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A Level Biology > Carbohydrates & Lipids > Flashcards

Carbohydrates & Lipids Flashcards

1
Q

What are monomers?

A

small identical or similar molecules which can be condensed (joined/linked together) to make larger molecules called polymers

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2
Q

What are polymers?

A

large molecules made from joining many (3 or more) identical or similar monomers together

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3
Q

How can monomers become polymers?

A

-monomers are linked into polymers by condensation reactions.
-a condensation reaction joins two monomer units together with the removal of a water molecule which forms a bond

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4
Q

How can polymers become monomers?

A

-polymers are broken down into monomers by hydrolysis reactions
- a hydrolysis reaction involves the addition of a molecule of water to break the bond between two monomers

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5
Q

What is a condensation reaction?

A

removing a molecule of water to join two monomers together

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6
Q

What is a hydrolysis reaction?

A

involves adding a molecule of water to break the bond between two monomers

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7
Q

What is a dimer?

A

two monosaccharides stuck together

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8
Q

What is a monosaccharide?

A

a carbohydrate monomer

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9
Q

What is a polysaccharide?

A

a carbohydrate polymer

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10
Q

If a monomer is a monosaccharide such as alpha/beta glucose, examples of it be?

A

polysaccharides

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11
Q

What type of bond is formed between two monosaccharides?

A

glycosidic

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12
Q

Give some examples of monosaccharides

A

starch, glycogen and cellulose

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13
Q

If amino acid is the monomer, what would the polymer be?

A

polypeptide or protein

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14
Q

What type of bond is formed between two amino acids?

A

Peptide Bonds

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15
Q

Give some examples of amino acids

A

enzymes & haemoglobin

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16
Q

If nucleotides were the monomer, what would the polymer be?

A

polynucleotide or nucleic acid

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17
Q

What type of bond is formed between two nucleotides?

A

phosphodiester bonds

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18
Q

What are some examples of nucleotides?

A

DNA & RNA

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19
Q

Draw an Alpha Glucose Molecule

A
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20
Q

What is the formula for a carbohydrate?

A

C6 H12 O6

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21
Q

what elements are found in carbohydrates?

A

carbon, hydrogen and oxygen

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22
Q

What are some examples of monosaccharides?

A

glucose, galactose and fructose

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23
Q

What are substances with the same formula but different arrangements called?

A

isomer(ism)

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24
Q

What is the formula for glucose, galactose and fructose?

A

C6 H12 O6

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25
Q

How can two monosaccharides join together?

A

-in a condensation reaction
-forms a disaccharide ( a dimer not a polymer)
-forms a glycosidic bond

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26
Q

What is the basic (simplified) structure of Alpha glucose

A
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27
Q

What is the equation for a condensation reaction?

A

C6 H12 O6 + C6 H12 O6 = C12 H22 O11 + H2O

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28
Q

Describe the basic stucture of galactose

A
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29
Q

Describe the basic structure of fructose

A
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30
Q

which monosaccharides is maltose made from?

A

(alpha) glucose + (alpha) glucose

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31
Q

which monosaccharides is lactose made from?

A

(alpha) glucose + galactose

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32
Q

which monosaccharides is sucrose made from?

A

(alpha) glucose + fructose

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33
Q

what is the hydrolysis enzyme for maltose?

A

maltase

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34
Q

what is the hydrolysis enzyme for lactose?

A

lactase

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35
Q

what is the hydrolysis enzyme for sucrose?

A

sucrase

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36
Q

what is the equation for 2 monosaccharides?

A

2 monosaccharides - glycosidic bond= disaccharide+water

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37
Q

what does a hydrolysis reaction do to polysaccharides/ disaccharides?

A

disaccharide (maltose) =hydrolysis reaction (requires H2O and maltase enzyme) + two monosaccharides (glucose)

38
Q

what happens during a hydrolysis reaction?

A

-the removal of one monomer requires one molecule of H2O
-the glycosidic bond is broken

39
Q

what is a polysaccharide ( and give an example)

A

a type of polymer formed by joining many monosaccharides together
example-starch

40
Q

what are the two types of sugars?

A

monosaccharides and disaccharides

41
Q

what are the two types of poluysaccharides?

A

storage and structural

42
Q

what are the 3 monosaccharides?

