Unit 2 Flashcards
(232 cards)
1
Q
What is a catabolic reaction?
A
- Break down of complex molecules into smaller molecules
- Energy is released
2
Q
What is an anabolic reaction?
A
- Build up of complex molecules
- Energy is used
3
Q
What does an enzyme do within a metabolic pathway?
A
Catalyses each step
4
Q
What is the name of an alternative route in respiration?
A
sorbitol
5
Q
What are membranes made up from?
A
- Phospholipids
- Protein molecules
6
Q
How are membranes described?
A
Fluid mosaic model
7
Q
Definition of Diffusion?
A
Movement of molecules from a high concentration to a region of low concentration down a concentration gradient.
8
Q
What are the 3 proteins in membranes?
A
Pumps
Pores
Enzymes
9
Q
What do protein pores do?
A
Transport water molecules and certain ions from one side to the other; requires no energy
Span the membrane
10
Q
What do protein pumps do?
A
Transport Sodium and Potassium ions across the membrane using energy.
11
Q
What does Temperature, concentration of glucose and oxygen affect?
A
Rate of active transport, the rate of respiration and the release of ATP.
12
Q
What is the role of ATP synthase?
A
Catalyses the synthesis of ATP
13
Q
What is an important feature in cell organelles?
(ratio) and what does this allow?
A
Large surface area: volume
Allows high concentrations and reaction rates
14
Q
What are lysosomes and what do they do?
A
They are a powerful digestive enzyme
Localise the metabolic activity of the cell.
15
Q
What is the main substrate in respiration? and what does it do?
A
Glucose
Broken down to release energy as ATP
16
Q
What breaks down Lactose?
A
B-galactosidase
17
Q
What is the equation for the breakdown of Lactose?
A
Lacose = Glucose + galactose
18
Q
What is a regulator gene?
A
Codes for a repressor molecule
19
Q
What is a repressor gene?
A
“Switches off” the operator gene
20
Q
What is an Operator gene?
A
Controls the structural gene by “switching it on/off”
21
Q
What is a structural gene?
A
Codes for the enzyme B-galactosidase
22
Q
What are the stages if Lactose is absent in the production of B-galactosidase?
A
1- Regulator gene switched on
2- Repressor molecule produced
3- Repressor molecule binds with the operator gene
4- Operator gene is switched off
5- Structural gene is switched off
6- No enzyme produced - no B-galactosidase
23
Q
What are the stages if Lactose is present in the production of B-galactosidase?
A
1- Regulator gene switched on 2- Repressor molecules produced 3- Repressor molecule binds with Lactose (inducer) 4- Operator gene switched on 5- Structural gene switched on 6- Enzyme produced - B-galactosidase
24
Q
What happens when all the lactose has been used up? and what does that prevent?
A
The repressor molecule can bind to the operator gene; switching it off - enzyme is no longer produced.
This prevents any unnecessary use of resources such as amino acids and ATP
25
What is the control of metabolic pathways due to?
The presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes within the pathway
26
What controls the regulation of metabolic pathways?
Both intra- and extra-cellular signal molecules.
27
Why are enzymes important?
Speed up a chemical reaction,
lower the activation energy
Remain unchanged at the end of the reaction
Biological catalysts
28
What happens at higher temperatures within a metabolic pathway?
The reactant molecules absorb more energy and their chemical bonds become more and more unstable.
29
What is the activation energy?
The energy needed to break the chemical bonds in the reactant molecules and so start the reaction.
30
What are enzymes made of?
Proteins
31
What determines the shape of the protein?
Sequence of amino acids
32
What is the shape of most enzymes?
Globular
33
What determines the shape of the active site?
Sequence of amino acids
34
What is induced fit?
How closely the active site fits around the substrate.
35
What are the factors needed for enzyme action?
- suitable temperature
- pH
- supply of substrate molecules
36
Orientation of reactants
The substrate molecules can only fit into the active site if they are correctly orientated.
