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Biological Molecules Flashcards

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1
Q

How many different amino acids are used in proteins?

A

20

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2
Q

What do all amino acids contain?

A

Carbon, hydrogen, oxygen, nitrogen

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3
Q

What do some amino acids also contain?

A

Sulfur

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4
Q

Do all amino acids have the same structure?

A

Yes, but R can be one of 20 different chemical groups

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5
Q

What holds a chain of amino acids together?

A

Strong peptide bonds

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6
Q

How many amino acids long can proteins be?

A

Up to several hundred

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7
Q

What determines the structure of a protein?

A

The order of amino acids

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8
Q

What does the structure of a protein determine?

A

How the protein works

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9
Q

What is the primary structure?

A

The sequence of amino acids

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10
Q

What is the secondary structure ?

A

-Hydrogen bonds form between the amino acids all along the polypeptide chain (this is due to the polarity of the CO and the NH groups).

-These hydrogen bonds cause the polypeptide chains to twist and fold into shapes .

-The twisted 3d shape formed can either be an alpha helix cylindrical shape or a beta pleated sheet .

-Both these structures are maintained by hydrogen bonds

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11
Q
A
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12
Q

What are globular proteins?

A

Proteins that have a roughly spherical shape

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13
Q

What elements do carbohydrates contain?

A

Carbon, hydrogen and oxygen

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14
Q

What do the different types of carbohydrates include?

A

Sugars, starch and cellulose

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15
Q

What are sugars?

A

Small, water-soluble molecules that taste sweet

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16
Q

What groups are sugars divided to?

A

Monosaccharides and disaccharides

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17
Q

Why are the single units from which all carbohydrates are built?

A

Monosaccharides

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18
Q

What are glucose and fructose?

A

Monosaccharides

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19
Q

What 2 forms does glucose have?

A

Alpha and beta

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20
Q

How are disaccharides formed?

A

When 2 monosaccharides are joined together by a chemical reaction. A molecule of water is also formed

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21
Q

What sort of reaction is the reaction between 2 disaccharides?

A

A condensation reaction

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22
Q

What 2 polysaccharides are starch molecules made up of?

A

Amylose and amylopectin

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23
Q

Why is starch good at storing glucose?

A

Because it insoluble

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24
Q

What is cellulose?

A

A polysaccharide made up of glucose molecules

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25
Q

How do cellulose molecules lie?

A

Long and straight

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26
Q

Several cellulose molecules can lie side to side to form….

A

Microfibrils

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27
Q

Microfibrils are held together by…

A

Weak hydrogen bonds

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28
Q

Is cellulose found in animal cells?

A

No, only plant cells

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29
Q

What do the microfibrils do to the plant cell wall?

A

Strengthen it

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30
Q

What do lipids contain?

A

Carbon, hydrogen and oxygen

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31
Q

What 2 things can lipids be?

A

Fats and oils

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32
Q

What 2 things can lipids be?

A

Oils and fats

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33
Q

What are plant oils and animal fats mostly made up of?

A

Lipids called triglycerides

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34
Q

What does a tryglyceride consist of?

A

A molecule of glycerol with 3 fatty acids attached to it

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35
Q

What is a fatty acid molecule?

A

A long chain of carbon atoms with an acid group (COOH) at one end

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36
Q

What are attached to the carbon atoms in a fatty acid?

A

Hydrogen atoms

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37
Q

What is a fatty acid with many double bonds called?

A

Polyunsaturated

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38
Q

What is a special type of lipid?

A

A phospholipid

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39
Q

What are phospholipids?

A

Lipids that have 2 fatty acid chains and a phosphate group

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40
Q

What are cell membranes made from?

A

A double layer of phospholipids

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41
Q

What are enzymes?

A

Biological catalysts that increase the rate of the reaction

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42
Q

What do enzymes do to the activation energy?

A

Lower it

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43
Q

What type of enzymes are all proteins?

A

Globular proteins

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44
Q

What are enzymes involved in?

