Chemistry of Life Flashcards

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1
Q

What is an Acid?

A

A compound that released H+ ions into solution. pH < 7

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2
Q

What is a Base?

A

A compound that takes up H+ ions into solution. pH > 7

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3
Q

What is a buffer?

A

A solution that resists change in pH. Usually a combination of a weak acid and one its soluble salts

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4
Q

What is the pH of blood?

A

Between 7.35 - 7.45

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5
Q

What is the formula for carbohydrates?

A

Cx(H2O)y

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6
Q

What does dissociation mean?

A

Separates into constituent ions

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7
Q

99% of all living matter consists of which four atoms?

A

Nitrogen, hydrogen, carbon, oxygen

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8
Q

How many elements make up the cell?

A

16

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9
Q

Which elements make up lipids?

A

Carbon, Hydrogen, Oxygen

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10
Q

HCl is an example of an acid or a base?

A

Acid

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11
Q

How is HCl dissociated in solution?

A

H+ and Cl-

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12
Q

Positively charged ion is

A

Cation

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13
Q

Cation is…

A

a positively charged ion

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14
Q

Negatively charged ion is

A

Anion

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15
Q

Anion is…

A

Negatively charged ion

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16
Q

Forumla for pH

A

-log10 (H+ concentration)

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17
Q

Sodium hydroxide formula

A

NaOH

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18
Q

Sodium hydroxide dissociates into

A

Na+ and OH-

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19
Q

Ethnic acid formula

A

C3H3COOH

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20
Q

How does ethanoic acid dissociate in water?

A

C2H5COO- and H+

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21
Q

How is blood buffered?

A

Phosphate ions, hydrogen carbonate, blood proteins

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22
Q

Why is it important to use buffers in laboratory experiments?

A

To keep the pH of a solution under control when diluting or adding acids or bases.

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23
Q

Metabolism is…

A

All the chemical reactions that occur within an organism

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24
Q

The role of (nitrate) NO3- in plant metabolism is…

A

Required for DNA, RNA and protein synthesis

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25
Q

The role of calcium (Ca2+) in plant metabolism is…

A

Used to synthesize calcium pectate

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26
Q

What is calcium pectate?

A

Forms the lamella, a layer between the walls of adjacent plant cells

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27
Q

The role of magnesium (Mg2+) in plant metabolism

A

Used in chlorophyll production

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28
Q

The role of phosphate (PO4 3-) in plant metabolism

A

For energy in the synthesis of ATP from ADP, and in DNA and RNA replication/transcription.

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29
Q

A human cells consists of **% water

A

80%

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30
Q

What type of bond does water use?

A

Covalent

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31
Q

Charge of a H2O molecule

A

Neutral

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32
Q

Which atom(s) in H2O are electro negative?

A

Oxygen

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33
Q

Which atom(s) in H2O are electro positive?

A

Hydrogen

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34
Q

Why is Oxygen electro-negative in H2O?

A

Because the large nuclei of oxygen pulls the electrons away from the small nuclei of hydrogen

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35
Q

Why is hydrogen electro-positive in H2O?

A

Because the large nuclei of oxygen pulls the electrons away from the small nuclei of hydrogen, therefore giving oxygen additional elections and hydrogen fewer

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36
Q

What is a polar molecule?

A

The unequal distribution of electrical charge across a molecule

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37
Q

What is a polar molecule?

A

The unequal distribution of electrical charge across a molecule

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38
Q

How are water molecules bound?

A

Hydrogen bonds

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39
Q

What is a covalent bond?

A

A bond between two atoms in which electrons are shared between them.

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40
Q

What is a hydrogen bond?

A

A link between two polar molecules which combines using the weak positive of one and weak negative charge of the other to form a bond.

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41
Q

How strong is a covalent bond?

A

Kinda strong, but not the strongest

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42
Q

How strong is a hydrogen bond?

A

Weak

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43
Q

What is cohesion?

A

The force that attracts hydrogen bonds between polar molecules or other charged surfaces together

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44
Q

What kind of molecule is water?

A

Polar

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45
Q

Name some examples of solutes that water is a good solvent for:

A
  1. ionic substances i.e. sodium chloride (NaCl-)

2. Organic molecules with ionized groups (COO-, NH3+)

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46
Q

NaCl- is added to water. Which is the solvent and which is the solute?

A
Solvent = NaCl-
Solute = water
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47
Q

A polar molecule that can dissolve in water is known as

A

Hydrophilic

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48
Q

Are non-polar molecules hydrophilic or hydrophobic?

A

Hydrophobic

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49
Q

What does hydrophilic mean?

A

Dissolves in water

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50
Q

What does hydrophobic mean?

A

Does not dissolve in water

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51
Q

Give an example of a hydrophobic substance

A

Oil

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52
Q

Give an example of a hydrophilic substance

A

NaCl-

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53
Q

What does the term “Specific Heat Capacity” mean?