37
What is the rate of reaction against substrate concentration?
At low concentration, the reaction rate is low. As the substrate concentration increases, more and more of the active sites are filled.
38
What is an inhibitor?
A substrate that slows down or inhibits the rate of an enzyme catalysed reaction.
39
What are the 3 types of inhibitors?
Competitive inhibitors
Non-competitive inhibitors
Feedback inhibition or (end product inhibition)
40
What is a competitive inhibitor?
- Competes with the substrate molecule for the active site.
- Similar shape to substrate
- rate of reaction to be slower; as the concentration of substrate increases, so does the rate of reaction
41
What is a non-competitive inhibitor?
Binds to another part of the enzyme, altering the shape of the active site
42
What is feedback inhibition (end product inhibition)
If the end product of a final reaction in a metabolic pathway builds up, it may bind to the active site or another part of the 1st enzyme. The active site is altered and the pathway stops.
43
What does feedback inhibition prevent?
Prevents too much end product being produced.
44
What are the 3 stages of cellular respiration?
- Glycolysis
- Citric acid cycle
- Electron transfer
45
What is the ATP released in respiration used for?
Active transport, DNA Replication, protein synthesis, cell division and contraction of muscle fibres
46
What is the word equation for respiration?
Glucose + oxygen = carbon dioxide + water + ATP
47
What can Pyruvate be broken down into during Fermentation?
Lactate (3C) or ethanol (2C) + CO2 (1C)
48
What happens when Glucose is broken down?
Hydrogen ions and electrons are removed
| energy is released
49
What removes hydrogen ions and high-energy electrons?
Dehydrogenase enzymes
50
What is Phosphorylation?
An enzyme-catalysed chemical reaction that attaches a phosphate group to another
51
Where does Glycolysis occur?
In the cytoplasm
52
What are the two stages of Glycolysis?
- Energy investment stage
| - Energy pay-off stage
53
What happens during the 1st stage of Glycolysis?
Glucose turns into an intermediate
| 2ATP -> 2ADP + Pi
54
What happens during the 2nd stage of Glycolysis?
The intermediate turns into 2x Pyruvate
4ADP + Pi -> 4ATP
2NAD -> 2NADH
55
What happens if oxygen is present during Glycolysis?
Pyruvate enters the second stage; the citric acid cycle then electron transfer stage
56
Where does the citric acid cycle take place?
Matrix of the mitochondria
57
Benefit of a folded inner membrane?
increases the surface area so more of the electron transport chain molecules can fit in
58
What is the main site of ATP synthesis
Mitochondria
59
What helps maintain high reaction rates?
Accumulation of reactants
60
What is needed for the citric acid cycle to occur?
Oxygen
61
What is Pyruvate broken down into?
Carbon dioxide and an acetyl group
62
What does the acetyl group combine with? and what does it form?
Combines with Coenzyme A to produce: Acetyl Coenzyme A
63
What does Acetyl Coenzyme A join with when entering the cycle? and what does the form?
```
Oxaloacetate (4C)
Forms Citrate (6C)
```
64
Name another Hydrogen carrier present in the citric acid cycle?
FAD -> FADH2
65
What happens when electrons are passed down the electron transfer chain?
Energy is released
66
What is the energy used for during the Electron Transfer chain?
Used to pump hydrogen ions from the mitochondrial matrix to the inner membrane space
67
How to hydrogen ions return to the matrix?
Through a channel in the enzyme ATP synthase
68
What is needed for the electron transfer chain?
Oxygen
69
What does the Electron transfer chain produce?
The most ATP molecules
70
What releases the high energy electrons?
NADH and FADH2
71
What is oxygen described as during the Electron transfer chain?
The final electron acceptor
72
What is the word equation for the Electron transfer chain?
Low energy electrons + hydrongen ion + oxygen = Water
| e- + 2H+ + 1/2 O2 = H2O
73
How many molecules of ATP does the electron transfer chain generate?
