module 1 Flashcards
(306 cards)
1
Q
What’s are substances taken into the body used for/in?
A
Metabolism
Digestion -then rebuilt ti form different parts of the organism
2
Q
What happens if a substance can’t do this
A
Removed from body
3
Q
Talk about fibre as an example
A
Doesn’t provide nutrients but is essential component of the duet cz it helps in flow of materials through the gut
Also helps remive waste products
Lack if it could lead to intestinal cancer
4
Q
Name the 6 chemical groups
A
Carbohydrates Vitamins & minerals Water Nucleic acid Lipids Proteins
5
Q
What’s carbs for
A
Energy storage & supply
6
Q
Proteins for?
A
Enzymes & hormones, antibodies/antigens, structure
7
Q
Lipid s
A
Membranes, thermal insulation, electrical insulation in neurones
8
Q
Vitamins & minerals
A
Act as coenzymes (some)
Take part in metabolic reactions
9
Q
Nucleic acids
A
Info molecules
Carry instructions for life
10
Q
Water
A
Take part in many reactions
Support in plants
Medium in many reactions
Transport
11
Q
What are the key biological molecules
A
Carbohydrates
Proteins
Lipids
Nucleic acids
12
Q
What are the chemical elements found in biological molecules
A
Carbon
Hydrogen
Oxygen
Nitrogen
13
Q
Whys water described as a biological molecule sometime?
A
Cz of its important role to life
14
Q
What is biochemistry
A
Chemical reactions that involve biological molecules
15
Q
What is metabolism
A
Sum total of all the biochemical reactions taking place in the cells of an organism
16
Q
What are catabolic reactions
A
Breaking down larger molecules to smaller ones
17
Q
What are anabolic reactions
A
Building smaller molecules into larger ones
18
Q
Examples of catabolic & anabolic
A
Digestion catabolic
Muscle growth anabolic
19
Q
Why is carbon a kind of frame - work atom
A
Cz of its multiple - bonding feature
Can bond with other carbon atoms for longer chains & rings
Can bond with other atoms yo form molecules with different properties & structures
20
Q
What is a risk factor
A
Factor that increases your chances if developing a particular disease
21
Q
What is a covalent bond
3 points
A
When electrons are shared between atoms
They’re strong
Covalently bonded atoms form new molecules
22
Q
Hiw many covalent bond can carbon form
A
4
23
Q
Why can carbon form form a vast variety of molecules
A
Cz it can bond to other carbon atom to produce longer chains & rings and other atoms to produce molecules with different properties and structures
24
Q
2 examples if carbon double bonds
A
C=c
C=o
25
Why are lipids not polymers?
Cz the monomers are very different from each other
26
What reaction links monomers together. Also includes lipids
Condensation reaction
27
3 steps of condensation reactions
Water molecules released
Cove Kent bond formed
Larger molecule formed by binding of smaller ones
28
What's the chemical reaction that splits larger molecules
Hydrolysis reaction
29
3 steps of hydrolysis reaction
Water molecule used
Covalent bond broken
Smaller molecules formed by splitting of larger molecule
30
When do hydrogen bond form
When a slightly negatively charged part of a molecules comes close to a slightly positively charged hydrogen atom in same or other molecule
31
Strength of hydrogen birds?
Not strong
| But if many form eg in polymers it stabilises the structure
32
Function of carbohydrates in organisms
| 4 points
Store energy (starch)
Source of energy (released from glucose during respiration)
Structure (cellulose)
Also form part of larger molecules (nucleic acids & glycolipids)
33
Elements are found in what proportion in carbs
Cn (H2O) n
| For every carbon present equal number of water molecule present too
34
Monomer of carbohydrates?
Monosaccharides
35
3 properties of monosaccharides
Soluble in water
Sweet tasting
Form crystals
36
3 carbon monosaccharides called?
| 5 & 6 too?
Triose
Pentose
Hexose
Sugars
37
What are most common monosaccharides
| Give 2 examples
Hexose Sugars
| Glucose & fructose
38
Structure of Pentose & Hexose Sugars?
Ring structure
39
What are the 2 forms of glucose?
Alpha and beta
40
Difference is true tyre between alpha glucose and beta glucose
Alpha has its OH at C1 below the plane of the ring
| Beta has its OH at C1 above the plane of the rjng
41
2 monosaccharides in condensation reaction firm what?
Disaccharide molecule
42
Type if bond formed and specific name of bond when disaccharide is formed
What happens to water
Covalent bond
Glycosidic bond
Water is eliminated
43
Are disaccharides sugars?
Yes
44
What are the 2 products of a condensation reaction?
Polymer
| Water molecule
45
What releases energy in respiration?
| What can this energy be used for?
Breaking down of glucose to water and carbon dioxide
| To make ATP
46
Respiration equation
Glucose + oxygen --> carbon dioxide + water + energy used to form ATP
47
How can you ensure you can use glucose in respiration?