A

Breaking down molecules or building molecules

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45
Q

Why are digestive enzymes important in the digestive system ?

A

Because they help to break down food into smaller molecules

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46
Q

What do enzymess involved in DNA replication do?

A

They help to build molecules

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47
Q

What is the active site?

A

A region on the surface of an enzyme molecule where a substrate molecule can attach itself

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48
Q

The shape of the substrate molecule and the shape of the active site are …

A

Complementary

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49
Q

What happens as soon as the enzyme substrate complex is formed?

A

The products of the reaction are released and the enzyme is ready to accept another substrate molecule

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50
Q

Only one substrate will fit the enzyme correctly , so each enzyme only catalyses one specific reaction, true or false?

A

True

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51
Q

What happens when the temperature of an enzyme is increased?

A

The enzyme reactions become faster because the molecules have more energy.

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52
Q

What happens to enzymes at really high temperatures?

A

-The enzymes atoms vibrate quicker and break the weak bonds that hold the tertiary structure together.

-The shape of the active site changes and the substrate can no longer fit in.

-The enzyme is said to be denatured

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53
Q

What can acids and alkalis do to enzymes?

A

Denature them. Hydrogen ions in acids and hydroxyl ions in alkalis disrupt the weak bonds and change the shape of the active site

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54
Q

What are monosaccharides?

A

The monomers of carbohydrates

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55
Q

What are examples of monosaccharides?

A

Glucose, galactose, fructose, ribose, deoxyribose, glyceraldehyde

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56
Q

What type of bond form when monosaccharides like glucose bond?

A

Glycosidic bonds

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57
Q

What make up maltose?

A

Alpha glucose + alpha glucose

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58
Q

What forms sucrose?

A

Alpha glucose + fructose

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59
Q

What is the molecular forma of sucrose?

A

C12 H22 O11

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60
Q

What forms lactose?

A

Alpha glucose + galactose

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61
Q

What does sucrose and sucrase make?

A

Alpha glucose + fructose

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62
Q

what does amylose and amylopectin make ?

A

Starch

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63
Q

Is amylose a monosaccharide or a polysaccharide?

A

A polysaccharide

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64
Q

Is amylopectin a monosaccharide or a polysaccharide?

A

A polysaccharide

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65
Q

What is the common formula for monosaccharides?

A

Cn(H20)n

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66
Q

What are some examples of polysaccharides?

A

Glycogen, starch and cellulose

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67
Q

What polymers are formed by the condensation of alpha glucose?

A

Glycogen and starch

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68
Q

What polymer is formed from the condensation of beta glucose?

A

Cellulose

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69
Q

What is the difference between alpha glucose and beta glucose ?

A

The differenc is the differing positions of the -OH groups. Alpha is a same-sided 1-4 hydroxyl group , while beta refers to opposite sided 1-4 groups.

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70
Q

Draw alpha glucose

A

Answer in book

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71
Q

Draw beta glucose

A

Answer in book

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72
Q

What is the difference between ribose and deoxyribose?

A

Ribose has a hydroxyl group at position 2, whereas deoxyribose has a hydrogen atom at position 2. Due to this, deoxyribose sugar is more stable than ribose sugar

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73
Q

Draw ribose

A

Answer in book

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74
Q

Draw deoxyribose

A

Answer in book

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75
Q

What is an isomer?

A

Something with the same molecular formula but a different structure

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76
Q

What is respiration?

A

The process in which glucose is broken down to release energy in the form of ATP

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77
Q

What is the word equation for respiration?

A

Oxygen + glucose-≥ carbon dioxide + water

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78
Q

What is the symbol equation for respiration?

A

6O2 + C6H12O6 -≥ 6H2o + 6CO2

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79
Q

What is glucose stored as in plants?

A

Starch

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80
Q

What is glucose stored as in animals?

A

Glycogen

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81
Q

Why can’t beta glucose be respired?

A

Because of its shape

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82
Q

Is starch a polysaccharide?

A

Yes

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83
Q

What is amylose?

