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AQA A Level Biology > Topic 1 - Biological molecules > Flashcards

Topic 1 - Biological molecules Flashcards

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1
Q

Define denature

A

When the active site changes shape so the enzyme is no longer complementary to its substrate (high temperatures do this)

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2
Q

Define emulsify

A

Break down into smaller pieces of fat to increase the surface area

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3
Q

Define active site

A

Where on the enzyme the substrate binds to

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4
Q

Define enzyme

A

A protein that speeds up the rate of reaction, a biological catalyst

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5
Q

Where is amylase produced/secreted?

A

Salivary gland
Pancreas
Small intestine

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6
Q

Where is protease produced/secreted?

A

Stomach
Pancreas
Small intestine

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7
Q

Where is lipase produced/secreted?

A

Pancreas

Small intestine

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8
Q

Where is bile produced/secreted and stored?

A

Produced in liver, stored in gall bladder

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9
Q

What does amylase break down and into what?

A

Carbohydrates (starch) into sugars (glucose)

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10
Q

What does protease break down and into what?

A

Proteins into amino acids

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11
Q

What does lipase break down and into what?

A

Fats (lipids) into fatty acids and glycerol

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12
Q

What does bile break down and into what?

A

Emulsifies fats (lipids), so big fats (lipids) into small fats (lipids)

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13
Q

Name the parts of the digestive system

A 
Salivary gland
Oesophagus
Liver
Stomach
Pancreas
Small intestine
Large intestine
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14
Q

What does the prefix ‘poly’ mean?

A

Many

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15
Q

What does the prefix ‘tetra’ mean?

A

4

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16
Q

What are carbohydrates made of?

A

Carbon molecules and water

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17
Q

Name 3 monosaccharides and state what they are

A

glucose
galactose
fructose
all singular units of saccharides

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18
Q

Name 3 disaccharides and state what they are

A

maltose
lactose
sucrose
two monosaccharides together

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19
Q

Name 3 polysaccharides and state what they are

A

Starch
glycogen
cellulose
multiple disaccharides together

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20
Q

How can you link monosaccharides together to form disaccharides?

A

Condensation reactions between monosaccharides form dimers called disaccharides

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21
Q

What are dimers?

A

Like monomers but for two (di) instead of one (mono)

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22
Q

What are monosaccharides known as?

A

Simple sugars

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23
Q

What do the names of all the monosaccharides end with?

A

-ose

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24
Q

What is the monosaccharides general formula?

A

Cn(H2O)n

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25
Q

What are disaccharides made from?

A

two monosaccharides

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26
Q

What bond holds disaccharides together?

A

A glycosidic bond

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27
Q

The maltose disaccharide is composed of

A

two glucose monosaccharides

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28
Q

The sucrose disaccharide is composed of

A

one glucose and one fructose monosaccharides

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29
Q

The lactose disaccharide is composed of

A

one glucose and one galactose monosaccharide

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30
Q

What are glucose, fructose, and galactose structurally?

A

They are all structural isomers

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31
Q

What is an isomer?

A

They have the same molecular formula (for example glucose, fructose, and galactose all have C6H12O6) but different structures/arrangements of atoms

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32
Q

Glucose + fructose –>

A

Sucrose + water

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33
Q

Glucose + glucose –>

A

maltose + water

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34
Q

Glucose + galactose –>

A

Lactose + water

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35
Q

C6H12O6 + C6H12O6 –>

A

C12H22O11 + H2O

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36
Q

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

A

C12H22O11

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37
Q

What are the two types of glucose?

A

Alpha and beta

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38
Q

What does a long chain of alpha glucose make?

A

Starch or glycogen

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39
Q

What does a long chain of beta glucose make?

A

Cellulose

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40
Q

Is starch a mono, di or polysaccharide?

A

Polysaccharide

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41
Q

What do plants use starch for?

A

As a storage molecule in the form of granules or grains

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42
Q

What is starch made up of?

A

Repeating units of 200-100,000 glucose monomers

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43
Q

What is the test for starch?

A

Add iodine

Colour change from brown to blue/black if starch is present

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44
Q

What is a reducing sugar?

A

A simple sugar that includes all monosaccharides and most disaccharides (excluding sucrose)

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45
Q

Test for reducing sugars

A

Add benedicts solution
Heat up in a water bath
See colour change (blue to brick red) if reducing sugars present

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46
Q

What does the colour of precipitate formed in the test for reducing sugars test correlate with?

A

The concentration of the reducing sugar

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47
Q

What does the colour range show about the benedicts test show? What does this mean?

A

It shows the test is semi-quantitative i.e. it can be used to estimate the amount of reducing sugar in a sample

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48
Q

What elements do carbohydrates contain?

A

Carbon, hydrogen, oxygen

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49
Q

Are monosaccharides soluble or insoluble in water? Why?

A

Soluble, they have a lot of OH groups so they are more susceptible to hydrogen bonding

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50
Q

Which type of reaction joins two monomer monosaccharides together to form a disaccharide?

