Biology Metabolism Flashcards
___ is the sum of all chemical reactions that occur in the body
Metabolism
Metabolism can be divided into ___ reactions, which break down chemicals and release energy, and anabolic reactions
catabolic
___ respiration describes the biochemical conversion of chemical energy stored in molecular bonds into usable energy (ATP), a catabolic process
cellular
Aerobic (cellular) respiration occurs in the presence of ___, while anaerobic (cellular) respiration occurs in the absence of ___
oxygen
External respiration refers to the inhaling and exhaling of air into and out of the lungs as well as the ___ of gas between the alveoli and the blood
exchange
Internal respiration refers to exchange of gas between ___ cells and the extracellular fluid
individual
If energy is released during a reaction, then the products must have less ___ energy than the reactants
potential
The primary difference between metabolism and combustion is that cellular respiration releases this energy in a series of smaller steps, thereby allowing the cell to capture the energy for use rather than the ___ being released to the environment as heat as seen in combustion
energy
___ literally means “sugar breaking” and is a series of reactions that lead to the oxidative breakdown of glucose into two molecules of pyruvate, the production of ATP, and the reduction of NAD+ into NADH
Glycolysis
In a redox reaction there is always a compound that is oxidized and one that is ___
reduced
In the case of glycolysis, ___ is oxidized and NAD+ is reduced
glucose
The entirety of glycolysis occurs in the ___ and, therefore , can be completed by both eukaryotic and prokaryotic cells
cytoplasm
The ___ (steps 1 - 3) gets its name from the fact that two ATP’s are used to add two phosphate groups to glucose, producing fructose 1,6-biphosphate (6 carbon)
energy investment stage
The second stage of glycolysis (step 4), ___, splits fructose 1,6-biphosphate into glyceraldehyde 3-phosphate (PGAL) and dihydroxyacetone phosphate (DHAP), each being a 3 carbon compound with an added phosphate group
cleavage
___ is then isomerized to form a second PGAL
DHAP
The third stage of glycolysis (steps 5-9), ___, results in the production of ATP
energy payout
Energy payout occurs ___ per glucose molecule because there are two PGAL’s
twice
In this series of steps, PGAL is ___ converted to pyruvate resulting in the reduction of NAD+ to NADH (catalyzed by dehydrogenase) and the production of two ATPs (catayzed by kinases)
converted
For glycolysis, one molecule of glucose yields two molecules of ___ which are obtained
pyruvate
During this sequence of reactions, two ATP are used and four ___ are generated
ATP
For glycolysis, there is a net production of two ATP per ___ molecule
glucose
Substrate level phosphorylation takes place in glycolysis because ATP synthesis is directly coupled with ___ of glucose without participation of an intermediate molecule such as NADH or FADH2
oxidation
Oxidative phosphorylation does require an intermediate ___ carrier such as NADH or FADH2
electron
After glycolysis, energy remains in pyruvate and pyruvate ___ can take place in aerobic or anaerobic conditions
degradation
NAD+ must be regenerated for glycolysis to continue in the ___ of O2
absence
In anaerobic respiration, fermentation does not produce any ATP itself; therefore, glucose metabolized in the ___ pathway only produces the two ATP through glycolysis
anaerobic
Alcohol fermentation coverts the pyruvate produced in ___ to ethanol
glycolysis
In lactic acid fermentation, the NAD+ used in step 5 of glycolysis is regenerated when ___ is reduced
pyruvate
Whereas anaerobic respiration yields only 2 ATP per molecule of ___ from glycolysis, aerobic respiration can yield 36-38 ATP
glucose
The pyruvate produced from glycolysis is transported through both mitochondrial membranes into the mitochondrial matrix where it undergoes ___ decarboxylation to produce acetyl-CoA
pyruvate
In aerobic respiration, acetyl-CoA undergoes a cycle of reactions known as the citric acid cycle (sometimes called the TCA or Krebs cycle) producing electron carriers (NADH and FADH2) and regenerating ___, allowing the cycle to happen continuously
oxaloacatate
In aerobic respiration when electron carriers NADH and FADH2 are made these elelctron carriers power protons (H+) against their concentration gradient into the ___ space
intermembrane
When electron carriers take part in the Electron Transport Chain (ETC) this method of ATP production is termed ___ phosphorylation
oxidative
