Biological Molecules Flashcards
BIOCHEM IS FUN WHEYYYYY
1
Q
What are the 4 organic molecules?
A
Carbohydrates, Lipids, Proteins, Nucleic acids.
2
Q
What nucleic acids do all organisms use?
A
The same ones as each other.
3
Q
How many amino acids are there?
A
20.
4
Q
What molecules do all organisms use for energy?
A
Carbohydrates.
5
Q
What do all organisms use for cell membranes?
A
Lipids.
6
Q
What thory does the biological similarities between organisms support?
A
Theory that all animals and plants share a commono ancestor.
7
Q
What are monomers?
A
The smaller units that can join together to make larger molecules.
8
Q
What are polymers?
A
Molecules made from lots of repeating unts joined together.
9
Q
Give 3 examples of monomers.
A
Monosaccharides, amino acids and nucleotides.
10
Q
What happens in condensation?
A
Two monomers join together and form a covalent bond with the elimination of water.
11
Q
What happens in hydrolysis?
A
Addition of a water molecule is used to break apart the covalent bond between monomers.
12
Q
What is a monosaccharide?
A
Monomer of a carbohydrate.
13
Q
What are 3 examples of monosaccharides?
A
Glucose, fructose, galactose.
14
Q
What are the differences between hexose and pentose sugars?
A
Hexose sugars have 6 carbons and pentose sugars have 5 carbons.
15
Q
MAKE PAPER CARDS FOR DIAGRAM OF ALPHA AND BETA GLUCOSE.
A
please remove when done
16
Q
Is glucose a hexose or pentose sugar?
A
Hexose.
17
Q
What is an isomer?
A
Molecules with the same forumla but have different structures.
18
Q
What are the 2 isomers of glucose?
A
alpha and beta.
19
Q
How are glucose’s isomers different.
A
The hydrogen and hydroxide on carbon 1 are the other way around.
20
Q
How are carbons numbered in diagrams of glucose?
A
Clockwise, with carbon 1 being first after the oxygen.
21
Q
How do monosaccharides bond together?
A
Condensation reactions.
22
Q
What type of bond forms from condensation of monosaccharides?
A
A glycosidic bond.
23
Q
DRAW OUT GLYCOSIDIC BOND CARD
A
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24
Q
What are disaccharides?
A
Two monosaccharides bonded together.
25
Give 3 examples of disaccharides.
Maltose, Sucrose, Lactose.
26
What monosaccharides make maltose?
Glucose-glucose
27
What monosaccharides make sucrose?
Glucose-fructose
28
What monosaccharides make lactose?
Glucose-galactose.
29
What can reducing sugars do?
Donate electrons to other compounds.
30
Give 5 examples of reducing sugars.
Glucose, fructose, galactose, maltose, lactose.
31
Give an example of a non-reducing sugar.
Sucrose.
32
What are polysaccharides?
Polymer carbohydrates.
33
What are polysaccharides made of?
Lots of monosaccharides bonded together.
34
Give 3 examples of polysaccharides.
Glycogen, cellulose, starch.
35
What is starch made of?
Alpha glucose.
36
What is the diference between 1-4 and 1-6 glycosidic bonds?
The carbons that are joining together.
37
DRAW ALPHA 1-4, ALPHA 1-6, AND BETA 1-4 GLYCOSIDIC BONDING
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38
What 2 polysaccharides is starch made up of?
Amylose and amylopectin.
39
Describe the shape of amylose.
A long unbranched chain that forms a coiled helical shape.
40
What type of bonds does amylose contain?
Alpha 1-4 glycosidic bonds.
41
What is amylose used for?
Storing excess glucose to convert back for energy.
42
How does the structure of amylose help with its function?
Helical shape allow it to be compact so lots can be stored in a small space.
43
Describe the structure of amylopectin.
A long branched chain of alpha glucose.
44
What is amylopectin used for?
Storing excess glucose that can be used later.
45
How does the structure of amylopectin aid its function?
Branches increase the surface area so it can be hydrolised for glucose easily.
46
How do the properites of starch aid their function? (2)
It is too large to leave cells so will always be readily available.