A

Condensation reaction

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51
Q

What is the name of the bond which links two monosaccharides together?

A

Glycosidic bonds

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52
Q

What is the name of the reaction which breaks down disaccharides into monosaccharides?

A

Hydrolysis

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53
Q

Which additional molecule is required in hydrolysis?

A

Water (H2O)

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54
Q

What is a monomer?

A

A single unit

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55
Q

What makes a sugar a reducing sugar?

A

All monosaccharides and most disaccharides are able to reduce oxidising agents (the rings open to reveal an aldehyde group which can be oxidised to a carboxylic acid group)

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56
Q

Why can’t sucrose be a reducing sugar?

A

In sucrose the ring form of glucose and fructose cannot become linear so there is no free aldehyde group to react, so it is described as a non-reducing sugar

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57
Q

Name all reducing sugars

A 
Glucose
Galactose
Fructose
Maltose
Lactose
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58
Q

Name all non-reducing sugars

A

Sucrose

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59
Q

What is a colorimeter?

A

a colorimeter is a device used for measuring colours, or colorimetry. It measures the absorbance of different wave lengths of light in a solution. It can be used to measure the concentration of a known solute.

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60
Q

% of diluted solution =

A

(volume of stock solution / volume of diluted solution) x 100

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61
Q

Starch uses

A 
.Plant storage in the form of grains
.Seeds and storage organs (potatoes)
.Component of food
.Major source of energy
.Energy store
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62
Q

Starch made from

A

.Alpha glucose chains

.Monomers linked with glycosidic bonds during condensation reactions

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63
Q

What are the chains like in starch?

A

Branched or unbranched

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64
Q

How does starch being insoluble help its function?

A

Doesn’t draw water into cells by osmosis, therefore the water potential of the cell is not affected

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65
Q

How does starch being large and insoluble help its function?

A

Can’t diffuse out of the cell

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66
Q

How does starch being compact help its function?

A

Large amount stored in a small space

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67
Q

How does starch being easily hydrolyzed help its function?

A

Glucose readily transported and available for use in respiration

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68
Q

How does starch being very branched with many ends help its function?

A

More sites for enzyme action

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69
Q

Where is starch never found?

A

Animal cells

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70
Q

Where is glycogen found?

A

Animal and bacteria (never plants)

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71
Q

Glycogen uses

A

.Carbohydrate storage (called animal starch)

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72
Q

Glycogen made from

A

Alpha glucose chains

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73
Q

What are the chains like in glycogen?

A

Similar to starch, shorter chains but more branched

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74
Q

Where is glycogen found?

A

Small granules in the liver and muscles

Stored in small amount, fat main storage molecule

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75
Q

What is glycogen readily hydrolyzed into?

A

Alpha glucose

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76
Q

How does glycogen being insoluble help its function?

A

Doesn’t draw water into the cells by osmosis, therefore the water potential of the cell is not affected

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77
Q

How does glycogen being large insoluble help its function?

A

Cant diffuse out of the cell

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78
Q

How does glycogen being compact help its function?

A

Large amount stored in a small space

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79
Q

What does glycogen have more of than starch and what does that mean?

A

Glycogen has more branches than starch so has more ends, this speeds enzyme action so it’s more rapidly broken down to glucose monomers which are used in respiration, which means animals have a higher metabolic rate than plants

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80
Q

Cellulose uses

A

.Major component of cell walls
.Stop cell lysis due to osmosis
.exert inwards pressure that stops water influx
.This makes plant cells turgid and push against each other
.Allows stems to be semi-ridged
.Allows maximum area for photosynthesis

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81
Q

Cellulose made from

A

Beta glucose monomers held together by 1, 4 (which carbons) glycosidic bonds

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82
Q

Where is cellulose found?

A

Plants (their cell walls)

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83
Q

What sort of chains does cellulose form?

A

Straight, unbranched chains

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84
Q

How is cellulose so strong?

A

.Straight chains run parallel with hydrogen bonds forming cross-linkages between them
.Each hydrogen bond is weak but the huge number of them strengthens the molecule
.This makes cellulose a valuable structural material
.The cellulose molecules group to form microfibrils
.Microfibrils arrange in parallel groups to form fibres, which have really strong tensile strength

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85
Q

What do Lipids contain?

A

.Contain carbon, hydrogen and oxygen

.The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates

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86
Q

What are Lipids soluble and insoluble in?

A

.They are insoluble in water

.They are soluble in organic solvents such as alcohols and acetone

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87
Q

What are the main groups of lipids?

A

The main groups are triglycerides (fats and oils), phospholipids and waxes. But they can also include cholesterol and steroids.

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88
Q

What is the main role of lipids?