Prokaryotes do not have mitochondria but aerobic bacteria are still able to partake in aerobic respiration, but the citric acid cycle occurs in the ___ and the electron transport chain is located on the bacterial membrane itself
cytosol
The pyruvate formed during glycolysis is transported from the cytoplasm into the mitochondrial matrix where it is decarboxylated (i.e., it loses a CO2), and the acetyl group that remains is transferred to ___ A to form acetyl-CoA
coenzyme
During pyruvate decarboxylation NAD+ is ___ to NADH
reduced
The cycle begins when the two-carbon acetyl group from acetyl-CoA combines with oxaloacetate, a four-carbon molecule, to form the six-___ citrate
carbon
Through a series of reactions, two CO2 are released and oxaloacetate, a four-carbon molecule is regenerated for use in ___ turn of the cycle
another
For each turn of the citric acid cycle, one ATP is produced by substrate-level ___ via a GTP intermediate
phosphorylation
During the citric acid cycle, electrons are transferred to NAD+ and FAD, generating three ___ and one FADH2
NADH
These reduction reactions in the TCA are coupled with the ___ of carbon, producing two CO2
oxidation
For each molecule of glucose in the TCA, two pyruvate are decarboxylated and ___ into the citric acid cycle
channeled
At this stage of TCA cycle, two of each type of molecular product at this stage are created for each ___ molecule
glucose
The electron transport chain (ETC) is a complex ___ mechanism located on the inside of the inner mitochondrial membrane
carrier
During oxidative phosphorylation, ATP is produced when high-energy potential electrons are transferred from NADH and FADH2 to oxygen by a series of carrier molecules located in the inner ___ membrane
mitochondrial
As electrons are transferred in the ETC, ___ energy is released which is then used to form ATP
free
Most molecules of the ETC are ___, electron carriers that resemble hemoglobin in the structure of their active site
cytochrome
The last carrier of the ETC passes its electron to the ___ electron acceptor, O2
final
O2 picks up a pair of hydrogen ions from the surrounding medium, forming ___
water
The coupling agent for the TCA and ETC is a proton gradient across the inner mitochondrial membrane ___ by the ETC
maintained
As NADH and FADH2 pass their electrons to the ETC, H+ ions are pumped out of the matrix, across the inner mitochondrial membrane, and into the ___ space at each of the ETC protein complexes
intermembrane
The continuous translocation of H+ creates a positively charged, acidic environment in the ___ space
intermembrane
In order to pass through the membrane (which is impermeable to ions), H+ must flow through specialized channels provided by enzyme complexes called ___ synthases, enough energy is released to allow for the phosphorylation of ADP to ATP
ATP
___ phosphorylation is the coupling of the oxidation of NADH and FADH2 with the phosphorylation of ADP
oxidative
Fat molecules are stored in adipose tissue in the ___ of triglycerides
form
When needed, they are hydrolyzed by lipases to fatty acids and glycerol and are carried by the ___ to other tissues for oxidation
blood
With each round of beta-oxidation of a ___ fatty acid, one NADH and one FADH2 are generated
saturated
The process of photosynthesis can be divided into light reactions and dark reactions which although ___ with the light reactions do not require sunlight
coupled
When light strikes a P700 molecule, it excites electrons, these ___ energy electrons can flow along two pathways giving cyclic electron flow or non cyclic electron flow
high
During photosynthesis, the series of redox reactions are harnessed using an electron transport chain, a proton gradient, and ATP ___ to produce ATP from ADP and Pi in a process called cyclic photophosphorylation
synthase
P700 then P680 are used to undergo the electron transport chain upon a photon ___ electrons
exciting
The dark reactions use the ATP and NADPH produced by the light reactions to reduce ___ to carbohydrates
CO2
Although these reactions do not directly require light, they will only occur during the day, when the light ___ are replenishing the supply of ATP and NADPH
reactions
CO2 is the source of ___ in the Calvin Cycle
carbohydrate
The product of the ___cycle is the three carbon sugar phosphoglyceraldehyde (PGAL)
Calvin
Calvin cycle is similar to the Krebs cycle in reverse: (1) carbon dioxide is fed into the cycle; in the Krebs cycle it was produced and released; (2) reducing power is utilized during the cycle (NADPH); in the Krebs cycle NADH was removed; (3) ___ is used in the cycle (conversion of ATP to ADP); in the Krebs cycle, energy was produced when ATP was formed from ADP and inorganic phosphate
energy