A

The heat needed to break bonds

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54
Q

What is the specific heat capacity of water?

A

4.184 kj / kg /^celcius.

This means that it takes 1.184 kj of heat to increase the temperature of 1kg of water by 1 degree Celsius

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55
Q

Why is the specific heat capacity important for humans?

A

Because it means humans can tolerate large fluctuations in environmental temperature without changing internal temperature.

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56
Q

What is the force by which charged molecules stick together?

A

Cohesion

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57
Q

Are ionic substances hydrophilic or hydrophobic?

A

hydrophilic

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58
Q

Are alcohols and sugars hydrophilic or hydrophobic?

A

hydrophilic

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59
Q

Are oils hydrophilic or hydrophobic?

A

hydrophobic

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60
Q

Are oils polar or non-polar molecules?

A

non-polar?

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61
Q

The term used to describe the heat needed to break bonds

A

The specific heat capacity

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62
Q

A link between two polar molecules which combines using the weak positive of one and weak negative charge of the other to form a bond.

A

Hydrogen bond

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63
Q

A bond between two atoms in which electrons are shared between them.

A

Covalent bond

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64
Q

4.184 kj / kg /^celcius is…

A

The specific heat capacity for water

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65
Q

The intramolecular bonds in water

A

covalent

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66
Q

The intermolecular bonds in water

A

hydrogen

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67
Q

Surface tension is..

A

The cohesion of water at the water-air interface. Occurs because more molecules of H2O are present here.

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68
Q

Is water compressible?

A

No

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69
Q

Is water incompressible?

A

Yes

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70
Q

What does it mean if water is incompressible?

A

The distance between molecules is very small and can therefore not be shortened (or, compressed)

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71
Q

Maximum density of Water is at what temperature?

A

4^C

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72
Q

Is H2O-ice more or less dense than liquid water?

A

less

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73
Q

Why does it mean that ice floats on water?

A

Because ice is less dense than water

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74
Q

Water is at its maximum density at 4^C, what is a consequence of this to living organisms?

A

In rivers and lakes, the floating layer of ice insulates the large mass of water so that it can’t freeze solid. Therefore the aquatic life in such spaces can survive.

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75
Q

What shape does the water molecule take? (almost)

A

Tetrahedron

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76
Q

What symptoms would be shown by a plant grown in magnesium deficient soil?

A

Lack of chlorophyll production

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77
Q

In plants, what is chlorophyll?

A

Great pigment found in the chloroplasts of cells. It is essential in photosynthesis and allowing plants to absorb energy from plants

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78
Q

What are 5 properties of water that make it essential for life?

A

1.

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79
Q

What is xylem tissue?

A

One of two types of transport tissue in vascular plants

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80
Q

Phloem is?

A

One of two types of transport tissue in vascular plants

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81
Q

Why can a pond skater walk on water but humans can’t

A

because the surface tension of the water is strong enough to hold the tiny weight of the pond skater, and because this weight is distributed across a large diameter relative to its size and weight.

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82
Q

Carbon is the — most abundant element in cells and living organisms

A

Third

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83
Q

What is the third most abundant element in cells and living organisms

A

carbon

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84
Q

What is an organic compound?

A

A large carbon compound which carbons are covalently linked to each other and to hydrogen molecule

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85
Q

What bonds are used between carbons are organic compounds?

A

covalent

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86
Q

Organic compounds are made up (mostly) from which two elements?

A

Carbon and Hydrogen

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87
Q

Properties of carbon

A
  1. Can form four strong, stable, covalent bonds (four lone pairs of electrons)
  2. Carbon atoms can react with one another ro form extended chains, or skeletons
  3. Can form covalent bonds with other atoms too, e.g. oxygen, nitrogen, hydrogen and sulfur.
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88
Q

How many covalent bonds does carbon form? And why?

A

Four, because it has four lone pairs

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89
Q

What shape does methane form?

A

Tetrahedron.

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90
Q

What are the four families of organic molecules?

A

Lipid, nucleic acid, carbohydrate, protein

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91
Q

Examples of carbohydrates

A

sugars, starch, glycogen, cellulose

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92
Q

Types of carbohydrate

A

Monosaccharide, disaccharide, polysaccharide

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93
Q

Features of a monosaccharide

A
Smalll molecules, soluble in water and sweet in taste
Simple sugars e.g.
1. trioses (C3-H6-O3)
2. Pentoses (C5-H10-O5)
3. Hexoses (C6-H12-O6)
*Numbers should be sub-script
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94
Q

What is the formula for a Triose?

A

C3-H6-O3

*Numbers should be sub-script

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95
Q

What is the formula for Pentoses?

A

C5-H10-O5

*Numbers should be sub-script

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96
Q

What is the formula for hexoses?

