Unit 2 - Metabolism & Survival Flashcards
(175 cards)
1
Q
metabolism
A
all the chemical reactions taking place within a cell
2
Q
metabolic pathways
A
most chemical reactions occur as part of integrated and interconnected pathways, catalysed by enzymes
3
Q
catabolic pathways
A
is a degradation reaction that releases energy
4
Q
anabolic pathways
A
bio-synthesis reaction that uses energy
5
Q
catabolic and anabolic reactions are usually closely ______________ and therefore often rely on one another
A
integrated
6
Q
___ acts as an important means of energy transfer between reactions
A
ATP
7
Q
most metabolic pathways have both ___________ ____ ______________ steps
A
reversible and irreversible
8
Q
what does the irreversible conversion of glucose to intermediate 1 mean?
A
this allows a concentration gradient to be maintained which promotes the diffusion of glucose into the cell
9
Q
what does the reversible conversion of intermediate 1 to intermediate 2 mean?
A
if there is more of intermediate 2 made that the body requires it can be converted back into intermediate 1 and be used in an alternative pathway
10
Q
alternative pathways
A
are pathways that exists through substances that allow certain stages controlled by enzymes to be bypassed
11
Q
the cell membrane
A
separates the intracellular environment from the extracellular environment
12
Q
the cell membrane ___________ the flow of materials into and out of the cell
A
regulates
13
Q
Two examples of organelle bounded by double membrane
A
Mitochondria and chloroplasts, inner membrane acts as highly metabolic membrane surfaces
14
Q
molecular transport
A
proteins embedded in membranes allow various functions to be carried out
15
Q
protein pores
A
transport molecule that contains pores, the provide channels for specific substances to diffuse across membrane
16
Q
active transport
A
the movement of molecules and ions across the cell membrane from a low to high concentration, against concentration gradient
17
Q
enzymes in membrane
A
some protein molecules are embedded in membrane of phospholipids, enzymes catalyse the steps in a metabolic process essential to cell
18
Q
protein pores allow ___________ diffusion
A
selective
19
Q
pumps allow __________ _____________
A
active transport
20
Q
enzymes in membrane __________ reactions
A
catalyse
21
Q
smaller compartments have __________ volume to surface area ratio
A
larger
22
Q
high surface area of membranes allows:
A
the high concentration of substances to be maintained and faster reaction rates to be achieved
23
Q
how does high surface area of membranes allow high concentration of substances to be maintained?
A
as they are involved in the active transport of substances
24
Q
how does high surface area of membranes allow faster reactions rates to be achieved?
A
as they can provide surfaces for metabolic reactions
25
enzymes ________ the activation energy and by doing so increase the reaction rate
lower
26
affinity
an attraction or force between particles that cause them to combine
27
the substrate binds readily to the enzyme because it has ________ ___________ for the active site
high affinity
28
the product is released because it has a _____ __________ for the active site
low affinity
29
induced fit of enzymes
when the active site changes shape to create a tighter fit around substrate, returns to original shape after product is released
30
ways of increasing rate of enzyme activity
changing temperature towards optimum, changing pH towards optimum, increasing substrate concentration
31
ways of decreasing substrate concentration
changing temperature away from optimum, changing pH away from optimum, decreasing substrate concentration, use of an inhibitor
32
why does the reaction rate increase as the substrate concentration increases?
because more of the available active sites can become occupied by substrate molecule
33
when does the reaction rate become constant
when the concentration is reached whereby all active sites are occupied
34
in a metabolic pathway the product of each enzyme reaction is the ___________ for the next
substrate
35
the direction in which the reaction proceeds at any given time depends on the _____________ ___ _________ and product present
concentration of substrate
36
metabolic pathways can be controlled by ______________ _______ __________________ signalling molecules
intracellular and extracellular
37
to control a metabolic pathway the rate of ____________ __________ must be controlled
enzyme action
38
non-competitive inhibitor
completely changes the active site so no matter how much you increase substrate concentration it wont increase enzyme activity
39
competitive inhibitor
slowly the substrates out compete the inhibitor so it will increase to same end point as having no inhibitor but slower
40
competitive inhibitors bind on the _______ _____ of the enzyme
active site
41
structure of ATP
composed of one molecule of adenosine bonded to three molecules of inorganic phosphate
42
importance of ATP
it is the link between catabolic and anabolic reactions, it also provides energy for other cellular processes e.g. active transport
43
what is phosphorylation?