Using specific enzymes in each step
48
Animals and plants break which type of glucose only?
Alpha
49
Why can't animal and plant enzymes break down beta glucose?
Because of the different arrangements of the H and OH atoms at C1
50
Why can animals and plants only use alpha glucose not beta for respiration?
Because the enzymes function is based on shape.
| Shape of alpha is different to shape of beta do same enzymes can't break both
51
What do 2 alpha glucose form
What if you keep bonding them together what does that form?
Maltose
| Amylose
52
Where does the Glycosidic bond between all the glucose subunits occur?
2 points
Carbon number 1 of one molecule and carbon number 4 of another hence the 1,4-Glycosidic bond
53
What causes the Amylose chains to coil
The shape of the glucose molecules and the formation of Glycosidic bonds
54
How does coiling affect the structure of Amylose
Makes it compact
55
What is trapped in the coils of the spring of Amylose
Iodine molecules
56
What causes iodine to change colour to from yellow/brown to bkue/black in the starch test?
The fact that iodine molecules are trapped in the coils of the spring of Amylose
57
Difference between Amylose and similar molecules ti glucose molecules
Thwy aren't water soluble
58
Starch in what organisms?
Plants
59
Structure of starch
| 3 points
Made of alpha glucose molecules that have bonded together
Made of Amylose
Made of amylopectin
60
Where is starch stored in plants?
Chloroplasts
61
Why is starch a source of energy
Starch can be broken down to glucose molecules which can be respired down to release energy
62
Glycogen in what organisms
Animals
63
How is glycogen similar to starch?
Made of alpha glucose molecules
64
How us glycogen different to starch
Glycogen is branched
| Starch is straight chained
65
How is glycogen different to amylopectin
How does this show difference to starch?
3 points
1-4 Linked glucose chains in glycogen are shorter
Have more branches
So glycogen is more compact than starch
66
2 features of glucose and starch
Explain further
Don't dissolve
So the stored glucose doesn't affect the water potential of the cell
They hold glucose molecules in chains
This means they can easily be broken off from the ends to provide glucose for respiration
67
What catalyses condensation and hydrolysis reactions
Enzymes
68
How us beta glucose different to aloha glucose when they condense
In beta glucose the resulting chain is straight and long
| In alpha glucose the chain is coiled and spring-like
69
What are beta glucose polymer chains called
Cellulose
70
Which are stronger cellulose or Amylose
Cellulose
71
Which organism is cellulose only found in
| And where
Plants
| Plant cell walls
72
Why are many hydrogen bonds formed between glucose monomers in cellulose
Cz they contain a lot of OH groups
73
Describe the cellulose chain
Beta glucose units in cellulose chain
Hundred of chains = microfabric linked by hydrogen bonds
Microfibrils held together by hydrogen bonds to form macrofibrils
74
Mechanical strength of macrofibrils
Strong close to that of steel
75
Where are macrofibrils embedded, to form what?
Embedded in pectin to form cell walls
76
Structure and function of plant cell wall
| 4 points
Cell walls around plant cells give strength to cell, supporting the whole plant
Arrangement of macrofibrils allows water to move through and along cell walls and water can pass in and out of the cell easily
Walls prevent cell to burst, in turgid plants it helps to support the whole plant
Cell walls can be reinforced with other substances to provide extra support
77
2 different types of structural carbohydrate than cellulose
| And info
Chitin and peptidoglycan
Chitin = forms exoskeleton of insects
Peptidoglycan = is the basis of cell walls found around most bacterial cells
78
What is cellulose
A carbohydrate polymer made by bonding beta glucose molecules
79
Why do differences between starch and cellulose occur
Cz of the difference between alpha glucose and beta glucose
The OH at C1 is below the plane of the ring in alpha glucose
The OH at C1 is above the plane of the ring in beta glucose
80
Functions of proteins
| 5 points
They are membrane carriers and pores (in active transport and facilitated diffusion)
All enzymes are proteins
Many hormones are proteins
Antibodies are proteins
They're structural components (of muscle and bone)
81
Overall importance of proteins
| 2 points
Provide growth and repair
| Crucial to most metabolic activity
82
Monomers that make proteins?
Amino acids
83
Basic Structure of all amino acids?
Amino group, acid group and carbon in between and an r group
84
What causes the difference in structure and properties in amino acids if their basic Structure if very similar?
The different r groups
85
How mant naturally amino acids are there
20
86
How can r groups differ?