34 molecules
74
What is the total amount of ATP molecules from respiration?
38 ATP
75
What can be broken down to make Glucose, used in respiration?
Starch
| Glycogen
76
What other sugars can be converted into Glucose or other intermediates?
Sucrose, Lactose and Maltose
77
What can be used as alternative respiratory substrates in respiration?
Fats and proteins
78
What can fat molecules be broken down into? and what are they converted into?
Glycerol - an intermediate
| Fatty acids - Acetyl Coenzyme A
79
What are proteins digested into? and what are they converted into?
Amino acids - Pyruvate, Acetyl Coenzyme A and intermediates in the citric acid cycle
80
What piece of apparatus measures oxygen consumption?
Respirometer measures oxygen uptake over a period of time
81
What is used to measure metabolic rate (apparatus)
Calorimeter
82
How can metabolic rate be measured?
Monitoring an animals heat loss
83
In unicellular organisms, how to exchanges occur? (oxygen delivery)
Directly with the external environment
84
In which type of organisms are closed circulatory systems found?
All vertebrates and few invertebrates
85
What is an advantage about closed circulatory systems?
Blood is carried at high pressure which enables efficient delivery of O2 and nutrients to the cells of larger and more active animals
86
Features of arteries :
- carry blood away from the heart
- High pressured blood
- thick muscular walls; withstand the pressure
- narrow central lumen
87
Features of Veins :
- Carry blood back to the heart
- lower pressure
- Valves prevent backflow of blood
- thinner muscular walls
- Larger central lumen
88
Features of capillaries :
- Walls are only one cell thick
| - Across the thin walls; the exchange of dissolved gases and other chemicals occur
89
Single circulatory system:
A fish
Two chambers
Blood only passes through the heart once
90
Disadvantages of a single circulatory system
reduces pressure so limits the rate that the blood can flow
91
Features of double circulatory systems:
- Birds and mammals
- 2 atria and 2 ventricle
- no mixing of blood
- oxygen rich blood and oxygen poor blood
- blood passes through the heart twice
92
Features of incomplete circulatory systems:
Frogs and other amphibians
- 3 chambers [ 2 atria and 1 ventricle ]
- mixing of blood
93
What is the metabolic rate of a fish?
Low
94
What is the metabolic rate of a Reptile and an Amphibian?
Low
95
What is the metabolic rate of a bird?
High
96
What is the metabolic rate of a mammal?
Very high
97
What are the 2 types of lungs ?
```
Alveolar lungs (mammals)
Septate lungs (one giant alveolus)
```
98
When is gas exchange fast?
When the area for diffusion is large and the path for diffusion is short
99
Lung arrangement in Amphibians:
- Diffusion of gases across its external body surface
- Skin has a dense network of capillaries
- Diffusion takes place directly through the skin as blood vessels are close to the permeable skin
100
Internal anatomy of snakes?
They reply on muscles used in locomotion to ventilate their lungs
101
What does a Trachea do?
Splits into the two primary bronchi airways that direct air into either the left or right lung.
102
What kind of lungs do snakes have?
Septate
103
How many airsacs do Birds have and what do they act as?
8 or 9
| They act as "bellows" to keep air flowing through the lungs
104
In birds, what is the site of gas exchange called?
Tiny channels called parabronchi
105
What is unusual about the passage of air in birds? and what does that improve?
requires 2 cycles of inhalation and exhalation
| - Improves efficiency of ventilation and provides the bird with high levels of O2.
106
What are the 2 airsacs called in birds?
Posterior
| Anterior
107
How do animals transport most of their oxygen?
Bound to proteins called respiratory pigments
108
What happens if the tissues don't receive enough oxygen? (high altitudes)
The kidneys synthesise and secrete the hormone erythropoietin (EPO) that stimulates the generation of more erythrocytes (red blood cells)
109
What is TheVO2 max?
The volume of oxygen used by the person, per kilogram of body mass, per minute.