the addition of a phosphate group to a molecule
44
what is an example of phosphorylation?
the regeneration of ATP
45
phosphorylation is a common mechanism used to __________ __ _________ proteins within a cell
activate or deactivate
46
the phosphate from phosphorylation can be supplied by the breakdown of _____
ATP
47
cellular respiration
a series of metabolic pathways which brings about the release of energy which is stored as ATP
48
dehydrogenase enzymes
are involved in glycolysis and the citric acid cycle, they remove H+ ions and electrons from compounds
49
what happens to the H+ ions and electrons after they are removed by dehydrogenase enzymes?
then passed to coenzymes NAD or FAD
50
what are the H+ ions and electrons used for?
to generate ATP during ATP synthesis
51
first stage of respiration
glycolysis
52
second stage of respiration
the citric acid cycle
53
third stage of respiration
the electron transport chain (ETC) and ATP synthesis
54
what happens during glycolysis?
occurs in cytoplasm, intermediates are phosphorylated before ATP is generated, NET gain of 2ATP, NADH generated
55
what happens during the citric acid cycle?
occurs in the matrix of the mitochondria, acetyl coenzyme A combines with oxaloacetate, citrate is formed, H+ ions and electrons are accepted by NAD and FAD, 2ATP and CO2 is generated
56
what happens during the electron transport chain and ATP synthesis?
receives H+ ions and electrons from coenzymes NAD and FAD
57
what are the two stages of glycolysis?
energy investment phase, energy payoff phase
58
what happens in energy investment phase?
the intermediates are phosphorylated and 2 molecules of ATP are used to provide phosphates for the phosphorylation
59
what happens in the energy payoff phase?
4 molecules of ATP are produced and the hydrogen ions and electrons are released and accepted by NAD
60
what happens during breakdown of pyruvate?
pyruvate is broken down into an acetyl group and carbon dioxide, the acetyl group combines with a molecule of coenzyme A and produces acetyl coenzyme A, more hydrogen ion and electrons are released and accepted by NAD
61
what happens to the carbon dioxide from the breakdown of pyruvate?
it is released as a by product
62
where does the electron transport chain occur?
inner membrane of the mitochondria
63
what do the NADH and FADH2 also release doing ETC?
high energy electrons which provide energy for the active transport of H+ ions across the membrane
64
what happens to the electrons after they come out of ETC?
they combine with oxygen, the final electron acceptor, and at the same time oxygen combines with a pair of hydrogen ions to form water
65
what happens during ATP synthesis?
hydrogen ions that have been pumped across membrane diffuse back into the matrix of the mitochondria through protein ATP synthase causing part of protein to spin, enzyme ATP synthase is able to catalase regeneration of ATP from ADP+Pi
66
what happens if oxygen is absent, for animals?
the pyruvate is converted into lactate (lactic acid)
67
what happens if oxygen is absent, for plants and yeast ?
the pyruvate is converted into ethanol and carbon dioxide
68
metabolic rate
the energy consumed by an organism per unit time
69
how can energy consumption be measured indirectly?