Some are positively charge some are negatively charged
| Some are hydrophobic some are hydrophilic
87
How do plants manufacture amino acids
Nitrate from the soil is converted to amino groups and bonded to organic groups made from the products of photosynthesis
88
Difference of amino acids in plants and animals
Plants manufacture them
| Animals take in port wins to obtain amino acids
89
How do animals get amino acids
The proteins they take in are digested to amino acids and other proteins can be built from these amino acids
90
What are essential amino acids
They are an essential part of the diet
| They can't be built from materials taken into the organisms body
91
Hiw many of the naturally occurring amino acids are essential acids in animals
8-10 out of 20
92
Why should vegetarians be careful with their diet I terms of amino acuds
Because most essential amino acids are found in meat not plants. So they need to balance their diet properly
93
Why can't animals store excess amino acids
Because the amino group makes them toxic
94
Hiw is the amino group removed
Where does this take place?
What is the amino group converted to?
Where is it removed?
Deamination
Liver
Urea
Urine
95
Where is the covalent bond formed in amino acids
The amino group of one amino acid and the acid group of another amino acid
96
What is the covalent bond called that bonds amino acids
Peptide bond
97
What are the 2 products formed in a condensation reaction of 2 amino acids
Peptide bond and water molecule
98
Why is the making and breaking of peptide bonds important
| 2 points
Building and rebuilding of protein molecules
| Breaking down proteins ti amino acids for example in digestion
99
What is it called when many amino acids join together not just 2
Polypeptide
100
Why are amino acids in a polypeptide chain referred to as amino acid residues
Cz part of the molecule is lost in the condensation reaction that produces the peptide bond
101
Where in a cell are polypeptides made?
Ribosomes
102
What process makes polpeotude/proteins
Protein synthesis
103
From what molecule is info used to form polpeptides/proteins
mRNA
104
Briefly describe process of protein synthesis
| 4 steps
mRNA Passes through the ribosome
Amino acids join are joined together one at a time
Peptide bond formed after a condensation reaction
This produces a linger chain of amino acids
105
What determines the sequence of amino acids
The mRNA
106
How do you make sure you can make different types of proteins
Make sure different mRNA molecules pass through ribosomes
107
What do all proteins have at each end
An amino group and an acid group at the other end
108
What determines the function of a protein
It's primary structure (it's amino acid seqyence)
109
How do you calculate the total number of different possibilities of amino acid sequences?
4 amino acid polypeptide chain example
E.g. A polypeptide chain with 4 amino acids
20x4 = 160000 different sequenced of four amino acids are possible
110
Why is the formation and breakage of covent bonds uses enzymes to catalyse the reactions
Cz covalent bonds are very strong, they can't just appear or fall apart
111
What are the enzymes called that catalyse the breaking of peptide bobds
Protease enzymes
112
Examples of when organism break down and rebuild proteins
Digestion
Hormone regulation
Ageing
113
Why does hormone regulation (break down) occur
So that their effects aren't permanent and can be controlled
114
Why does skin lose its elasticity and become wrinkled - ageing
Cz older skin is less able to rebuild the protein collagen that gives skin it's smooth and elastic properties
115
How do coils and pleats in amino acid chains help
They help avoid tangling and breaking
116
What holds the coils and pleats on place
Hydrogen bonds
117
What does the amount of coiling and pleating in a chain depend on
The types of amino acids being added to the chain (primary structure)
118
What is the primary structure of a protein
The sequence of amino acids
119
What is the secondary structure of proteins
What holds the coils in place
Although they're weak how do they help?
When an alpha helix is formed die to the coils and pleats
Hydrogen bonds hold the could in place
There are many hydrogen bonds, so their overall effect is stability for the chain
120
What is the tertiary structure of a protein
| What holds its shape at this stage?
```
It's the 3D shape of a protein
When the coils and pleats themselves coil or fold
4 bonds - disulfide
Hydrogen
Ionic
Hydrophobic and hydrophilic interactions
```
121
What forms hydrogen bonds in tertiary structure of a protein
When a negatively charged groups are found near positively charged groups
122
What lead to the formation of ionic bonds in proteins
R groups sometimes carry a charge
| When oppositely charged amino acids are found close to each other
123
What causes a disulfide bond in proteins
When two cysteines are found close to each other -they contain sulfur
124
What determines a proteins function
| Examples of importance of structure for function
It's tertiary structure
Hormones must be a specific shape to fit into a receptor
An enzyme must have the right active site shape that is complimentary to its substrate
125
Effect of heat on tertiary structure of proteins
Kinetic energy increases in the molecule
Causes molecule to vibrate
This causes some of the weaker bonds not including covalent or disulfide bond to break
With enough heat, the entire tertiary structure can be unravelled which stops the protein from functioning well
It becomes denatured
126
What are the 2 main categories of 3D shape of proteins
Globular and structural proteins
127
3D Feature
Solubility in water
Role
Example of globular proteins
Roll up to form balls
Soluble mainly
Usually metabolic roles
Enzymes & antibodies
128
3D features
Solubility in water
Role
Example of fibrous proteins
Form fibres
Insoluble usually
Structural roles
Collagen in bone and cartilage/keratin in hair and nails
129
What does a quaternary structure of a protein mean
It has more than one polypeptide subunit or has an inorganic component with a polypeptide
130
2 examples of protein with a quaternary structure
Insulin and haemoglobin
131
How many polypeptide chains does haemoglobin have
Types of chains in the 4 chains
Type of protein
Water solubility
4
2 alpha chains and 2 beta chains
Globular
It's soluble in water
132
Function of haemoglobin
Carry oxygen from the lungs to the body tissues
133
What is the prosthetic group found in haemoglobin
Haem group
134
What are prosthetic groups
Groups that aren't amino acids but are an essential part of a protein
135
What is responsible for the colour of haemoglobin
The haem group
136
What does haem groups contain that binds to oxygen
(Fe2+) iron ion
137
How many oxygen molecules can bind to one haemoglobin to be transported to body tissues from lungs
4
4 haem groups
4 iron ion groups that bind to oxygen
138
Structure if collagen:
What type of protein is it
How many polypeptide chains is it made out of
How does it look like
What happens to the 3 chains
What gives the structure of collagen strength, between what?