A

A polymer of glucose joined by a -1,4- glycosidic bonds. Amylose is unbranched and helical

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84
Q

What is amylopectin?

A

polymers of glucose joined by -1,4- glycosidic bonds but with branches of 1,6 glycosidic bonds. This causes the molecule to be branched rather than helical

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85
Q

Why is starch good for storage?

A

Because it is insoluble (due to its lack of polar areas)

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86
Q

In starch, why can more energy be stored in a small space?

A

Because the helix is compact

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87
Q

Why is starch an excellent long term storage molecule?

A

Because there are only a few branches for the enzyme amylase to act on so the release of energy is relatively slow.

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88
Q

Which has more branches, amylopectin or glycogen?

A

Glycogen

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89
Q

What is glycogen made up of?

A

Alpha glucose molecules with much shorter 1,4 chains and many more branches of alpha 1,6 glycosidic bonds than amylopectin

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90
Q

Why does glycogen have more branches than amylopectin?

A

Because animals have a higher energy requirement and so more branches allows for more free ends, where glucose molecules can either be added or removed, allowing for condensation reactions to occur more rapidly

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91
Q

Why is cellulose strong?

A

-Because it’s alternate arrangement causes straight chains to form

-these chains are then cross linked by hydrogen bonds which form between the hydroxyl group

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92
Q

Why are microfibrils strong?

A

Because hundreds of them are arranged in overlapping sheets that run at different angles. The hydrogen crosslinks also make cellulose very resistant to hydrolysis

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93
Q

Where is chitin found?

A

In the exoskeleton of insects

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94
Q

Does chitin have complex crosslinks?

A

Yes

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95
Q

Does alternate molecules/inversion occur in chitin?

A

Yes

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96
Q

What are the side chains of peptidoglycan?

A

Amino acids

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97
Q

What is peptidoglycan similar in structure to?

A

Cellulose

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98
Q

Does cross linking occur in peptidoglycan?

A

Yes

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99
Q

Are there alternate molecules in peptidoglycan?

A

Yes

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100
Q

Does peptidoglycan contain nitrogen?

A

Yes

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101
Q

Why can amylose store a lot of energy?

A

because it is coiled and therefore it is a very
compact molecule

102
Q

What are lipids?

A

Lipids are macromolecules that contain carbon, hydrogen and oxygen atoms. Unlike carbohydrates, lipids contain a lower proportion of oxygen

103
Q

Are lipids polar or non polar?

A

non-polar

104
Q

Are lipids hydrophobic or hydrophilic?

A

hydrophobic (insoluble in water)

105
Q

What does hydrophobic mean?

A

Insoluble in water

106
Q

What reactions form the ester linkage?

A

Condensation reactions

107
Q

What are the main groups of lipids?

A

Phospholipids and triglyerides

108
Q

What are the roles of lipids?

A

-Energy storage
-Insulation(electrical and thermal)
-Buoyancy(floating)
-Waterproofing
-Protection
-Membranes
-Source of water- from respiration
-Aids absorption

109
Q

What is the only thing lipids are soluble in?

A

organic solvents, such as alcohols

110
Q

Describe the structure of the triglyceride molecule

A

Has one molecule of glycerol and 3 fatty acids joined together by ester bonds (which are formed in a condensation reaction)

111
Q

Are triglycerides polar or non-polar?

A

non-polar

112
Q

what are the monomers of tryglycerides?

A

glycerol and fatty acids

113
Q

What is glycerol?

A

an alcohol (an organic molecule that contains a hydroxyl group bonded to a carbon atom)

114
Q

What is on either end of a fatty acid chain?

A

at one end is a methyl group, at the other end is a carboxyl group

115
Q

what is the shorthand chemical formula for a fatty acid?

A

RCOOH

116
Q

What is a difference between lipids from animals and those from plants?

A

Lipids from animals are saturated, whereas lipids from plants are unsaturated

117
Q

What are the monomers of phospholipids?

A

glycerol and fatty acids

118
Q

What is the structure of a phospholipid?