110
"the higher the value for VO2 max..."
the greater the aerobic fitness for that individual
111
What are organisms affected by?
Abiotic factors such as pH, water salinity or temperatures
112
What happens if an organism is not living in its optimal abiotic conditions?
The population density is lower
113
What are abiotic factors a major factor in determining?
The distribution of a species
114
What is a Conformer?
Allows its internal conditions to change in accordance with changes in the variable
115
What is a Regulator?
Uses internal mechanisms to control internal changes in the face of external fluctuations.
116
What are Regulators able to alter?
Their normal metabolic rate by employing physiological means
117
What is Tolerance?
If the change of the conditions is small, the conformer is still able to function
118
How is a Conformers ability to control internal environment by physiological means?
Limited
119
How is a Regulators ability to control internal environment by physiological means?
Efficient
120
What do conformers have in terms of ecological niches that can be exploited?
Narrow range
121
What do Regulators have in terms of ecological niches that can be exploited?
Wider range
122
What strategy to conformers have?
Behavioural
123
What strategy do regulators have?
Physiological
124
What is Negative Feedback control?
A principle which brings about Regulation.
| Corrective mechanisms are switched on and effector organs respond.
125
What does Negative Feedback control require?
Energy
126
What can body temperatures outside the normal range do?
Can reduce the efficiency of enzymatic reactions and alter the fluidity of cellular membranes with potentially fatal results
127
What happens when there is a DECREASE in body temperature?
- Shivering
- increased metabolic rate
- sweating decreases
- vasoconstriction
- hair erector muscles contract
128
What detects that their is an increase/decrease in body temperatures?
Thermoreceptors in the hypothalamus (skin)
129
What happens when there is an INCREASE in body temperature?
- decreased metabolic rate
- sweating increases
- vasodilation
- hair erector muscles relax
130
What is the role of the hypothalamus?
Sending appropriate nerve impulses to the effector organs
131
What is the role of the skin?
leading role in temperature regulation
132
What is Vasodilation?
When arterioles leading to the skin become dilated, which increases the volume of blood at the skin surface and as a result; heat lost by radiation increases
133
What is Vasoconstriction?
When arterioles leading to the skin become constricted. This limits the volume of blood at the surface of the skin and therefore less heat lost through radiation
134
What features do Ectotherms have?
- Gain most of their heat from external sources
- unable to regulate its body temperature
- have behavioural means
- lower metabolic rates
135
What features do Endotherms have?
- warmed mostly by heat generated by metabolism
- steady body temperature
- high metabolic rates
136
What are all metabolic processes within an organism controlled by?
Enzymes
137
Within enzyme activity, what happens to reactant molecules when temperatures rises?
Have more and more kinetic energy , which increases the chances of successful collisions and this increases the rate of reaction
138
What happens to enzymes when temperature goes above 37 degrees?
Enzyme structure begins to denature as bonds break and the active site changes.
139
What are diffusion rates?
The rate of diffusion of a substance is directly proportional to the temperature.
140
What happens to molecules of a substance at high temperatures?
Have greater kinetic energy and therefore diffuse at a faster rate
141
Reduction in metabolic rate
The mechanism involves some reduction of the metabolic rate to minimise the energy expenditure
142
What is dormancy?
When an organisms metabolism is reduced to promote survival during adverse conditions
143
What are the 2 types of Dormancy?
Predictive or consequential
144
What is predictive dormancy?
a regular pattern, before the onset of the adverse conditions
145
What is consequential Dormancy?
less predictable habitats, enter a period of dormancy in response to the arrival of the adverse condition
146
What is Torpor?
A period of reduced activity in organisms with high metabolic rates. They save energy while avoiding difficult and dangerous conditions
147
What happens to the organism during Torpor?
A short time energy saving response
breathing and heart rate decreases
body temperature falls
oxygen consumption is lowered
148
What is Hibernation?
An extended period of torpor; an adaptation to cold winter conditions and food scarcity
149
What happens to the organism during Hibernation?