```
Fibrous
3
A twisted rope
Theyre coiled
Hydrogen bonds, between the chains
```
139
What increases the strength of the collagen molecule further?
The formations of covalent bonds (cross-links) with other collagen molecules
140
What are the stages of collagen strength? 3 points
Collagen cross-links with other collagen molecules
This forms fibrils
Which forms fibres
141
Function of collagen
| And 5 examples
Provides mechanical strength
Walls of arteries - prevents walls from bursting due to high blood pressure
Tendons - they're mostly collagen and form a strong connection that allows muscles to pull bones
Bones are made from collagen, this makes them hard
Cartilage and connective tissue made from collagen
Cosmetic treatments - colkagen ibjected into lips, used to give fuller lips
142
What is a solid lipid and a liquid lipid called
Fat
| Oil
143
Functions of lipids
| 6 functions
Electrical insulation around neurones
Some hormones are lipids
Source of energy (lipids can be respired like glucose to release energy to generate ATP)
energy storage in adipose cells
All biological membranes arw made from lipids
Waxy cuticle of plant leaves - helps prevent them from drying out
144
Solubility of lipids in water
Insoluble
145
Where are glycerol and fatty acids found
| 2 places
All lipids that perform energy storage and supply and those found in membranes
146
Is it fatty acid molecules or glycerol molecules that differ
Fatty acids
| Glycerol molecules stay the same
147
What are essential fatty acids
Fatty acids that can't be made by animals
| They need them from raw materials
148
How are fatty acids similar but very different
They always have the same acid group
| But their hydrocarbon chain differs (can be 2-20 carbons long)
149
What do saturated and unsaturated fat refer to?
Whether the hydrocarbon chain is saturated with hydrogen or not
150
What are unsaturated fatty acids
| 2 points
Fatty acids that c=c bonds
| So fewer hydrogen atoms can be bonded to the molecule
151
How can you predict whether a lipid is oil or fat
Oils tend to have many unsaturated fatty acids cz the many c=c bonds changed the shape of the hydrocarbon chain which makes it more fluid
Fats are more saturated and don't have a major change to their hydrocarbon chain cz of lack of c=c bonds so they aren't very fluid
152
What type of lipid is animals lipid
What about plant lipid
Solid/Fat e.g. lard
Liquid/Oil e.g. olive oil
153
What is a triglyceride made out of
One glycerol molecule and 3 fatty acids
154
Where does the condensation reaction occur that forms triglycerides
Between the acid group if a fatty acid molecule and an OH group if the glycerol molecules
155
What type and name of bond is formed between the condensation reaction between a fatty acid and a glycerol
Covalent bond
| Ester bond
156
What are the 2 molecules produces after a condensation reaction between a fatty acid and a glycerol
A water molecule and a mono/di/triglyceride
157
Why are triglycerides hydrophobic/ water insoluble
| 3
Cz the charges on the molecules are dirtied evenly across the molecules
This means that the hydrogen bonds can't form with water molecules
So the two types of molecules don't mix together
158
What CAN lipids dissolve in
Alcohol
159
Examples of lipids
| 5 points
```
Fatty acids
Triglycerides
Cholesterol
Phospholipid
Glycolipids
```
160
How is a phospholipid molecule similar to a triglyceride molecule
Contains fatty acids and glycerol that are bonded together by a condensation reaction to produce an ester bond
161
How is phospholipid formation different to triglyceride formation
In a phospholipid the 3rd fatty acid doesn't bond to the OH group, instead a phosphate group bonds to it
It's a covalent bond which also releases water
162
Features of the heads and tails of phospholipids
Head is hydrophilic
| Tail is hydrophobic
163
What allows phospholipids to form membranes
The water solubility of their heads
164
Fatty acids of phospholipids can be in saturates or saturated
How does this help
Allows organism ti control the fluidity of membranes
165
Hiw does respiration of lipids occur
| 3 points
The ester bonds holding the fatty acids and glycerol are hydrolised by using a water molecule
Both glycerol and fatty acids can be further broken down into water and carbon dioxide
This releases energy which is used to generate ATP
166
Which hives more energy and by hiw much
| Respiration of one gram of carbohydrates or lipid
Lipid
| Twice as much energy
167
Why are lipids excellent energy storage molecules
They're stored in a compact way and don't affect water potential of the cell cz they're insoluble in water
168
What type is chokestrol
Lipid
169
What is cholesterol made out of, not like triglycerides and phospholipids
4 carbon based rings
170
What is its function in the membrane due to its hydrophobicness
Can sit in between phospholipid hydrocarbon tails
| Regulated fluidity and strength of the membrane
171
Examples of things made from cholesterol
Hormones testosterone and oestrogen
Vitamin D
172
How does the lipid nature of steroid hormones help them in their functions
Can pass through the phospholipid bilayer easily to reach target receptor and can pass the nuclear envelope
173
Example of where cholesterol is formed
Liver cells
174
