Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Level Biology > Topic 1A-Biological Molecules > Flashcards

Topic 1A-Biological Molecules Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are monomers?

A

Small basic molecular units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Give three examples of monomers

A

Monosaccharides, amino acids and nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What elements are carbohydrates made of?

A

Carbon, hydrogen and oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the three carbohydrate monomers/monosaccharides?

A

Glucose, fructose and galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many carbons does glucose have? What type of sugar is it?

A

6- hexose sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two types of glucose?

A

Alpha and beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the difference between alpha glucose and beta glucose?

A

In an alpha glucose molecule, H is arranged above OH but in a beta glucose molecule, OH is arranged above H on the right hand side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of reaction joins monosaccharides together?

A

Condensation reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is released in a condensation reaction?

A

A water molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of bond forms between the two monosaccharides in a condensation reaction?

A

Glycosidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the name given to a molecule consisting of two monosaccharides that have joined together?

A

Disaccharide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Glucose + glucose ->

A

Maltose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Glucose + fructose ->

A

Sucrose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Glucose + galactose ->

A

Lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name three disaccharides

A

Maltose, galactose and sucrose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What reaction breaks polymers apart?

A

Hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A hydrolysis reaction is the opposite of what reaction?

A

Condensation reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a hydrolysis reaction?

A

Adding water to break down a chemical bond between monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In a hydrolysis reaction, carbohydrates are broken down into what?

A

Their constituent monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What test is used to test for sugars?

A

The Benedict’s Test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the Benedict’s test for reducing sugars

A

1) Add Benedict’s reagent (which is blue) to a sample and heat it in a water bath until it begins to boil
2) If the test is positive it will form a coloured precipitate
3) The higher the concentration of the reducing sugars, the further the colour changes
4) Filter the solution and weigh the precipitate for quantitative results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do all reducing sugars contain?

A

Monosaccharides and some disaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What colour is Benedict’s reagent?

A

Blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What colour changes occur in the Benedict’s test? (List the whole spectrum)

A

Blue to green to yellow to orange to brick red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What colour does the solution turn in a positive Benedict’s Test for a reducing sugar?

A

Brick red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How are results determined qualitatively in the Benedict’s Test for reducing sugars?

A

Compare the colours of the precipitate and solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How are results determined quantitively from the Benedict’s Test for reducing sugars?

A

The solution is filtered and the precipitate is weighed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are polymers?

A

Large complex molecules composed of long chains of monomers joined together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Describe the Benedict’s Test for non-reducing sugars

A

1) Perform the test for reducing sugars and obtain a negative results
2) Get a new sample of the test solution and add dilute hydrochloric acid then heat in a water bath
4) Neutralise with sodium hydrogencarbonate
5) Carry out the test as normal (leave to boil and then observe a colour change)
6) If the test is positive it will form a coloured precipitate and if it’s negative the solution will stay blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

If the Benedict’s test for reducing sugars is negative, what does this show?

A

The absence of a reducing sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

If the Benedict’s test for non-reducing sugars is positive, what colour will the solution be?

A

Brick red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

If the Benedict’s Test for non-reducing sugars is negative, what colour will the solution be?

A

Blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are polysaccharides?

A

More than two monosaccharides joined together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What reaction forms polysaccharides?

A

Condensation reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Name three polysaccharides

A

Starch, glycogen and cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the main energy store in plants?

A

Starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Where do cells get their energy from?

A

Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How do plants store glucose?

A

As starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

When a plant needs more glucose for energy, what does it do?

A

It breaks down starch to release glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What two polysaccharides of alpha-glucose does starch consist of?

A

Amylose and amylopectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is amylose?

A

A long unbranched chain of alpha-glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the structure of amylose like?

A

Coiled, cylindrical structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why us amylose good for storage?

A

It’s compact so can fit more in a small space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is amylopectin?

A

A long branched chain of alpha glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Why is amylopectin branched?

A

So that enzymes can break down the molecule and get to the glycosidic bonds quickly and release glucose for energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Is starch soluble in water?

A

No, it’s insoluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the benefits of starch being insoluble?

A

It doesn’t affect the water potential of cells so doesn’t cause water to enter by osmosis. This also makes it good for storage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What test is used for starch?

A

Iodine test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Describe the iodine test

A

Add iodine dissolved in potassium iodide solution to a test sample.
If starch is present the sample changes from browny-orange to blue-black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What colour does a negative test for starch show?

