metabolism for survival Flashcards
(151 cards)
1
Q
what makes up the metabolism of a cell
A
metabolic pathways
1
Q
what are metabolic pathways
A
chains of different enzyme-catalysed biochemical reactions
1
Q
what controls metabolic pathways
A
primarily the cell, also enzymes controll each step of a metabolic pathways with an enzyme present between each metabolite
2
Q
what is a reversible step (metabolic pathways)
A
when metabolite ‘x’ can be converted to ‘y’ and back to ‘x’ again with the possibility of being used in another pathway
2
Q
what does an irreversible step result in (metabolic pathways)
A
one metabolite being fully converted to another woth no alternative pathway available
3
Q
what are alternative routes
A
specific steps in a pathway can be bypassed using an alternative route or ‘short cut’ so for example, metabolite A is converted directly to C
4
Q
what does ‘put out the cat’ mean and relate to
A
catabolic reactions let energy out
5
Q
Anabolic reactions …
A
make or synthesise new molecules
require energy in the form ATP
e.g. building upr protein molecules from amino acids
6
Q
Catabolic reactions …
A
break down larger complex molecules into their subunits
relesase energy in the form ATP
e.g. cell respiraton involves breakdown of glucose with oxygen tow form ATP, CO2 and water
7
Q
what is an integrated metabolic pathway
A
when anabolic and catabolic reactions become interdependant
8
Q
what are the 2 types of membrane proteins
A
protein pores and protein pumps
9
Q
what is a protein pore
A
channels in large protein molecules which span the plasma membrane
10
Q
what does a protein pore do
A
it acts as a gateway for large molecules to pass through the plasma membrain of a protein by diffusion
11
Q
what is a protein pump
A
a carrier protein on the plasma membrane
12
Q
what do protein pumps do
A
move molecules and ions across the membrane from a low concentration to a high concentration (opposite of diffusion). This is an active process
13
Q
what is active transport/and active process
A
the biological process in which molecules move against the concentration gradient and require chemical energy to move biochemical compounds from a lower region to the high region
14
Q
what is needed to maintain cellular metabolism
A
optimal enzyme activity and high diffusion rates
15
Q
state one method of molecular transport which involved a carrier protein
A
active transport
16
Q
what is the transition state
A
when the reactants have reached a threshold energy level (before the reaction proceeds to form products)
17
Q
what do enzymes do
A
lower activation energy speeding up a reaction
18
Q
what are enzymes
A
3D globular proteins which can be used as catalysts in a reaction and are senstitive to temperature and pH
19
Q
what is the active site of an enzyme
A
the site where a substrate bonds to an enzyme with a similarly shaped active site to the substrate structure
20
Q
when does a substrate have high affinity for an enxyme
A
if they are similarly shaped
21
Q
what is induced fit
A
it is when the enzymes active site alters itself to fit a substrate
22
what allows substrates of differing shape to an active site to bind to it
induced fit
23
what is required for a substrate to bind to an active site
correct shape, size and orientation of the reactants
24
what influences the rate of an enzyme catalysed reaction
both the concentration of the substrate and the products
25
what is feedback inhibition
when the product of the last reaction in metabolic pathway reaches a critical concentration inhibiting the enzyme that catlyses the first reaction of the pathway
26
what do inhibitors do
slow down the metabolic pathways that are controlled by enzymes
27
what are the 2 types of inhibitor molecule
competitive and non-competetive inhibitors
28
What is competetive inhibition
When competitive inhibitor molecules actively compete against the substrate present in a reaction to fill the enzyme's active site meaning that the substrate cannot bind with it
29
how can competitive inhibition be overcome
increased substrate concentration (makes it more likely for a succesful collision before the active site is filled by inhibitor)
30
other than increased substrate concentration waht else can pvercome competitive inhibition
increased enzyem concentration
31
what is non-competetive inhibition
whe non competitive inhibitor bind away from the active site. once bound to the enzyme they alter the active site preventing the substrate from binding to it
32
describe how lowering the activation energy affects the rate of reaction
increased rate of reaction
33
describe the principle of induced fot in an enzyme substrate reaction
if the active site and substrate are not completely the same in strucutre the enzyme will alter its active site to allow the substrate to bind to it
34
describe the affect of increasing substrate concentration on the rate of reaction
increased rate of reaction
35
state the type of inhibitor which alters the shape of the active site of an enzyme
non-competetive
36
what sis cellular respiration
Cellular respiration refers to the breakdown of glucose and other respiratory substrates to make energy carrying molecules called ATP.
