Glucose + Galactose = Lactose
33
What is an oligosaccharide?
A molecule with between three and ten monosaccharide units.
34
What is a molecule with more than ten monosaccharide units?
A polysaccharide.
35
How is an oligosaccharide created?
Between three and ten monosaccharide units are joined through condensation reactions, releasing water molecules.
36
What do Glucose, Galactose and Fructose have in common?
They are all common monosaccharides from which larger carbohydrates are made from.
37
What bond is formed during a condensation reaction between two monosaccharides?
A glycosidic bond
38
State the general formula of the following:
- alpha glucose
then
- beta glucose.
They have the same general formula, (C6 H12 06)
39
What is formed by the condensation of Alpha-Glucose?
Starch and Glycogen
40
What is formed by the condensation of Beta-Glucose?
Cellulose
41
What is the valency of the following elements?
- Carbon,
- Hydrogen,
- Oxygen,
- Nitrogen,
- Sulfur.
```
Carbon = 4
Hydrogen = 1
Oxygen = 2
Nitrogen = 3
Sulfur = 2
```
42
What do the following all have in common?
- Alpha glucose,
- Beta glucose,
- Fructose,
- Galactose.
They are all hexoses (that have an n value of 6).
43
What do the following all have in common?
- Ribose,
- Deoxyribose.
They are all pentoses (that have an n value of 5).
44
What kind of monosaccharide is a glyceralhyde?
A triose (it has an n value of 3)
45
Where can Sucrose be obtained from?
Sucrose can be found in plants such as sugar cane.
46
Which disaccharide is found in sugar cane?
Sucrose.
47
What is a calorimeter?
A device used to quantify colour by measuring transmission or absorbance.
48
Which compound, amylose or amylopectin would you expect to be hydrolysed faster? Explain why.
Amylose, it has more terminal ends where monomers can be broke off from.
49
State a difference between a pentose and a hexose sugar.
A pentose has 5 carbons whereas a hexose has 6 carbons.
50
Starch is a polymer, state what this means.
A chain of repeated monomer units.
51
Both starch and glycogen can be broken down to provide glucose for respiration. Name the type of reaction from which both are broken down:
Hydrolysis reaction.
52
What are small, water-soluble molecules that are sweet tasting?
Sugars.
53
Are sugars water-soluble?
Sugars are small and water-soluble.
54
Starch is a large polymer that is made from two smaller polymers, state these smaller polymers.
Amylose and Amylopectin.
55
Amylose and Amylopectin are two constituents to the polymer of Starch, however they are both polymers of what molecule?
Amylose and Amylopectin are both polymers of Glucose.
56
Is Starch soluble or insoluble?
Starch is insoluble.
57
What is the function of Starch?
Starch stores glucose in plant cells.
58
Why is Starch so ideal for storing glucose?
It is insoluble and compact which means it can store lots of glucose in a small space without any dissolving into the cell.
59
In which cells is Starch found?
Starch is found solely in plant cells.
60
In plants, how is carbohydrate moved from one region of the plant to another?
Sucrose.
61
In animals, what is the main form in which carbohydrate is transported around the body?
Glucose.
62
Monosaccharides, Disaccharides and Oligosaccharides are all types of what?
They are all sugars, they are short (less than 10 monomers).
63
Sugars such as oligosaccharides are very sweet, are polysaccharides sweet?
Polysaccharides are not sweet like their shorter chain counterparts.
64
Which type of chain do 1 - 4 glycosidic bonds create?
1 - 4 Glycosidic bonds form straight chains.
65
Which type of chain do 1 - 6 glycosidic bonds create?
1 - 6 Glycosidic bonds form branched chains.
66
What is the difference in the structure of amylose and amylopectin?
Amylose contains many 1 - 4 glycosidic bonds and therefore is an unbranched chain. Amylopectin has many 1 - 6 glycosidic bonds which produces highly branched chains.
67
As a storage molecule, starch is broken down into substances for use in the cell. What is starch broken down into?
Glucose for respiration and also organic carbon for making organic substances.
68
What is glycogen?
Glycogen is an energy storage polysaccharide in animal cells.
69
What is glycogen?
Glycogen is an energy storage polysaccharide in animal cells which is found as small granules.
70
Where in particular is glycogen particularly abundant?
The liver and muscle cells.
71
Which molecule is commonly referred to as the 'animal starch'?
Glycogen.
72
How is glycogen found?
Glycogen is found in small granules.
73
Compare the structure of starch with that of glycogen and how this affects their roles.
Glycogen contains more 1 - 6 glycosidic bonds meaning it is much more branched than starch which contains more 1 - 4 bonds. This makes glycogen less dense and more soluble than starch, this means it can be hydrolysed much easier than starch.
74
Suggest why glycogen must be more easily hydrolysed than starch.
Glycogen needs to be easier to metabolise because animals require energy more readily than plants.
75
What is cellulose?
Cellulose is a tough structural polysaccharide that is a major constituent of plant cell walls.
76
What is a major use of cellulose?
Plant cell walls are made largely out of cellulose.
77
Cellulose is completely permeable, suggest why this would be beneficial for its useage as a plant cell wall.
It allows water and dissolved substances to enter and leave plant cells freely.
78
How easily is cellulose hydrolysed?
Unlike starch and glycogen, cellulose cannot be hydrolysed easily.
79
Even though cellulose is not easy to hydrolyse, animals such as cows can easily digest them. Suggest why this is?
They release an enzyme such as cellulase, an enzyme which digests cellulose.
80
What is lignin?
A highly complex non-carbohydrate polymer that further strengthens the cellulose in wood.
81
In what cells is cellulose found in?
Plant cells only.
82
Name the monomers from which a maltose molecule is made?
Glucose and Glucose.