A

glucose, fructose and galactose

43
Q

what are the three disaccharides?

A

sucrose, maltose and lactose

44
Q

what are the storage polysaccharides?

A

glycogen (human) and starch (plants)

45
Q

what is the structural polysaccharide?

A

cellulose

46
Q

what are the two types of starch?

A

amylose and amylopectin

47
Q

describe the features of amylose

A

-core of starch grain
-coiled=compact
-alpha (1-4) glycosidic bonds
spiral shape

48
Q

describe the features of amylopectin

A

-outside of starch grain
-branched chains
-1:4 and 1:6 glycosidic bonds

49
Q

describe the features of starch

A

-carbon (1:4) glycosidic bonds so chains of alpha glucose coil into a helix making it compact
-structure is compact so good for storage
-branched chains of alpa glucose with carbon (1:4 and 1:6 glycosidic bonds)
-large surface area for rapid hydrolysis by enzymes to release glucose for respiration
-insoluble so does not affect water potential
-large so does not diffuse out of cells

50
Q

describe the structure of glycogen

A

-only found in animal cells
similar to starch however:
-shorter chains
-more highly branched
-larger surface area
-stored in muscles and liver
-shorter chains = more rapidly hydrolysed into glucose used in respiration
-insoluble so doesnt affect water potential

51
Q

describe the structure of cellulose

A

-beta glucose molecules join through condensation reactions to form long straight unbranched chains
-every other beta glucose molecule is rotated 180 degrees to allow 1:4 glycosidic bonds to form
-several chains of cellulose are joined together in layers, chains are held by weak H bonds, form microfibrils

52
Q

Describe the test for reducing sugars

A

-add equal volume of Benedicts
-heat to 95 degrees celcius
-red/orange/yellow/green precipitate forms

53
Q

Describe the test for NRS

A

-complete benedicts test and it should have a negative result/ stay blue
-boil it with an acid then neutralise with an alkali
-brick red precipitate is it is present

54
Q

Describe how to test a sample of food for the presence of starch

A

-add potassium iodide solution to the food sample
-blue/black/purple indicates starch is present

55
Q

Desrcibe the structure of a triglyceride

A

-1 glycerol and 3 fatty acids
-joined by ester bonds
-in a condensation reaction

56
Q

Draw a triglyceride

A
57
Q

Draw the structure of a glycerol

A
58
Q

Draw the structure of a glycerol

A
59
Q

Draw the structure of a saturated fatty acid

A
60
Q

Draw the structure of an unsaturated fatty acid

A
61
Q

Draw the structure of an unsaturated fatty acid

A
62
Q

Draw a diagram to show how glycerol and fatty acids turn into triglycerides

A
63
Q

Where is the carboxylic acid group (COOH) found in a hydrocarbon chain?

A

the very left- the first carbon that has a HO and a double bond Oxygen attatched to it

64
Q

what happens when a glycerol and 3 fatty acids turn into a triglyceride molecule?

A

-3 ester bonds formed
-3 condensation reactions
-3 water molecules released

65
Q

what is a saturated fatty acid?

A

a fatty acid without any double bonds between carbon atoms within the hydrocarbon chain (fully saturated with hydrogens)

66
Q

what is a polyunsaturated fatty acid?

A

a fatty acid with multiple double bonds between the carbon atoms within the hydrocarbon chain

67
Q

what is a monounsaturated fatty acid?

A

a fatty acid with 1 double bond between the carbon atoms within the hydrocarbon chain

68
Q

Describe the structure of phospholipids

A

has a similar structure to triglycerides however one of the fatty acids is replaced by a phosphate group so the glycerol combined with two fatty acids and 1 phospate group

69
Q

What happens to phospholipids when they are mixed with water?

A

-form droplet spheres called micelles when mixed with water
-hydrophilic polar heads face the water
-hydrophobic non polar tails face each other

70
Q

what do the components of a phospholipid do when placed in water?

