Microbial Metabolism Flashcards
Metabolism
to change
Catabolism
breaking things down to release energy (create ATP)
Anabolism
creating molecules (requires energy)
What macromolecule are enzymes typically?
proteins
What do enzymes do?
increase the rate of a chemical reaction by lowering activation energy
activation energy
energy required to get any reaction to occur
How do enzymes aid the reaction?
distorts the molecule
Reactant
input
Product
output
Active site
location on the enzyme where the substrate stimulation a reaction
Simple enzyme
amino acid chain formed into a protein
Conjugated enzyme
have a protein and non-protein component
Apeoenzyme
protein component in conjugated enzymes
Cofactor
non-protein component in conjugated enzymes
Types of cofactors
metal ion and organic molecule
Coenzyme
small organic molecules (eg. vitamins) that binds to the apeoenzyme and is a transient carrier from one molecule to another
Metal ion
charged atom that enters the active site and pull the substrate in acting as a magnet
Holoenzyme
apeoenzyme and coenzyme are together
What are the two enzyme-substrate interactions?
lock and key fit & induced fit
Induced fit
distort bonds of the substrate as it approaches the enzyme to connect better
Constitutive enzyme
enzymes which are made at a constant rate during the whole life of a cell
Where are constitutive enzymes released?
externally/outside of the cell
Regulated enzymes
enzymes which are only made when the cell needs it
Where are regulated enzymes released?
internally/inside of the cell
Exoenzymes
enzymes which function externally/outside of the cell
What happens when exoenzymes are still inside the cell?
inactive
Andoenzymes
enzymes which are made inside and function internally/inside of the cell
Labile
heat sensitive
How does heat effect enzymes?
the hydrogen bonds break due to heat which causes them to denature
What are the two types of metabolic pathways?
Hydrolysis and condensation reaction
Hydrolysis reaction
breaking covalent bonds in digestion in order to obtain the monomers; must add water for this reaction to occur
Condensation reaction
form covalent bonds and polymers; produce water as a byproduct
Rate-limiting step
enzyme that is the slowest in the pathway which determines the speed of the entire pathway; enzyme used to change the rate of the pathway
What are the three multienzyme systems?
linear, cyclic, branched
Linear
no output or inputs
Cyclic
input is reformed to start the reaction again
Branched
one input can create/form two different pathways
How do cells regulate enzyme activity?
simple competitive inhibitor, allosteric competitive inhibitor, non-competitive inhibitor
Simple competitive inhibitor
a different molecule that is similar in structure to the substrate can fit and bind to the active site blocking any reaction from occurring
Example of simple competitive inhibitor
antibiotics
Allosteric competitive inhibition
molecule which binds to the allosteric site which changes the shape of enzyme/active site making the substrate unable to bind
Confirmational shape
structural change enzyme takes when inhibitor binds to allosteric site
Allosteric site
secondary site in enzyme
Example of allosteric competitive inhibition
when cell regulates its own enzymes
Non-competitive inhibitor
substrate able to bind at the same time as the inhibitor; substrate and inhibitor able to bind separately
In non-competitive what happens when only the inhibitor is present?
no reaction occurs unless only the substrate occupies the enzyme
What is the main difference between non-competitive and competitive inhibitors?
in non substrate and inhibitor can bind at the same time
How are enzymes also regulated/reduced that does not include inhibitors?
repressed/induced gene expression
Repressed gene expression
stop/reduce
Induced gene expression
create
What is the difference between genetic control of enzymes to inhibitors?
takes long and is more permanent
Dehydrogenation reaction
loss of electrons/energy
OIL RIG
oxidation is loss of energy/electrons, reduction is gain of energy/electrons
Electron carriers
move energy from one part of the cell to another (they are often coenzymes)
What vitamin aids in effectively transporting electrons within the cell at a faster rate?
vitamin B
Oxidized: NAD+ –> NADH
NAD+
Aerobic cellular respiration reaction
FAD –> FADH2 (typically carries less energy)
What vitamin helps create NAD+?