A

two fatty acids bonded to a glycerol molecule and a phosphate ion

119
Q

is the phosphate in phosholipids polar or non-polar?

A

Polar and it is soluble in water (hydrophilic)

120
Q

are the fatty acid ‘tails’ in phospholipids polar or non-polar?

A

non polar and therefore insoluble in water (hydrophobic)

121
Q

why are phospholipids amphipathic?

A

because they have both hydrophobic and hydrophilic parts

122
Q

what is a function of triglycerides?

A

energy storage

123
Q

when does an ester bond form in a lipid?

A

when a hydroxyl (-OH) group from the glycerol bonds with the carboxyl (-COOH) group of the fatty acid

124
Q

what 2 categories do triglycerides fall in to?

A

fats and oils

125
Q

why do lipids help animals to float?

A

because fats have a low density

126
Q

why are trigylcerides good at storing energy?

A

because they store more energy per gram due to their hydrocarbon chains

127
Q

where are molecules of cholesterol synthesised?

A

in the liver and transported via the blood

128
Q

what steroid-based hormones is cholesterol used to produce?

A

oestrogen, testosterone and progesterone

129
Q

what does cholesterol affect in the cell membrane?

A

the fluidity and permeability

130
Q

what is the structure of cholesterol?

A

contains 4 carbon based rings, a hydrocarbon tail, and a hydroxyl group

131
Q

is the hydroxyl group in cholesterol water soluble or not?

A

it’s water soluble (hydrophilic)

132
Q

is the hydrocarbon tail in cholesterol oil soluble?

A

yes and it is hydrophobic

133
Q

what family of lipids is cholesterol part of?

A

sterols

134
Q

what can the hydrophilic hydroxyl group on the cholesterol molecule interact with?

A

the head groups of phospholipids. the rest of the cholesterol molecule can interact with the hydrophobic fatty acid tails

135
Q

what are the functions of cholesterol?

A
  • producing steroid-based hormones
  • making vitamin D, this process takes place in the skin in response to ultraviolet light.
    -producing bile in the liver
    -fluidity and permeability of cell membranes
136
Q

what is vitamin d needed for?

A

the proper development of bones

137
Q

what does bile do?

A

increases the rate of digestion of lipids by the enzyme lipase

138
Q

do saturated lipids melt at higher or lower temperatures to unsaturated lipids?

A

higher

139
Q

do unsaturated lipids melt at higher or lower temperatures to saturated lipids?

A

lower

140
Q

What are the 3 main parts to an amino acid?

A

Tha amine group, the carboxyl group and the R group

141
Q

Is the R group different for each of the 20 amino acids?

A

Yes

142
Q

What is the R group in glycine

A

A hydrogen atom

143
Q

What is the R group in alanine?

A

A methyl group

144
Q

What is the R group in glycine

A
145
Q

What does a dipeptide contain?

A

2 amino acids bonded together

146
Q

What does a polypeptide consist of?

A

3 or more amino acids bonded together

147
Q

Why is the primary structure very important?

A

Because it helps to determine the final 3D shape of the protein and so the protein function is dependent on the primary structure

148
Q

What can changing a single amino acid in the primary structure lead to?

A

A change in the proteins function. The protein hence may not be able to carry out it’s function effectively

149
Q

What is the tertiary structure?

A

The overall 3D shape of a polypeptide after proteins fold even further.additional bonds will be made between the r groups, such as ionic, hydrogen, disulfide and weak hydrophobic interactions . The function of the molecule also depends on the tertiary structure

150
Q

What is an example of a tertiary structure?

A

An enzymes active site

151
Q

What 2 changes can disrupt the tertiary structure and denature the protein?

A

pH and temperature

152
Q

What is the quaternary structure existent?

A

In proteins that have more than 1 polypeptide chain working together as a functioning macromolecule

153
Q

What is an example of a protein with a quaternary structure?

A

Haemoglobin

154
Q

What is each polypeptide chain referred to as?