37
what is the main repiratory substrate
glucose
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what is released in cellular respiration
ATP
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what removes hydrogen ions and electrons in cellular respiration
dehydrogenase enzymes
40
what is ATP
ADENOSINE TRIPHOSPHATE
is a highe energy molecule needed by cells for the enrgy they need to function
41
what are some processes which use ATP
Replication, cell division, active transport, molecule synthesis and muscle contraction
42
what is phosphorylation
is a reaction taht involves the addition of phophate to a molecule. The source of phophate usually being ATP
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what does phosphorylation do
increases the energy content of the molecule to which the phophate group is attached to
44
what forms ATP
breakdown of glucose produces energy which joins the additional phophate group to ADP
45
what are the 3 pathways in cellular respiration
glycolysis, citric acid cycle, electron transport chain
46
where does glycolysis occur
the cytoplasm
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where does the citric acid cycle occur
central matrix of a mitochondrion
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where does electrontransport chain occur
inner mitochondrial membrane
49
what happens in glycolysis
glucose is broken down to form pyruvate
2ATP molecules are used
2 pyruvate molecules are formed, producing 4ATP in a pay-off phase
the net gain of enrgy is 2ATP
during pay off phase hydrogen ions and electrons are removed from the intermediates by dehydrogenase
The unstable hydrogens are picked up immediately by coenzyme NAD to form NADH
50
write an equation to illustrate the process of phophorylation
ADP + Pi → ATP
51
explain why there is only a very small mass of ATP present in the body at any one time
as it is constantly being broken down and regenerated
52
what does NAD stand for
nicotinamide adenine dinucleotide
53
state one example of a hydrogen carrier in cellular respiration
NAD
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state the name of the molecule that glucise is broken down in to in glycolysis
pyruvate
55
where does the citric acid cycle take place
matrix of a mitochondrion
56
what is one condition for the occurence of the citric acid cycle
the cell must have oxygen
57
summarise what happens in the citric acid cycle
pyruvate, produced in glycolysis is broken down into acetyl coenzyme A, with the release of carbondioxide and more hydrogen ions and electrons picked up by NAD. The acetyl group of acteyl coenzyme A combines with oxaloacetate to form citrate
58
what happens to pyruvate in anaerobic cinditions
pyruvate is converted to lactate in animals or to ethanol and carbon dioxide in plants
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5 steps of citric acid cycle
pyruvate is broken down into acetyl group that combines with coenzyme A to form acetyl coenzyme A
dehydrogenase enzymes remove hydrogen ions and electrons and pass them on to coenzyme NAD to form NADH
The acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate
Several enzyme controlled steps occur within the cycle resulting in the regeneration of more oxaloacetate
Carbon dioxide is released ATP synthesised and NADH generated
60
Where does the electron transport chain take place
inner membrane of mitochondrion
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what happens in electron transportt chain
a chain of carrier protein accept hydrogen ions and electrons from NADH. The electrons and hydrogen ions are finally transferred to oxygen to form water
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what enzyme brings about ATP synthesis
ATP synthase
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where is ATP synthase located
inner membrane of a mitochindrion
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what does ATP synthase do to the reaction
catalyses the synthesis of ATP from ADP and P
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Describe ATP synthesis in 4 stages
1. electrons flow along chain of protein electron carrier molecules
2. energy released from the flw of electrons is used to pump hydrogen ions across the inner membrane of the mitochondria
3. the return flow of hydrogen ions rotates part of a membrane protein called ATP synthase, phosphorylating ADP + P to ATP
4. Whenn hydrogen ions and electrons reach end of protein carrier chain, they combine woth oxygen to form water
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why is breathing important in the electron transport chain
we need to breathe every few seconds to provide oxygen as the final hydrogenion and electron acceptor in the electron transport chain
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where does fermentation take place
in the cytoplasm
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when/ why does fermentation take place
when there is no available oxygen
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id fermentation more or less efficient than aerobic respiration
much less efficient
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what happens in fermentation
pyruvate is converted into lactate in animal cells and ethanol and carbon dioxide in yeast and plant cells
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how much ATP is producced in fermentation
2
72
when is fermentation reversible
in animals
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is fermentation reversible in yeast and plant cells
no
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where does the energy to drive metabolism come from
breakdown of glucose durinng aerobic respiration
75
why is it possible to compare the metabolic rates
because oxygen is used up and carbon dioxide and heat energy released
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what 3 factors can be looked at to compare metabolic rates
how much:
1. oxygen is consumed
2. carbond dioxide is produced
3. energy released in the form of heat
77
what is a respirometer used for in metabolic rate
the oxygen consumption per hour of a small organism can be measured
78
what is a calorimeter used for during metabolic rate
the heat energy released during metabolism can be measured
79
what is it possible to measure using gas probes for metabolic rate
1. carbon dioxide output
2. oxygen consumption
80
How does the respirometer meausure
Carbon dioxide produced by the living organism is absorbed by the chemical. Oxygen consumed lowers the air pressure in the apparatus and can be quantified by measuring how far along the capillary tube the coloured water has travelled, taking the place of the consumed oxygen
81
what is the relationship between metabolic rate and the oxygen demand of an organism
and what has been developed to accomodate that trend
the higher the metabolic rate the higher the demand for oxygen
These organisms have evolved efficient transport systems to deliver oxygen from the lungs to body cells
82
what do complete double circulatory systems allow
delivery of full oxygenated blood under high pressure to respiring cells. This enables more efficient delivery of oxygen and removal of carbon dioxide and helps higher metabolic rates to be maintained.
