FINALS PHYSIOLEC 1 (Metabolism)

What is the term for the metabolic process involving the breakdown of complex molecules to release energy?

Catabolism

What is the term for the metabolic process involving the synthesis of complex molecules from simpler ones?

Anabolism

Which type of metabolic pathway can function both catabolically and anabolically?

Amphibolic pathway

Nutrients serve two primary functions in metabolism: providing building blocks and being oxidized to provide _____.

Energy

What are the three major central metabolic pathways for carbohydrate degradation in microbes?

Embden-Meyerhof-Parnas (EMP), Pentose Phosphate (PPP), and Entner-Doudoroff (EDP).

All three major carbohydrate pathways initially convert glucose into which common intermediate?

Phosphoglyceraldehyde ($G3P$)

How many substrate-level phosphorylation events occur during the complete oxidation of glucose via the TCA cycle?

Three

In the central metabolic pathways, where do the two substrate-level phosphorylations specific to carbohydrate metabolism occur?

Glycolysis

How many oxidation reactions occur in the Tricarboxylic acid cycle ($TCA$) per turn?

Four

What is the primary organic product of glycolysis that is subsequently used in either respiration or fermentation?

Pyruvate

Which glycolytic intermediate serves as a precursor for the glycerol used in fat synthesis?

Dihydroxyacetone Phosphate ($DHAP$)

In Stage I of the Embden-Meyerhof-Parnas ($EMP$) pathway, how many $ATP$ molecules are consumed per glucose molecule?

Two

What is the net yield of $ATP$ produced by the $EMP$ pathway per molecule of glucose?

Two

Which stage of the $EMP$ pathway involves the oxidation of $G3P$ to pyruvate?

Stage II

The Pentose Phosphate Pathway ($PPP$) operates parallel to glycolysis to generate pentoses and which reducing agent?

$NADPH$

Which specific 5-carbon sugar produced by the $PPP$ is a precursor for nucleotide synthesis?

Ribose 5-phosphate

The $PPP$ is divided into two phases: the oxidative phase and the _____ phase.

Non-oxidative

What is the primary purpose of the oxidative phase of the Pentose Phosphate Pathway?

Production of $NADPH$

Which $PPP$ intermediate is required for the biosynthesis of aromatic amino acids like Phenylalanine and Tyrosine?

Erythrose 4-phosphate

Which enzyme in the $PPP$ is responsible for transferring a $C2$ fragment from a ketose to an aldose?

Transketolase ($TK$)

Which enzyme in the $PPP$ is responsible for transferring a $C3$ fragment from a ketose to an aldose?

Transaldolase ($TA$)

What is the total $NADPH$ yield from the oxidation of one molecule of glucose-6-phosphate ($G6P$) in the $PPP$?

Six $NADPH$

In which group of organisms is the Entner-Doudoroff Pathway ($EDP$) most commonly found?

Aerobic Gram-negative bacteria

What is the net $ATP$ yield per glucose molecule metabolized via the Entner-Doudoroff Pathway?

One $ATP$

Which toxic intermediate is a hallmark of the Entner-Doudoroff Pathway?

2-keto-3-deoxy-6-phosphogluconate ($KDPG$)

Under aerobic conditions, which enzyme complex oxidizes pyruvate to Acetyl-$CoA$?

Pyruvate Dehydrogenase Complex

Which vitamin-derived cofactor is required by the $E1$ component of the Pyruvate Dehydrogenase Complex?

Thiamine Pyrophosphate ($TPP$)

In anaerobic growth, which enzyme decarboxylates pyruvate to produce formate instead of $CO_2$?

Pyruvate-Formate Lyase

Which enzyme catalyzes the conversion of Acetyl-phosphate into acetate and $ATP$?

Acetate Kinase ($ACK$)

What is the secondary name for the Tricarboxylic Acid ($TCA$) Cycle?

Krebs Cycle

How many molecules of $CO_2$ are released per turn of the $TCA$ cycle from one Acetyl-$CoA$?

Two

In the $TCA$ cycle, which intermediate is the direct precursor for the synthesis of tetrapyrroles like cytochromes?

Succinyl-$CoA$

Which $TCA$ cycle intermediate is the primary precursor for the synthesis of the amino acid Glutamate?

$\alpha$-ketoglutarate

The Glyoxylate Cycle is primarily used when which compound is the sole carbon source?

Acetate

What is the main advantage of the Glyoxylate Cycle over the $TCA$ cycle for anabolism?

It bypasses the decarboxylation steps, preventing the loss of carbon as $CO_2$.

Which pathway is used by autotrophs to fix $CO_2$ and regenerate Ribulose 1,5-diphosphate?

The Calvin Cycle

What is the process of synthesizing glucose from non-carbohydrate precursors like oxaloacetate?

Gluconeogenesis

Which activated form of glucose is a precursor for the synthesis of peptidoglycan components like $NAG$ and $NAM$?

Uridine diphosphoglucose ($UDPG$)

What inorganic molecule is the typical source for the amino group in amino acid biosynthesis?

Ammonia ($NH_3$)

Under low ammonia concentrations, which energy-consuming enzyme is used to incorporate nitrogen?