Why excess cholesterol can be harmful
| 2 examples
In the blood:
Cholesterol can be deposited in the inner lining of blood vessels causing atherosclerosis which can result in CHD
In bile:
Cholesterol can stick together to form gallstones
175
Why and how is the genetic disorder hypercholeserolaemia bad
Cz cells manufacture and secrete too much cholesterol
This happens cz the cells don't obey the signals to stop cholesterol production as they lack a particular cell surface receptor
People can die at 2 years of age
176
What 3-2 forms do nucleic acids come in
DNA
| RNA
177
What do dna and RNA hold?
Coded info to build that organism
178
Where is dna found in a eukaryotic cell
Nucleus
179
Where is RNA found
In 3 different forms
180
What os the monomer of all nucleic acids
Nucleotide
181
What makes up a nucleotide
| 3 subunits
Organic nitrogenous base
Phosphate group
Sugar molecule
182
What bond is used to join the 3 sub units
Covalent bond
183
Variations of a phosphate group in nucleic acuds
None
| They're always the same
184
Variation of sugar molecule in nucleic acuds
Either deoxyribonucleic sugar
Or ribose sugar
185
Variation of organic nitrogenous bases in nucleic acids?
```
Adenine
Guanine
Thymine
Cytosine
Uracil
```
186
What join together in a condensation reaction to form a chain of nucleotides
The sugar molecule of one nucleotide with the phosphate group of another
187
What consist of the backbone of nucleic acids
Phosphate group and sugar molecule
Base projects from them
188
What forms coded info in nucleic acids
The sequence of bases
189
Can ribose bond with deoxyribose
Why
So what?
No
Cz they aren't the same sugar
So it's either RNA or DNA
190
How many pyramidines
| Hiw many purines
3 pyramidines
| 2 purines
191
What are the 3 pyramidines
Thymine Uracil
| Cytosine
192
What are the 2 purines
Adenine
| Guanine
193
How do pyramidines and purines differ
Pyramidines are smaller
194
What causes gout
Too much nucleic acids (uric acid)
195
Nucleotide monomers produce what type of monomer
Polynucleotide
196
How is a dna molecule formed after a polynucleotide is formed
When 2 polynucleotide stands come together
197
What strengthens the rungs of the ladder by forming bonds between the bases
Hydrogen bonds
198
How do hydrogen bonds help in dna
Give it a stable structure
199
Why is it vital for dna to have a stable structure
Because it holds instruction for life and to make an organism. Of unstable instruction would go wrong too easily
200
Why is the term anti parallel used in dna crap
Because the dna strands run in opposite direction to each other
The sugars are pointing in opposite directions
201
Why are the chains always the same distance apart
Cz of the way the nitrogenous bases pair up
| Purines with pyramidines
202
What forms between the bases when they cones together
Hydrogen bonds
203
What is the base pairing described as
Complementary
204
What is the final structure of a dna molecule known as
| How does it form
Double helix
| Twisting of the strands
205
When does dna replication take place
Interphase
206
What does dna replication create
Identical sister chromatids
207
How do you make a new copy of a dna molecule
| 5 steps
Untwist double helix
Hydrogen bonds between base pairs broken which makes them exposed
Dna unzips
Free dna nucleotides are bonded by hydrogen bonds to the exposed bases
Covalent bond formed between phosphate group of one nucleotide and sugar molecule of another to seal the backbone
This continues until 2 new dna molecules are formed
208
Why is it called semi conservative replication
Because each new dna molecule consists of one conserved strand and one new strand hence semi
209
4 ways RNA is structurally different to dna
Only has one strand
Uracil rather than thymine
Ribose sugar not deoxyribose
3 forms of RNA molecules exist
210
What can RNA molecules do/be due to the base pairing rules
(Basis of copying the genetic code of the dna base sequence) transcription
They can be complementary to dna
So they can bond to exposed Dna nucleotides
A chain of RNA nucleotide is then formed (transcription)
211
What are the 3 forms of RNA molecules
tRNA
mRNA
rRNA
212
What is an mRNA
It's a copy of the coding strand of the dna molecule
| Complementary ti the template strand
213
What is rRNA
Found in ribosomes
214
What is tRNA
Carries amino acids to ribosomes where they are bonded together to form polypeptides in protein synthesis
215
Briefly explain protein synthesis in 7 steps
Sequence of bases code for particular protein molecules
They code for the sequence of amino acids in the protein
Hydrogen bonds split to expose a gene with this coding
RNA nucleotides form a complementary strand mRNA (which is a copy of the DNA coding strand or the gene
The mRNA peels away from the dna and leaves through a nuclear pore
mRNA attaches to a ribosome
tRNA bring amino acids in correct order to ribosomes, according to the base sequence on the mRNA
Amino acids joined together by peptide bonds to give a specific primary structure which gives rise to the secondary and tertiary structure
216
What is a gene
Length of dna that codes for a polypeptide
217
What does a gene occupy
Locus - a specific place on a chromosome
218
What is an allele
Different version of the same gene
219
How are all enzymes similar?