A

C6-H12-O6

*Numbers should be sub-script

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97
Q

Triose, pentose and hexose are all types of what?

A

Monosaccharide

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98
Q

C3-H6-O3 is the formula for…

*Numbers should be sub-script

A

Triose - monosaccharide

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99
Q

C5-H10-O5 is the formula for…

*Numbers should be sub-script

A

Pentose - monosaccharide

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100
Q

C6-H12-O6 is the formula for…

*Numbers should be sub-script

A

hexose - monosaccharide

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101
Q

Features of a disaccharide…

A

Two simples sugars chemically linked by a glycosidic bond during a condensation reaction e.g.
Sucrose = glucose + fructose
lactose = glucose + galactose
Maltose = glucose + glucose

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102
Q

Sucrose =

A

glucose + fructose

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103
Q

glucose + fructose =

A

Sucrose

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104
Q

lactose =

A

glucose + galactose

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105
Q

glucose + galactose =

A

lactose

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106
Q

Maltose =

A

glucose + glucose

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107
Q

glucose + glucose =

A

Maltose

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108
Q

Features of polysaccharides

A

Lots of simple sugars in a chain chemically linked by glycosidic bonds, e.g.
Starch (Fuel storage in plants)
Glycogen (energy storage in animals)
Cellulose (major component of plant cell walls)

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109
Q

Importance of monosaccharides

A

All green leaves produce glucose using light and glucose is important in respiration

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110
Q

Glucose is which type of monosaccharide?

A

Hexose (C5-H10-O5)

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111
Q

What is the chemical formula for glucose?

A

C6-H12-O6

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112
Q

What shape does glucose take?

A

Cyclic

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113
Q

How many carbons does glucose have?

A

6 (hexose)

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114
Q

What is an isomer?

A

Molecules that have the same molecular formula but different structural formula

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115
Q

What is the molecular formula?

A

Shows the name and number of atoms in a molecule

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116
Q

What is the structural formula?

A

shows the way atoms are arranged in the molecule

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117
Q

Alph-glucose and beta-glucose differ by…

A

The positions of the H and the OH bound to the carbon-1.

In solution, glucose transitions between both structures

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118
Q

What is Benedict’s test?

A

When heated with Benedicts solution, the COOH group from the sugar reduces Cu2+ ions of copper(II) sulfate to Cu+ ions, which then form a brick-red precipitate of copper(I) oxide. In this process, the aldehyde group is oxidized to a carbonyl group (C=O).
If no reducing sugar is present the solution remains blue after heating.
The greater the sugar content, the bigger the color change.
blue -> green -> yellow –> brown -> red

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119
Q

What is Benedict’s solution?

A

An alkaline solution of copper(II) sulfate

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120
Q

What color is the solution in Benedicts test if there is no reducing sugar present?

A

Blue

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121
Q

What is the color sequence in Benedicts test if there is reducing sugar present?

A

blue -> green -> yellow –> brown -> red

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122
Q

blue -> green -> yellow –> brown -> red

is the sequence for which test? And what does it measure?

A

Benedicts test.

Measures the concentration of reducing sugar in a solution

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123
Q

Examples of hexose sugars

A

Glucose, fructose and galactose

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124
Q

Glucose, fructose and galactose are examples of what type of monosaccharide?

A

hexose

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125
Q

Ribose is what type of monosaccharide?

A

pentose. C5

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126
Q

Glyceraldehyde is what type of monosaccharide?

A

triose

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127
Q

What is the purpose of glyceraldehyde?

A

An intermediate in respiration and photosynthesis

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128
Q

What is the purpose of ribose

A

basic building block of RNA, ATP, NAD and NADP

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129
Q

Where would you find deoxyribose?

A

DNA

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130
Q

Where would you find deoxyribose?

A

DNA

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131
Q

What is the byproduct of the formation of disaccharides?

A

H2O

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132
Q

When two monosaccharides come together to form a disaccharide, what reaction occurs between the two macromolecules?

A

condensation

Because a H2O is produced

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133
Q

The bond between two monosaccharides in a disaccharide is known as a…

A

glycosidic bond

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134
Q

How strong is the glycosidic bond?

A

Strong

135
Q

What type of bond is a glycosidic bond?

A

Covalent

136
Q

Breaking up of a disaccharide in to two monosaccharides is called a….. reaction

A

hydrolysis

137
Q

What is a hydrolysis reaction

A

A reaction that requires H2O

138
Q

Polysaccharides comprise of how many types of monosaccharide

A

One

139
Q

What is a condensation reaction?

A

A reaction which binds two molecules, producing H2O as a byproduct

140
Q

What is a polymer

A

A long chain of Monomers

141
Q

Starch is a mixture of which two types of polymer?