- body temperature drops and its internal "thermostat" is turned down
- breathing rate falls
- heart rate is lowered
- oxygen consumption decreases as metabolic rate drops
150
What is Aestivation?
Response to the onset of very hot and dry conditions
151
What happens to the organism during Aestivation?
- Metabolic rate drops
- heart rate drops/stops
- breathing rate stops
152
What is Migration?
A regular, long distance change in location which is to avoid metabolic adversity
153
Advantages of migration include:
- Access to more favourable feeding opportunities
- avoidance of extreme of temperatures
- better breeding grounds with fewer predators
154
What are the factors which trigger migration?
Decreased number of daylight hours, temperature, changes in food availability and genetic factors
155
What provides signals that guide migration?
Environmental stimuli
156
What is Photoperiod?
The length of time that is in daylight; primary trigger to migration
157
What does increasing photoperiod do?
Stimulates the production of hormones and other physiological changes that prepare a bird for migration
158
Name techniques used for observing and tracking migratory behaviour.
- Tagging and ringing (metal bands)
- satellite tracking (waves)
- Radar (pulses of electromagnetic waves)
159
What is innate behaviour?
When it will be observed by all individuals in a population; fixed, flexible and inherited
160
What is learned behaviour?
Acquired or modified as a result of the specific experiences of an individual.
Vary between members of the same species
161
What are extremophiles?
Organisms that can live in environments so extreme that to most other organisms, the conditions would be fatal.
162
What "extremes" can extremophiles thrive in?
extremes of temperatures, high sulphur and salt levels and complete absence of oxygen
163
What is an example of an extremophile?
Thermophilic bacteria living in hot springs or seabed vents may generate ATP by removing high energy electrons from inorganic molecules.
164
What are the 3 domains of life?
Archaea
Bacteria
Eukaryotes `
165
What is another name for microorganisms?
Microbes
166
Microorganisms are said to be:
Highly adaptable and able to make use of a wide variety of substances for their metabolism
167
Where are microorganisms found?
A wide range of ecological niches
168
What must every organism obtain?
all of the substances required for energy generation and cellular biosynthesis from its environment
169
What is bacteria grown in?
Culture medium
170
What are the chemicals and elements that are used for bacterial growth?
Nutrients or nutritional requirements
171
What do microorganisms require?
An energy source which may be chemical or light.
172
What other requirements might some microorganisms need?
A supply of raw materials to produce cellular building blocks such as amino acids and nucleotides.
173
What specific complex molecules might some microorganisms need?
Fatty acids or certain vitamins to be present in their growth medium
174
In the growth of a microorganism, what are the correct ranges of physical conditions required?
Oxygen concentration, temperature and pH
175
What are microorganisms normally grown in?
Liquid medium (broth) or on a solid medium (agar jelly)
176
What is the growth medium contain within?
Petri dishes, flasks or bottles
177
Industrially, what are microorganisms cultured in?
Industrial fermenters (bioreactor)
178
What are the features of an Industrial fermenter?
- Water jacket
- Filter
- Thermostatic control
- Air inlet
- Paddle
179
What is the function of the Water jacket?
Maintains temperature by continual stream of cold water
180
What is the function of the Filter
Maintains sterility by filtering out air-borne microorganisms
181
What is the function of the Thermostatic control?
Controls temperature of cold water in jacket
182
What is the function of the air-inlet?
Controls oxygen levels; providing steam of air
183
What is the function of the paddle?
mixes culture and growth medium
184
What optimum environmental conditions must be maintained to produce the maximum yield of a product?
- sterility
- suitable temperature
- oxygen levels
- pH
185
What is sterility?
The growth of unwanted microorganisms is prevented using aseptic techniques
186
Examples of sterility:
all equipment and culture media; by heating under pressure in an autoclave or in large industrial fermenter vessels, steam cleaned
187
What are the 4 stages in growth of unicellular organisms?
- lag phase
- exponential (log) phases
- stationary phase
- death phases
188
What happens during the lag phase?
