cellular respiration Flashcards
is the controlled release of energy from the breakdown of organic compounds.
cellular respiration
these compounds are produced by autotrophs (via photosynthesis) or can be synthesized from other pre-existing molecules within the cell
organic compounds
the main organic molecule used in cell respiration is the monomer glucose (C6H1206)
Carbohydrates
usable carbon compounds include:
carbohydrates
triglycerides
proteins
fats produce more energy per gram than sugars, but are harder to transport and digest
triglycerides
not a primary source as produces nitrogenous by-products (which are toxic if not excreted)
proteins
store energy in their chemical bonds
organic molecules
cell respiration transfers this stored energy into
coenzymes
two type of coenzymes
ATP
Hydrogen carriers
immediately available energy source
(energy is released for use when it is hydrolyzed to ADP)
ATP
transitional energy source
(carries high energy electrons and protons for transfer)
hydrogen carriers
can be directly produced directly from organic molecules via substrate level phosphorylation or it can be indirectly synthesized by hydrogen carriers (need O2) via oxidative phosphorylation
ATP`
types of cell respiration
anaerobic respiration
aerobic respiration
partial breakdown of glucose
oxygen is NOT required for a small ATP yield
occurs entirely in the CYTOSOL
involves GLYCOLSIS AND FERMENTATION
Products: LACTIC ACID/ ETHANOL +CO2
Anaerobic respiration
complete breakdown of glucose
oxygen is REQUIRED for a large ATP yield
occurs in the MITOCHONDRIA
involves glycolysis, krebs cycle and ETC
Products: Carbon dioxide and water
Aerobic respiration
involved the partial breakdown of carbohydrates (glucose) in the absence of oxygen
anaerobic respiration
anaerobic respiration occurs in the —- and results in a low yield of ATP (net production = 2 ATP)
cytosol
involves glycolysis and fermentation
anaerobic respiration
both anaerobic and aerobic respiration begins with the breakdown of glucose in the cytosol via ——
glycolysis
glycolysis splits glucose into two molecules of —— that consumes two molecules of ATP
pyruvate
four molecules of ATP are produced via substrate level phosphorylation, resulting in a ——
net gain of two ATP molecules
coenzymes NAD is loaded with hydrogen to form molecules of —-
NADH
involves the conversion of pyruvate via a reaction that unloads hydrogen carriers to restore stocks of NAD
Fermentation
In plants and yeasts, pyruvate is irreversibly converted into ——–
ethanol and carbon dioxide
In animals, pyruvate is converted into
lactid acid
fermentation is reversible in —-
animals
fermentation is irreversible in —-
plants or yeast
lactic acid can be converted back into pyruvate when exercise is over and the pyruvate can then be digested aerobically to make ———-
ATP ( via oxidative phosphorylation
completes the breakdown of glucose begun by glycolysis
this process requires oxygen and occurs within the mitochondrion
aerobic respiration
aerobic respiration occurs via two distinct reactions:
krebs cycle
electron transport chain
pyruvate is broken down to make carbon dioxide and large amounts of hydrogen carriers
krebs cycle
hydrogen carriers are unloaded to produce ATP (oxidative phosphorylation)
electron transport chain
is an organelle in eukaryotic cells that is responsible for aerobic respiration
mitochondrion
mitochondrion is believed to have evolved via –
endosymbiosis
what is endosymbiosis
when an aerobic bacterium was engulfed by another prokaryotic cell
endosymbiotic origin includes the fact that the mitochondrion possesses ——–
circular DNA
The central region of the structure in mitochondrion is called ——-
the matrix
the location of the krebs cycle
the matrix
mitochondria contain an ———– that is highly folded into ———–
inner membrane, cristae
are the site of the electron transport chain
cristae
small space to quickly accumulate protons
intermembrane space
contains ETC and ATP synthase for oxidative phosphorylation
inner membrane
appropriate enzymes and suitable pH for krebs cycle
matrix
highly folded to raise SA:VOL ratio
cristae
contains transport proteins