A

A subunit

155
Q

Many proteins contain a p… group

A

Prosthetic

156
Q

What prosthetic group does haemoglobin have?

A

Haem, which binds to oxygen

157
Q

What is a protein with a prosthetic group called?

A

A conjugated protein

158
Q

What are disulfide bonds?

A

strong covalent bonds that form between two cysteine R groups (as this is the only amino acid with a sulphur atom)

159
Q

What is the strongest protein bond?

A

The disulfide bond

160
Q

How can disulfide bonds be broken?

A

By oxidation

161
Q

In which proteins are disulfide bonds common in?

A

proteins secreted from cells eg. insulin

162
Q

Where do Ionic bonds form in a protein?

A

Ionic bonds form between positively charged (amine group -NH3+) and negatively charged (carboxylic acid -COO-) R groups

163
Q

Are Ionic bonds broken by pH changes?

A

No

164
Q

Where do hydrogen bonds form in proteins?

A

between strongly polar R groups.

165
Q

What is the weakest type of bond that forms in proteins?

A

Hydrogen bonds, but they are also the most common as they form between a wide variety of R groups

166
Q

Where do hydrophobic interactions form?

A

between the non-polar (hydrophobic) R groups within the interior of proteins

167
Q

What is the difference between the hydrogen bonds in the secondary structure and the hydrogen bonds in the tertiary structure?

A

The hydrogen bonds in the secondary structure form only between the amino and carboxyl groups. Whereas the hydrogen bonds in the tertiary structure form between the R groups as well

168
Q

Are fibrous proteins elongated or spherical?

A

Elongated

169
Q

Are globular proteins elongated or spherical?

A

Spherical

170
Q

Are fibrous proteins soluble or insoluble in water?

A

Insoluble

171
Q

Are globular proteins soluble or insoluble in water?

A

Soluble

172
Q

What are some examples of fibrous proteins?

A

Collagen, keratin, elastin

173
Q

Describe the amino acid sequence of globular proteins

A

Irregular and wide range of R groups

174
Q

Describe the amino acid sequence of fibrous proteins

A

Repetitive with a limited range of R groups

175
Q

What type of functions do globular proteins have?

A

Physiological

176
Q

What type of functions do fibrous proteins have?

A

Structural

177
Q

What is a good way of distinguishing between fibrous and globular proteins?

A

SAFES (Shape, Amino acid sequence, Function, Examples and Solubility).

178
Q

Do fibrous proteins have a tertiary structure?

A

They usually have little/ no tertiary structure

179
Q

Do globular proteins have a tertiary structure?

A

They have a complex tertiary structure and usually a quaternary structure as well

180
Q

What is chromatography?

A

A method used to separate mixtures of substances into their components.

These mixtures can be analysed and their components can be identified.

181
Q

What is the stationary phase?

A

A solid or a liquid supported on a solid e.g chromatography paper, TLC

182
Q

What is TLC?

A

Silica on plastic

183
Q

What is the mobile phase?

A

A liquid or a gas(normally an organic solvent)

184
Q

What happens during chromatography?

A

The mobile phase picks up the molecules and carries them through the stationary phase

185
Q

What groups stick out of the stationary phase?

A

OH- groups

186
Q

What does the distance the molecules in chromatography move depend on?

A

The hydrogen bonds they make with the stationary phase and their solubility in the mobile phase

187
Q

What type of molecule sticks to the stationary phase more?

A

A polar molecule

188
Q

How do you calculate Rf values?

A

Rf value = distance travelled by sample / distance travelled by solvent

189
Q

what type of covalent bond is present in carbohydrates?

A

glycosidic

190
Q

what type of covalent bond is present in proteins?

A

peptide

191
Q

what type of covalent bond is present in lipids?

A

ester

192
Q

what type of covalent bond is present in nucleic acids?

A

phosphodiester

193
Q

.

A

.

194
Q

all monomers of carbohydrates are reducing…

A

sugars

195
Q

what is a monosaccaride?

A

a single sugar unit, all are reducing sugars

196
Q

what is a disaccharide?