83
what happens to blood in a comblete double circulation
blood passes through the heart twice per cycle and there is no mixing of oxygenated and deoxygenated blood
84
list for fish:
- no. of heart chambers
- type of circulation
- relative rate of metabolism
2 - 1 atrium, 1 ventricle
single - blood passes through the heart once
lowest
84
list for amphibians:
- no. of heart chambers
- type of circulation
- relative rate of metabolism
3 - 2 atria, 1 ventricle
Incomplete double - blood passes through heart twice
lower - than birds and mammals
85
list for reptiles:
- no. of heart chambers
- type of circulation
- relative rate of metabolism
3 - 2 atria, 1 ventricle
double and mostly incomplete
lower - than birds and mammals
86
list for birds:
- no. of heart chambers
- type of circulation
- relative rate of metabolism
4 - 2 atria, 2 ventricles
complete double
highest
87
list for mammals:
- no. of heart chambers
- type of circulation
- relative rate of metabolism
4 - 2 atria, 2 ventricles
complete double
highest
88
what is the circulatory system termed in amphibians and most reptiles and why
incomplete double. because although blood passes through the heart twice per cycle, mixing of oxygenateda nd deoxygenated blood occurs in the ventricle hence - incomplete
89
explain why a mammalian heart is more efficient at delivering oxygen than a fish heart
in a mammalian heart oxygenated blood is kept seperate from deoxygenated blood and is pumped at higher pressure than fish.
90
what is an abiotic factor
a non-living part of an ecosystem that shapes its environment
91
what abiotic factors need to be in range for an organism to survive and why
temp, salinity and pH need to be in range that allows the organisms metabolism to function optimally
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what a biotic factors are organisms sensitive to
temp salinity pH
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what is theinternal environment of an organism made up of
body cells and their aurrounding tissue fluid, which contains water, glucose and other important molecules
94
define homeostasis
the maintenance of the internal environment independantly of the external environment
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what are the 3 C's for conformers
**C**onformers **C**annot **C**ontrol their internal environment by physiological means and therefore cannot control metabolic rate by the same means either
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how do conformers regualte internal environment
behavioural responses
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examples of conformers
reptiles invertebrates
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is the metabolic cost in conformers low or high and why
low because they have no physiological mecanism to control metabolic rate
99
examples of regualtors and what they do
mammals and birds
use metabolism to control their internal environments usually involving physiological mecansims
100
what does the ideal internal temp of mammals facilitate
37°C allows optimum enzyme activity and movement of molecules by diffusion
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how is the ideal internal temp of mammals maintained
thermoregulation by negative feedback
102
describe thermoregulation by negative feedback in 3 main steps
- change in temp of internal environment is detected by the receptors that generate nerve messages travelling to the hypothalamus, the temp control centre of the brain
- electrical impulse sent along nerves communicates info to effectors in the skin
- the effectors in the skin bring about corrective response to restore the body temp to normal set point
103
what is the hypothalamus
temp control centre of brain
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what is a receptor
A receptor is a cell or group of cells that receive information from stimuli such as a change in temperature
105
what is an effector
effectors include muscles and glands - they produce a specific response to a detected stimulus
106
what is the corrective response to increased body tem from an effector
- sweat glands activate so that the water in sweat evaporates and cools skin
- hairs on skin lie flat due to hair erector muscles relaxing
- vasodilation
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what is the corrective response to decreased body tem from an effector
- sweat glands stop producing sweat
- hairs on skin stand up sue to contraction of hair erector muscles trapping air as insulation
- vasoconstriction
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what is vasodilation
blood vessels widen, bringing blood to surface of skin increasing the loss if heat by radiation
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what is casoconstriction
blood vessels narrow, diverting blood away from surface of skin, thus decreasing heat loss
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regualtors use physiological mecanisms to control their internal environment. These include:
- control of blood glucos
- control of blood water
- contol of body temp
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how can some organisms survive major changes in environmental conditions
through dormancy, or avoid environmental changes by migration
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what is dormancy
dormancy is a stage in the life cycle of an organism where metabolic rate decreases and growth of the organism stops
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wht does dormancy allow
allows the animal to conserve energy when otherwise, the energy cost of normal metabolism would not allow it to survive
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what are 2 types of dormancy
predictive
and consequential
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what is predictive dormancy
organisms enter into a dormant stage before environmental conditions deteriorate
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what is an example of predictive dormancy