A

Amylose and amylopectin

142
Q

Amylose is…

A

an unbranched chain of alpha-glucose resides

143
Q

Amylopectin is…

A

branched chains of alpha-glucose

144
Q

What is the function of starch?

A

storage of carbohydrate in most plant species.It is useful because it takes up little space (compact and insoluble) and are readily hydrolyses to form sugar when required.

145
Q

The starch in processed food is different too that found in plants by…

A

The starch chains have been broken down, making it easier for the consumer to digest.

146
Q

Storage of carbohydrate in most plant species.It is useful because it takes up little space (compact and insoluble) and are readily hydrolyses to form sugar when required.

A

Starch

147
Q

branched chains of alpha-glucose

A

Amylopectin

148
Q

an unbranched chain of alpha-glucose resides

A

Amylose

149
Q

Amylose and Amylopectin are types of what?

A

Starch

150
Q

A reaction which binds to molecules producing H2O as a byproduct

A

Condensation reaction

151
Q

A reaction which separates two molecules, requires H2O for completion

A

Hydrolysis reaction

152
Q

How do you test for the presence of starch?

A

Add a solution of iodine in potassium iodide, if it turns blue-black color starch is present.
The iodine molecules fit in to the centre of the starch helix

153
Q

Add a solution of iodine in potassium iodide is a test for what?

A

Starch

154
Q

Glycogen is..

A

A polymer of glucose

155
Q

A polymer of glucose is called

A

Glycogen

156
Q

Difference between glycogen and amylopectin

A

They are similar but glycogen is larger and more highly branched

157
Q

Where are you likely to see granules of glycogen in the human body?

A

Via an electron microscope: liver cells and muscle fibers

Though glycogen stores are found throughout the body except the brain

158
Q

What organ would you not find carbohydrate stores in?

A

Brain

159
Q

Similar to glycogen, but glycogen is larger and more highly branched

A

amylopectin

160
Q

Similar to amylopectin, but larger and more highly branched

A

Glycogen

161
Q

During exercise, what does the body use up first? Glycogen stores or fat?

A

Glycogen

162
Q

Roughly how many polymers od beta-glucose would you find in a chain of celluose?

A

2000-3000

163
Q

Alpha-glucose… Where are the carbon-1 -H and -OH groups positioned?

A

-H is on top and -OH is on the bottom

164
Q

beta-glucose… Where are the carbon-1 -H and -OH groups positioned?

A

-OH is on top and -H is on the bottom

165
Q

-OH is on top and -H is on the bottom… Which type of glucose am I?

A

beta-glucose

166
Q

-H is on top and -OH is on the bottom, which type of glucose am I?

A

Alpha-glucose

167
Q

How do beta-glucose chains form?

A

The adjacent molecules are upside down to one another

168
Q

Cellulose is comprised of which type of glucose?

A

beta-glucose

169
Q

What kind of structure does cellulose form

A

long, straight chains

170
Q

What bonds hold the cellulose chains together?

A

hydrogen bonds

171
Q

Cellulose is found in the plant cell wall, how is it suited for a strong cell boundary?

A

Bonds between beta-glucose molecules
Hydrogen bonds between and within the chains of beta-glucose
The various beta-glucose fibers are arranged in difference directions

172
Q

What is the difference between molecular formula and structural formula

A

Molecular formula doesn’t display the arrangement of the atoms. You can have many isomers with the same molecular formula but not the same structural formula

173
Q

alpha-glucose and beta-glucose are isomers, what does this mean?

A

They have the same molecular formula but different structural formulas.

174
Q

What is in an iodine solution?

A

Iodine and potassium iodide

175
Q

How do you test for the presence of starch?

A

with an iodine solution

176
Q

What are the color changes that occur with a starch test?

A

If no starch is present the solution won’t change colour

If starch is present, a blue/black/purple solution is produced

177
Q

What is a reducing sugar?

A

A sugar that can carry out a chemical reaction (reduction) which involves giving electrons to another substance.

178
Q

Which is the only sugar which will not give a positive result in the Benedict’s test?

A

Sucrose.

why? Because it is not a reducing sugar.

179
Q

What reaction forms between the glycerol and fatty acid during the production of Triglycerides? And what type of bonds are formed?

A

Condensation reaction

Ester bonds

180
Q

What molecules make up a triglyceride?

A

Glycerol and three fatty acids

181
Q

Fatty acids are:

A

Long hydrocarbon chains between 14 and 22 C atoms long.

182
Q

Molecular formula for glycerol

A

C3H5(OH)3

*numbers are subscript

183
Q

Two main class of lipid

A
  1. Triglyceride

2. phospholipids

184
Q

What is an Acid?

A

A compound that released H+ ions when dissolved in water.

185
Q

What is the difference between a strong acid and a weak acid?

A

Strong acids completely dissociate in solution, i.e. complete loss of H+. Weak acids only partially dissociate.

