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Biology A-Level > Biological Molecules > Flashcards

Biological Molecules Flashcards

1
Q

What are the 5 main biological molecules that living organisms are made up of

A

carbohydrates
lipids
protein
DNA/RNA
water

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2
Q

What are the 2 types of carbohydrates

A

simple carbohydrates
complex carbohydrates

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3
Q

What are the 2 types of carbohydrates

A

simple carbohydrates
complex carbohydrates

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4
Q

What are monomers

A

individual units that makes a polymer

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5
Q

what are polymers

A

many repeating units of monomers

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6
Q

What are carbohydrate monomers called?

A

monosaccharides

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7
Q

what is a dissacharide

A

two monosaccharides

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8
Q

what is a polysaccharide

A

multiple monosaccharides

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9
Q

What is a condensation reaction

A

a reaction that makes up bonds
a glycosidic bond forms between the two monosaccharides as a molecule of water is released

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10
Q

what is a hydrolysis reaction

A

a reaction that breaks down bonds(water is taken in)

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11
Q

Name 4 types of monosaccharides

A

alpha glucose
beta glucose
galactose
fructose

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12
Q

which monosaccharides are examples of reducing sugars

A

all of them

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13
Q

Name 3 disaccharides

A

maltose(alpha glucose and alpha glucose)
lactose(alpha glucose and galactose)
sucrose(alpha glucose and fructose)

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14
Q

Which disaccharides are examples of reducing sugars?

A

maltose and lactose

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15
Q

Name 3 polysaccharides

A

starch(multiple alpha glucose)
glycogen(multiple alpha glucose)
cellulose(multiple beta glucose)

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16
Q

What does the alpha glucose structure look like

A
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17
Q

what does the beta glucose structure look like

A
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18
Q

what does the galactose structure look like

A
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19
Q

How does a condensation reaction change the structure of a monosaccharide

A
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20
Q

What things do you need to know about starch

A

-energy store found in plant cells in the form of grains
-a polysaccharide of alpha glucose joined via condensation reactions to form glycosidic bonds
-includes alpha 1,4 and 1,6 glycosidic bonds

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21
Q

describe the structure of starch

A

-large
-insoluble
-alpha helix shape
-branched

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22
Q

explain how the structure of starch aids it’s function

A

large-won’t diffuse out of cells
insoluble-osmotically inactive
alpha helix shape-compact energy store
branched-rapidly release alpha glucose when needed

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23
Q

what things do you need to know about glycogen

A

-it’s a polysaccharide of many alpha glucose joined via condensation reaction to form glycosidic bonds
-it’s an energy store in the form of granules in cytoplasm
-has alpha 1,4 glycosidic bonds and many more alpha 1,6 glycosidic bonds compared to starch

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24
Q

describe the structure of glycogen

A

-large
-insoluble
-alpha helix shape
-branched

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25
Q

explain how the structure of glycogen aids it’s function

A

large-won’t diffuse out of cells
insoluble-osmotically inactive
alpha helix shape-compact energy store
branched-rapidly release alpha glucose when needed

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26
Q

What things do you need to know about cellulose

A

-it’s a polysaccharide of many beta glucose molecules joined through condensation reactions to form beta 1,4 glycocidic bonds
-it’s used to make cell walls
-every other beta glucose is inverted

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27
Q

Describe the structure of cellulose

A

Made from beta- glucose
Parallel chains can form hydrogen bond “cross links”
cellulose can form microfibrals which join to form fibres

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28
Q

Explain how the structure of cellulose aids its function

A

Allows long straight chains to form
Adds strength to the cell wall
Adds strength

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29
Q

Finish the sentence:
A reducing sugar is able to…

A

…lose an electron and give it to another compound

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30
Q

What do we use to test for reducing sugars

A

We test for reducing sugars by giving them something to reduce:Benedict’s reagant

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31
Q

How do we test for reducing sugars?

A

-Add benedict’s solution
-Heat it up
-Colour change from blue-red to

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32
Q

Why does a substance containing a reducing sugar go from blue to red?

A

Benedict’s contains Cu2+ ions in the form of copper(II) sulfate
When the Cu2+ ions gain an electron(from a reducing sugar), they become Cu+ ions in the form of red (I) oxide

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33
Q

What are the possible results of the benedict’s test?

A

Blue- negative (no concentration)
Green- very low
Yellow- low
Orange- moderate
Red- high (high concentration)

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34
Q

How do we test for non reducing sugars?