A

The main role of lipids is in plasma membranes, phospholipids increase the flexibility of the membranes and the transfer of lipid soluble substances across them

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89
Q

The role of lipids as an energy source

A

when oxidised, lipids provide more than twice the energy as the same amount of carbohydrates

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90
Q

The role of lipids in waterproofing

A

lipids are insoluble in water so therefore make good waterproofs, both plants and insects have waxy cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin

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91
Q

The role of lipids in insulation

A

Fats are slow conductors of heat and when stored beneath the body surface help to maintain body heat

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92
Q

The role of lipids in protection

A

Fat is often stored around delicate organs, such as the kidney

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93
Q

What are fats and oils at room temperature?

A

Fats are solid at room temperature, whereas oils are liquids.

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94
Q

Why are triglycerides called triglycerides ?

A

Triglycerides area called so as they have 3 (tri) fatty acids combined with glycerol (glyceride). Each fatty acid forms a bond with glycerol in a condensation reaction, therefore hydrolysis of a triglyceride produces glycerol and three fatty acids.

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95
Q

What makes the differences in triglycerides?

A

.As the glycerol in every triglyericide is the same, the differences come from the different fatty acids
.There are over 70 fatty acids that all have a carboxyl group (-COOH) with a hydrocarbon chain attached

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96
Q

What is a carboxyl group?

A

-COOH

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97
Q

What does a saturated lipid mean?

A

.If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because all the carbon atoms are linked to the maximum possible number of hydrogen atoms

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98
Q

What does a monounsaturated lipid mean?

A

.If there is a single double bond, it is monounsaturated

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99
Q

What does a polyunsaturated lipid?

A

.If there is a single double bond, it is monounsaturated

.If there is more than one double bond it is polyunsaturated

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100
Q

What are phospholipids?

A

Similar to lipids except one fatty acid molecule is replaced with a phosphate molecule

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101
Q

What do fatty acids do with water?

A

Fatty acids repel water (they are hydrophobic)

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102
Q

What do phosphate molecules do with water?

A

Phosphate molecules attract water (they are hydrophilic)

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103
Q

What two parts are phospholipids made of?

A

A hydrophilic head - which is attracted to water but not to fat
A hydrophobic tail - which orientates itself away from water but mixes readily with fat

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104
Q

Why are phospholipids called polar?

A

It has two heads which behave differently

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105
Q

What happens when phospholipids are put in water?

A

So when they are placed in water the hydrophobic heads try and get as far away from the water as possible and the hydrophilic heads do the opposite

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106
Q

What is the lipid test known as?

A

The emulsion test

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107
Q

Describe the emulsion test

A
  1. Take a completely dry and grease-free test-tube
  2. To the 2cm^3 of sample being tested, add 5cm^3 of ethanol
  3. Shake the tube vigorously to dissolve any lipid in the sample
  4. Add 5cm^3 of water and shake gently
  5. A cloudy white colour indicates the presence of a lipid
  6. As a control, repeat the procedures using water instead of the sample; the final solution should remain clear
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108
Q

In the emulsion test, what is the cloudy colour due to?

A

The cloudy colour is due to any lipid in the sample being finely dispersed in the water to form an emulsion. Light passing through this emulsion is refracted as it passes from oil droplets to water droplets, making it appear cloudy.

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109
Q

What are amino acids?

A

Amino acids are the monomers that form the polymer called polypeptides

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110
Q

What do polypeptides join together to form?

A

Proteins

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111
Q

How many amino acids naturally occur in proteins? What is this proof of?

A

There are 20 amino acids that occur naturally in proteins

The fact that the same 20 occur in every living organism is proof for evolution

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112
Q

Whats a dipeptide?

A

2 amino acids linked by a peptide bond

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113
Q

Whats a tripeptide?

A

3 amino acids linked by peptide bonds

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114
Q

Whats a polypeptide?

A

Many amino acids linked by peptide bonds

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115
Q

Whats a protein made of?

A

one or more polypeptide chain

A protein can be a singly polypeptide but it is more common for a protein to be made of a number of polypeptide chains

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5
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116
Q

What are the five basic parts of of amino acids?

A
  1. Central carbon atom
  2. Amino groups (-NH3) basic
  3. Carboxyl group (-COOH) acidic
  4. Hydrogen
  5. A variable R group
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117
Q

What is the R group in amino acids?

A

The R group is the side chain, contains mainly hydrogen, carbon and oxygen atoms but can sometimes have sulphur or nitrogen

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118
Q

List some functions of proteins

A 
.Structure (collagen and keratin)
.Enzymes (amylase)
.Some hormones (insulin)
.Membrane transport
.Antibodies
.Mass transport (haemoglobin)
.Receptors
.Cell recognition
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119
Q

What is it called when many amino acids are joined together through condensation reactions?

A

This is called polymerisation many 100’s of amino acids are linked this way

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120
Q

Why are there a huge variety of primary protein structures possible?

A

polypeptides have many of the 20 naturally occurring amino acids, joining together in any sequence

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121
Q

What determines the structure and shape of protein?