bears hibernate before the onset of winter
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what is consequential dormancy
enter into a dormant stage after a significant detrimental change in environmental conditions
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what are the 2 forms of dormancy
aestivation and daily torpor
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what is aestivation
a state of inactivity during periods of high temp or drought, occuring in some animals such as lungfish, where metabolic processes are slowed down
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what is daily torpor
a period of reduced activity in some animals with a high metabolic rate. Such animals can reduce their metabolic rate every 24 hours by becoming inactive and reducing their breathing rate considerably. This helps to conserve energy
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what does hibernation allow
allows survival by reducing heartbeat, body temp and oxygen uptake. This is coupled with minimal activity and these changes drastically reduce the need for energy by lowering the metabolic rate
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why does migration occur
maintain metabolism and allows the animal to avoid adverse conditions
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what is innate behaviour
genetically based behaviour
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how do scientists monitor long distance
satellite tracking and legs rings
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examples of micro-organisms
archae, bacteria and some types of eukaryote
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what does a fermenter do in micro-organism growth
this chamber allows the medium in which the micro-organism is grwoing to be closely regulated
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how does a fermenter regulate growth medium of a micro-organism
often by computer cntrol, it regulates culturing conditions like glucose levels and nutrient levels
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what are the alterable culturing conditions in micro-organism growth
- glucose conc
- temp
- pH levels (using buffer solution)
- oxygen conc. by aeration of growth medium
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what conditions must micro-organsims be grwon in and why
aseptic conditions
eliminate growth of wild micro-organisms in the air, which may contaminate the medium
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what do micro-organisms priduce
all the complex molecules required for biosynthesis
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what are the complex molecules required for biosynthesis
amino acids, vitamins, fatty acids, etc.
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where do photosynthetic micro-organisms derive their energy from
light
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what factors may allow micro-organisms to be used geochemically or industrially
specific metabolism
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why are micro-organisms widely exploited by humans
because they grow so quickly , are adaptable and are esy to culture
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what can bacteria do every 20 mins related to growth
double their number
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what is generation time
the time taken for one cell to divide by mitosis into 2 daughter cells
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lag phase
period during which enzymes are induced to metabolise substrate
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exponential (log) phase
cells divide at maximum rate due to plentiful nutrients
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stationary phase
nutrients start to get used up and toxic end products accumulate, the no. of micro-organisms being produced is balanced by the numbers dying
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death phase
eventually, the micro-organisms are starved of nutrients or cannot tolerate their own toxic wastes, so they die
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mutagenesis
using agents such as ultra-violet radiation or mutagenic chemicals to induce a mutation resulting in the production of an improved strain of micro-organism
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recombinant DNA technology allows
allows genetic material to be transferred between different organisms, allowing the micro-organism to code for a useful protein
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recombinant DNA technology
is the process of transferring gene(s) from one species to another. This involves the use of plasmids and artificially produced chromosomes as vectors.
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why are artificially produced chromosomes preferred to plasmids in recombinant DNA technology
they are prefferred as vectors as they can carry a lot more genetic material
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process of gene transfer in recombinant DNA technology
- a plasmid in bacterial cell is cut open using special enzymes called restriction endonuclease that cut at a specific base sequence called a restriction site.
- restriction endonucleases cut out the desired specific gene from a chromosome, leaving stick ends.
- complementary sticky ends are produced when the same restriction endonuclease is used to cut open the plasmid and extract teh gene from the chromosome
- the desired gene is inserted into the open bacterial plasmid and sealed in place by the enzyme ligase
- the bacterial plasmid containing the new gene is called a recombinant plasmid
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What is scissors and glue in relation to recombinant DNA technology
DNA resstriction endinuclease acts as 'scissors' cutting a gene
ligase acts as 'glue' sealing the transferred gene in place
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