A

-Get a negative benedict’s test
-Boil with HCl to hydrolyse non reducing sugar
-Neutralise HCl using NaOH
-Add benedict’s
-Heat
-Colour change from blue- red

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35
Q

How do we test for starch?

A

Add iodine
Colour change should be orange-dark blue/ black

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36
Q

How does a colorimeter that gives an absorbance reading work?

A

There’s a light source which the solution inside a test tube absorbs. There’s a light receptor on the other side of the test tube which absorbs the light they comes out of the test tube. The higher the value, the more light is being absorbed/blocked. 0=dilute, 1=max concentration

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37
Q

How does a colorimeter that gives a transmission reading work?

A

Same as absorbance reading but the higher the number, the more light can pass through so 0=max concentration and 1=dilute

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38
Q

What are the steps to identify an unknown glucose solution?

A

Pour unknown glucose solution into a beaker and leave to the side
step 1. have 5 known glucose concentrations in beakers (0mol dm-3 to 100mol dm-3)
step 2.perform a benedict’s test(lowest concentration will be blue, highest cone i’ll be red)
step 3. perform colorimetry to identify absorbance
step 4. perform a calibration curve with concentration on x and absorbance on y(straight line)
step 5.perform benedict’s and colorimetry on unknown sample+identify absorbance
step6. read off graph to identify concentration of unknown solution

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39
Q

What are lipids

A

They are biological molecules that are used for:
energy store
insulation(thermal, electrical-myelin sheaths cover nerves)
water proofing(waxy cuticle)
protection(heart, kidneys)

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40
Q

What are the two types of lipids

A

triglycerides
phospolipids

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41
Q

What are triglycerides

A

consists of fats(solids at room temp) and oils(liquid at room temp)
they are not polymers as they are not made of many repeating units of monomers

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42
Q

What is the general structure of triglycerides

A
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43
Q

What is the chemical structure of tryglicerides

A
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44
Q

How does a glycerol molecule bond with the 3 fatty acid molecules to form a triglyceride?

A

They bond through a condensation reaction (where water is lost) to form an ester bond

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45
Q

Describe the features of a triglyceride

A

-insoluble
-low mass to energy ratio
-high ratio of hydrogen atoms to oxygen atoms
-high ratio of energy storing C-H bonds

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46
Q

Explain how the features of a triglyceride aids its function

A

-osmotically inactive
-don’t have to carry a heavy energy store
-water can be released during breakdown
-energy dense molecule

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47
Q

What is a phospholipid

A

A major component of cell membranes

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48
Q

What’s the general structure of a phospholipid

A
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49
Q

What does a phospholipid consist of?

A

A phosphate molecule
2 fatty acids
A glycerol molecule

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50
Q

In the general structure of a phospholipid, a phosphate molecule and glycerol molecule are usually called what?

A

a phosphate ‘head’

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51
Q

In the general structure of a phospholipid, the fatty acids are usually called what

A

the fatty acid ‘tails’

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52
Q

Is the phosphate ‘head’ polar or non polar

A

polar
There are delta positive and delta negative regions and the electrons are unevenly distributed so therefore, the polar head is hydrophilic(attracted to water)

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53
Q

Is the fatty acid tails polar or non polar and why?

A

They are non polar
The electrons are spread out evenly so the non polar tails are hydrophobic

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54
Q

What is an amphipathic molecule?

A

A molecule with polar and non polar regions can. This property is essential for form a phospholipid bilayer(2 layers-a double membrane)

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55
Q

How do phospholipid layers react in water

A

The tails of the layers point inwards, towards each other so the hydrophilic head can interact with the water and the hydrophobic tails avoid the water

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56
Q

What is the chemical structure of phospholipids

A
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57
Q

What is the chemical structure of phospholipids

A
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58
Q

Describe and explain the functions of phospholipids

A

hydrophobic/hydrophilic regions-allows phospholipid bilayer formation
glycolipids can form-allows for cell recognition

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59
Q

What are the functions of proteins

A

Structural-collagen(connected tissues), keratin(hair,nails,horns)
Involved in signalling-hormones(insulin and FSH
Catalysts-enzymes that speed up a reaction
Transport-haemoglobin transports oxygen

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60
Q

What is the name of a protein monomer?

A

amino acid

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61
Q

What is the name of a protein dimer ?