rate of oxygen consumption, rate of carbon dioxide production, rate of heat production
70
respirometer
measures changes to air being pumped through a sealed chamber for example oxygen and carbon dioxide content and temperature
71
calorimeter
measures temperature change of water being passed through a sealed chamber
72
_______ metabolic rates require efficient delivery of oxygen to cells
high
73
circulatory system of fish
have a single circulatory system, one atrium on ventricle. The blood is delivered at high pressure to the gills after being pumped from the heart but is at low pressure by the time it reaches the body
74
circulatory system of amphibians and reptiles
have an incomplete double circulatory system. 2 atriums and one ventricle. some mixing of oxygenated blood from the lungs and deoxygenated blood from body occurs in the ventricle, tissue blood in incompletely oxygenated
75
circulatory system of mammals and birds
have a complete double circulatory system. 2 atriums and ventricles completely separated by a septum
76
which is the most efficient circulatory system?
mammals and birds, it enables an endothermic (warm blooded) vertebrate to deliver large quantities of oxygen to respiring tissues which release heat during metabolism and keep its body warm
77
organism will be either one of two categories, conformers or ___________
regulators
78
conformers
cannot alter their metabolic rate and conform to the condition in the environment, their internal environment is dependent upon the external environment
79
regulators
alter their metabolic rate to maintain a steady state, they regulate their internal environment
80
conformers have low __________ _____ as they do not expend energy maintaining their internal environment
metabolic cost
81
where must conformers live?
in stable environments as they are less adaptable
82
how can conformers maintain an optical metabolic rate?
using behavioural responses, for example lizards sunbathe to control body temperature
83
conformers have a _________ ecological niche
narrow
84
regulators occupy a vast range of __________ _______
ecological niches
85
example of a conformer
spider crab, pros are that it doesn't need much energy, cons are that it is unable to osmoregulate and dies in water that is less salty that sea water
86
example of a regulator
shore crab, pros are that animal is able to osmoregualte and survive in estuaries which is less salty than sea water, cons are that it has to find more food to provide energy expended during osmoregulation
87
to maintain homeostasis, organisms require ____________ ______________
negative feedback
88
Negative feedback
System of maintaining homeostasis in a regulator organism
89
thermoregulation
Use of negative feedback in regulation of body temperature in mammals. Either ectotherms or endotherms
90
ectotherms
are unable to regulate body temperature
91
examples of ectotherms
fish, amphibians and reptiles
92
endotherms
are able to regulate body temperature, maintain temperature in the best range for enzyme controlled reactions and optimises diffusion rates
93
examples of endotherms
mammals and birds
94
how the hypothalamus controls temperature?
the skin has thermo receptors that detect changes in the temperature, nerve impulses sent to the hypothalamus relaying this information, the hypothalamus also contains thermo, hypothalamus sends out nerve impulses to effectors to return body temp to normal levels receptors
95
the two main mechanisms employed by the skin to regulate body temperature in a mammal
vasodilation, vasoconstriction
96
vasodilation
the blood vessels that supply blood to the skin dilate (widen), increasing the amount of blood flowing to the skin. this increases the surface area from which heat can be lost to environment by radiation
97
vasoconstriction
Blood vessels supplying blood to the skin constrict ( narrow) reducing the amount of blood flowing to the skin. as a result less heat is lost by radiation from the surface of the body
98
how else does the body cool down?
sweat glands in the skin secrete sweat which cools the body down when it evaporates from the skin, decreasing metabolic rate as it reduces the amount of heat energy produced
99
how else does the body warm up?
less sweat is produced to conserve heat, shivering warms the body up, as does increasing the rate of metabolism (generates more heat energy)
100
dormancy
a period of suspended growth and development in response by the organism to tolerate adverse conditions
101
predictive dormancy
when an organism becomes dormant before the arrival of the adverse conditions
102
example of predictive dormancy
many trees respond to decreasing day length and temperatures by shedding leaves and entering dormancy
103
consequential dormancy
when an organism becomes dormant after the arrival of the adverse condition
104
example of consequential dormancy
snails enter dormancy during extremely dry periods
105
hibernation can be consequential or ________________
predictive
106
what does hibernation allow animals (usually mammals) to survive?