A

The primary structure of protein determines its shape and therefore its structure

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122
Q

What happens if you change the shape of a single amino acid?

A

A change in a single amino acid in the primary sequence can change the shape of the protein
.This could lead to it being unable to carry out its function
.A proteins shape is very specific to its function

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123
Q

What do the linked amino acids that make up a polypeptide each have on either side of the peptide bond?

A

a –NH and –C=O group

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124
Q

What is the charge of the H in the -NH group?

A

positive

125
Q

What is the charge of the O in the -C=O group?

A

negative

126
Q

What do the -NH and -C=O groups do?

A

more likely to do hydrogen bonding because of the opposing charge, the two groups easily form weak hydrogen bonds

127
Q

What does hydrogen bonding cause?

A

This causes the long polypeptide chain to twist (for example an alpha-helix or beta-pleated sheet)

128
Q

What is a tertiary structure?

A

.The a-helix of the secondary protein structure can be twisted and folded even more
.This forms a complex and often unique 3d structure known as the tertiary structure

129
Q

What 3 bonds are present in a tertiary structure?

A
  1. Disulphide bonds – strong
  2. Ionic bonds – between carboxyl and amino groups not involved in forming the peptide bonds. Weaker than disulphide and easily broken by pH changes
  3. Hydrogen bonds – lots of them and easily broken
130
Q

What does a Quaternary structure consist of?

A

Large proteins can form complex molecules consisting of many individual polypeptide chains

131
Q

Whats a non-protein group called?

A

prosthetic

132
Q

Give an example of a prosthetic group associated with amino acids?

A

iron containing haem groups found in haemoglobin

133
Q

What is haemoglobin?

A

Haemoglobin is the protein that carries oxygen in red blood cells

134
Q

Describe the test for Biuret

A

Place the test solution into a boiling tube
.Add an equal amount of biuret agent
.Gently mix
.If it turns purple this indicates the presence of peptide bonds, and therefore proteins
.If it remains blue, the test is negative for protein

135
Q

What does the Biuret test detect?

A

peptide bonds

136
Q

The bond is the primary structure of protein is

A

peptide bonds

137
Q

The bond in the secondary structure of protein is

A

hydrogen bonds

138
Q

The bonds in the tertiary structure of protein is

A

disulphide bonds
Ionic bonds
Hydrogen bonds

139
Q

What are the two types of proteins

A

.Fibrous – collagen, structural

.Globular – haemoglobin, enzymes, metabolic functions

140
Q

Describe fibrous proteins

A

.Form long chains parallel to each other
.The chains link by cross bridges
.Form very stable molecules
.For example collagen

141
Q

What makes tendons so strong?

A

.Tendons are made of collagen
.Individual collagen polypeptide chains in the fibres are linked together by cross linkages between amino acids of adjacent chains
.The points where one collagen molecule ends and the next begins is staggered
.This increases strength

142
Q

List the function of lipids

A
  1. Energy store, waterproofing, insulation (slow conductors of heat and electrical insulation), protection, respiration, buoyancy, cell membrane, hormones
143
Q

Hydrophobic -

A

molecules are not polar or charged and cannot mix/dissolve in water

144
Q

Hydrophilic -

A

molecules are polar or charged and can mix/dissolve in water

145
Q

Saturated -

A

a hydrocarbon chain with no C=C double bond

146
Q

Unsaturated -

A

a hydrocarbon chain with one or more C=C double bond

147
Q

What happens when a carboxylic acid group and a hydroxyl group react?

A

When a carboxylic acid group (-COOH) reacts with a hydroxyl group (-OH) an ester bond is formed. A triglyceride, in which 3 fatty acids have reacted with 3 –OH groups, contains 3 ester bonds.

148
Q

What is the reaction that bonds fatty acids and glycerol called? And whats the opposite?

A

Condensation reaction bonds fatty acids and glycerol, hydrolysis produces glycerol and 3 fatty acids

149
Q

Why are unsaturated triglycerides more likely to be oils?

A

Double bonds cause the molecule to bend

.They cannot pack as tightly together

150
Q

How does a triglyceride having a high ratio of energy storing C-H to C atoms relate to its function?

A

Excellent energy store

151
Q

How does a triglyceride having a low mass : energy ratio relate to its function?

A

Good energy store – large amounts stored in a small space (animals carry less weight)

152
Q

How does a triglyceride being large, non-polar and insoluble ratio relate to its function?

A

Storage does not affect water potential/osmosis in cells

153
Q

How does a triglyceride having a high hydrogen : oxygen atoms ratio relate to its function?

A

Release water when oxidised, good for desert animals like camels

154
Q

A membrane is not a straight line, what is it?

A

A phospholipid bilayer

155
Q

How do phospholipids differ from triglycerides?

A

Phospholipids differ from triglycerides in that instead of 3 fatty acids they contain 2
The 3rd is replaced by a polar (hydrophilic) phosphate group

156
Q

What do phospholipids do in water?