186
Q

Organic molecules that are acids are… weak or strong acids?

A

Weak.

187
Q

What is a base?

A

A compound that reacts with the free H+ ions, removing them from the solution to neutralize it. Bases that soluble in water are alkalis

188
Q

pH > 7 is

A

Alkali

189
Q

pH < 7

A

Acid

190
Q

pH of acid (A)

A

A < 7

191
Q

pH of Alkali (Al)

A

Al > 7

192
Q

pH represents the concentration of…

A

H+ ions in solution

193
Q

What is an indicator

A

A compound that changes color in solutions of different pHs.

194
Q

Universal indicator changes to which color at pH 7?

A

Green

195
Q

Universal indicator changes to which color at pH 14

A

Blue/violet

196
Q

Universal indicator changes to which color at pH 1

A

Red

197
Q

What is a buffer?

A

A compound that resists changes to pH when an acid or alkali are added to the solution.

198
Q

How does a buffer work?

A

It binds to H+ ions when they are present in solution (i.e. adic added) and loses H+ ions when they are absorbed (i.e. alkali added).

199
Q

Triglyceride ester bonds use which groups?

A

-OH of the carboxylate group of the fatty acid and one of the OH groups of the glycerol

200
Q

What groups comprise a fatty acid molecule?

A

Carboxyl group and hydrocarbon chain

201
Q

A molecule with a carboxyl group and a hydrocarbon chain (14-22 C atoms in length) would be…

A

Triglyceride

202
Q

What does saturated and unsaturated fatty acid mean?

A

Saturated fatty acids only have single bonds in their tailsand therefore no more hydrogen can be added to the chain. Unsaturated fatty acids have one or more double bonds in the C chain and therefore additional hydrogen can be added.
If there is only one double bond the molecule is called a monounsaturated fatty acid. If the molecule has more than one double bond it is a polyunsaturated fatty acid

203
Q

Polyunsaturaated fatty acids have a higher or lower melting temperature?

A

Lower. Think of Margarine.

204
Q

Why is a triglyceride insoluble in water?

A

Because the large fatty acid chains are non-polar

205
Q

Does a triglyceride contain more or less energy than carbohydrate? Why?

A

More energy because (1) there is less oxygen in a triglyceride than a carb of the same size/mass. (2) the molecules are packed closer together therefore more molecules per size/mass of glycogen or starch.

206
Q

What properties of triglycerides make them idea for energy storage in humans?

A
  1. hydrophobic and insoluble in water
  2. hydrocarbon tails are chemically unreactive
  3. lack of O2 and increased energy storage
207
Q

Why are triglycerides better energy storage molecules than glycogen?

A

more energy can be stored per mass therefore more energy and less weight to carry.

208
Q

What are the uses of triglycerides in animals?

A
  1. Energy storage
  2. Insulation
  3. Waterproofing
209
Q

Where is glycogen mainly stored?

A

Liver and muscles

210
Q

Why are triglycerides important in plants?

A

Generally found ion seeds, the seeds need to disperse further from the mother plant so the seeds need to store energy and be light.

211
Q

Do plants get most of their energy storage from starch or lipids?

A

lipids - triglycerides

212
Q

Are liquid or solid triglycerides easier to break down?

A

Liquid.

213
Q

The more C=C bonds, the higher or lower the melting temperature?

A

Lower

214
Q

Are you more likely to find saturated or unsaturated fats ion animals?

A

Saturated fats

215
Q

Are you more likely to find saturated or unsaturated fats in plants?

A

Unsaturated

216
Q

Are phospholipids hydrophilic or hydrophobic?

A

Both.

217
Q

What reaction joins two amino acids together?

A

Condensation

218
Q

What are the four groups attached the the central carbon in an amino acid

A
  1. A single hydrogen
  2. A carboxyl group
  3. Amino group
  4. R group
219
Q

Name the two functional groups of amino acids

A

carboxyl and amino groups

220
Q

Molecular formula for amino acids

A

NH2-CHR-COOH

221
Q

Amino acids can ionise and both acids and bases, True or false?

A

True

222
Q

What is a Zwitterion

A

an ion with both positive and negative charges

223
Q

Whaat bond forms between two amino acids?

A

Peptide bond

224
Q

What type of bond is a peptide bond?

A

Covalent

225
Q

The primary structure of the protein is

A

amino acid sequence

226
Q

The secondary structure of the protein is

A

the folded protein with a-helices and b-sheets.

227
Q

a-helices and b-sheet are bonded together with which type of bond?

A

hydrogen bonds of the backbone

228
Q

Tertiary structure

A

Formed by bonds of the side chain

229
Q

Tertiary structure

A

Formed by bonds of the side chain

230
Q

What types of bonds are used in bonding side chains of amino acids?