A

dipeptide

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62
Q

What is the name of a protein polymer?

A

polypeptide

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63
Q

What is the chemical structure of an amino acid

A
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64
Q

How many different amino acids are there and what is the relationship with them all?

A

20
They all have the same ‘general structure’. Only the ‘R’ group changes

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65
Q

What is the chemical structure for a dipeptide(formation)

A

Proteins are the only molecules that don’t have condensation reactions between carboxyl groups!!

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66
Q

Exam Q: How does dipeptide form?

A

A condensation reaction occurs between the carboxyl group of one amino acid and amine group of the other

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67
Q

How many levels of polypeptide structure are there?

A

4

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68
Q

What happens in the first level of polypeptide formation?

A

The sequence of amino acids are formed. This is determined by your ur genes.

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69
Q

What happens in the 2nd level of polypeptide formation?

A

The initial folding of a polypeptide into an alpha-helix or beta-pleated sheet due to hydrogen bonding

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70
Q

What happens in the 3rd level of polypeptide formation?

A

Further folding of polypeptide into a 3D shape held together by more hydrogen bonds(disulfide bonds and ionic bonds)

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71
Q

What is a disulfide bond?

A

The strongest type of bond that holds proteins together

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72
Q

What is an ionic bond

A

A bond that occurs between C=0(carboxy) and N-H(amine) groups

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73
Q

What happens in the 4th level of polypeptide formation?

A

Multiple polypeptides bonded together
e.g haemoglobin

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74
Q

What happens in the 5th(extra)level of polypeptide formation?

A

Prosthetic group
Non-protein based molecule that aids function
e.g. iron is needed for haemoglobin to carry oxygen

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75
Q

Exam Q:Describe how the secondary structure of a polypeptide is produced by bonds between amino acids

A

Polypeptides are folded into alpha helix or beta pleated sheets due to hydrogen bonding between C=O and N-H groups

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76
Q

Exam Q: Explain how two proteins have the same number and type of amino acids but different tertiary structures

A

Different sequence of amino acids leads to hydrogen/ionic/disulfide bonds forming in different places, resulting in 3D shapes being different

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77
Q

What is an enzyme?

A

A protein catalyst that lowers activation energy without being used up

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78
Q

What are the 2 types of enzyme action?

A

-catabolic(breaking down) reaction
-anabolic(building up) reaction

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79
Q

What does activation energy mean

A

it is the amount of kinetic energy needed for a reaction to occur

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80
Q

How do enzymes work in a catabolic reaction?

A

An enzyme works by forming an “enzyme-substrate complex” which strains bonds, lowering the activation energy.

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81
Q

How do enzymes work in an anabolic reaction?

A

They work by bringing substrates closer together. This lowers the activation energy needed for the reaction to take place.

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82
Q

Explain the induced fit model of enzyme action

A

-Before the reaction, enzyme action is not complimentary to substrate.
-The shape of active site changes as enzyme-substrate complex forms
-This stresses bonds or brings substrates closer together
-Lowering activation energy

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83
Q

Explain the first stage of the progress of reaction graph

A

-Initially there’s lots of the substrate and empty active sites
-So there are many E-S complexes that can form
-So the reaction starts off fast

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84
Q

Explain the first stage of the progress of reaction graph

A

-Initially there’s lots of the substrate and empty active sites
-So there are many E-S complexes that can form
-So the reaction starts off fast

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85
Q

Explain the second stage of the progress of reaction graph

A

-There’s less substrate, so more product
-So it’s more difficult for E-S complexes to form
-So the reaction slows

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86
Q

Explain the second stage of the progress of reaction graph

A

-There’s less substrate, so more product
-So it’s more difficult for E-S complexes to form
-So the reaction slows

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87
Q

Explain the third stage of the progress of reaction graph

A

-There’s no more substrate
-So no E-S complexes can form
-So the reaction stops

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88
Q

Explain the third stage of the progress of reaction graph

A

-There’s no more substrate
-So no E-S complexes can form
-So the reaction stops

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89
Q

How can you calculate the mean rate of reaction?

A

amount of product formed/time taken to form product

90
Q

Explain how this progress of reaction graph shows the effect of temperature on ROR

A

Enzymes have more Ek at 37 degrees C so more E-S complexes form which leads to a faster reaction(steeper line, earlier plateau)

91
Q

Explain how this ROR graph shows the effect of temperature on ROR

A

1.As temperature increases, the rate increases due to more Ek
2.Optimum temp- where the most E-S complexes form
3.As temp increases, rate decreases due to enzymes being denatured(tertiary-3D- structure of enzyme active site changes so no E-S complexes form)

92
Q

What is an acid?