It is insoluble so cannot affect water potential and osmosis.
47
What type of bonds does amylopectin contain?
Alpha 1-4 and alpha 1-6 glycosidic bonds.
48
What is glycogen made out of?
Alpha-glucose.
49
Describe the structure of glycogen.
Long branched polysaccharide.
50
How does the structure of glucose compare to amylopectin?
Glucose has many more branches.
51
What type of bonds does glycogen contain?
Alpha 1-4 and alpha 1-6 glycosidic bonds.
52
Where is glycogen found?
In animal cells.
53
What is glycogen used for?
Storing excess glucose.
54
Where in the body is glycogen usually found in cells?
Muscles and the liver.
55
How does the structure of glycogen aid its function? (2)
The branches increase the surface area so it can be hydrolysed more easily.
It is a compact molecule so is good for storage.
56
Where is cellulose found?
In plant cell walls.
57
What is cellulose made of?
Beta-glucose
58
What bonds make up glucose?
Beta 1-4 glycosidic bonds.
59
How are the glucose molecules oriented in cellulose? (why?)
Alternating molecules are inverted so the -OH groups are lined up to form bonds.
60
Describe the general structire of cellulose.
Long unbranched chains held together by hydrogoen bonds.
61
What do the cellulose chain form when joined by hydrogen bonds?
Fibres called microfibrils.
62
What is cellulose used for?
Providing structure in cell walls, allowing the wall to stay rigid.
63
How do the properties of cellulose help with its function?
Hydrogen bonds make microfibrils very strong but also flexible.
64
Where are 1-6 glycosidic bonds found?
At points where polysaccharide chains are branched.
65
How are lipids different from carbohydrates and proteins?
Lipids are NOT polymers.
66
What are the main functions of lipids? (4)
Waterproofing, insulation, protection/membranes, and emergency energy supplies.
67
What is a triglyceride made up of?
A glycerol molecule and three fatty acid chains.
68
What can triglycerides be used for?
An energy store, as lots of energy can be released as chains are broken down.
69
What bonds do lipids form during condensation?
Ester bonds.
70
What do ester bonds form between?
Between -OH groups on fatty acid chains and on the glycerol molecule.
71
DRAW STRUCTURE OF A TRIGLYCERIDE CARD
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72
DRAW ESTER BOND CARD
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73
What property can the fatty acid HYDROCARBON chain have in triglycerides?
They can be saturated or unsaturated.
74
Define saturated.
Only single bonds between the carbons in the chain, so the maximum number of hydrogens can bond to each carbon atom.
75
Define monounsaturated.
There is only one c=c double bond between carbons in the chain.
76
Define polyunsaturated.
More than one c=c double bonds between carbons within the chain.
77
Why are lipids insoluble in water?
They are not polar (do not have a charge)
78
How do phospholipids react in water?
They bundle together as insoluble droplets with the glycerol heads shield the tails from the water.
79
What are phospholipids made up of?
A glycerol molecule, a phosphate group, and two fatty acid chains.
80
How does the structure of a phospholipid differ from a triglyceride?
In phospholipids, one of the fatty acid chains is replaced by a phosphate group.
81
What can phospholipids be used for?
Membranes and hormones.
82
How do the different parts of a phospholipid behave near water?
The head is hydrophilic and the 2 tails are hydrophobic.
83
What is different about the specific structures of the fatty acid chains in phospholipids?
There is always one saturated and one unsaturated chain.
84
What feature do unsaturated fatty acid chains have? (why?)
The c=c double bond causes the chain to bend and create a kink, as the lack of hydrogens in the way allows the carbons to move closer together.
85
How do the properties of phospholipids aid its function?
Thy hydrophobic tails and hydrophilic head allow phospholipids to form bilayers for membranes.
86
DRAW BILAYER MEMBRANE
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87
Why can water soluble substances not easily pass through a phospholipid bilayer?
The centre of the bilayer is hydrophobic.
88
What is the monomer for proteins?
Amino acids.
89
How many amino acids are there?
20.
90
What do all amino acids share?
A basic structure.