A

Disulfide bonds - between cysteine residues
ionic bonds - between charged side chains
Hydrogen bonds - between O and/or N with a delta- charge and a hydrogen with a delta+ charge.
Van der Waal bonds - forms between polar side chains

231
Q

Disulfide bonds

A

Forms in amino acids between cysteine residues
very strong, difficult to break
Organisms which live in extreme environments have a lot of them

232
Q

What’s the difference between fibrous and globular proteins?

A

Fibrous are long chains like collagen

Globular form tertiary ball-like structures

233
Q

Quaternary structure

A

When a protein has many components, when all the parts of the complex come together to form the complex, this is the quaternary structure. i.e. collagen.

234
Q

A hemoglobin molecule consists of…

A

four poly peptide chains, each bound to an iron-containing haem group. This iron binds to oxygen.

235
Q

Each red blood cell contains ? molecules of haemoglobin

A

~280 million

236
Q

What is a prosthetic group?

A

A “helper” molecule, enabling other molecules too be biologically active. e.g. harm.

237
Q

Haem is…

A

A flat molecule of four pyrrole groups, held together by =C- groups with an iron atom at the centre.

238
Q

The collagen super helix is known as

A

Tropocollagen

239
Q

Several collagen proteins form…

A

Collageen Fibril

240
Q

Several collagen proteins form…

A

Collageen Fibril

241
Q

Collagen fibrils form to create…

A

Collagen Fibres

242
Q

What % of collagen is made from glycine

A

35%

243
Q

What benefit does glycine give to the composition of collagen

A

glycine side chain is only H, so it is small and this can form more and stronger hydrogen bonds creating a stronger protein.

244
Q

What conditions might cause a protein to denature

A

Change in pH
high temp
exposure to certain chemicals

245
Q

Define denaturation

A

A change in the shape of a protein that alters or destroys that proteins ability to function normally. A result of the breakage in bonds.

246
Q

What is the test for the presence of protein

A

Biuret teest

247
Q

How does the Biuret test work?

A

Equal volumes of sodium hydroxide and pale blue copper sulphate are added to a solution.
If the solution turns purple there is protein present.

248
Q

Photosyntthesis requires CO2, H20 and which 4 other inorganic ions

A

Nitrogen, phosphorus, magnesium and calcium

249
Q

Why does a plant need nitrogen?

A

Nitrogen is required to make amino acids (NH2 - amino group).

250
Q

How does a plant absorb nitrogen?

A

Through nitrate ions (NO3-)

251
Q

Why do plants need phosphorus?

A

For the phospholipid bilayer

For ATP and ADP

252
Q

How is phosphorus absorbed in plants?

A

Through phosphate ions (PO43-)

253
Q

Why do plants need magnesium?

A

It is a component of the Chlorophyll

254
Q

How do plants absorb magnesium?

A

Through magnesium ions (Mg2+)

255
Q

Why do plants need calcium?

A

It is a component of calcium pectate, found in the middle of lamellae plant cells.

256
Q

How do plant cells absorb calcium?

A

Through calcium ions (Ca2+)

257
Q

Two types of cell

A

Prokaryote and eukaryote

258
Q

Organism with one cell

A

unicellular organism

259
Q

What is a Unicellular organism?

A

Organism with one cell

260
Q

Multicellulaar organism

A

organisms with multiple cells, i.e. humans and animals

261
Q

Prokaryotic vs Eukaryotic cell

A

Eukaryotic cell is more than a thousand times bigger than a prokaryote
Eukaryote has a nucleus surrounded by a nuclear envelope and several other membrane-bound organelles. A prokaryote does not have a nucleus nor any other membrane bound organelles.
Prokaryotes almost never form multicellular organisms

262
Q

What are three parts of cell theory

A
  1. All living organisms are composed of one or more cells.
  2. The cell is the basic unit of structure and organization in organisms.
  3. Cells arise from pre-existing cells.
263
Q

Three types of unicellular organism

A

Chlamydomonas, Amoeba and Escherichia coli.

264
Q

Differentiation

A

The process of specializing a cell

265
Q

Organization of cells

A

Cells > Tissue > Organs > Systems

266
Q

Typically, how big are eukaryotic cells?

A

10-100um in diameter.

267
Q

Features of the cell membrane

A
  1. phospholipid bilayer allows tight control of what goes in and out of the cell
  2. Cholesterol within the bilayer to help make it more flexible
  3. Proteins
    • Channel proteins (and carrier proteins)
    • hybrid glycoproteins and glycolipids as recognition
268
Q

Plasma membrane is –nm thick?

A

7-9nm thick

269
Q

How big is the nucleus, roughly?

A

10-20um

270
Q

What is the purpose of the nucleolus?

A

rRNA synthesis

271
Q

The Endoplasmic reticulum is…

A

A network of membranes folded into cisternae

272
Q

What does the ER do?