| 5 ways
Globular proteins
Soluble in water
Act as catalysts
Affected by pH and temperature
Have an active site
Specific
220
What determines enzymes function
It's shape and amino acid sequence
Primary, secondary and tertiary structures
221
What is an active site
Area of an enzyme where catalytic activity of the enzyme occurs
222
What does it mean that the active site of an enzyme is very specific
The reaction an enzyme can catalyse is also very specific
223
What is a catalyst
A molecule that speed up chemical reaction s but isn't used up in the reaction. The catalyst remains unchanged at the end of the reaction
224
Advantage of enzymes over inorganic catalysts
As biological catalysts they aren't used up and don't produce waste product (unwanted byproducts)
225
Metabolic reaction that are enzyme driven
```
Glycosidic bond
Ester bonds
Peptide bonds
Protein synthesis
Respiration
Photosynthesis
Digestion
```
226
What happens to a substrate in a reaction catalysed by an enzymes
An example
The substrate turns into a product
| E.g. maltose hydrolysed into 2 glucose molecules with the enzyme maltose as the catalyst of the reaction
227
What is sucrose made out of
Glucose and fructose
228
What is an enzyme
Protein molecule that acts as a biological catalyst
229
What happens if the shape of an enzyme changes
It's can't function/ work
230
What makes an organism adapted to live in extreme environments
Their enzymes con it ie to function
231
What does it mean to be able to regulate core body temperature independently (endothermic)
Enzymes can function at near optimum temperature
232
Disadvantage and advantages of having enzyme activity
Dis
Using too much energy
More food need cz it components are used up
Adv
Allows organism to survive well by helping it live in more extreme environment
233
3 examples of where enzymes can be found
Heterotrophs break down the body of organism they're consuming in order to extract the nutrient molecules they need
In digestion. Catabolic reaction that break down larger molecules into their subunits (Glycosidic bonds, ester bonds, peptide bonds)
Some organism secrete enzymes onto the food source. They digest the molecules into their monomers
234
What are extracellular enzymes
Example
Enzymes that are released from the cells that makes them
Eg 3 Nymet in digestive system
235
What are intracellular enzymes
Enzymes that have their catalytic action take place inside the cells that make them
236
How can enzymes be useful in protecting an organism
Example
They can help break down the molecules that may be harmful to the organism
Phagocytosis
Lysosome enzymes are used to digest bacteria that are engulfed by a phagocyte
237
What is activation energy
The amount of energy that is need to enable the reaction to take place
238
What's the level of activation energy
It depends on reaction
239
What role do enzymes play in activation energy
They reduce the amount of activation energy need to proceed with the reaction
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How can we allow metabolic reaction to take place without damaging the cells Involved
Use enzymes as catalysts
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What would happen if enzymes didn't exist
Metabolic reaction would occur much slower to even maintain life
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What relations does the shape of active site have with substrate
They're complementary to each other
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Why is it called the lock and key hypothesis
Because the substrate usually small, fits into the active site
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What is the induced fit hypothesis
The idea that changes to the enzyme occur as the substrate binds to the active site
Charges on the amino acids on the active site also contribute in the holding of the substrate molecule so that the reaction can proceed
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What happens if the substrate molecule is no longer held in active site
Reaction cannot occur
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7 steps of the induced fir hypothesis
Enzyme molecule changes shape slightly once a substrate molecules bond with the active site
This makes the active site fit the substrate better
Charge on active site also hold substrate in place (oppositely charged groups from active site and substrate) (enzyme substrate complex)
Change in enzyme shape also places strain on thus destabilise the substrate molecule which makes the reaction occur more easily
This produces a product (enzyme-product complex)
Product(s) are a different shape from substrate molecule
Product(s) no longer fits into active site so it moves away
Enzyme able to catalyse SAME reaction with another substrate molecule
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Which type of molecules have natural kinetic energy
Liquids and gas
248
What happens if gas or liquid is heated
4 things
An increase in kinetic energy
Molecules vibrate and move aroubd more
They collide more often
They collide at a greater speed and force
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What lead to collision if active sit and substrate
Random movements of substrate and enzyme
250
What happens if you increase temp in substrate and enzyme
| 5 things
Higher kinetic energy
Move around more
More likely to collide
Increased reaction rate
Increased number of products at a given time
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Example and steps of how enzymes van be denatured
| 7 steps
Increasing heat
More vibration
Vibrations cause weaker bond eg hydrogen and ionic bonds to break (which hold tertiary structure and maintain active site shape)
Thus alters it's active sit shape
Rate of reaction decreases
Enzyme will stop function with increased heat
Structure too damaged to function so it's irreversible and becomes denatured
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What does denaturation not change
Primary structure
253
What is an optimum temperature
The temperature in which an enzymes rate of reaction is maximum
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What is the optimum temperature a balance of
Increasing kinetic energy and increasing vibration
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How can we measure the effect of temperature on enzyme action
Varying out an enzyme controlled reaction at different temperatures using a water bath.
