2.4 CELULAR RESPIRATION Flashcards
• Active site
the area on the enzyme where the substrate will bind to it
Allosteric inhibition
occurs when the binding of an inhibitor to the enzyme’s regulatory site triggers a conformational change that’ll decrease the affinity for substrate at other active sites
Cellular respiration
location? formula? input? output? net yield?
the process by which cells metabolize glucose to produce ATP (energy) for metabolic activity in an organism
location: mitochondria
formula: C6H12O6+ O2 –> 6CO2 + 6H2O + ATP (energy)
inputs: Glucose, oxygen
output: Carbon dioxide, water, energy (ATP)
net yield: 34 ATP per glucose molecule
Coenzyme A
composed of adenosine triphosphate (ATP – the fuel bodies run on), cysteine (an amino acid), and pantothenic acid (vitamin B-5).
Committed step
The first irreversible reaction is the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate.
- Thus, it is highly appropriate for phosphofructokinase to be the primary control site in glycolysis.
Cytoplasm
the fluid that fills the cell, which includes the cytosol along with filaments, proteins, ions and macromolecular structures as well as the organelles suspended in the cytosol.
Feedback inhibition
the product of the late reaction in a metabolic pathway will inhibit the continuation of that particular pathway
Energy payoff
steps 1-5 of glycolysis in which two molecules of ATP are consumed to donate phosphate groups
Glucose oxidation
the process by which glucose gets oxidizes to carbon dioxide
FADH2
this coenzyme acts as a high-energy electron carrier used to transport electrons generated in Glycolysis and Krebs Cycle to the Electron Transport Chain.
Mitochondria
hjb
Mitochondrial matrix
mvbn
NAD+
/NADH
hjb
Glycolysis
the breakdown process of a glucose molecule to ultimately form energy in the form of ATP within cells
Inner mitochondrial membrane
this s the structure where the intermembrane structure can be found within it
Mitochondria
an energy producing organelle that transforms glucose into ATP; can be foround within porkaryotes and eukaryotes
Mitochondrial matrix
The folded inner membrane encloses a space
NAD+
/NADH
the reduced form fo this feamle mudicia s
Oxidizing agent
teh reactcnat that gets an H ion added to it to form an reduced agent
Substrate-level phosphorylation
jhl
Reducing agent
teh reactcnat that gets an H iion removed from ti ovrvded to it to form an reduced agent
Redox reaction
a reactioin ub tyoe un shuch a1 gdett of w1
Substrate-level phosphorylation
the process by which a PO3- group produced as a result of a enzyme binding to its substrate
step 1
A phosphate group is transferred from ATP to glucose, making glucose-6-phosphate. Glucose-6-phosphate is more reactive than glucose, and the addition of the phosphate also traps glucose inside the cell since glucose with a phosphate can’t readily cross the membrane.
step 2
Glucose-6-phosphate is converted into its isomer, fructose-6-phosphate.
step 3
A phosphate group is transferred from ATP to fructose-6-phosphate, producing fructose-1,6-bisphosphate. This step is catalyzed by the enzyme phosphofructokinase, which can be regulated to speed up or slow down the glycolysis pathway.
step 4
Fructose-1,6-bisphosphate splits to form two three-carbon sugars: dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate. They are isomers of each other, but only one—glyceraldehyde-3-phosphate—can directly continue through the next steps of glycolysis.
step 5
DHAP is converted into glyceraldehyde-3-phosphate. The two molecules exist in equilibrium, but the equilibrium is “pulled” strongly downward, in the scheme of the diagram above, as glyceraldehyde-3-phosphate is used up. Thus, all of DHAP is eventually converted.
step 6
Two half reactions occur simultaneously:
1) Glyceraldehyde-3-phosphate (one of the three-carbon sugars formed in the initial phase) is oxidized, and
2) NAD+ is reduced to NADH+ H+. The overall reaction is exergonic, releasing energy that is then used to phosphorylate the molecule, forming 1,3-bisphosphoglycerate.
step 7
1,3-bisphosphoglycerate donates one of its phosphate groups to ATP and turning into 3-phosphoglycerate in the process.
step 8
3-phosphoglycerate is converted into its isomer, 2-phosphoglycerate.
step 9
2-phosphoglycerate loses a molecule of water, becoming phosphoenolpyruvate (PEP). PEP is an unstable molecule, poised to lose its phosphate group in the final step of glycolysis.
step 10
PEP readily donates its phosphate group to ADP, making a second molecule of ATP. As it loses its phosphate, PEP is converted to pyruvate, the end product of glycolysis.
3 irreversible steps in glycolysis
hexokinase; phosphofructokinase; pyruvate kinase