A

transport material around the cell and chemically modifies them.

273
Q

Two types of ER

A

rough and smooth

274
Q

What is the rough ER?

A

The ER with lots go small ribosomes attached. These ribosomes are where the polypeptide chains of amino acids are assembled.

275
Q

Where do you find ribosomes?

A

At the rough ER and scattered around the cytoplasm

276
Q

What are the constituent parts of a ribosome?

A
ribosomal  RNA (rRNA) and protein.
Eukaryotic ribosome is 80S and is bigger than the 70S found in prokaryotic cells
277
Q

What is the smooth ER?

A

Important for making , modifying and transporting lipids

278
Q

Mitochondria

A

Where aerobic respiration takes place - ATP is produced here

Found richly in muscle cells because movement and biosynthesis require energy

279
Q

How big are mitochondria?

A

~ 0.5-1.5 um wide and 3-10 um long.

Smaller than the nucleus

280
Q

Structure of the mitochondria

A

Surrounded by two membranes
The inner membrane folds into the cristae where many enzymes associated with respiration are attached
The rest of the organelle is called the matrix
Small circular molecules of NDA are also located in the mitochondria matrix.

281
Q

What is a Golgi?

A

A stack of membrane bound sacs or cisternae, each similar to a short section of smooth ER

282
Q

What does the Golgi do?

A

modifies and transports materials like proteins.
New sacs containing material join from the rough ER on to one side of the Golgi, move through and eventually are pinched off as vesicles containing the modified material on the other side.

283
Q

What are the potential downstream applications of the Golgi vesicles?

A

Some of these vesicles then fuse to the cell membrane and release the contents into the ECM. This is particularly important in secretory cells.
Other vesicles form lysosomes which fuse with vacuoles containing old, worn out organelles, or ingested food particles to digest them.

284
Q

What is a lysosome?

A

Small spherical vesicles bound by a single membrane.

They contain a concentrated mixture of ~50 hydrolytic enzymes which are produced in the rER and modified in the Golgi.

285
Q

What is a vacuole?

A

Membrane bound containers

286
Q

Organelle

A

A structure within the cytoplasm of eukaryotic cells that performs a discrete function. With the exception of ribosomes, organelles are surrounded by at least one layer of membrane.

287
Q

Structure of the nucleus

A

double Nuclear membrane with nuclear pores which allow transport of macromolecules such as mRNA.
Chromosomes and nucleolus are contained within the nucleus and

288
Q

What does a lysosome do?

A

Involved in the breakdown of imported food vacuoles, old organelles and harmful bacteria that have invaded the body and been engulfed by one of the body’s defense cells.

289
Q

How do lysosomes work?

A

Once engulfed into a larger vacuole, lysosomes fuse with the vacuole and release their hydrolytic enzymes into it. As a result, the food, organelle or bacterium is digested and the products of digestion escape into the cytosol.

290
Q

What is a centriole?

A

The cell has two centrioles, each comprised of nine triplets of microtubules.
Microtubules are short, hollow, unbranched cylinders composed of the globular protein, tubulin.

291
Q

What is the function of centrioles?

A

Moving organelles around the cytoplasm, important during cell division as they become the spindle.

292
Q

Positioning of the centriole

A

Occur in pairs normally at right angles from one another, just outside the nuclear membrane.

293
Q

Which structure only occur in plant cells

A

Cell wall, chloroplast, vacuole.

294
Q

What is the cell wall of plants made from?

A

Cellulose bound together with hydrogen bonds which form long, straight fibres known as microfibrils. Microfibrils combine at angled layers to form cellulose fibres.

295
Q

Features of the cell wall

A

Fully permeable so any material can pass in and out
Because the microfibrils are slayed out in different directions/angles the cell wall can resist stretching in any direction

296
Q

Function of the cell wall

A

Stop the cell from bursting by taking on too much water by osmosis

297
Q

What is the layer than forms between two cell walls?

A

Middle lamella

298
Q

What is middle lamella?

A

A gel-like layer that forms between two cell walls

299
Q

What is middle lamella made from?

A

Calcium pectate

300
Q

Why are calcium ions important for plant growth?

A

Calcium pectate is the main component of the middle lamella. Middle lamella is the layer between two plant cell walls.

301
Q

Plasmodesmata is…

A

Cytoplasmic connections between plant cells through gaps in their cell walls.
Part of the symplast pathway.

302
Q

The name for the holes found in cell walls which link the cytoplasm of the two cells

A

Plasmodesmata

303
Q

Lignin is…

A

A tough substance which is found in some cell walls

304
Q

Vacuole is…

A

The cytoplasm and cell surface membrane of a plant cell are pressed firmly against its cell wall by a large, permanent fluid-filled vacuole.

