Metabolisms Flashcards
What is metabolism
all biochemical processes within a cell
what are the two main types parts of metabolism and describe them
1 - Anabolism: formation of biomass (growing)
2 - Catabolism: formation of energy from substrate (getting smaller but producing energy)
Describe Anabolism and give an example
use of chemical energy to convert nutrients and simple compounds into complex molecules
example: photosynthese
what are the two main types of Catabolism
and
describe it
fermentation and respirations are the two mains types
oxidation of organic or inorganic compounds, accompanied by the release of energy (ATP) and waste
What is ATP
Adenosine triphosphate is a nucletide
it carries energy in a form that cells can use
Which process produces ATP and which process uses it
Anabolism uses ATP and Catabolism produces it
What is a PED
primary electron donor
What is a TEA
terminal electron acceptor
what causes more energy to be conserved (less lost as heat) in the ETC (electron transport chain)
-when there is a greater difference in the electrode potential between the PED and the TEA
-there are more steps in the chain
-the more steps there are the more energy is conserved
What is an enzyme
a biological catalyst
(without which most biological reactions would occur too slowly for life)
Why might fermentation occur instead of respiration?
no need for external TEA, so redox reactions can occur internally regardless of exturnal environments
why might respiration occur instead of fermentation?
- more efficient: more ATP produced
- the electrode potential is bigger between the products meaning a bigger chain and less energy loss
- fermentation end products are still relatively complex molecules containing usable energy
What are the TEAs for aerobic and anaerobic respiration
aerobic TEA - Oxygen
anaerobic TEA - Sulfate, ferric iron (3+), arsenate, nitrate (any oxidised species that can accept electrons
what is a facultative anaerobe
respire aerobically but can use other TEA when no oxygen is available
which type of respiration is more favourable aerobic or anaerobic
aerobic
What does photo or chemo refer to
energy source
photo: sunlight
chemo: preformed molecules
What is an obligate anaerobe
can only survive in an environment that is oxygen depleted
what does hetero or litho refer to
electron donor
hetero: organic compounds
litho: inorganic compounds
what does hetero or auto refer to
carbon source
hetero: organic compound
auto: inorganic compound
what are two examples of chemoheterotrophy and
what produces more ATP
Fermentation and Respiration
Respiration produces more ATP
What is the process of chemoheterotrophy
uses chemical energy sources and organic carbon
what is the generalised equation for AEROBIC chemoheterotrophic respiration
C6H12O6 + 602 = 6CO2 + 6H2O
- organic C is oxidised by O2
- oxygen is reduced by organic C
- produces more ATP than other respiration pathways
Types of ANAEROBIC chemoheterotrophy
Reductions of other TEAs
including:
- Dissimilatory nitrate reduction
- Dissimilatory manganese reduction
- Dissimilatory iron reduction
- Dissimilatory reduction of other metals or
metalloids
- Dissimilatory sulfate reduction
- Methanogenesis
Dissimilatory nitrate reduction: who does it and where is it important
- bacteria only
- important role in soils and freshwaters subject to agricultural pollution or sewage