vitamin D
Photosynthesis energy reaction
NADP+ –> NADH
What is added/removed to change the energy of ATP?
phosphate
ATP formation
phosphate is removed by breaking covalent bond from a phosphorylated molecule to create ATP
When is ATP created from taking a phosphate from another molecule?
molecule with the phosphate must have more energy than ATP making it very uncommon
Oxidative phosphorylation
uses energy from oxidizing sugar/fat to create a redox series (ATP synthase) to create a covalent bond from scratch (ADP and phosphate) to create ATP
Where does oxidation phosphorylation occur?
mitochondria and chloroplasts
Aerobic cellular respiration pathway
glycolysis > TCA cycle > respiratory chain
TCA cycle either forms…
2 ATP and lactic acid or 2 ATP and CO2
Aerobic cellular respiration electron acceptor
oxygen/O2
Aerobic cellular respiration products
ATP, CO2, H2O
How much ATP does aerobic cellular respiration produce?
36/38
Where does electron transport and respiratory chain occur in aerobic cellular respiration?
cristae/matrix or mitochondria
Anaerobic metabolism includes both…
fermentation, respiration
Fermentation pathway
glycolysis > specialized fermentation
Fermentation electron acceptor
organic molecules (pyruvic acid)
Fermentation products
ATP, CO2, alcohol ethanol or lactic acid
How much ATP does fermentation produce?
2
Respiration pathway
glycolysis, TCA cycle, electron transport/respiratory chain
Respiration electron acceptor
inorganic salts
Respiration products
ATP, CO2, vary depending on type of salt
How much ATP does respiration produce?
20-25
True or False: obligate aerobes, obligate anaerobes, faculatative aerobes all have a respiratory chain
true
Glycolysis
process of breaking down glucose into two equal molecules
What are the two molecules glucose (6-carbon molecules) breaks into?
3-carbon molecule pyruvic acid (C3H4O3)
How is glucose transported in glycolysis?
active transport (pumped into cell)
How does glucose become phosphorylated?
ATP transfers phosphate over to the glucose
Glycolysis inputs
glucose and 2 ATP
Pyruvic acid
C3H4O3 (3-carbon molecule)
During glycolysis where do intermediate molecules reside?
inside of the cell; unable to escape outside of the cell
What method is used in order to transport glucose?
active transport
How much ATP is used to start glycolysis?
2 ATP
Glycolysis inputs:
glucose, 2 ATP
Glycolysis outputs
2 ATP, 2 NADH, 2 pyruvic acid
What occurs during glycolysis?
activate glucose w/2 ATP > intermediate molecules oxidized to form NAD+ into NADH and also reduced > ATP formed from substrate level phosphorylation
Preparatory step
step which turns pyruvic acid into acetyl CoA
Why do prokaryotic cells create more ATP?
eukaryotic cells have to use ATP to pump pyruvic acid into the mitochondria from the cytoplasm during the preparatory step while prokaryotes preform all steps in the cytoplasm
Preparatory step input
pyruvic acid
Preparatory step output
2 acetyl CoA, 2 CO2, 2 NADH (2 per glucose)
TCA cycle
acetyl group binds to oxaloacetic acid (OAA) to create citric acid which is then oxidized
TCA cycle input
2 Acetyl CoA
TCA cycle output
6 NADH, 2FADH2, 4 CO2, 2 ATP; this is amount for 2 cycles for each acetyl CoA
TCA cycle either forms…
2 ATP and lactic acid or 2 ATP and CO2
When is glucose fully oxidized?
end of the TCA cycle
Respiratory chain
create a source of stored energy
In what process do cells use all the energy created?
respiratory chain; used to form 34 ATP
Where does the electron transport chain occur in prokaryotes?
cell membrane
Respiratory chain input
10 NADH, 2 FADH2, 6 O2
Respiratory chain output
34 ATP, 6 H2O
Proton motive force
generated electron transport chain as it moves the electrons down