A

-phosphate group has a negative charge (polar) whereas the fatty acid has no charge (non polar)
-the head becomes hydrophilic and the fatty acid tails are hydrophobic
-this allows phospholipids to form a bilayer in water

71
Q

The structure of cellulose is related to it’s role in plant cell walls. explain how (3)

A

-long, unbranched chains
- of beta glucose
-joined by many weak H bonds
-form microfibrils
-provide strength

72
Q

Hydrogen bonds are important in cellulose molecules. Explain why (2)

A

-holds cellulose chains together by forming microfibrils
-provide strength to cell wall

73
Q

A starch molecule has a spiral shape. explain why the shape is important for its function in cells (1)

A

compact so good for storage

74
Q

Explain one way in which the structure of cellulose is linked to its function (2)

A

long straight unbranched chains provide strength and rigidity

75
Q

What is an unsaturated fatty acid (2)

A

a fatty acid with double bonds between the carbons within the hydrocarbon chain

76
Q

Some seeds contain lipids. Describe how you could use the emulsion test to show that a seed contains lipids (3)

A

-crush the seeds
-with ethanol
-add water then shake
-forms an emulsion (cloudy)

77
Q

Describe how the structure of a phospholipid is different to the structure of a triglyceride (2)

A

-phospholipids have two fatty acids whereas triglycerides have three
-phospholipids have a phosphate group whereas triglycerides do not

78
Q

Name the type of reaction that would break down carbohydrates into their monomers (1)

A

hydrolysis

79
Q

Give three features of starch and explain how each feature enables it to act as a storage substance (3)

A

-coiled/ helix = tightly packed = stores more
-insoluble= wont gain/lose any substances through osmosis
-branched so the enzyme can break down the starch faster

80
Q

Describe three differences between the structure of a cellulose and a glycogen molecule (3)

A
  • glycogen is alpha glucose and cellulose is beta glucose
  • cellulose has straight chains and glycogen is highly branched
    -glycogen has 1:4 and 1:6 glycosidic bonds whereas cellulose only has 1:4 glycosidic bonds
81
Q

Describe how you would test a piece of food for the presence of a lipid (2)

A

-crush/grind the food
-add ethanol and an equal volume of water and shake

82
Q

Compare and contrast the structure and properties of triglycerides and phospholipids (5)

A

-both contain ester bonds
-both are insoluble
-both contain glycerol and fatty acids
-in both fatty acids may be saturated or unsaturated
-a triglyceride has 1 glycerol and 3 fatty acids whereas a phospholipid has a glycerol, 2 fatty acids and a phosphate group

83
Q

Describe how lactose is formed and where in the cell it would be attached to a polypeptide to form a glycoprotein

A

-glucose and galactose
-condensation reaction
-glycosidic bonds
-attached to polypeptide in Golgi

84
Q

Describe how an ester bond is formed in a phospholipid molecule (2)

A

-condensation reaction/loss of water
-between a glycerol and a fatty acid

85
Q

A student carried out the Benedict’s test. Suggest a method other than a colorimeter that this student could use to measure the quantity of reducing sugar in a solution (2)

A

-filter and dry (the precipitate)
-find the mass/weight

86
Q

Describe & explain how you could use the Biuret’s test to distinguish a solution of enzyme, lactase, from a solution of lactose (2)

A

-add Biuret’s to both solutions
-Lactase/enzyme will turn purple/lilac/mauve

87
Q

Why are lipids not classed as polymers? (3)

A

-made from fatty acids and glycerol
-not made from identical or similar repeating units
-polymers are 3 or more similar or identical monomers

88
Q

Describe how an ESTER bond is formed in a phospholipid molecule (2)

A

-condensation reaction or loss of water
-between OH of glycerol and OH of carboxyl group of fatty acid

89
Q

Describe the structure of a phospholipid molecule and explain how phospholipids are arranged in a plasma membrane (3)

A

-Glycerol joined to 2 fatty acids. Phosphate group joined to glycerol on opposite side (joined by condensation reaction with ester bonds)
-Phospholipid has a charged hydrophilic head (phosphate and glycerol) and a non polar hydrophobic tail (fatty acid chains)
-arranged to form a phospholipid bilayer- hydrophilic head faces out towards water and hydrophobic fatty acid chains face in away from water

90
Q

Describe how a triglyceride molecule is formed [3]

A

-ONE glycerol molecule and THREE fatty acids
-Condensation reactions AND removal of THREE molecules of water
-Ester bonds are formed.

A Level Biology (7 decks)

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