adverse cold conditions
107
what happens during hibernation?
the animals metabolic rate drops with a resulting decrease in body temperature, heart rate and breathing rate
108
the bare minimum of energy is used during hibernation for what?
to maintain vital cellular activities using fat stores built over the summer
109
example of an animal that hibernates
hedgehogs
110
aestivation is an example of ________________ dormancy
consequential
111
what does aestivation allows animals to survive?
periods of excessive drought or heat during the summer
112
two examples of animals that go through aestivation
crocodiles and land snails
113
daily torpor
a period of reduced activity and metabolism in organisms as part of a 24 hour cycle. additional decrease in breathing rate, body temperature and heart rate
114
torpor decreases the rate of ___________ _________________ at a time when searching for food would likely be unsuccessful or risk of predation is too high
energy consumption
115
what kind of animals is daily torpor often found in?
organisms with high metabolic rate
116
example of animal that goes through torpor
bats are torpid during the day and feed at night
117
migration
is the regular movement by the members of a species from one place to another over a relatively long distance
118
migration avoids ______________ __________ caused by shortage of food and low temperatures by expanding energy to relocate to a more suitable environment
metabolic adversity
119
what does long distance migration normally involve?
an annual round trip between two regions that both provide favourable condition for each part of the year
120
when studying long distance migration what do biologists want to find out?
when the animal migrated, where they overwintered,whether or not they returned to their original summer territory, how long they lived for
121
specialised techniques for studying migration
ringing with metal bands, tagging, colour marking, tracking using transmitters
122
ringing with metal bands
a metal band carrying a birds individual identification number is attached to birds leg. of the bird is recaptured then its information can be recorded
123
tagging
a small circular tag is attached to the hind wing of a monarch butterfly. this carries a code entered in a database. if the tag is recovered at a later date, the route and distance covered by the butterfly can be determined
124
colour marking
the use of bright coloured marks ( and flags on larger birds) has allowed biologists to observe the birds with binoculars without needing to recapture them
125
tracking using transmitters
lightweight transmitters are glued to the animals body or implanted under its skin. the transmitter emits signals that are picked up by satellites, signals are beamed back to ground stations
126
advantage of tracking using transmitters
they provide the most accurate information so far on the exact locations of flyways used by birds during their migratory cycle
127
disadvantage of tracking using transmitters
are expensive and may have a drag effect on some small birds
128
inate behaviour
is inherited and inflexible. this pattern of behaviour is performed in the same way by every member of the species
129
learned behaviour
begins after birth and is gained by experience. it is flexible and occurs as a result of trial and error and the transmission of knowledge and skills among the members of a social group
130
what are considered microorganisms?
archaea, bacteria and some species of eukaryotes
131
in general why are microorganisms used?
because of their adaptability, ease of cultivation and speed of growth
132
microorganisms include species that can sue a wide variety of substances for metabolism and produce a range of __________ from their metabolic pathways
products
133
why microorganisms are useful?
they are easy to cultivate, they reproduce and grow quickly, their food substrate is often A cheap substance (or even A waste product from another source ), they produce many different useful products, their metabolism can be manipulated relatively easily
134
microorganisms are normally grown under controlled conditions in a laboratory, they can be grown in two ways:
in a growth medium called broth jar, on a solid medium called agar jelly
135
all processes will provide the following growth requirements:
energy source ( chemical or light), simple chemical compounds, suitable environmental condtions
136
why must simple chemical compounds be provided?
microorganisms being grown in culture must be provided with this for the biosynthesis of more complex molecules
137
some microorganisms can synthesis all the ____________ ________ e.g. amino acids they require if provided with simple chemical compounds
complex molecules
138
other microorganisms must be provided with complex compounds as they are unable to synthesis, such as _______ ______ and ____________
fatty acids and vitamins
139
sulphur is a chemical requirement, where can it be sourced and why is it needed?