There is little or no increase in cell number; enzymes are induced
189
What happens during the exponential phase?
Cells grow and multiply at the maximum rate
190
The exponential growth takes place due to what?
high availability of substrate and conditions which are close to optimal.
191
What happens during the stationary phase?
The number of cells produced by binary fission is equal to the number of cells dying so the growth rate is 0.
Cells produce secondary metabolites
192
What is the stationary phase due to?
the nutrients in the culture medium being depleted
193
What happens during the death phase?
number of cells dying is greater than the number of new cells dividing
194
What is the death phase due to?
The lack of substrates and toxic accumulation of metabolites
195
What is mean generation time (doubling time)?
The time taken for a cell to divide into 2
196
What does a total cell count involve?
counting all cells present in the sample whether alive or dead
197
What does a viable cell count involve?
counting only the number of cells which are alive and able to grow
198
What are primary metabolites?
compounds related to the synthesis of microbial cells and are produced in the active growth phase (exponential)
199
What do primary metabolites include?
amino acids and nucleotides
200
What are secondary metabolites?
population is in the stationary growth phase and are of economic value.
201
What is a precursor?
large quantities of an early metabolite
202
What is an inducer ?
Induced the formation of certain key enzymes
203
What is an inhibitor?
Reduces or stops the activity of an enzyme
204
How can the wild strain of microorganisms be improved?
- Mutagenesis
- Selective breeding and culture
- Recombinant DNA
205
What is Mutagenesis?
a process which changes the genetic information of an organism and results in a mutation
206
What is selective breeding and culture?
individual strains of microorganisms each with desirable characteristics are selected and allowed to breed
207
What are 2 examples of desirable characteristics?
rapid growth and genetic stability
208
Transfer of DNA is always what?
one way
209
What is horizontal gene transfer?
when some bacteria can transfer plasmids or pieces of chromosomal DNA to each other to produce new strains
210
What happens when bacteria dies?
Their DNA may be released into the environment
211
What is recombinant?
When a different cell now contains DNA fro from two different cells combined
212
What is one aim of recombinant DNA technology?
to obtain many copies of a particular gene; by marking transgenic bacteria or yeast cells containing the desired gene
213
what does recombinant DNA technology enable?
transfer gene sequences from one organism to another
214
What is a safety mechanism of genes being introduced?
to prevent the microorganisms from surviving in an external environment
215
What does restriction endonuclease do?
cuts the DNA into smaller fragments
216
What 3 features does a plasmid have?
- restriction site
- origin of replication
- marker gene(s)
217
What is a restriction site?
a specific sequence of bases on the plasmid's DNA
218
What can the restriction endonuclease produce?
Sticky ends
219
What is the origin of replication?
the one point where DNA synthesis always begins.
220
What does the origin of replication contain?
genes that control its self-replication
221
What is important about the origin of replication?
the one point where DNA synthesis always begins.
222
What is the function of the marker gene?
enables the scientist to determine whether a host cell has taken up the recombinant plasmid or not.
223
What do plasmids act as?
Vectors
224
What can plasmids be used for?
to transfer a section of DNA from one organism to another
225
What does a plasmid have? (4)
- only one origin of replication
- multiple regulatory sequences
- two or more genes with particular properties such as resistance
- only one restriction site
226
What is ligase used for?
to seal the open plasmid
227
advantage of artificial chromosomes:
can carry far more foreign DNA than a plasmid.
228
What is a consequence of bacteria not containing introns?
the desired protein may be incorrectly folded or lack post-translational modifications.
229
Why are safety procedures put in place?
to limit the occurrence of any potential hazards.
230
What do aseptic techniques include?
- use of sterile equipment
- sterilising working areas
- thoroughly washing hands before and after all procedures
231
Definition of ethics
the moral principles governing or influencing conduct.
232
Examples of microorganisms made from microorganisms that could be used as a biological weapon:
- anthrax
- smallpox
- ricin