83
Name the type of chemical bond that joins two monomers to form maltose?
Alpha 1,4 Glycosidic Bond.
84
Name the monomers that form a cellulose molecule?
Beta - glucose.
85
What type of bonds does cellulose contain?
1 - 4 glycosidic bonds.
86
What type of bonds do starch contain?
1 - 4 and 1 - 6 glycosidic bonds.
87
Explain the difference in the structure of the starch molecule and the cellulose molecule: (2)
- Starch is formed from alpha-glucose but cellulose is formed from beta-glucose.
- Position of hydrogen and hydroxyl groups on carbon atom 1 is inverted.
88
The enzyme sucrase catalyses the breakdown of sucrose into monosaccharides, what type of reaction is this?
Hydrolysis.
89
Describe the biochemical test to show that a solution collected contains a reducing sugar: (2)
- Heat with Benedicts solution
| - Brick red formed.
90
Lactose + Water ---> Glucose + Galactose
| The formula for galactose is C6 H12 06, what is the formula for Lactose?
C12 H22 011
91
Describe the test you would carry out on a sample to show that lactose is a reducing sugar. (2)
- Heat with Benedicts solution,
| - Brick red.
92
How can you tell the difference between alpha and beta glucose?
In alpha glucose the OH group on Carbon 1 is below the H, whereas on beta glucose the OH group is above.
93
What is a heptose?
A monosaccharide with 7 carbons.
94
What is a tetrose?
A monosaccharide with 4 carbons.
95
Name two isomers that are carbohydrates / sugars.
Alpha and Beta glucose.
96
(Trivial) name for malt sugar?
Maltose.
97
(Trivial) name for table sugar?
Sucrose.
98
(Trivial) name for milk sugar?
Lactose.
99
What enzyme is used to digest milk sugar?
Lactase.
100
Which disaccharide is formed from two monosaccharides of glucose?
Maltose.
101
Which disaccharide is formed from one monosaccharide of glucose, and one of fructose?
Sucrose.
102
Which disaccharide is formed from one monosaccharide of glucose, and one of galactose?
Lactose.
103
Glycogen is a storage polysaccharide that is very branched, why would this be a benefit for its function?
It reduces density and increases solubility and can easily be broken down to provide rapid energy.
104
Which storage polysaccharide is very branched and why?
Glycogen is very branched due to many 1 - 6 glycosidic bonds.
105
Which polysaccharide is formed from alpha glucose units?
Starch.
106
Starch is formed from two units of alpha glucose, which are these?
Amylose and Amylopectin
107
Starch consists of almost 30% amylose, what other molecule makes up the rest of starch?
Amylopectin.
108
Which type of chain is formed through 1 - 6 Glycosidic Bonds?
A branched chain.
109
Which type of chain is formed through 1 - 4 Glycosidic Bonds?
A straight chain.
110
What is the use of starch?
A storage product in plants and broken down for energy for respiration.
111
What is Benedicts test used to find?
The presence ofreducing or nn-reducing sugars.
112
Starch and Glycogen are both used as energy stores, what the main difference about them?
Starch is storage in plants whereas glycogen is storage in animals.
113
What is the difference between a pentose and hexose sugar?
Pentose sugars have 5 carbons while hexose sugars have 6 carbons.
114
Which polysaccharide is formed through the condensation of beta-glucose?
Cellulose.
115
Which polysaccharides are formed through the condensation of alpha-glucose?
Starch and Glycogen.
116
Is starch branched or unbranched?
Starch is unbranched.
117
Name a polysaccharide that is important in plant cell walls.
Cellulose.
118
Glycogen can be broken down faster than starch, suggest why this is necessary.
Animals have a higher metabolic rate than plants and require energy more readily to facilitate the high rate of respiration.
119
Which type of reaction is catalysed by the enzyme lactase? (lactase)
Lactose + Water ---------> Galactose + Monosaccharide X
Hydrolysis.
120
Name the monosaccharide X
(lactase)
Lactose + Water ---------> Galactose + Monosaccharide X
(alpha) Glucose.
121
Describe how you would use a biochemical test to show that a reducing sugar is present. (2)
- Add Benedict's (reagent) and heat / warm.
| - Red / orange / yellow / green (colour); accept brown.
122
A high concentration of galactose slows down the breakdown of lactose by lactase. Use your knowledge of competitive inhibition to suggest why. (2)
(lactase)
Lactose + Water ---------> Galactose + Monosaccharide X
- Galactose is a similar shape / structure to lactose / both complimentary.
- Galactose binds with the active site (of enzyme).
- Prevents substrate fitting into a.s, fewer e-s complexes formed
123
The following statement is true for how many of these?
(Starch , Cellulose, Glycogen)
- It is found only in plant cells.
Only starch is true.
124
The following statement is true for how many of these?
(Starch , Cellulose, Glycogen)
- It contains glycosidic bonds.
All three contain glycosidic bonds as they are all carbohydrate molecules.
125
The following statement is true for how many of these?
(Starch , Cellulose, Glycogen)
- It contains beta-glucose.
Only Cellulose.
126
The following statement is true for how many of these?
(Starch , Cellulose, Glycogen)
- It contains alpha-glucose.
Starch and Glycogen.
127
A quantitative Benedict's test produces a colour whose intensity depends upon the concentration of reducing sugar in a solution. A calorimeter can be used to measure the intensity of this colour.
A scientist used the test to produce a calibration curve of calorimeter reading against concentration of maltose. Describe how the scientist would have produced the results in the graph.
- Use maltose solutions of different known concentrations.
- Carry out Benedicts test on each of these.
- Use calorimeter to measure the intensity of colour for each solution.
- Plot the results on a graph, creating a calibration curve.
- Find concentration of sample from calibration curve.