A

.In solution phospholipids form spherical structures called micelles
.Hydrophobic tails pointing inwards and the hydrophilic heads on the outside
.They can also form a monolayer on the water surface

157
Q

When the substrate is in the active site it is called an ……

A

enzyme substrate complex

158
Q

What are enzymes made of?

A

Long folded chin of amino acids

159
Q

What type of protein is an enzyme?

A

globular protein

160
Q

What sort of bonds hold the enzyme in the correct shape?

A

Hydrogen bonds

161
Q

What dictates the order in which amino acids join in the enzyme?

A

DNA

162
Q

What gives enzymes their specific shape?

A

.The different amino acid chains fold in different ways to give enzymes a specific shape

163
Q

What is the induced fit model?

A

.The active site changes shape as the substrate binds, at the same time causing a change in shape of the substrate
.This results in a tight fit where the active site is now complementary to the altered substrates

164
Q

How does the induced fit model lower the activation energy needed?

A

The change in substrate shape induces strain in the substrate bonds which lowers the activation energy required for the reaction to occur by lowering the amount of energy needed to break the bonds in the substrate

165
Q

Advantages of the induced fit model

A

.Explains how the enzyme-substrate complex lowers the activation energy
.Explains how products are released – because active site is complementary to transition state not products
.Flexibility of active site explains how an enzyme may act on two similar but non-identical substrates
.Flexibility of protein also provides better explanation of non-competitive inhibition

166
Q

What U is our genetic code? What does this mean?

A

Universal, the same in all living organisms and cells (eukaryotes and prokaryotes)

167
Q

What is genetic code composed of?

A

Composed of DNA (deoxyribonucleic acid)

168
Q

Describe the structure of DNA

A

A always pairs with T
C always pairs with G
Hydrogen bonds keep the nitrogenous bases together
A double helix called a sugar phosphate backbone (deoxyribose and phosphate)

169
Q

What is the double helix called?

A

sugar phosphate backbone

170
Q

What is the sugar phosphate backbone made of?

A

deoxyribose and phosphate

171
Q

What does A pair with

A

T

172
Q

What does C pair with

A

G

173
Q

What does the nucleus contain?

A

The genetic material/our DNA

174
Q

What is our DNA contained in?

A

Large molecules caled chromosomes

175
Q

How many chromosomes are in a body cell?

A

23 pairs of chromosomes in every body cell but not gametes

176
Q

What are chromosmes made of?

A

Genes

177
Q

What are genes

A

short sections of DNA that code for one polypeptide or functional RNA

178
Q

The hierarchy of eukaryotic DNA

A

DNA
Combined with histones (proteins)
Linear Chromosomes
Nucleus

179
Q

What are the monomers that make up DNA?

A

Nucleotides

180
Q

How are nucleotides joined?

A

Phosphodiester bonds formed through condensation reactions

181
Q

What does each nucleotide consist of?

A
  1. Phosphate group
  2. Pentose sugar (deoxyribose)
  3. Nitrogenous base
182
Q

Where are the phosphodiester bonds?

A

between the phosphate group and pentose sugar (deoxyribose) of different nucleotides

183
Q

DNA Base A -

A

Adenine

184
Q

DNA Base T -

A

Thymine

185
Q

DNA Base G -

A

Guanine

186
Q

DNA Base C -

A

Cytosine

187
Q

DNA Base A pairs with …

A

T

188
Q

DNA Base G pairs with …

A

C

189
Q

DNA Base C pairs with …

A

G

190
Q

DNA Base T pairs with …

A

A

191
Q

What ‘C’ are the two chains of bases in DNA?

A

Complementary

192
Q

What does the sequence of one chain of bases in DNA determine?

A

The sequence of the other

193
Q

How did Chargaff investigate the bases in DNA

A

using paper chromatography to separate them and UV spectrometry to measure how much of each were present

194
Q

What two rules did Chargaff discover?

A

.The number of cytosine always equals the number of guanine

.The number of A, C, T and G present differs in species

195
Q

What did Watson and Crick deduce?

A

.The double helix structure
.G is base-paired with a C by 3 hydrogen bonds
.A is paired with a T by 2 hydrogen bonds

196
Q

How many hydrogen bonds are G and C connected by in DNA?

A

3

197
Q

How many hydrogen bonds are A and T connected by in DNA?

A

2

198
Q

What are enzyme inhibitors?

A

substances that directly or indirectly interfere with the active site of an enzyme

199
Q

Difference between competitive inhibitors and non-competitive inhibitors simply

A

Comp bind to active site and non-comp bind away from active site

200
Q

Describe and explain how competitive inhibitors work

A

.Similar shape to substrate, so can fit into the active site and prevent the substrate from binding
.In other words they ‘compete’ with the substrate for the active site

201
Q

What does the amount of inhibition from a competitive inhibitor depend on?