305
Q

Structure of the vacuole

A

Surrounded by a specialist single-membrane called the tonoplast - this is the barrier between the fluid contents of the vacuole and the cytoplasm.

306
Q

Tonoplast

A

The single membrane surrounding thee large, fluid-filled vacuole found in plants.

307
Q

How do animal and plant vacuoles differ?

A

Plant vacuoles take up most of the cell and are permanent

Animal vacuole are small and temporary

308
Q

Prokaryotic cells

A

Typically only 0.2 2 um in diameter - much smaller than eukaryote
Lack most of the organelles found in eukaryotic cells, particularly the nucleus as they have a single circular DNA in the cytoplasm
Typically unicellular

309
Q

Nucleoid

A

The circular DNA molecule found in prokaryotic cells.

310
Q

Plasmids

A

In addition to the nuclei, some prokaryotic cells have small, circular DNA molecules in their cytoplasm. They don’t often contain many genes and some of the genes they carry are often anti-biotic resistance genes

311
Q

70S ribosome

A

Involved in protein synthesis

Smaller than the 80S found in eukaryotes

312
Q

Organelles not found in prokaryotes

A

mitochondria, chloroplasts, Golgi, ER

313
Q

Cell wall of prokaryotes is made from:

A

peptidoglycan

314
Q

What is Pili and flagella:

A

Pili help prokaryotic cells attach t surfaces or to each other.
Flagella help cells move around

315
Q

Function of the prokaryotic cell wall

A

Gives it permanent shape

Protects against rupture due to osmosis

316
Q

What is peptidoglycan?

A

Polymers of amino acids and sugars

317
Q

Polymers of amino acids and sugars that form the prokaryotic cell wall…

A

peptidoglycan

318
Q

What is the staining properties of gram negative and gram positive baacteeria

A

All bacteria have a cell wall, but some bacteria have additional layers Ono the outer surfaces of the wall.
Gram positive - thick walls made almost entirely of peptidoglycan. Will turn purple when stained with crystal violet.
Gram negative - thin walls of peptidoglycan with an additional outer membrane. High lipid content of this outer membrane prevents the crystal violet stain getting to the cell wall, so they will not turn purple with crystal violet.

319
Q

What is the functional importance between gram negative and gram positive bacteria?

A

The outer, lipid-rich membrane of gram negative bacteria is relatively impermeable to antibiotics. Therefore, many gram-negative bacteria are antibiotic resistant, including penicillin.

320
Q

What is horizontal gene transfer

A

When plasmids move between cells, transferring new genetic information.

321
Q

What is a nucleotide

A
The monomer from which nucleic acids are formed.
Each nucleotide comprises: 
- A pentose 
- A phosphate group
- A purine or pyrimidine base
322
Q

Specific structure of DNA

A
  1. Deoxyribose - a 5-carbon sugar (pentose). It has one Oxygen atom less than ribose. The oxygen is lost from the 2nd carbon.
  2. Phosphate - derrived from phosphoric acid
  3. Nitrogenous base -
323
Q

What reactions join the three components of DNA?

A

condensation reactions - a water molecule is released in each case

324
Q

Four nitrogenous DNA bases

A

Cysteine, guanine, thymine, adenine

325
Q

Which of the five bases are purines and why.

A

Adenine and guanine

because they comprise of two rings

326
Q

Which of the fives bases are pyrimidines and why.

A

Thymine, cysteine and uracil

Because the comrpise of only one ring.

327
Q

What enzyme catalyses the binding of two DNA nucleotides and what type of reaction is it, what type of bond does it form and which groups is this bond between?

A
  1. DNA polymerase
  2. Condensation reaction
  3. A type of covalent bond called a phosphodiester bond 4. An OH of the phosphate group and the OH of the 3rd carbon of the deoxyribose. (OH + OH => O + H2O)
328
Q

What is a phosphodiester bond

A

The covalent bond found between the phosphate group of one and the pentose ring of another nucleotide.

329
Q

What type of bonds hold the two DNA strands together?

A

Hydrogen bonding between the nitrogenous bases

330
Q

What cell cycle phase does DNA replication occur?

A

Interphase - S phase.

331
Q

Four steps of DNA replication

A
  1. DNA helicase binds to the replication site, breaks the hydrogen bonds and 2. holds them separated as two separate templates.
  2. New, free nucleotides attach in a complementary sequence and hold together with hydrogen bonding.
  3. DNA polymerase catalyses the formation of the phosphodiester bonds between the new nucleotides.
  4. DNA ligase joins the larger polynucleotides together
332
Q

Functions of DNA polymerase

A

Formtion of the phosphodiester bonds

“proof reading” of the DNA during replication

333
Q

What is semi-conservative replication?

A

Each new double-stranded DNA molecule contains one of the two strands from the original molecule.

334
Q

Which direction does replication work?

A

5’ -> 3’