A

A compound that releases hydrogen ions(H+) when in solution

93
Q

What is an alkali?

A

A compound that releases hydroxyl ions (OH-) when in solution

94
Q

Explain how this progress of reaction graph shows the effect of temperature on ROR

A

-At pH2, the increases number of H+ ions are attracted to amino acids of enzymes
-Ionic/hydrogen bonds of tertiary structure are disrupted
-Active site of enzymes denature

95
Q

Explain how this progress of reaction graph shows the effect of pH on ROR

A

-At pH2, the increases number of H+ ions are attracted to amino acids of enzymes
-Ionic/hydrogen bonds of tertiary structure are disrupted
-Active site of enzymes denature

96
Q

Explain how this ROR graph shows the effect of pH on ROR

A

1.active site denatures so no E-A complexes form
2.Optimum pH
3.Active site denatures so no E-S complexes can form

97
Q

Explain how this ROR graph shows the effect of pH on ROR

A

1.active site denatures so no E-A complexes form
2.Optimum pH
3.Active site denatures so no E-S complexes can form

98
Q

Explain how this progress of reaction graph shows the effect of enzyme concentration on ROR

A

-At 2M, the reaction is faster because there’s more enzymes so more E-S complexes

99
Q

Explain how this ROR graph shows the effect of enzyme concentration on ROR

A

-As enzyme concentration increases, rate also increases in direct proportion
-Because more E-S complexes can form
-Rate is only limited by the amount of substrate

100
Q

Explain how this progress of reaction graph shows the effect of substrate concentration on ROR

A

-For the 2M substrate, the reaction is faster
-More substrate means more E-S complexes

101
Q

Explain how this progress of reaction graph shows the effect of substrate concentration on ROR

A

-For the 2M substrate, the reaction is faster
-More substrate means more E-S complexes

102
Q

Explain how this ROR graph shows the effect of substrate concentration on ROR

A

-As substrate concentration increases, rate also increases in direct proportion
-Because more E-S complexes can form
-Rate is only limited by the amount of enzyme

103
Q

What are proteins?

A

Polymers made from many amino acids joined by peptide bonds

104
Q

what do enzyme inhibitors do

A

they slow down enzyme catalysed reactions

105
Q

what are the two types of enzyme inhibitors

A

competitive inhibitors
non competitive inhibitors

106
Q

what are competitive inhibitors

A

molecules with a similar shape to a substrate
they bind to active sites and prevent enzyme- substrate complexes forming

107
Q

how do competitive inhibitors work

A

•Reaction slows as
•C. I. binds to active site
•Prevents E-S complexes

108
Q

how can we increase the rate of product formation

A

by adding more substrate
the additional substrate will outcompete the inhibitor

109
Q

what is a non competitive inhibitor

A

•Molecules that attach to a binding site on an enzyme – NOT the active site (allosteric binding site)
•This changes the 3⁰ of the active site permanently.
•No longer complementary.
•No E-S complexes can form.

110
Q

how do non competitive inhibitors work

A

•Reaction slows and does not complete.
•NCI binds to allosteric binding site.
•A.S. changes shape (permanently)
•No E-S complexes form.

111
Q

how can we increase the rate of product formation

A

You CAN’T increase the rate of product formation by adding more substrate.
The enzymes are out of action. The only way to overcome this is to add more enzyme.

112
Q

what is digestion

A

the hydrolysis of large, insoluble food molecules into small, soluble food molecules that can be absorbed into the blood

113
Q

what do the salivary glands do

A

release salivary amylase enzymes

114
Q

what does the stomach do

A

if produced HCl and protease enzymes. And physically churns food

115
Q

what does the liver do

A

produces bile

116
Q

what does the gall bladder do

A

stores/releases bile into ileum

117
Q

what does the ileum do

A

absorbs products of food digestion into the blood

118
Q

what does the large intestine do

A

absorbs water

119
Q

what do the teeth do

A

physically break down food into smaller pieces

120
Q

what does the oesophagus do

A

carries food to the stomach

121
Q

what does the pancreas do

A

produces pancreatic amylase, proteases and lipase

122
Q

what do the rectum and anus do

A

rectum stores faeces
faecus exits via anus

123
Q

what is the enzyme for starch

A

pancreatic/salivary amylase

124
Q

what is the product of the digestion of starch

A

maltose

125
Q

where is the product of the digestion of starch made

A

salivary glands, pancreas

126
Q

where does the enzyme of starch act?