91
DRAW AMINO ACID BASIC STRUCTURE
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92
What is the variable part of a molecule called?
R-group
93
What is the R-group of molecules?
The part of the molecule that may vary between different molecules.
94
What is the R-group of glycine?
Just a hydrogen.
95
What can the R-group contain other than C,O,H?
Other elements (cytesine has sulfur).
96
How do amino acids join?
Condensation reactions.
97
What bond forms between amino acids?
Peptide bonds.
98
Where does the peptide bond form between amino acids?
Between the amine group of one and the carboxyl group of another amino acid.
99
DRAW FORMATION OF A PEPTIDE BOND.
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100
What is made when 2 amino acids are joined?
Dipeptide.
101
What is the amine group?
-H2N
102
What is the carboxyl groups?
-COOH
103
How are dipeptides and polypeptides broken down?
Hydrolysis.
104
What is a hydroxyl group?
-OH
105
How many levels of protein structure are there?
4.
106
How do proteins form? (get to each stricture)
The polypeptides fold.
107
What is the primary structure of proteins?
Simple polypeptide chains.
108
Can a primary structure protein function?
NOPE AND THATS A BIT OF AN L.
109
What is important about the structure of primary proteins?
The number and sequence of the amino acids determines the tertiary structure.
110
What about enzymes can the the order and number of amino acids in a polypeptide affect?
The shape of the active site.
111
What is the secondary structure of proteins?
Alpha-helix or beta-pleated sheet.
112
Why do polypeptides start to fold into the secondary structure?
Hydrogen bonds forming between the amino acids.
113
What does hydrogen bonds forming between amino acids cause?
Folding into an alpha-helix or a beta-pleated sheet.
114
Why is the secondary structure of proteins stable?
The hydrogen bonds keep the structure stable.
115
What is a use of alpha-helices?
Channel proteins in membranes.
116
What is the structure of teriary proteins?
The fully formed shape of the 3D polypeptide chain.
117
What is a tertiary protein? (description)
A complex folded 3D shape made of a polypeptide chain.
118
Why do tertiary proteins have a very specific shape?
Thw sequence of amino acids determines which R-groups begin to form bonds.
119
What types of bond can form between the R-groups of tertiary proteins? (3)
Hydrogen bonds, ionic bonds, disulphide bridges (covalent).
120
Give 3 examples of tertiary proteins.
ALL enzymes, ALL anitibodies, SOME hormones.
121
WHO'S THE MOST SIGMA
GRACE OFC
122
What are quaternary proteins made of?
Multiple polypeptide chains.
123
Give an example of a quaternary protein
Haemoglobin.
124
What is a prosthetic group?
A non-protein group that is part of a quaternary protein.
125
What is the prosthetic group in haemoglobin, and what does it contain?
The haem group that contains iron.
126
What is a glycoprotein?
A protein that also contains a carbohydrate group.
127
What is a lipoprotein?
A protein that also contains a lipid group.
128
What is the function of enzymes?
Speed up rates of reaction.
129
What are enzymes?
Biological catalysts.
130
How do enzymes achieve their function?
By lowering activation energy.
131
What is a catalyst?
A substance that can speed up a chemical reaction without getting used up in the process.
132
What reactions can a single enzyme catalyse? (how broad)
Enzymes catalyse a specific ?, typically only one.
133
What is a catabolic reaction?
A reaction that breakes a substrate down.
134
What is an anabolic reaction?
A reaction that joins substrates together.
135
What type of structure do enzymes have?
3D tertiary protein structure.
136
What sort of shape is an enzyme's active site?
Specific.
137
What type of substrates can a certain enzyme bind to?
Certian substrates only.
138
What is formed when an enzyme and a substrate bind?
An enzyme-substrate complex (E-S complex).
139
What is an enzyme-substrate complex?
A substance formed of an enzyme that has bound to a substrate.
140
How can you describe an enzyme's active site when compared to the substrate?
The shapes are complimentary.
141
Define complimentary.
The way that 2 shapes fit together (enzymes)
142
What does a lower activation energy allow in reactions?
The reaction can take place at a lower temperature.