A

.Concentration of inhibitor

.Concentration of substrate

202
Q

For competitive inhibitors, as substrate concentration increases

A

.The degree of inhibition is reduced

.The rate of reaction even with the inhibitor increase

203
Q

Describe and explain how non-competitive inhibitors work

A

.Doesn’t bind to the active site, instead it competes for the allosteric site
.This distorts the shape of the active site

204
Q

What site does the non-competitive inhibitor bind to?

A

Allosteric site

205
Q

Describe the effects on the RoR for non-competitive inhibitors when the concentration of substrates increases?

A

.Not affected by concentration of substrates, can put loads of substrates in but they can’t get onto the active site so has no affect

206
Q

Describe the general RoR of non-competitive inhibitors

A

.The RoR in the presence of a non-competitive inhibitor is always lowered even at high substrate concentrations

207
Q

What factors affect enzyme action?

A 
.Temperature
.pH
.Enzyme concentration
.Substrate concentration
.Concentration of inhibitors
208
Q

How is enzyme rate of reaction normally measured?

A

Normally measured by measuring the enzyme reaction time course

209
Q

How can accurate data be achieved when measuring enzyme RoR?

A

The events must be frequently measured

210
Q

What do you measure when measuring the enzyme RoR?

A

.Measuring products or measure the consumption of substrate

211
Q

Describe and explain the temperature and enzyme RoR graph

A

Rapid increase to optimum (highest point) due to increasing kinetic energy so the active site and substrates collide more and so more reactions occur within a smaller space of time, past this the RoR goes down quickly and suddenly as the enzyme has become denatured and now no longer works as the active site has changed shape, it has gotten to hot and the hydrogen bonds break

212
Q

How does an enzyme denature due to temperature?

A

the active site has changed shape, it has gotten to hot and the hydrogen bonds break

213
Q

Describe and explain the pH and enzyme RoR graph

A

Rapid increase to optimum point (highest) then decrease of the same rate, past this pH the enzyme has become denatured and now no longer works as the amino acids charges on the active site change so the substrate can now no longer connect to form an enzyme–substrate complex, the pH can break the bonds in the enzymes tertiary structure which causes a change in the shape of the active site and it can no longer fit in – it has become denatured.

214
Q

How does pH denature an enzyme?

A

, the pH can break the bonds in the enzymes tertiary structure which causes a change in the shape of the active site and it can no longer fit in – it has become denatured.

215
Q

Describe and explain the enzyme concentration and enzyme RoR graph

A

Gradually increases RoR, due to more enzymes to break down the substrate, till a plateau at the top at the maximum (Vmax), this plateau shows there is a limiting factor (for example there is now more enzymes than substrate so increasing the enzyme concentration has no affect)

216
Q

Describe and explain the substrate concentration and enzyme RoR graph

A

Gradually increases RoR, due to more substrates for the enzyme to break down, more collisions so more enzyme–substrate complexes formed, till a plateau at the top, this plateau shows there is a limiting factor (for example there is now more substrate than enzymes so increasing the substrate concentration has no affect)

217
Q

What does RNA stand for?

A

Ribonucleic Acid

218
Q

What is RNA made of?

A

A polymer of nucleotides

219
Q

Nucleotide composition in RNA

A

.Phosphate
.Nitrogenous Base
.Pentose sugar (ribose sugar)

220
Q

RNA size in comparison to DNA

A

Shorter

221
Q

What are the 4 bases in RNA

A

A, U, C and G – Uracil replaces Thymine

222
Q

Sugar present in DNA

A

Deoxyribose (pentose sugar)

223
Q

Sugar present in RNA

A

Ribose (pentose sugar)

224
Q

Structure of DNA

A

DOuble helix

225
Q

Structure of RNA

A

Single strand

226
Q

Base pairing in DNA

A

A to T, C to G

227
Q

Base pairing in RNA

A

A to U, C to G

228
Q

Length of DNA

A

Long as two times the bases in RNA

229
Q

Length of RNA

A

Short, less bases than DNA

230
Q

Is DNA and RNA a polymer or monomer?

A

Both polymers of nucleotides

231
Q

What type of base pairing is in DNA??

A

Complementary

232
Q

Type of base pairing in RNA

A

No base pairing

233
Q

Can you predict the percentage of other bases from one base percentage in DNA?

A

Yes

234
Q

Can you predict the percentage of other bases from one base percentage in RNA?

A

No

235
Q

Name the 3 types of RNA

A

mRNA
rRNA
tRNA

236
Q

What is mRNA?

A

messenger RNA, copies of the DNA sequence which leaves the nucleus through membrane pores and give instructions to the ribosomes to make proteins

237
Q

What is rRNA?

A

ribosomal RNA, combines with protein to make up the ribosomes structure

238
Q

What is tRNA?

A

transfer RNA, carries specific amino acids during the process of protein synthesis (called translation)

239
Q

How do all the RNA’s work together in protein synthesis?

A

.The mRNA gives the instructions to make the proteins and brings it to the ribosome, the rRNA makes up the ribosome to make the protein and the tRNA reads the mRNA and interact to make the protein

240
Q

What is DNA replication vital for?