A

mouth
ileum

127
Q

what bonds are broken when starch is digested

A

alpha 1-4 and 1-6 glycosidic bonds

128
Q

what is the enzyme for maltose

A

maltase

129
Q

what is the product of the digestion of maltose

A

2 alpha glucose

130
Q

where is the product of the digestion of maltose made

A

ileum lining

131
Q

where does the enzyme of maltose act?

A

ileum

132
Q

what bonds are broken when maltose is digested

A

alpha 1-4 glycosidic bond

133
Q

what is the enzyme for sucrose

A

sucrase

134
Q

what is the product of the digestion of sucrose

A

alpha glucose, fructose

135
Q

where is the product of the digestion of sucrose made

A

ileum lining

136
Q

where does the enzyme of sucrose act?

A

ileum

137
Q

what is the enzyme for lactose

A

lactase

138
Q

what is the product of the digestion of lactose

A

alpha glucose
galactose

139
Q

where is the product of the digestion of lactose made

A

ileum lining

140
Q

where does the enzyme of lactose act?

A

ileum

141
Q

what is the enzyme for proteins

A

endopeptidase

142
Q

what is the product of the digestion of proteins

A

smaller peptides

143
Q

where is the product of the digestion of proteins made

A

stomach, pancreas

144
Q

where does the enzyme of protein act

A

ileum
stomach

145
Q

what bonds are broken when protein is digested

A

peptide

146
Q

what is another enzyme for proteins

A

exopeptidase

147
Q

what is another product of the digestion of proteins

A

amino acids,
dipeptides

148
Q

where is the product of the digestion of proteins made

A

pancreas, stomach

149
Q

where does the enzyme of protein act

A

ileum
stomach

150
Q

what bonds are broken when protein is digested

A

peptide

151
Q

what is the enzyme for dipeptides

A

dipeptidase

152
Q

what is the product of the digestion of dipeptides

A

amino acids

153
Q

where is the product of the digestion of proteins made

A

ileum lining

154
Q

where does the enzyme of dipeptides act

A

ileum

155
Q

what bonds are broken when dipeptides are digested

A

peptide

156
Q

what is the enzyme for lipids

A

lipase

157
Q

what is the product of the digestion of lipids

A

2 fatty acids
monoglyceride

158
Q

where is the product of the digestion of lipids made

A

ileum lining
pancreas

159
Q

where does the enzyme of lipids act

A

ileum

160
Q

what bonds are broken when lipids are digested

A

ester

161
Q

how are lipids digested

A

bile salts emulsify the fat globules into micelles (smaller lipid droplets)associated with bile salts. this means that they have a larger surface area for faster lipase action
lipase then digests these droplets into micelles containing monoglycerides and fatty acids in bile

162
Q

what are the advantages of micelle formation

A

droplets increase surface areas (for lipase/enzyme action)
so faster hydrolysis/ digestion of triglycerides/ lipids
micelles carry fatty acids and glycerol/ monoglycerides to/through membrane/ to inestinal epidermal cell

163
Q

describe the structure of the ileum

A

walls are folded into villi
walls are 1 cell thick
epithelial cells have microvilli
many capillaries
muscle in villi

164
Q

explain how the structure of the ileum aids function

A

larger SA for faster absorption
short diffusion distance=faster absorption
larger SA for faster absorption
Rich blood supply maintains diffusion gradient
maintain diffusion gradient by moving contents of lumen

165
Q

how are monosaccharides abosorbed

A

sodium is removed (from epithelial cells) by active transport via sodium potassium carrier protein into blood, maintaining low concentration of sodium(in epithelial cells); Glucose moves into blood via carrier protein by facilitated diffusion.

166
Q

how are lipids absorbed

A

fatty acids and glycerol are non polar
enter epithelial cells via simple diffusion
travel to smooth ER
tryglicerides are formed
then travel to golgi for processing

167
Q

what is the role of the golgi in lipid absorption

A

golgi apparatus modifies/ processes triglycerides.
it combines triglycerides with proteins
forms vesicles

168
Q

what is DNA made of?

