aerobic cellular respiration Flashcards
cellular respiration definition
process by which cells create useable energy in the form of ATP from a series of biochemical reactions involving the breakdown of glucose
what are the 2 pathways by which cellular respiration occurs?
aerobic cellular respiration and anaerobic fermentation
what is the difference between these 2 pathways?
the absence of oxygen
stage 1 of aerobic cellular respiration?
glycolysis
where does glycolysis occur?
cytosol of the cell
inputs for glycolysis?
1 glucose
2 ADP + 2PI
2NAD+ + 2H+
outputs for glycolysis?
2 pyruvate
2 ATP
2 NADH
what happens when glucose is broken down into pyruvate? what does the product of that break down aid in?
energy is released that can be harnessed by the cell. this energy powers the reactions of 2ADP + PI into 2ATP, which is now free to power cellular reactions.
What does the breakdown of 2NAD+ + 2H+ into 2NADH allow for?
the breakdown of 2NAD+ + 2H+ into 2NADH allows for electrons and protons to be transported to the mitochondria, but they are modified and broken down in the krebs cycle first.
what exactly happens to the 2NAD+ + 2H+ into 2NADH
the 2NAD+ + 2H+ reduces into 2NADH so that it can accept those protons and electrons
what happens to the pyruvate and NADH that is produced in glycolysis?
it goes on to make even more ATP in krebs cycle and electron transport chain.
where does the krebs cycle occur?
mitochondrial matrix
what is the link reaction?
link reaction links glycolysis and krebs cycle, whereby pyruvate is transported the the matrix of the mitochondria and forms acetyl coa. also produces nadh for later use at the electron transport chain and one wasteful co2.
inputs for krebs cycle?
2-acetyl coa
2ADP + PI,
6NAD+ + 6H+
2 FAD + 4H+
outputs for krebs cycle?
4 CO2
2 ATP
6 NADH
2 FADH2
what happens when acetyl coa in the krebs cycle breaks down?
high energy electrons are released. these electrons are loaded on to NAD+ and FAD molecules to generate NADH and FADH2
how many pyruvates produce one wasteful CO2 product?
2 pyruvates
what is the krebs cycle?
The second stage of aerobic cellular respiration is the Krebs cycle. It occurs in the matrix of mitochondria and it produces four CO2, two FADH2, six NADH, and two ATP for every two pyruvate molecules created via glycolysis.
in what form does the krebs cycle produce a small amount of energy in?
2atp (one per acetyl coa molecule)
how many molecules of co2 are produced for every original glucose molecule?
6co2 molecules are produced for every original glucose molecule.
why does the krebs cycle occur twice
because each glucose molecule is broken down into 2 pyruvates, and each pyruvate breaks down into 1 acetyl coa molecule, meaning 2 acetyl coa are produced for each pyruvate.
what is stage 3 of aerobic cellular respiration?
the electron transport chain
location of the electron transport chain?
cristae of mitochondria
what happens during the electron transport chain?
energy from electrons unloaded by NADH and FADH2 generates a proton gradient that drives significant ATP production by ATP synthase.
what happens to the loaded coenzymes nadh and fadh2 in electron transport chain?
they are converted back into NAD+ and FAD+, which are then recylced for continued use in glycolysis and Krebs cycle.
what happens to any spare electrons and protons at the electron transport chain?
they are collected by O2 and attached to O2 to produce water molecules.
why is oxygen so significant in the electron transport chain?
if it doesn’t collect those spare electrons and electrons it will cause disasterous reactions in the cell to happen, and cell will die. so basically the cell will die without O2.
inputs for electron transport chain?
6O2 + 12H+
26 OR 28 ADP + 26 OR 28 PI
10 NADH
2 FADH2
outputs for electron transport chain?
6H2O
26 OR 28 ATP
10 NAD+ + 10H+
2 FAD+ + 4H+
how much ATP in total is produced from each original glucose molecule that is commited to aerobic cellular respiration?
combined with the 2 atp produced during glycolysis, and the 2 ATP from the krebs cycle, a total of 30 or 32 ATP can be produced from each original glucose molecule that is committed to aerobic cellular respiration
what do enzymes do in cellular respiration
enzymes, with the help of their coenzyme assistants catalyse the reaction of cellular respiration to allow them to proceed at significantly higher and biologically relevant rates.
what are the 3 key coenzymes and what do they do?
ATP, NAD+ and FAD. they are cycled between the unloaded (ADP, NAD+, FAD+ COA) and loaded (ATP, NADH, FADH2, ACETYL COA) enzymes as they help catalyse the reactions of cellular respiration.
what do coenzymes do in reactions that need extra energy?
they are unloaded in reactions that need extra energy (donate their protons and electrons)
what docoenzymes do in reactions that produce energy?
they become loaded in reactions that produce energy (accept protons and electrons)
what does the unloading and loading of coenzymes mean?
it means that they will always be efficiently recyled.