A

.Growth .Development/specialisation

.Reproduction

241
Q

What are the 3 proposed methods of DNA replication?

A

Conservative replication
Dispersive replication
Semi-conservative replication

242
Q

What is conservative replication?

A

.One DNA molecule contains both parental DNA strands

.The other molecule contains only newly-synthesised DNA

243
Q

What is dispersive replication?

A

.Parental DNA is interspersed between the two molecules

.Both new strands have some new and some original DNA

244
Q

What is semi-conservative replication?

A

.BOTH DNA double helices, consist of one parental and one new DNA strand

245
Q

What are the 5 key requirements of semi-conservative replication?

A 
.DNA template
.Free nucleotides
.DNA helicase
.DNA polymerase
.Energy
246
Q

Describe the process of semi-conservative replication (6 marks)

A

The parental DNA is gets broken apart by the enzyme DNA helicase V, which breaks the hydrogen bonds between bases. These open bases attract free nucleotides V which come and loosely attach to the complementary bases (A to T and C to G) on the original (template V) strand of parental DNA. Hydrogen bonds V form between the nitrogenous bases. DNA polymerase V helps form the sugar-phosphate backbone of the DNA which gives the new strand structure and support, it holds it in place. This has now formed a daughter DNA’s double helix. V 6/6

247
Q

What does ATP stand for?

A

Adenosine Triphosphate

248
Q

What is ATP?

A

A nucleotide derivitave

249
Q

What is ATP made up of?

A

. A molecule of ribose
. A molecule of adenine
. Three phosphate groups

250
Q

What is hydrolysis?

A

Hydrolysis – the breakdown of a molecule using water

251
Q

What is ATP hydrolysed into?

A

ADP and phosphate ion, releases energy

252
Q

What enzyme helps with the hydrolysis of ATP?

A

ATP hydrolase

253
Q

What does ADP stand for?

A

Adenosine diphosphate

254
Q

Why are phosphate ions useful?

A

. Phosphorylate compounds

. More reactive so reacts with water

255
Q

Name some metabolic processes that rely on energy

A 
.	Active transport
.	Respiration
.	Cell reproduction
.	Digestion
.	Protein synthesis
.	Formation of urea
.	Movement/muscle contraction
.	Breakdown and synthesis of new molecules
.	Enzyme controlled reactions (respiration, photosynthesis, digestion)
256
Q

How does ATP re-synthesise?

A

ADP and the phosphate ion use energy to synthesise ATP through a condensation reaction that joins them together with the help of the enzyme ATP synthase

257
Q

When does re-sythesis occur?

A

during photosynthesis and respiration

258
Q

Where is our water from?

A

.Oceans
.Atmosphere (keeps the planet warm)
.80% of our bodies

259
Q

Describe the structure and bonding of water

A

.Covalent compound
.H2O
.Water is a polar molecule meaning it is charged
.There polar bonds are arranged asymmetrically

260
Q

What is cohesion in water?

A

.The negative end of the oxygen is attracted to the positive end of the hydrogen on the adjacent molecule
.Hydrogen bonds form
.This cohesive force give water its unique properties

261
Q

What 5 properties does water have?

A

.High heat capacity
.Large latent heat of vaporization
.Forms strong cohesion between water molecules
.An important solvent
.A metabolite in many metabolic reactions

262
Q

Define specific heat capacity

A

: the amount of energy required to change 1g of a substance to 1’C

263
Q

What is waters specific heat capacity?

A

High

264
Q

Why is water having a high specific heat capacity important?

A

.Absorb large amounts of heat energy before its temperature raises a significant amount
.Water surrounding cells absorb heat energy produced in reactions
.Buffers any temperature changes
.Releases heat energy slower
.Helps living organisms to regulate their body temperature
.Moderates Earth’s climate
.Thermoregulation

265
Q

When does cohesion with water cause surface tension?

A

When water meets air

266
Q

What does cohesion with water help water do?

A

Flow in a continuous stream when in tube like columns

267
Q

How does cohesion cause surface tension?

A
  • The surface has an elastic tendency

- acquires the least surface area possible

268
Q

Why is water having cohesive properties important?

A

.Support
.Movement of water up the stem (transpiration) no matter how tall
.Surface tension (makes water behave like skin when it meets the air, allows small animals to live on the surface of some water bodies)
.Droplets of water can form

269
Q

Define latent heat

A

heat energy that is taken in or given out by a substance when it changes state

270
Q

Define latent heat of vaporization

A

When the substance changes from liquid to vapor

271
Q

How does latent heat of vaporisation work?

A

.In a body of water some molecules are moving at faster speeds (have a higher kinetic energy)
.Some have enough of this energy to escape the water, called vaporization
.This reduces the average energy of the water, cooling it
.Provide a cooling effect to maintain internal temperatures
.Little water is lost through evaporation

272
Q

Define metabolic reactions

A

set of life-sustaining chemical transformations within the cell of living organisms

273
Q

Why is water being

a metabolite important?