Glutamine Synthetase

What is the term for the reaction where an amino group is transferred from one molecule to a carbon skeleton to form a new amino acid?

Transamination

Which molecule is the key precursor for the synthesis of the purine nucleotides Adenine and Guanine?

Inosinic acid

All pyrimidines, such as Thymine and Cytosine, are derived from which initial compound?

Uridylate

Which protein holds the growing fatty acid chain during its biosynthesis?

Acyl Carrier Protein ($ACP$)

Fatty acids are constructed two carbons at a time, but each unit originates from which 3-carbon compound?

Malonate (as Malonyl-$ACP$)

Unlike Bacteria and Eukarya, Archaea use hydrophobic _____ side chains in their membrane lipids.

Isoprenoid

In feedback inhibition, which enzyme in a biosynthetic pathway is typically inhibited by the end product?

The first enzyme

In the biosynthesis of Isoleucine, which enzyme is specifically inhibited by Isoleucine via feedback?

Threonine deaminase

What defines a 'focal metabolite' in microbial metabolism?

An intermediate that links anabolic and catabolic pathways as a precursor for building blocks.

Which molecule acts as the 'energy currency' of the cell, linking catabolism to anabolism?

$ATP$

The process of generating $ATP$ using a proton motive force ($PMF$) is known as _____ phosphorylation.

Oxidative

Which enzyme converts Glucose to Glucose-6-Phosphate in the first step of glycolysis?

Hexokinase

Which intermediate is formed by the action of Phosphofructokinase in glycolysis?

Fructose 1,6-bisphosphate

Which enzyme splits Fructose 1,6-bisphosphate into two 3-carbon molecules?

Aldolase

The conversion of Phosphoenolpyruvate ($PEP$) to pyruvate generates one molecule of _____.

$ATP$

Which type of fermentation produces only lactic acid as its end product?

Lactic acid fermentation

Which organism is noted for reducing Nitrate ($NO_3^-$) to Nitrite ($NO_2^-$) during anaerobic respiration?

Escherichia coli

Which genus of bacteria reduces Sulfate ($SO_4^{2-}$) to Hydrogen Sulfide ($H_2S$)?

Desulfovibrio

Which type of organisms reduce Carbonate ($CO_3^{2-}$) to Methane ($CH_4$)?

Methanogens

Phosphoenolpyruvate ($PEP$) can be synthesized from which $TCA$ cycle intermediate to initiate gluconeogenesis?

Oxaloacetate

Which activated glucose form is used specifically for the synthesis of glycogen or starch?

Adenosine diphosphoglucose ($ADPG$)

In the $DAP$ pathway for lysine biosynthesis, which two molecules serve as the starting materials?

Pyruvate and Aspartate

The $AAA$ pathway for lysine biosynthesis is found in which group of organisms?

Fungi and Euglenoids

Which enzyme catalyzes the oxidative decarboxylation of pyruvate to Acetyl-$CoA$ in anaerobic organisms using ferredoxin?

Pyruvate-Ferredoxin Oxidoreductase

The Pentose Phosphate Pathway provides $NADPH$ for reduction reactions during which metabolic process?

Biosynthesis

Which 4-carbon dicarboxylic acid is a focal metabolite in the $TCA$ cycle and gluconeogenesis?

Oxaloacetate

In the $TCA$ cycle, one molecule of $FADH_2$ is produced by the oxidation of which intermediate?

Succinate

How many enzyme subunits make up the $E2$ (Dihydrolipoate Transacetylase) component of the Pyruvate Dehydrogenase complex?

24 molecules

What is the function of the enzyme Hydrogenase in anaerobic pyruvate metabolism?

It transfers electrons from reduced ferredoxin to $H^+$ to form hydrogen gas.

Which intermediate serves as the primary $CO_2$ acceptor in the Calvin Cycle?

Ribulose 1,5-bisphosphate ($RuBP$)

In the $PPP$, which enzyme produces Ribulose 5-phosphate from 6-phosphogluconate?

6-phosphogluconate dehydrogenase

Which enzyme converts Acetyl-$CoA$ to Acetyl-phosphate?

Phosphotransacetylase ($PTA$)

What is the net yield of $NADH$ from one turn of the $TCA$ cycle starting from Acetyl-$CoA$?

Two $NADH$

Which metabolic pathway is considered a more ancient but less efficient alternative to glycolysis?

Entner-Doudoroff Pathway

In the $TCA$ cycle, which intermediate is the precursor for the synthesis of the amino acid Aspartate?

Oxaloacetate

Which bacterial genus can use the Entner-Doudoroff pathway anaerobically?

Zymomonas

Which $TCA$ intermediate is synthesized from Acetyl-$CoA$ and Oxaloacetate?

Citrate

Unsaturated fatty acids are typically formed through the _____ of a saturated fatty acid.

Desaturation

Which metabolic pathway is found in aerobic Gram-negative bacteria like Pseudomonas but is rare in anaerobes?

Entner-Doudoroff Pathway

What mechanism allows microorganisms to conserve carbon when growing on two-carbon substrates?

Glyoxylate Shunt