ch 7 Flashcards
cellular respiration:
a series of chemical reactions that convert the energy stored in fuel molecules into a chemical form that can be used by cells (converts energy stored in food into ATP)
> catabolic
CR stage 1:
glycolysis: breakdown of glucose to make 2 pyruvate
> glucose, fatty acids, or amino acids are partially broken down and a modest amount of energy is released
> takes place in cytoplasm
CR stage 2:
pyruvate is converted into acetyl-CoA and CO2 is produced
CR stage 3:
citric acid cycle: acetyl-CoA is broken down and more CO2 is released, along with a modest amount of energy, and electron carriers
__ __ are molecules that store and transfer energy in the form of “high energy” or “excited” electrons
electron carriers
CR stage 4:
oxidative phosphorylation: The electron carriers from stages 1−3 release their high-energy electrons to the electron-transport chain to produce ATP
in eukaryotes, glycolysis takes place in the __, and the citric acid cycle and phosphorylation take place in __.
cytoplasm; mitochondria
oxidation-reduction reactions:
Oxidation: loss of electrons/decrease in electron density
Reduction: gain of electrons/increase in electron density
> these reactions always yield a water and CO2
because oxygen gains electrons, it’s called an __ __. it also oxidizes glucose, so it can be called an __ __. glucose is an __ __ and therefore a __ __.
electron acceptor; oxidizing agent
electron donor; reducing agent
what is the final electron acceptor?
oxygen
substrate-level phosphorylation:
a phosphorylated organic molecule transfers a phosphate group to ADP to produce ATP
> occurs during stages 1 and 3 of CR
glycolysis:
a single molecule of glucose (6 carbons) is split into 2 molecules of pyruvate (3 carbons each), net production of 2 ATP and 2 NADH
in mitochondria, the space between the inner and outer membranes is called the __ and the space enclosed by the inner membrane is called the mitochondrial __.
intermembrane space; matrix
Acetyl CoA synthesis:
pyruvate from glycolysis is transported in mitochondria,, and converted into acetyl CoA in the mitochondrial matrix. results in the formation of one carbon dioxide and one NADH.
TOTAL= 2 acetyl CoA, 2 CO2 and 2 NADH
what is produced in the citric acid cycle?
1 glucose produces 2 acetyl CoA which yields 2 ATP, 6 NADH, and 2 FADH2
when oxygen accepts the final electron, it is reduced to __.
water
electron transport chain:
transfers electrons through complexes I, III, and VI and is coupled with pumping of protons. result is accumulation of protons in the inter membrane space from mitochondrial matrix
ATP synthase:
enzyme composed of F0 and F1
F0 forms the channel in inner mitochondrial membrane through which protons flow
F1 is catalytic unit that synthesizes ATP through mechanical rotational energy
the complete oxidation of glucose yields __ molecules of ATP
32
during __, electrons from NADH are transferred to pyruvate to produce lactic acid and NAD+.
> occurs in animals and bacteria
lactic acid fermentation
during __, pyruvate releases carbon dioxide to form acetaldehyde, and electrons from NADH are transferred to acetaldehyde to produce ethanol and NAD+.
> occurs in plants and fungi
ethanol fermentation
the breakdown of a molecule of glucose by fermentation yields _ molecules of ATP.
2
glucose is stored as __ in animals and as __ in plants
glycogen; starch
__ are a good source of energy because of their chemical structure: they are rich in carbon-carbon and carbon-hydrogen bonds
lipids
ATP is not produced in β-oxidation, but instead __ and __ are produced
NADH; FADH2
the complete oxidation of palmitic acid, a fatty acid with 16 carbons, produces __ molecules of ATP
106
PFK-1 is an allosteric enzyme with many activators and inhibitors, describe how it works
When levels of ADP or AMP are high in the cell, these molecules will bind to PFK-1 and activate the enzyme so that glycolysis continues, increasing the amount of ATP in the cell. When levels of ATP are high, it will bind to the enzyme, inhibiting its activity and causing glycolysis to slow down.
> is also regulated by citrate, an intermediate of the citric acid cycle. When citrate binds to the enzyme, its activity is also slowed.