A

.Hydrolysis (digestion of large molecules in animals)

.Condensation reactions (synthesis of important molecule such as proteins in living organisms)

274
Q

Define solvent

A

a liquid or other substance can dissolve in water

275
Q

Define solution

A

– The mixture formed when a solute has dissolved in a solvent

276
Q

Define solute

A

The substance that dissolved in a liquid

277
Q

Why does water make for a good solvent?

A

.Positive and negative charges of water attract other molecule causing them to separate form each other and dissolve
.When they dissolve they are free to move around and react with other molecules
.Water is one of the best for transporting dissolved substances

278
Q

Why is it important that water is a good solvent?

A

Metabolic reactions only happens when reactants are dissolved in water
.Transported around bodies of living organisms

279
Q

Why is it important that water buffers and controls internal body temperature (thermoregulation) ?

A

so the enzymes don’t denature and the body’s internal functions still work at its optimum temperature (37’C)

280
Q

Why is it important that water provides a cooling effect to maintain internal temperature?

A

so the enzymes don’t denature and the body’s internal functions still work at its optimum temperature (37’C)

281
Q

Why is it important that water Allows columns of water to form and move through organisms, causes surface tension when water meets air?

A

allows for transpiration streams to occur in plants and water be transported around body for its uses, allows animals to live in the surface of some water bodies

282
Q

Why is it important that water allows metabolic reactions can occur, enables waste and essential molecules to be transported?

A

so that the body can function properly and allow things to be disposed of and transported around the body for reactions to occur that the body needs

283
Q

Why is it important that water is included in essential processes such as ATP, digestion and protein synthesis?

A

aids the transportation of substances but also essential in some process like hydrolysis (the breakdown of something via water)

284
Q

What is an ion?

A

An atom or molecule that carries a charge

285
Q

Why do ions carry a charge?

A

The total number of electrons and protons is not equal

Atom/molecule has a net +/- electrical charge

286
Q

What are inorganic ions?

A

In animals and plants ions necessary for vital cellular activity are called inorganic ions

287
Q

Where are inorganic ions generally found?

A

In solution in the cytoplasm and body fluids

288
Q

How many inorganic ions are present?

A

Some in high concentrations and some in very low concentrations

289
Q

How is the amount of inorganic ions present controlled?

A

Membrane permeability

290
Q

How do inorganic ions move?

A

Diffusion, active transport

291
Q

Main examples of inorganic ions

A

Hydrogen, iron, sodium, phosphate, calcium, magnesium and nitrate

292
Q

What is pH

A

Number of hydrogen ions per litre in unites of moles

293
Q

Why are hydrogen ions important?

A

Vitally important for buffering the blood and maintaining the pH of it.

294
Q

Why is it important the blood is buffered?

A

Maintaining a same number of pH is vital as any less or any more turns it acidic or alkali
.This could denature enzymes and any other proteins which would stop metabolic functions so you die
.Also the haemoglobin might not be able to carry blood anymore
.Also channel proteins could be denatured which means the permeability of the membrane is no longer correct and what needs to get in and out can’t but things that shouldn’t enter can.

295
Q

What makes your blood red?

A

Iron ions

296
Q

How much iron is in your blood?

A

On average 4 grams

297
Q

What do you need to take if you dont have enough iron ions?

A

Medication

298
Q

How can you get lots of iron ions in your blood?

A

Through eating brocolli and red meat

299
Q

Why are iron ions important?

A

Major component of haemoglobin which is important as this is what carries oxygen around our bodies, by letting it bind to the haemoglobin.
Also involved in the electron transport chain in respiration.

300
Q

Why are sodium ions important?

A

Help to move amino acids and glucose in and out of the cells.
Important when establishing a nervous impulse and responding to changes in the internal and external environment.

301
Q

Why are proteins and glucose important?

A

Amino acids make proteins for growth and repair while glucose is used in respiration to release energy.

302
Q

Why are phosphate ions important?

A 
Makes lots of different biological molecules – 
.Nucleic acids
.ATP
.Phospholipids
.NAD and NADP (photosynthesis)

Which makes it incredibly important in growth and repair as it is used a lot in the cell cycle and formation of proteins.

303
Q

Name the bonds that form between glucose monomers

A

1,4 glycosidic bonds

304
Q

Name the two forms of starch

A

amylopectin, amylose

305
Q

Name the following groups:
OH
COOH
H2N

A

Hydroxyl
Carboxyl
Amino group

306
Q

Can fat be hydrolyzed into water?

A

YES

307
Q

Draw alpha glucose

A

idk google it or check revision guide or something

308
Q

Draw an amino acid

A

idk google it or check revision guide or something

309
Q

What is a control (not a control variable)?

A

your reference you don’t change in an experiment

AQA A Level Biology (19 decks)

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