A

a double stranded helix structure, containing a sugar phosphate backbone with nitrogen-containing organic base pairs in the centre

169
Q

What is the structure of a nucleotide?

A

a strand of DNA or RNA is a polynucleotide made up from joined mononucleotides

170
Q

individual nucleotides are made from 3 components, what are they?

A

a phosphate group
a pentose sugar
an organic base

171
Q

which components are known as the backbone?

A

phosphate group
pentose sugar

172
Q

In a DNA mononucleotide, the organic base can either be…

A

adenine
thymine
cytosine
guanine

173
Q

In a DNA mononucleotide, what is the pentose sugar ?

A

it is always deoxyribose

174
Q

In an RNA mononucleotide, the organic base can either be…

A

adenine
uracil
cytosine
guanine

175
Q

In an RNA mononucleotide, what is the pentose sugar ?

A

it is always ribose

176
Q

Exam style question:
Give two ways in which the nucleotides in DNA are different from the nucleotides in RNA

A

RNA contains ribose whereas DNA contains deoxyribose
RNA contains Uracil whereas DNA contains thymine

177
Q

What bonds are the 2 strands of a DNA molecule joined by?

A

hydrogen bonds

178
Q

What bonds are adjacent nucleotides joined by?

A

phosphodiester bonds

179
Q

Base pairings are…?

A

specific. we say the these bases are complementary to each other

180
Q

What are the base pairings in DNA?

A

adenine-thymine
cytosine-guanine

181
Q

Explain how the organic bases help to stabilise the structure of DNA

A

-The phosphodiester backbone protects the more chemically reactive bases inside the double helix
-As there are more hydrogen bond between C-G, DNA molecules with a greater proportion of C-G pairings are more stable
-There are additional forces between base pairs that hold the molecule. This is called base stacking

182
Q

What is the DNA structure and function?

A

-phosphodiester backbone-prevents bases reacting with environment
-long molecule-stores a lot of info
-double helix structure- makes DNA compact
-Weak hydrogen bonds join base pairs- easily broken for DNA replication
-Double stranded-allows replication from template strand
-Base sequence- allows info to be stored
-‘Base stacking’- makes DNA stable

183
Q

when does DNA replication happen?

A

during interphase of the cell cycle

184
Q

What 4 things are needed for DNA replication?

A

-DNA molecule to be replicated
-Free DNA nucleotides
-DNA helicase enzyme
-DNA polymerase enzyme

185
Q

How does DNA polymerase act?

A

It acts in a 5’ - 3’ direction

186
Q

How does DNA polymerase act?

A

It acts in a 5’ - 3’ direction

187
Q

Exam Tech: Explain how DNA is replicated

A
  1. strands separate/H-bonds break
  2. DNA helicase(involved);
  3. Both strands act as templates
  4. Free nucleotides attracted
  5. H-bonds reform
  6. Complementary/specific base pairing /AT and GC;
  7. DNA polymerase joins nucleotides via phosphodiester bonds
  8. Semi-conservative replication/ new DNA molecules contain one old strand and one new strand
188
Q

What’s the Meselton and Stahl experiment?

A

Stage 1:
Grow E-coli bacteria in agar containing ‘heavy’ isomers of nitrogen
Stage 2:
Allow 15N bacteria to undergo one cell division
Stage 3:
Allow 14N and 15N bacteria to undergo one cell division

189
Q

What is energy used for ?

A

Active transport, muscle contraction, protein synthesis, phosphorylation

190
Q

How is energy used for active transport?

A

Used any named method( glucose absorption, ion uptake at roots)

191
Q

How is energy used for active transport?

A

Used any named method( glucose absorption, ion uptake at roots)

192
Q

How is energy used for muscle contraction?

A

For movement

193
Q

How is energy used for muscle contraction?

A

For movement

194
Q

How is energy used for protein synthesis?

A

For growth and repair

195
Q

How is energy used for a phosphorylation ?

A

Making molecules more reactive by lowering their activation energy

196
Q

What does the energy from respiration take the form of?

A

A nucleotide called Adenosine Triphosphate (ATP)

197
Q

What’s the ATP structure?

A
198
Q

How is energy released?