A

a sugar formed from 2 monosaccharides joined together by a glycosidic bond in a condensation reaction

197
Q

what is a polysaccharide?

A

a polymer formed by many monsaccharides joined by glycosidic bonds in condensation reaction

198
Q

is ribose a pentose or a hexose?

A

a pentose, with 5 carbon atoms

199
Q

is glucose a pentose or a hexose?

A

a hexose, with 6 carbon atoms

200
Q

give some examples of polysachharides

A

cellulose, starch, glycogen

201
Q

where is sucrose found?

A

in plants, such as sugar cane

202
Q

what elements do nucleic acids contain?

A

carbon, hydrogen, oxygen, nitrogen, and phosphorous (to form the phosphate groups)

203
Q

what do reducing sugars do?

A

donate electrons and they reduce the soluble copper sulphate to insoluble brick-red copper oxide

204
Q

what are some examples of reducing sugars?

A

glucose, fructose and galactose

205
Q

what do non-reducing sugars do?

A

they cannot donate electrons, therefore they cannot be oxidised

206
Q

what’s an example of a non-reducing sugar?

A

sucrose

207
Q

how many carbon atoms does a triose have?

A

3

208
Q

what’s an example of a triose?

A

glyceraldehyde

209
Q

what is the most well-known carbohydrate monomer ?

A

glucose

210
Q

what is the main function of glucose?

A

releasing energy for the production of ATP

211
Q

what do riboses and deoxyriboses make up?

A

RNA and DNA

212
Q

what glycosidic bond does maltose form?

A

a 1,4

213
Q

what glycosidic bond does sucrose form?

A

a 1,2

214
Q

what glycosidic bond does cellulose form?

A

b 1,4

215
Q

what glycosidic bond does amylose form?

A

a 1,4

216
Q

what glycosidic bond does amylopectin form?

A

a 1,4 and a 1,6

217
Q

what catalyses hydrolysis reactions?

A

enzymes

218
Q

what are examples of hydrolysis reactions?

A

the digestion of food in the alimentary tract and the breakdown of stored carbohydrates in muscle and liver cells for use in cellular respiration

219
Q

what is maltose?

A

the sugar formed in the production and breakdown of starch

220
Q

what is lactose?

A

a sugar found only in milk

221
Q

are starch and glycogen soluble or insoluble?

A

insoluble, so they will have no osmotic effect, unlike glucose

222
Q

why can starch be easily hydrolysed for use during cellular respiration?

A

because the amylopectin in starch has branches that result in many terminal glucose molecules that can easily be hydrolysed for use during cellular respiration

223
Q

summarise the test for proteins

A
  1. Add sodium
    hydroxide solution.
  2. Add copper (II)
    sulphate solution.
    Colour change should be from blue to purple
224
Q

summarise the test for starch

A
  1. Add iodine in
    potassium iodide
    solution.

Colour change from
brown-orange to
blue-black.

225
Q

summarise the test for lipids

A
  1. Add ethanol.
  2. Pour solution into
    water.
    A cloudy emulsion forms
226
Q

summarise the test for reducing sugars

A
  1. Add Benedict’s
    reagent to a sample and
    heat in a water bath
    that’s brought to a boil.
    Sample goes from blue to
    green to yellow to orange
    to brick red precipitate,
    depending on the
    concentration
227
Q

summarise the test for non reducing sugars

A
  1. Add dilute HCl.
  2. Put in a water bath
    brought to a boil.
  3. Neutralise with
    sodium hydrogen
    carbonate.
  4. Do Benedict’s Test
    for reducing sugars.
    Sample goes from blue to
    green to yellow to orange
    to brick red precipitate,
    depending on the
    concentration
228
Q

summarise the test for glucose

A
  1. Dip test strip in
    solution.
    Colour change will occur
    if glucose is present.
    Compare to chart of
    known colour changes to
    check for concentration.
229
Q

what is an ion?

A

an atom (or sometimes a group of atoms) that has an electrical charge

230
Q

what is a positive ion called?

