Chapter 7: Aerobic Cellular Respiration in Eukaryotes Flashcards
cellular respiration
catabolic pathway that uses oxygen in the breakdown of glucose to extract energy from chemical bonds in the form of ATP
cellular respiration takes place in
the mitochondria
autotrophs
organisms that are able to synthesize their own food (complex organic molecules)
heterotrophs
organisms that cannot synthesize their own food and must feed on other plants and animals to obtain energy
regardless of being autotrophs or heterotrophs…
energy has to be extracted from organic compounds through cellular respiration
___ is reduced to H2O
oxygen
___ is oxidized into CO2
glucose
the build up of ATP is ____
endergonic
cellular respiration is an _____ reaction and ____ energy
exergonic, releases
cellular respiration produces ____ ATP in eukaryotes
36
cellular respiration produces ____ ATP in prokaryotes
38
steps of aerobic cellular respiration in eukaryotes
- glycolysis
- pyruvate oxidation
- krebs cycle
- electron transport chain
glycolysis takes place in the __________
cytoplasm of the cell
step 1 of glycolysis
glucose is phosphorylated by ATP to become glucose 6-phosphate
step 2 of glycolysis
rearrangement to become fructose 6-phosphate
step 3 of glycolysis
ATP phosphorylates fructose 6-phosphate into fructose 1,6-bisphosphate
steps 4-5 of glycolysis
the 6 carbon molecule splits into two 3-carbon molecules, 1 G3P and one that is converted to G3P in another reaction
step 6 of glycolysis
G3P is oxidized and phosphorylated into two NADH molecules and two molecules of BPG, each with one high energy phosphate bond
step 7 of glycolysis
high energy phosphate bonds are removed by 2 ADP molecules, producing 2 ATP molecules and leaving 2 3PG molecules
step 8 of glycolysis
both molecules of 3PG are converted into 2 molecules of 2PG
step 9 of glycolysis
H2O is removed from 2PG, creating 2 PEP molecules each with a high-energy phosphate bond
step 10 of glycolysis
high energy phosphate bonds are removed by 2 ADP molecules, produces 2 ATP molecules and 2 pyruvate molecules
outcome of glycolysis
2 pyruvate
2 ATP
2 NADH
pyruvate oxidation occurs in _____
the matrix of the mitochondria
pyruvate oxidation
pyruvate is oxidized to an acetyl group by CoA and CO2 is removed. oxidation of pyruvate occurs twice
the enzyme that catalyzes pyruvate oxidation is _______
pyruvate dehydrogenase
the enzyme that removes CO2 is called ______
pyruvate decarboxylase
outcome of pyruvate oxidation
2 NADH
2 Acetyl CoA
2 CO2
the krebs cycle takes place in _______
the matrix of the mitochondria
step 1 of krebs cycle
the unstable bond attaching the acetyl group to CoA breaks. the acetyl group attaches to oxaloacetate, forming citrate
step 2 of krebs cycle
a molecule of water is removed and then added to change citrate into its isomer, isocitrate.
step 3 of krebs cycle
isocitrate is oxidized, a molecule of CO2 is removed, and NAD+ is reduced to NADH to form a-ketoglutarate
step 4 of krebs cycle
a-ketoglutarate is reduced and a molecule of CO2 is removed to form succinyl CoA
step 5 of krebs cycle
succinyl CoA is converted into succinate and substrate level phosphorylation takes place. the unstable bond between CoA and succinate breaks, which helps phosphorylate GDP to form GTP. GTP then transfers its phosphate to ADP to form ATP
step 6 of krebs cycle
succinate is oxidized when 2 of its hydrogens are transferred to FAD, forming FADH2, resulting in the compound fumarate
step 7 of krebs cycle
H2O is added to fumarate to convert it into malate
step 8 of krebs cycle
malate is oxidized and NAD is reduced to NADH, forming oxaloacetate. the oxaloacetate is able to combine with the other acetyl CoA and repeat the cycle
outcome of krebs cycle
6 NADH
4 CO2
2 FADH2
2 ATP
electron transport chain
reduced compounds from glycolysis, pyruvate oxidation, and krebs cycle enter the electron transport chain and carry their electrons into the inner mitochondrial membrane (cristae), where they transfer their electrons to a series of membrane associated proteins
step 1 of ETC
NADH contributes its electrons to the first protein in the electron transport chain (NADH dehydrogenase) while FADH2 feeds its electrons to Q later in the electron transport chain
step 2 of ETC
electrons are carried to the next carrier protein, bc1 complex, then to C, and finally to the cytochrome oxidase complex, where O2 is reduced into H2O
step 3 of ETC
some energy released as electrons is used to pump protons from the matrix into the intermembrane space, creating a proton gradient. the protons diffuse back into the matrix through specific channels. ATP synthase catalyzes the phosphorylation of ADP to create ATP (chemiosmosis)
oxidative phosphorylation
ATP production tied to the ETC where O2 is the final electron acceptor
theoretical yield of ATP in eukaryotes
32 ATP through ETC. each NADH produces 3 ATP & each FADH2 produces 2 ATP
actual yield of ATP in eukaryotes
30 ATP through ETC. each NADH produces 2.5 ATP & each FADH2 produces 1.5 ATP
the actual yield exists because _______
the inner mitochondrial membrane is leaky to protons, allowing some of them to re-enter the matrix without passing ATP synthase
in cellular respiration of fat, ______
fat is broken down into glycerol and fatty acids
step 1 of cellular respiration of fat
phosphate is added to glycerol, converting it to G3P or another compound that enters glycolysis
step 2 of cellular respiration of fat
fatty acids are oxidized in the matrix of the mitochondria and split enzymatically into 2-carbon acetyl groups that are bound to CoA (acetyl CoA formed will enter the krebs cycle)
the process of cellular respiration of fat is called _______
b-oxidation
b-oxidation
2-carbon acetyl groups are removed from a fatty acid and combined with CoA to form acetyl CoA until the entire fatty acid has been broken down
lipids are rich in energy because ______
they are highly reduced (many hydrogen atoms and few oxygen atoms)
in aerobic respiration of eukaryotes, a molecule of 6-carbon fatty acids generates up to ____ ATP
44
for every acetyl CoA that enters the krebs cycle, _____ ATP are produced
12
step 1 of cellular respiration of protein
proteins are broken down into their individual amino acids
step 2 of cellular respiration of protein
amino group (NH2) is removed from each amino acid in a process called deamination
step 3 of cellular respiration of protein
carbon molecule that is left is converted into a molecule that takes part in glycolysis or krebs cycle
