MCAT - Metabolism Word Scramble
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Question | Answer |
Cellular metabolism | sum of all chemical reactions that occur in cell |
Chem rxns in cell are either ________ or ___________ | anabolic; catabolic |
anabolic reactions | energy requiring - require synthesis of compounds |
catabolic reactions | release energy - break down compounds |
Autotrophic organisms | obtain energy anabolically by converting sunlight into bond energy (photosynthesis) |
Bond energy in autotrophic organisms stored in | organic compounds (mostly glucose) |
Heterotrophic organisms | obtain energy catabolically by ingestion of compounds to be broken down |
Net rxn of photosynthesis | 6CO2 + 6H2O + energy = C6H12O6 + 6O2 |
Rxn of glucose catabolism | reverse of photosynthesis |
Energy carriers | ATP, NAD+, NADP (only in plants), FAD |
Formation of and degrading of ATP = | energy stored and released |
ATP i synthesized during | glucose catabolism |
Components of ATP | adenine, ribose, 3 phosphate groups |
Energy of ATP is stored | in covalent bonds of phosphate groups |
Amount of energy released per mole of ATP | 7 kcal |
ATP provides energy for what? | endergonic reactions - examples: muscle contraction, motility, active transport of substances across plasma membrane |
NAD+, NADP, FAD are classified as __________ | coenzymes that are electron carriers |
Where do the electrons come from that are carried by electron carriers in glucose catabolism? | H atoms removed during glucose oxidation |
Where is the electron transport chain? | inner mitochondrial membrane |
Oxidation | loss of an electron (H) |
NAD+, NADP+, FAD are (oxidizing/reducing) agents | oxidizing |
NAD+, NADP+, and FAD are (oxidized/reduced) when they become NADH, NADPH, FADH2 | reduced |
NADH, NADPH, FADH2 are (oxidizing/reducing) agents | reducing agents |
2 steps of glucose catabolism | glycolysis, cellular respiration |
Glycolysis product | 2 pyruvate, 2 ATP (net), reduction of NAD+ to NADH |
Where does glycolysis occur? | cytoplasm |
Substrate-level phosphorylation | ATP synthesis that is direct from degradation of glucose without the participation of an intermediate molecule such as NAD+ |
Does glycolysis occur in prokaryotic cells? | yes |
Where is the energy of glucose after glycolysis? | pyruvate molecules (count 2) |
Pyruvate degradation can occur in what 2 ways? | Fermentation, cellular respiration |
During fermentation, pyruvate is (oxidized/reduced) | reduced |
During aerobic cellular respiration, pyruvate is (oxidized/reduced) | oxidized |
Fermentation is collectively what processes? | Glycolysis and formation of lactic acid |
2 types of fermentation | alcohol fermentation and lactic acid fermentation |
in what does does alcohol fermentation typically occur | yeast and some bacteria |
In what does lactic acid fermentation typically occur? | fungi, bacteria, and human muscles during strenuous activity |
During alcohol fermentation, pyruvate is ___________ to ____________ | decarboxylated; acetaldehyde |
In muscles, lactic acid accumulation causes a decrease in _______ that leads to muscle fatigue | blood pH |
Oxygen debt | the oxygen required to oxidize lactic acid back to pyruvate so that it can re-enter cellular respiration |
How many ATP does aerobic cellular respiration yield | 36 in eukaryotes; 38 in prokaryotes |
Why is cellular respiration more efficient with oxygen | b/c oxygen acts as the final electron acceptor and without it, electrons back up and NAD+ is not regenerated |
Where does aerobic cellular respiration occur in eukaryotes? | mitochodria |
3 stages of aerobic cellular respiration | pyruvate decarboxylation, citric acid cycle, electron transport chain |
Process of pyruvate decarboxylated | pyruvate transported to mitochondrial matrix and is decarboxylated (loses CO2) leaving an acetyl group; acetyl group is transferred to CoA to form acetyl CoA; NAD+ is reduced to NADH |
Citric Acid Cycle aka | Krebs cycle and tricarboxylic acid cycle (TCA cycle) |
Basics of citric acid cycle | acetyl CoA combines with oxaloacetate to form citrate; 2 CO2 released and oxaloacetate regenerated; electrons transferred to NAD+ and FAD; each turn of cycle produces 1 ATP vi a GTP intermediate |
Where is the electron transport chain? | inner mitochondrial membrane |
What are most of the molecules of the electron transport chain? | cytochromes |
1st molecule of ETC | FMN(flavin mononucleotide) |
Last molecule of ETC | cytochrome a3 |
Hindrances of the ETC | cyanide - blocks transfer of electrons from cytochrome a3 to oxygen and dinitrophenol - uncouples ETC from the proton gradient |
3 categories of protein complexes in ETC | NADH dehydrogenase, b-c1 complex, cytochrome oxidase |
When does the energy loss occur in the ETC? | as electrons are transferred from one complex to the next - released 1 ATP per complex |
Where does NADH deliver H? | dehydrogenase complex, thus producing 3 ATP |
Where does FADH2 deliver H? | between dehydrogenase complex and b-c1 complex to carrier Q, thus producing only 2 ATP |
What is the coupling agent of oxidation of NADH to phosphorylation of ADP? | proton gradient across the inner mitochondrial membrane |
What maintains the proton gradient? | as NADH passes electron, free H+ is released and accumulates in mitochondrial matrix creating a positive acidic environment which generates a roton-motive force driving H+ back through channels provided by enzyme complexes called ATP synthetases |
How many ATP are produced in substrate-level phosphorylation? | 4 |
How many ATP are produced by oxidative phosphorylation? | 32 in eukaryotes; 34 in prokaryotes |
What are other energy sources available when glucose runs low? | In order of body preference: other carbohydrates, fats, proteins |
Where are fats stored and what are they stored as? | in adipose tissue as triglyceride |
How are fats prepped for use as energy? | hydrolyzed by lipases to fatty acids and glycerol, then carried by blodd to other tissues for oxidation |
How are proteins prepped for use as energy? | amino acids undergo transamination to form alpha-keto acid; carbons of amino acid converted into acetyl CoA, pyruvate or another intermediate |
Created by:
susanivey
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