A

-The bonds between the outer phosphate groups in ATP are unstable so have a low activation energy
-A single hydrolysis reaction can remove a phosphate. The phosphate can form bonds with other molecules- which releases energy(phosphorylation)

199
Q

Describe the ATP to ADP reaction

A

The ATP->ADP reaction is a hydrolysis reaction. It is catalysed by the enzyme ATP hydrolase

200
Q

What is the equation for the hydrolysis of ATP?

A

ATP+H20->ADP+Pi+E

201
Q

How is ATP synthesised?

A

The enzyme ATP synthase catalyses a condensation reaction to join a phosphate to ADP to form ATP(phosphorylation)

202
Q

How is ATP synthesised?

A

The enzyme ATP synthase catalyses a condensation reaction to join a phosphate to ADP to form ATP(phosphorylation)

203
Q

What is the reaction to synthesise ATP?

A

ADP+Pi+E->ATP+H20

204
Q

What is the reaction to synthesise ATP?

A

ADP+Pi+E->ATP+H20

205
Q

Where does the energy for ATP synthesis come from?

A

light
respiration

206
Q

What are some pros/advantages of ATP?

A

1.releases energy in small/manageable amounts
2.broken down in a one step reaction
3.it phosphorelates to lower the activation energy needed for biological molecules to react
4.rapidly reformed
5.soluble-most biological reactions take place in solution - cytoplasm

207
Q

What are the cons/disadvantages of ATP?

A

ATP cannot be moved from cell to cell / stores because it is so reactive

208
Q

What kind of energy source is ATP?

A

immediate

209
Q

Compare the characteristics of ATP and carbs/lipids

A

ATP
-small quantities present within mitochondria of cells
-rapidly reformed
-energy released in small, suitable amounts
-single hydrolysis reaction to break down
-can not be stored
-soluble
Carbs/Lipids
-large quantities present as fat/glycogen
-slower to form
-energy released in larger, less soluble amount
-many reactions required to release energy from a glucose molecule
-can be stored
-glycogen/fat insoluble

210
Q

Describe water

A

It is 2 hydrogen atoms covalently bonded to 1 oxygen atom
Electrons have uneven distribution
We describe water as being a polar molecule

211
Q

What are hydrogen bonds?

A

-They form between polar molecules containing hydrogen
-They do not result in a permanent structure, bonds break and reform as water molecules move around

212
Q

What are the properties of water that make it good for the cytoplasm?

A

-polarity means it can act as a good solvent(chemical reactions happen faster in solutions)
-reactive(can be used in hydrolysis reactions)

213
Q

What are the properties of water that are due to hydrogen bonding?

A

-high specific heat capacity
-high latent heat of vaporisation
-cohesive
-adhesive
-transparent
-variable density

214
Q

Why is polarity a useful property of water?

A

polarity=good solvent
The + and - ions in ionic compounds are more attracted to the polar molecule than each other. This causes them to dissociate and dissolve.
Chemical reactions can happen faster in solution-more collisions

215
Q

Why is having a high specific heat capacity a useful property of water?

A

SHC is the energy required to increase 1kg of water by 1 degrees celsius
The SHC of water is 4148 J/Kg which is high due to many H-bonds which need lots of energy to overcome
This makes water a good temperature buffer.Enzymes are protected against denaturing.

216
Q

Why is having a high specific heat capacity a useful property of water?

A

SHC is the energy required to increase 1kg of water by 1 degrees celsius
The SHC of water is 4148 J/Kg which is high due to many H-bonds which need lots of energy to overcome
This makes water a good temperature buffer.Enzymes are protected against denaturing.

217
Q

Why is having a high latent heat of vaporisation a useful property of water?

A

LHV is the energy required to vaporise 1kg of Makes water useful for sweat. It can transfer a lot of thermal energy away from the body.

218
Q

Why are cohesion and adhesion useful properties of water?

A

H-bonds =cohesion/adhesion of water in xylem. Allows a continuous movement of water up xylem.
Cohesion leads to surface tension. Allows organisms to escape predators/ find prey.

219
Q

What are the main ions in biology?

A

iron, phosphate, nitrate, hydrogen, calcium, magnesium

220
Q

What do iron, nitrate and hydrogen ions do?

A

iron-involved in haemoglobin structure. Allows oxygen to bind
phosphate-involved in phospholipids, ATP, DNA/RNA
hydrogen-involved in photosynthesis and respiration

221
Q

What do calcium and magnesium ions do?

A

calcium-involved in muscle contraction
magnesium-involved in making chlorophyll

Biology A-Level (3 decks)

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