outer membrane
pyruvate from glycolysis is transported into the mitochondrion and converted into —-
acetyl coA
it is then completely broken down via a series of reactions collectively called the —
krebs cycle
or
citric acid cycle
the breakdown of one pyruvate produces ———- as well as ——–
three carbon dioxide molecules,
one ATP
as glucose produce two pyruvate molecules, the kreb cycle will produce ——–
6 x CO2 molecules and 2 x ATP per glucose
it will also result in the mass production of large quantities of —-
hydrogen carriers
(mainly NADH)
these hydrogen carriers are unloaded via —-
the electron transport chain
(formed in glycolysis and the krebs cycle)
are unloaded to release protons and electrons
hydrogen carriers
high energy electrons move through an —- which syphons this energy to synthesize ATP
electron transport chain
the de-energized electrons are taken up by ——– which combines with the protons to form ———–
oxygen , water
this methos of ATP production is known as —— as it requires the unloading of hydrogen
oxidative phosphorylation
electron transport chain can only continue to unload hydrogen carriers if ———— to accept the de-energized electrons
oxygen is present
aerobic respiration will not occur in the absence of
oxygen
hydrogen carriers produced by one molecule of glucose will result in the production of —–
26 molecules of ATP
if oxygen is unavailable the hydrogen carriers can be unloaded —— via fermentation
anaerobically
aerobic respiration has much higher ———- than anaerobic respiration
ATP yield
aerobic stages:
glycolysis
krebs cycle
electron transport
glycose - pyruvate
substrate level: 2 ATP
Glycolysis
pyruvate - CO2
substrate level: 2 ATP
krebs cycle
oxygen - water
Oxidative: 26 ATP
electron transport
this pyruvate is converted within the cytosol into either lactic acid (animals) or ethanol and carbon dioxide ( plants and yeast)
anaerobic respiration
this pyruvate is converted into carbon dioxide ad water within the mitochondrion
aerobic respiration
requires oxygen to proceed and produces a large yield of ATP
aerobic respiration
what are the ATP yield of aerobic cell respiration
glycolysis 2xATP
krebs cycle 2xATP
Electron Transport Chain 26xATP
what is the ATP yield in anaerobic fermentation
glycolysis 2xATP
are energy source produced from the anaerobic fermentation of biomass
biofuels
are a renewable resource and are typically associated with a lower carbon footprint
biofuels
biomass is typically produced via—— which uses CO2 as an input
photosynthesis
has historically been produced from agricultural feedstocks (edible crops)
biomass
it has been used as a source of biomass
algae
is a common biofuel that can be used to supplement or replace traditional fossil fuels in fuel tanks
bioethanol
the rate of respiration can be measured by
consumption of inputs (glucose and oxygen)
or the formation of product (carbon dioxide)
does not use oxygen
anaerobic respiration
is only produced as a by-product of yeast or plant fermentation
carbon dioxide
factors that affect aerobic respiration
temperature
glucose concentration
oxygen availability
cell respiration is catalyzed by a variety of — is therefore impacted by ambient temperatures
enzymes
if the temperature is too low the activation threshold
cannot be reached
as temperature increases reaction rate will also —— as more ——- results in more frequent enzyme-substrate collisions
increase, kinetic energy
at optimal temperatures, activity will peak, as ———- will denature the enzymes involved in the cell respiration
higher temperature
is the initial substrate for both pathways of respiration (aerobic and anaerobic)
glucose
higher glucose levels will result in ———-
increased frequency of collisions with glycolytic enzymes
above certain glucose level, the rate of respiration will
plateau
increasing oxygen levels will result in higher rates in
aerobic respiration
is needed to maintain the functioning of the electron transport chain
oxygen
higher oxygen concentrations will ———– to a certain point
increase the rate of respiration
on condition that will increase the rate of cellular respiration is
exercise