A

a cation

231
Q

what is a negative ion called?

A

an anion

232
Q

what is an inorganic ion?

A

An inorganic ion is an ion that does not contain carbon

233
Q

some inorganic ions act as cofactors.What are cofactors?

A

Cofactors are non-protein chemical compounds that are required for a protein to function

234
Q

What are the functions of hydrogen ions?

A

-hydrogen bonding
-ATP formation
-control of blood pH
-transport of carbon dioxide

235
Q

What are the functions of calcium ions?

A

-bone and enamel structure
-cofactor in blood clotting
- synaptic transmission of nerve impulses
-muscle contraption

236
Q

What are the functions of iron ions?

A

-transport of oxygen via haemoglobin
-transfer of electrons

237
Q

What are the functions of sodium ions?

A

-electrolyte
-nerve transmission
-reabsorption of water into the kidneys

238
Q

What are the functions of potassium ions?

A

-electrolyte
-nerve transmission
-reabsorption of water into the kidneys
-opening of the stomata

239
Q

What are the functions of ammonium ions?

A
  • deamination of proteins
240
Q

What are the functions of nitrate ions?

A

-source of nitrogen for plants

241
Q

What are the functions of hydrogen carbonate ions?

A

-carbon dioxide transport in the blood

242
Q

What are the functions of chloride ions?

A

-maintaining pH balance during carbon dioxide transport

243
Q

What are the functions of phosphate ions?

A

-component of the cell membrane(phospholipids)

-component of bones (calcium phosphate)

-component of ATP and nucleic acids

244
Q

What are the functions of hydroxide ions?

A

bonding between biochemical molecules

245
Q

what are 2 products of atp?

A

Adenosine diphosphate and (inorganic) phosphate

246
Q

What is the structure of collagen?

A
  • Peptide bonds between amino acids
  • Secondary structure is alpha helix
  • Has high proportions of glycine
  • 3 polypeptide chains and hydrogen bonds between them
  • No hydrophilic R groups on the outside of the molecules
  • Adjacent molecules joined by crosslinks
  • Crosslinks form fibrils
247
Q

What is the structure of heamoglobin?

A
  • Peptide bonds between amino acids
  • Secondary structure is alpha helix, with small regions of beta pleated sheets.
  • Hydrophilic R groups on the outside of the molecule
  • 4 polypeptide chains, 2 alpha, 2 beta
  • 4 haem groups per molecule
  • Made up of a wider range of amino acids
248
Q

Describe the ways in which the structure of collagen is similar to the structure of haemoglobin?

A
  • Both have an acid amino chain
  • Both vae amino acids joined by peptides
  • Both helical
  • Both have a quaternary structure
  • Both have more than 1 subunit
249
Q

How much heamoglobin differ from collagen?

A
  • Haemoglobin is globular, whereas collagen is fibrous.
  • Haemoglobin has hydrophilic R groups on the outside, whereas collagen doesn’t.
  • Haemoglobin has 4 polypeptide chains, whereas collagen has only 3.
  • Haemoglobin has a high wider range of amino acids- not predominantly glycine like collagen is
250
Q

What are the differences between glycogen and cellulose?

A
  • Glycogen doesn’t have hydrogen bonding, whereas cellulose does.
  • Glycogen has a- 1,4 bonds and a-1,6 bonds; whereas cellulose only has a-1,4 bonds.
  • Glycogen is branched, whereas cellulose is helical.
  • Glycogen doesn’t have fibrils, whereas cellulose does have fibrils.

-Glycogen has granules, whereas cellulose does not have granules.

-All glucose units in glycogen are in the same orientation, whereas adjacent glucose units in cellulose are in opposite orientation.

251
Q

Why does glucogen make a good storage molecule?

A
  • Glycogen is insoluble, so it doesn’t affect the water potential of the cell.
  • Can be broken down easily.
  • Has many branches for enzymes to attach to
  • It’s compact and so stores a lot of energy
252
Q
A

AS Biology (15 decks)

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