To measure production of products or disappearance of substrate check 2.1.27 &28
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Example of when heat resistant enzymes are used
Polymerase chain reaction in catalysing reaction to make many copies of DNA segments
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What determines the enzymes optimum temperature
What type of environment organism lives in
Organisms internal temperature that can be maintained
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What is ph
A measure of the hydrogen ion (H+) concentration
259
Concentration of h+ at a low pH
High
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Why is acid defined as a proton donir
Because hydrogen ions arw also known as protons
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How can hydrogen ions interference with the tertiary structure of an enzyme/active site
Cz of the charge of hydrogen ions and hydrogen and ionic bonds in the tertiary structure of an enzyme they can interfere with the tertiary structure thus function
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How can changes in pH affect enzyme
They interference with the bonds in the tertiary structure which leads to it changing which lead to it stopping from functioning which decreases reaction rate
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Hiw can change to active site cz of pH interfere induced fit hypothesis
Hydrogen ions will alter the charges around the active site cz they're attracted to any negative charges around active site. This alter shape and means substrate can no longer fit
264
What is optimum ph
The pH at which the rate of reaction is highest
265
How does the best overall shape help in terms of hydrogen ions and optimum pH
Holds the active site in the shape that best fits the substrate
266
Hiw do you measure effect of pH on enzyme action
Involves carrying out enzyme controlled reactions at different pH using buffer solution. To measure production of products or disappearance of substrate check 2.1.27 & 28
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Examples of enzymes operating at different pH leveks
Pepsin works in stomach with an optimu pH of 2 eg kills bacteria
Trypsin works in small intestine optimum pH is 7 neutralises food
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What I'd a buffer
A chemical solution that resist changes in pH by maintaining a constant level of hydrogen ions in the solution
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Difference between minor and major changes in pH in terms of denaturation
Minor changes don't denature enzymes, bonds can be reformed
Major changes aren't reversible, lead to denatured enzyme
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What happens if there's no substrate
Reaction can't proceed because enzyme substrate complexes can't be formed
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What happens if concentration of substrate increase with a fix amount of enzymes
What if it increases even further
Collision occur more often
Enzyme substrate complexes increase
Products increase
Reaction rate increases
Reaction rate reaches maximum value
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What does it mean when a reaction rate reaches maximum level in terms of increasing substrate concentration
All the active sites are occupied
| No effect if substrate concentration is increased
273
What happens if you increase enzyme concentration with a fix amount of substrate concentration
What if you keep increasing it
More collision
More enzyme substrate complexes
More products at a given time
Increase in reaction rate
But eventually maximum reaction rate will be reached
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What happens at a maximum reaction rate in terms of increasing enzyme concentration
All the substrate molecules are used up and no other are free to bind with other active sites
275
In an enzyme controlled reaction when is the reaction rate highest
When substrate and enzyme are mixed together
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What does the initial reaction rate do
Gives the maximum possible reaction rate for an enzyme under a particular experimental situation
277
What is another word for leveling off in graphs
Plateau
278
What is a limiting factor
A factor where if all other conditions are kept constant, increasing the concentration of that factor alone will increase the reaction rate
279
What is control of metabolism based on
Control/regulation of enzyme activity
280
How could you regulate enzyme activity
| 4 examples
PH concentration
Temperature concentration
Substrate concentration
Enzyme concentration
281
what is an enzyme inhibitor
a substance or molecule that slows down the rate of an enzyme controlled reaction by affecting the enzyme molecule in some way
282
what are the 3 types of inhibitors?