143
How do enzymes lower activation energy? (2)
Holding substrates together so there is less repultion and they can bond more easily.
Putting more strain on the bonds of a substrate so it can break apart.
144
What is the lock and key model?
The enzyme active site is exactly complimentary to the shape of the substrate so they fit together perfectly (hence enzymes are specific).
145
What is the induced fit model?
The active site can change slightly to fit the substrate when they collide and form an e-s complex.
146
What made the induced fit model more plausible?
Enzymes being able to catalyse multiple substrates.
147
DRAW LOCK AND KEY MODEL
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148
What factors are able to affect enzyme action? (4)
Enzyme concentration, substrate concentration, temperature, pH
149
DRAW GRAPH FOR EACH FACTOR, USE BOOKLET
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150
How does enzyme concentration affect rate of reaction?
There are more enzymes that are available to form E-S complexes so the rate will increase.
151
Why does a graph of enzyme concentration plateau?
The substrate becomes the limiting factor so increasing number of enzymes will not affect the rate.
152
How does substrate concentration affect rate?
It will initially increase as there are more collisions occuring, but then it will slow as enzymes become a limiting factor. As all active sites are occupied (saturation point) increasing the substrate will have less effect.
153
What is the saturation point (enzymes)?
Where all the enzyme active sites are occupied.
154
How does temperature affect enzyme concentration?
There is more kinetic energy so molecules move faster and there are more successful collisions. Rate will increase up to the point where it is too hot and bonds eithing the enzymes break, causing the tertiary structure to change so no more substrates can react (active site is different). The enzyme is permanently denatured.
155
What does denatured mean?
When the enzyme permanently changes shape as the bonds in the tertiary structure have broken.
156
How does pH affect enzyme function?
Above and below the optimum pH the concentrations of H+ and OH- ions disrupt ionic and hydrogen bonds, causing the enzyme to denature.
157
How do inhibitors prevent enzyme function?
They stop substrates from binding.
158
What is an inhibitor?
A substance that prevents enzyme function by stopping substrates from binding.
159
What are the 2 types of inhibitor?
Competitive and non-competitive.
160
How are competitive inhibitors similar to substrate molecules?
They both have a similar shape.
161
How do competitive inhibitors prevent enzyme function?
They compete with substrates to block the active site, so substrates cannot bind anymore.
162
How can competitive inhibitors be challenged?
Increasing the substrate concentration will increase the rate of reaction still as the substrates out-compete the inhibitor for enzyme active sites.
163
Where do non-competitive inhobitors bind?
The allosteric site of the enzyme.
164
How do non-comopetitive inhibitors affect enzyme function?
By binding to the allosteric site they change the shape of the active site so it is no longer complimentary to the substrate.
165
Can you out-compete a non-competitive inhibitor?
No. as the substrates can no longer bind anyway.
166
DRAW COMP AND NON COMP INHIBITOR FUNCTION
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167
What is the reducing sugars test used to find? (examples)
All monosaccharides, some disaccharides like maltose and lactose.
168
What is the reagent for the reducing sugars test?
Benedict's reagent.
169
What colour is benedict's reagent at the start of the test?
Pale blue.
170
What are hazards for the reducing sugars test? (2)
Benedict's reagent is an irritant.
Hot water can cause burns.
171
What are precautions taken for the reducing sugars test? (2)
Wear goggles, wash hands on contact (benedict's).
Use caution when pouring or carrying (hot water).
172
What is the method for the reducing sugars test?
Add excess benedict's to the sample, heat in boiling water bath (>80 degrees)
173
What is a positive result for the reducing sugars test?
A precipitate (colour from yellow to brick red based on amount of sugar) will form.
174
What is a negative result for the reducing sugars test?
The solution will remain blue.
175
What is the non-reducing sugars test to find? (examples)
Disaccharides or polysaccharides like sucrose.
176
When is the non-reducing sugars test used?
If a negative result is taken from the reducing sugars test.
177
How does the non reducing sugars test vary from the reducing sugars test?
Add dilute HCl and heat to break bonds FIRST.
Then add an alkali (NaOH) to neutralise
Continue as for reducing sugars.