A

Browny-orange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What colour does a positive test for starch show?

A

Blue-black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the main energy storage material in animals?

A

Glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Where do animal cells get their energy from?

A

Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How do animals store excess glucose?

A

Glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is glycogen?

A

A polysaccharide of alpha-glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Describe the structure of glycogen

A

It’s similar to amylopectin

It had many more side branches coming off it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Why is glycogen branched?

A

So that glucose can be released quickly which is important for animals because they need energy for movement and maintaining body temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

How is glycogen good for storage?

A

It’s a very compact molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is the major component of cell walls in plants?

A

Cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is cellulose made of?

A

Long, unbranched chains of beta-glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

When beta-glucose molecules bond, what do they form?

A

Straight cellulose chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What are cellulose chains linked by?

A

Hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What do the strong hydrogen bonds in cellulose chains form?

A

Microfibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is the purpose of microfibrils in cellulose?

A

They provide structural support for cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What are triglycerides a type of?

A

A type of lipid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What are triglycerides made of?

A

One molecule of glycerol and three fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are fatty acid molecules in triglycerides made of?

A

Hydrocarbons

68
Q

Describe the tail of a fatty acid

A

Hydrophobic tail (repel water)

69
Q

Why are lipids insoluble in water?

A

They have hydrophobic tails

70
Q

What is the basic structure of a fatty acid?

A

C in the centre single bonded to HO and also double bonded to O. The C is also bonded to the ‘R’ group; the variable hydrocarbon tail

71
Q

How are triglycerides formed?

A

Condensation reaction

72
Q

What bond is formed when a fatty acid joins to a glycerol molecule?

A

Ester bond

73
Q

Describe the difference between saturated and unsaturated fatty acids

A

Saturated fatty acids don’t have double bonds

Unsaturated fatty acids do have double bonds

74
Q

What lipids are found in cell membranes?

A

Phospholipids

75
Q

What is the difference between a triglyceride and a phospholipid?

A

A phospholipid replaces one of the fatty acids with a phosphate group

76
Q

Describe the structure of a phospholipid

A

Glycerol molecule bonded to two fatty acids and a phosphate group

77
Q

How does water behave with a phospholipid?

A

The phosphate group is hydrophilic and attracts water whereas the fatty acid tails are hydrophobic and repel water

78
Q

What are triglycerides used for?

A

Energy storage

79
Q

Where is the chemical energy stored in a triglyceride?

A

The hydrocarbon tail

80
Q

Why don’t triglycerides affect the water potential of a cell?

A

They’re insoluble. This is because the hydrophobic tails face inwards shielding themselves from water with the glycerol heads

81
Q

What makes up the bilayer of cell membranes?

A

Phospholipids

82
Q

What do cell membranes do?

A

Control what enters and leaves a cell

83
Q

In a phospholipid bilayer cell membrane, how do the phospholipids arrange themselves?

A

The hydrophilic heads face outwards on either side and the hydrophobic tails meet at the centre so water soluble substances can’t easily pass through

84
Q

What test is used to find lipids(fats)?

A

The emulsion test

85
Q

Describe the emulsion test

A

1) Shake the test substance with ethanol for a minute so that it dissolves then pour the solution into water
2) Any lipid will show up as a milky emulsion
3) The more lipid there is the more noticeable the milky colour will be

86
Q

What will the emulsion test for lipids show if it’s a positive result?

A

A milky emulsion

87
Q

What are proteins made from?

A

Long chains of amino acids

88
Q

What are the monomers of proteins?

A

Amino acids

89
Q

What is formed when two amino acids join together?

A

Dipeptide

90
Q

What is a polypeptide?

A

More than two amino acids joined together

91
Q

What are made up of one or more polypeptides?

A

Proteins

92
Q

What do all amino acids contain?

A

A carboxyl group (-COOH)
An anime or amino group (-NH2)
A carbon containing R group (variable group)

93
Q

How many amino acids are there?

A

20

94
Q

What is the only amino acid that doesn’t contain carbon in its R group? (Its R group consists of just 1 H atom)

A

The first amino acid: glycine

95
Q

How are amino acids linked together to form polypeptides?

A

Condensation reactions

96
Q

What is released in a condensation reaction?

A

A water molecule

97
Q

What is the bond between amino acids called?

A

Peptide bonds

98
Q

When does the reverse of a condensation reaction to form polypeptides happen?

A

During digestion

99
Q

What is the primary structure of a protein?