competitive and non-competitive and permanent
283
talk about competitive inhibitors
similar shape to that of the substrate molecule
so they can occupy the active site
they form an enzyme-inhibitor complex
doesn't lead to formation of products cz inhibitor isn't identical to the substrate
the enzyme doesn't catalyse a reaction
284
what happens to reaction rate during enzyme inhibition and why
decrease
| cz less enzyme-substarte complexes are being formed so less prodcts cz inhibitor is occupying the active site2
285
what does the level of inhibition depend on in competetive inhibition?
level of inhibiotrs or substrate molecules. the more the substrate mlecules the more likely theyll collide with an active site
286
talk about non-competitive inhibiotrs
dont compete with substrate molecules for the cative site because they dont bind with the active site
the attachment distorts the tertiary structure of the enzyme
this mean the active site shaoe changes
so the substrate no longer fit even though the inhiviotr isnt binded to the active site
which decreases amount of substrate-nzyme complexes which decreases reaction rate
287
what does the level of inhibition depend on in non comp inhibition
amount of inhbitor molecules
| substrate conc has no effect
288
what are most comp inhibitors
| what is their action described as
dont bind permanetnly
| reversible
289
what happens if an enzyme molecules is bound by a permanent inibitor?
denatured
290
whys inhibition not always bad
cz it controls reaction rate by regulating metabolic pathways
291
What are cofactors
Any substance that must be present to ensure enzyme controlled reactions take place at the appropriate rate
Some factors are a part of the enzyme (prosthetic groups) others affect an enzyme in a temporary basis (coenzymes and inorganic ion cofactors)
292
Talk about coenzymes
Small, organic, non protein molecules that bind for a short period if time to the active site
Bind just before or at the same time the substrate binds
Like substrate they change in some way
Unlike substrates they are recycled back to take part in the reaction again
Role ills often to carry chemical groups between enzymes so they link together enzyme controlled reactions that need to take place in sequence
293
Example of a coenzyme
Vitamin b3
Helps body break down carbohydrates and fat ti release energy
This vitamin is used to make a coenzyme that is required for the enzyme pyruvate dehydrogenase to function properly which catalysed one of the reactions in the sequence involved in respiration. Normal growth can't proceed without it
294
Talk about prosthetic groups
A coenzyme that is a permanent part of an enzyme
Also found in other protein molecules such as haemoglobin
Ar vital for the function, contribute to the final 3D shape and to other properties including its charges.
295
Example of a prosthetic group
Zinc based carbonic prosthetic group in carbonic anhydrase
Enzyme involved in catalysing the combining of CO2 and he to produce carbonic acid. Important reaction that enables CO2 to be transported in blood.
296
Talk about inorganic ion cofactors
In some enzyme controlled reactions the presence of some ions can increase the reaction rate
Ions may coming with either the substrate or the enzyme
The binding of the ion makes the enzyme substrate complex form more easily cz it affects the charge distribution and sometime the shape of the enzyme substrate complex
297
Example of inorganic ion cofactors
Chloride ion
Help amylase catalyse the breakdown of starch to maltose
298
What inhibits cell respiration
Why
Potassium cyanide
Cz it's a non competitive inhibitor for a vital respiratory enzyme called cytochrome oxidase found in mitochondria
Inhibition of it decreases use of O2 so ATP can't be made
The organism can only respire anaerobically which leads to build up of lactic acid
299
Talk about enzymes and medicines
Protease inhibits inhibit the viral protease enzymes often as competitive inhibitors
300
Talk about replacement enzymes and cystic fibrosis
Enzymes ate prescribed in tablet form to indvs with cystic fibrosis in order to overcome the problem of not having enzymes
301
Talk about ethylene glycol poisoning
if taken into the body it's broken down in the liver by the enzyme alcohol dehydrogenase
Product oxalic acid is extremely toxic
Treatment includes using the drug fomepizole, which is a strong inhibitor of alcohol dehydrogenase so reduces rate of production of oxalic acid
Ethanol cam also inhibit the same reaction but can lead to alcohol intoxication
302
Talk about antibiotics and bacterial enzymes
Antibiotics can kill or inhibit the growth of microorganisms
Inhibit a bacterial enzyme that forms cross links in the bacterial cell wall so walls of growing bacteria are not made so bacterial reproduction is halted
303
What dies snake venom contain inhibitor
Inhibitor of acetylcholinesterase, results in paralysis cz it's involved in nerve transmission
Contains enzyme hyaluronidase which breaks down connective tissue and so helps toxins to penetrates tissues quickly
Also contain ATP ases which are used for breaking down ATP to disrupt the preys use of energy.
304
What is the turnover number for an enzyme
The number of reactions an enzyme molecule can catalyse in one second
In catalase, the turnover number is up to 200k
305
What are chains of enzyme reactions called
Metabolic pathways
306
What are inborn errors of metabolism
Lack of functioning specific enzyme in a metabolic system