can be sourced from a compound containing sulphate group. it is needed for the synthesis of some amino acids
140
factors that need to be controlled:
sterility (eliminate contaminants), temperature, concentration of oxygen, pH, glucose concentration
141
what does using a fermenter allow?
a variety of environmental conditions to be monitored and controlled. this is done by computers when industrial sized fermenters are used
142
generation time
the time required for a population of unicellular organism to double in number
143
why does the pattern of growth of a population of microorganisms change over time?
nutrients provided are used up, metabolites produced by the microorganisms being secreted (released outside the cell)
144
growth of microorganism (phases of growth)
lag phase, log/exponential phase, stationary phase, death phase
145
lag phase
little to no increase in cell numbers. the cells are adjusting to growth medium and show increased metabolic activity, they are making substrates and turning on enzymes. flat line
146
the enzymes may need to be ________ in the lag phase for use in metabolising the new substrates
induced
147
log/exponential phase
the cells grow and multiply as maximum rate, providing there is no limiting factor. steep incline line
148
stationary phase
nutrients begin to run out and/or secondary metabolites produced by the microbe start to build up. at this point the rate of production of new cells is equal to the rate of death of old cells. line is level.
149
what happens when there is a build up of secondary metabolites?
it can have a toxic effect and causes rate of cell division to decrease
150
death phase
the lack of nutrient substrate and/or the accumulation of high concentration of toxic metabolites leads to death phase. number of cells dying now exceeds the number of new cells being produced. steep decline
151
total cell count
the number of cells in a culture
152
viable cell count
the number of living cells in a culture
153
secondary metabolites
substances produced which are not associated with growth but can confer an ecological advantage
154
example of secondary metabolite
penicillin, antibiotic stops fungi from getting infected
155
wild strains (wild type)
the phenotype of a species as it occurs in nature
156
one way wild strains be improved?
selecting particular strains by repeatedly subculturing those with the most desirable characteristics.
157
increase _____________ (mutation rate) using mutagenic agents such as UV, radiation and mutagenic chemicals also improves wild strains
mutagenesis
158
another way to improve wild strains is by genetic modification using ______________ _____ _____________
recombinant DNA technology
159
what is recombinant DNA?
DNA created artificially
160
genetic alteration of bacteria
plasmids and chromosomal DNA can be transferred between cells or taken up from the environment
161
restriction endonuclease
an enzyme extracted from bacteria which is used to cut up the DNA into fragments
162
selection markers
can be fluorescent proteins or genes for antibiotic resistance, scientists can select the cells that are for example glowing green and know they also contain gene of interest
163
restriction site
a site that is cut open by restriction enzymes to allow the gene to be transferred or be inserted
164
sticky end
a specific short sequence of DNA bases that is cut by restriction enzyme
165
vector
recombinant plasmids and artificial chromosomes are used as these to carry DNA between organisms
166
marker genes
a gene that is used by scientists to identify if recombinant DNA has been taken up into cells
167
regulatory sequences
a sequence of DNA that controls the expression of a gene
168
origin of replication
the site on a plasmid that allows it to control its own replication (self- replication)
169
artificial chromosomes
DNA that has been created artificially that allows for longer sequences of DNA to be transferred between organisms
170
ligase
combines complementary sticky ends on the vector with the target sequence e.g. seals the gene into the plasmid
171
what is a limitation of using eukaryotic animal/plant recombinant DNA in prokaryotic cells?
when the eukaryotic gene is expressed in the prokaryotic cells the required polypeptide may fold incorrectly or may lack post translational
172
how can limitations be reduced?
by using recombinant eukaryotic yeast cells instead of bacteria
173
sometimes genes that improve the ______________ of the organism can be inserted
function
174
genes can also be added that prevent the __________ of the microorganisms in an extern environment (outside of the lab)
survival
175
feedback inhibition
when an end product inhibits the activity of an enzyme that catalysed a reaction earlier in the pathway that produced it