A

The sequence of amino acids in the polypeptide chain

100
Q

What is the secondary structure in a protein?

A

The coiled alpha-helix or beta-pleated sheet

101
Q

What is the tertiary structure of a protein?

A

The final 3D structure: globular or fibrous

102
Q

What is the quaternary structure of a protein?

This is for proteins made from more than one polypeptide chain

A

The way some polypeptide chains are assembled together

103
Q

What bonds form in the proteins that affect the secondary structure?

A

Hydrogen bonds

104
Q

What are the types of bonds in a protein that affect its tertiary structure?

A

Hydrogen bonds, ionic bonds, disulphide bonds

105
Q

Give three examples of proteins with a quaternary structure

A

Haemoglobin, insulin and collagen

106
Q

What are enzymes?

A

A type of protein that acts as a biological catalyst and speeds up the rate of reaction without being altered structurally or used up

107
Q

What shape do most enzymes take? Why?

A

Spherical due to tight folding in the polypeptide chain

108
Q

Are enzymes soluble?

A

Yes

109
Q

What do enzymes have a key role in?

A

Digestion

110
Q

What are antibodies a type of?

A

Protein

111
Q

What are antibodies involved in?

A

Immune responses

112
Q

What are antibodies made up of?

A

Two light (short) polypeptide chains and two heavy (long) polypeptide chains bonded together

113
Q

Where are transport proteins present?

A

Cell membranes

114
Q

What do channel proteins do?

A

Transport molecules and ions across membranes

115
Q

What makes channel proteins fold up and form a channel?

A

They contain hydrophobic and hydrophilic amino acids

116
Q

What do structural proteins consist of?

A

Long polypeptide chains running parallel to each other with cross links between them

117
Q

Give two examples of structural proteins

A

Keratin and Collagen

118
Q

Give two examples of globular proteins

A

Haemoglobin and insulin

119
Q

Give three examples of fibrous proteins

A

Collagen, keratin and elastin

120
Q

Which protein, globular or fibrous, is soluble?

A

Globular-soluble

Fibrous-insoluble

121
Q

What is a globular protein?

A

A polypeptide chain folded into a globular shape

122
Q

What is a fibrous protein?

A

A structural protein which consists of long, parallel polypeptide chains

123
Q

What test is used for proteins?

A

Biuret test

124
Q

Describe the biuret test for proteins

A

1) Add a few drops of sodium hydroxide solution to ensure that the test solution is alkaline
2) Add copper (II) sulphate solution
3) If a protein is present it turns purple, if no protein is present it stays blue

125
Q

What is the positive result of the biuret test for proteins?

A

Purple colour

126
Q

What is the negative result for the biuret test for proteins?

A

Blue colour

127
Q

What do enzymes catalyse?

A

Metabolic reactions (at a cellular levels and for the organism as a whole)

128
Q

Enzymes can be intracellular or extracellular, what does this mean?

A

Intracellular-inside cells

Extra cellular- outside cells

129
Q

What is an enzymes active site?

A

It is the part of the enzyme where substrate molecules bind to and it has a specific shape

130
Q

How do enzymes affect the activation energy of a reaction?

A

They lower it

131
Q

What is activation energy?

A

The minimum amount of energy required for a reaction to take place

132
Q

What does enzyme-substrate complex mean?

A

When a substrate fits into the enzymes active site

133
Q

Give a reason why the enzyme-substrate complex lowers the activation energy of a reaction where two substrate molecules need to be joined together

A

if two substrate molecules need to be joined, being attached to the enzyme holds them closer together and reduces repulsion between the molecules so they can bond more easily

134
Q

Give a reason why the enzyme-substrate complex lowers the activation energy of a reaction where two substrate molecules need to be broken down

A

Fitting into the active site puts a strain on bonds in the substrate so it breaks more easily

135
Q

What is the lock and key hypothesis?

A

The substrate fits into the enzyme the same way a key fits into a lock

136
Q

What is the induced fit theory?

A

It states that the substrate doesn’t have to be the right shape to fit the active site but it has to make the active site change shape in the right way. It suggests that the substrate can change its shape to fit the active site of an enzyme

137
Q

Why are enzymes so very specific? (Why do they only catalyse one reaction?)

A

Only one complementary substrate will fit into the active site

138
Q

What is an enzymes active site determined by?

A

The enzymes tertiary structure which is determined by the proteins primary structure

139
Q

What happens if an enzyme and substrate don’t complement each other?