178
How can results from sugar tests be made quantitative? (2)
Filter and weigh the precipitate.
Remove precipitate and use a colourimeter.
179
How do you test for starch?
Add iodine.
180
What hazards and precautions are taken when testing for starch?
Iodine is an irritant so wear goggles and wash hands if comes into contact.
181
What are the possible results for a starch test?
Positive: goes blue/black
Negative: stays brown/yellow.
182
What type of data is a result from a starch test?
Qualitative only (it is yes/no)
183
What is the protein test for? (examples)
Presence of amino acids.
184
What is the reagent in the protein test?
Biuret reagent.
185
What colour is biuret reagent?
Pale blue (dilute CuSO4 and NaOH)
186
What hazards and precautions are found for the protein test?
Biuret is an irritant: goggles are worn, hands washed when in contact.
187
What is the method for the protein test?
Add excess biruet and shake.
188
What are the results for the protein test?
Positive: goes purple
Negative: stays blue.
189
How could you make a protein test quantitative?
Chromatography can be used to identify certian amino acids in a mixture by separating them by mass.
190
Why is the protein test qualitative?
A stronger purple means more amino acids are present.
191
What is the lipids test for?
Lipids you fool what else would it be for >:)
192
What is the reagent for a lipids test?
Emulsion test using ethanol and water.
193
What precautions and hazards can be found for the emulsion test?
Ethanol is flammable: do not do the test near a naked flame.
194
What is the method for the emulsion test?
Add ethanol (to emulsify), THEN water.
195
What are the results for the emulsion test?
Positive: a MILKY WHITE EMULSION forms on the top
Negative: nothingi happens.
196
Why is the emulsion test qualitative?
The more lipids are present the more opaque the emulsion will be, it is qualitiative only.
197
How can water be described? (importance)
Biologically important.
198
Is water a monomer or a polymer?
NO
199
What are the 2 types of bonding between molecules?
Ionic and covalent (chem flashbacks ewwww)
200
What is ionic bonding between?
Metals and non-metals.
201
How does ionic bonding work?
Metal donates electron to non metal.
202
What charges are gained in ionic bonding?
Metal becomes positive, non metal becomes negative.
203
What is covalent bonding between?
Non-metals only.
204
What happens in covalent bonding?
Atoms share electrons.
205
What is electronegativity?
Where some atoms attract electrons better than others.
206
Why does electronegativity happen?
Bigger nucleus means more protons to attract electrons with.
207
Is water more electronegative, or hydrogen?
WATERRRR
208
What is a polar molecule?
Molecule with a slight uneven distribution of charge.
209
How is water a polar molecule?
Electrons are pulled to the oxygen (becomes delta negative), while hydrogen becomes delta positive.
210
How would you describe an atom with a very slight charge?
Delta positive/negative.
211
What is hydrogen bonding? (in water)
Hydrogens get attracted slightly to the other oxygens.
212
What are properties of hydrogen bonding? (single/multiple)
Weak on their own, strong when there are lots.
213
What is cohesion?
When molecules attract each other.
214
How can you tell that water is cohesive?
It forms droplets.
215
How do the water molecules form up?
In a lattice structure.
216
DRAW WATER LATTICE STRUCTURE
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217
What is suface tension?
Intermolecular attraction at the surface of a liquid, agains a gas.
218
What is adhesion?
Water's tendency to stick to surfaces (inside of tubes)
219
Give some properties of water? (9)
* Wide temp range as a liquid
* below 4 degrees is less dense than above
* high shc (4200j/kg degree)
* high latent heat of evaporation (100j/degree)
* polar
* is a reactant (photosynthesis/hydrolysis)
* has many hydrogen bonds
* transparent
* is a solvent
220
How do the properties of water aid its function? (6)
* Lower density cold water allows ice to float and currents to occur in the sea
* High SHC makes water a good buffer as there is no rapid temperature change.
* High latent heat of vapourisation allows sweat to absorb heat
* As it is a polar molecule it allows things to be dissolved into it.
* The many hydrogen bonds lead to properties of cohesion, adhesion and surface tension.
* As water is a solvent it allows for transpiration