A

The enzyme will not catalyse the reaction

140
Q

What happens if the structure of an enzyme is altered?

A

The shape of the active site changes and the enzyme won’t catalyse the reaction

141
Q

What determines the primary structure (amino acid sequence) of a protein?

A

A gene

142
Q

If a mutation occurs in the gene that controls the primary structure of a protein, what happens to the enzyme produced?

A

The tertiary structure or active site would be changed

143
Q

What five factors affect enzyme activity?

A

Temperature, pH, enzyme concentration, substrate concentration and enzyme inhibitors

144
Q

When the temperature is increased what happens to the rate of an enzyme controlled reaction?

A

Increases to a certain point then decreases rapidly

145
Q

Why does the rise in temperature initially speed up an enzyme controlled reaction?

A

More heat means more kinetic energy so the molecules vibrate more and are more likely to have successful collisions and cause a reaction.

146
Q

In an enzyme controlled reaction, if the temperature goes above a specific point what happens and why?

A

The rate of reaction decreases suddenly because the vibrations brea the bonds that hold the enzyme in shape and alter the shape of the active site which is called the denaturation of the enzyme

147
Q

What happens when you increase the pH in an enzyme controlled reaction?

A

The rate of reaction increases to an optimum point then falls again

148
Q

Why do pH values above and below optimum affect the rate of reaction in an enzyme controlled reaction?

A

H+ and OH- ions found in acids and alkalis can mess up the ionic bonds and hydrogen bonds that hold an enzymes tertiary structure in place. This changes the shape of the active site so the enzyme is denatured.

149
Q

Explain how enzyme concentration affect the rate of reaction?

A

The more enzyme molecules in a solution the more likely a substrate molecule is to collide with another molecule. This increases the rate of reaction.

150
Q

If the amount of substrate is limited but the enzyme concentration is high, what will happen to the rate of reaction?

A

It has no further affect because all the available substrate reacts

151
Q

How does substrate concentration affect the rate of reaction?

A

The higher the substrate concentration the faster the reaction(because a collision is more likely) but only up to saturation point.

152
Q

What happens at saturation point in a reaction where substrate concentration is increased?

A

There is no further effect on the rate of reaction

153
Q

What are the two types of enzyme inhibitors?

A

Competitive and non-competitive

154
Q

Describe the shape of competitive inhibitors

A

Similar to the substrate molecule

155
Q

How do competitive inhibitors inhibit a reaction?

A

They compete with the substrate molecules and bind to the active site so they block active sites and no further reactions (with substrate molecules) can take place

156
Q

What factor affects how much the enzyme is inhibited

A

The relative concentrations of the inhibitor and the substrate

157
Q

A high concentration of competitive inhibitors to active sites has what effect?

A

Slows down the rate of reaction

158
Q

How do non competitive inhibitors affect the rate of reaction?

A

They bond to the enzyme away from its active site and cause the active site to change shape

159
Q

What effect would increasing the concentration of substrate have on the rate of reaction with non-competitive inhibitors?

A

No effect

160
Q

What are the two ways of measuring the rate of an enzyme controlled reaction?

A

Measure how fast the product is made or measure how fast the substrate is broken down

161
Q

How do you carry out the experiment for how fast the product is made in an enzyme controlled reaction?

A

1) Add equal volumes and concentrations of hydrogen peroxide to multiple test tubes and add the same volume of buffet solution
2) Set up the apparatus
3) Put 2 boiling tubes in a each water bath set to different temperatures
4) Add catalase to one of each boiling tube and add a bung to the delivery tube
5) record how much oxygen is produced
6) repeat for each temperature
7) calculate the average

162
Q

How can we measure how fast the substrate is broken down in an enzyme controlled reaction?

A

1) Add iodine potassium iodide to each well on a spotting tile
2) Mix a known concentration of amylase and starch on a test tube
3) Add a drop of this mixture into one of the wells at regular intervals an watch the colour change
4) it goes blue black when starch is present so time how long it takes for this colour change to occur

163
Q

What catalyses the breakdown of hydrogen peroxide into water and oxygen?

A

Catalase

164
Q

What is a buffer solution?

A

It resists changes in pH when small amounts of acid or alkali are added

165
Q

What enzyme catalyses the breakdown of starch to maltose?

A

Amylase

166
Q

What colour does iodine solution turn when starch is present?

A

Blue-black

A Level Biology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions