Lecture 8 - Glycolysis Energy Metabolism

What is the primary role of catabolism in energy metabolism?

To drive the synthesis of $ATP$ through exergonic reactions.

How is anabolism defined in the context of energy consumption?

It is an endergonic process that consumes $ATP$ for biosynthesis.

What does a negative free energy change ($\Delta G < 0$) indicate about a chemical reaction?

The reaction is exergonic and energy is released.

What does a positive free energy change ($\Delta G > 0$) indicate about a chemical reaction?

The reaction is endergonic and energy is required.

In which specific part of the cell does glycolysis occur?

The cytosol.

Where are the $TCA$ cycle and oxidative phosphorylation located within the cell?

In the mitochondria.

What molecule serves as the essential metabolic link between the cytosol and the mitochondria?

Pyruvate.

Under aerobic conditions (with $O_2$), what is the fate of pyruvate?

It is converted to Acetyl-CoA and enters the $TCA$ cycle.

In the absence of $O_2$, what does pyruvate become in muscle tissue?

Lactate.

What are the three primary potential fates of absorbed glucose?

Energy production, storage (glycogen or fat), and biosynthesis.

During catabolism, hydrogen atoms are transferred from glucose to _____ _____.

Reducing equivalents (such as $NADH$ and $FADH_2$).

The process of reducing equivalents being oxidized to release $ATP$ occurs in the _____.

Mitochondria.

What is the energy value of 1 mole of $ATP$?

$7.3 \text{ kcal/mol}$

Based on the provided energy conversions, 1 mole of $NADH$ is equivalent to how many $ATP$?

3 $ATP$

Based on the provided energy conversions, 1 mole of $FADH_2$ is equivalent to how many $ATP$?

2 $ATP$

What is the alternative name for the glycolysis pathway mentioned in the source?

Embden-Meyerhof Pathway.

Glycolysis consists of two main stages: the energy-_____ phase and the energy-_____ phase.

Requiring; releasing.

During Stage 1 of glycolysis, how many $ATP$ molecules are consumed per molecule of glucose?

Two.

Which six-carbon intermediate is produced at the end of the energy-requiring phase of glycolysis?

Fructose-1,6-bisphosphate.

What enzyme is responsible for splitting Fructose-1,6-bisphosphate into two three-carbon molecules?

Aldolase.

Into what molecule is $DHAP$ converted so it can proceed through glycolysis?

Glyceraldehyde-3-phosphate.

How many $NADH$ molecules are produced in total during the energy-releasing phase of glycolysis per glucose molecule?

Two.

What is the total number of $ATP$ molecules generated in the energy-releasing phase of glycolysis per glucose molecule?

Four.

What is the net gain of $ATP$ directly produced by the glycolysis of one glucose molecule (excluding reducing equivalents)?

Two.

What is the total net gain of $ATP$ from glycolysis when including the energy from $NADH$?

8 $ATP$

In metabolic Stage 1, proteins are broken down into _____ _____.

Amino acids.

In metabolic Stage 1, polysaccharides are broken down into _____ _____.

Simple sugars (glucose).

In metabolic Stage 1, fats are broken down into _____ _____ and _____.

Fatty acids; glycerol.

In metabolic Stage 2, simple subunits are broken down into _____, resulting in limited $ATP$ and $NADH$ production.

Acetyl-CoA.

What characterizes Stage 3 of energy metabolism?

Complete oxidation of Acetyl-CoA with high $NADH$ and $ATP$ production via the $ETC$.

How many molecules of $CO_2$ are released during the formation of two Acetyl-CoA molecules from two Pyruvic acid molecules?

Two.

How many $NADH$ molecules are produced during the conversion of two Pyruvic acid molecules into two Acetyl-CoA molecules?

Two.

How many $CO_2$ molecules are released specifically within the Krebs Cycle per molecule of glucose?

Four.

How many $NADH$ molecules are generated inside the Krebs Cycle per molecule of glucose?

Six.

How many $FADH_2$ molecules are produced in the Krebs Cycle per glucose molecule?

Two.

What is the total $ATP$ yield from the Krebs Cycle for one molecule of glucose?

2 $ATP$

How many $ATP$ molecules are produced by the Electron Transport Chain ($ETC$) per glucose molecule according to the summary diagram?

32 or 34.

What is the final electron acceptor in the Electron Transport Chain?

$O_2$

How many molecules of $H_2O$ are produced at the end of the Electron Transport Chain per glucose molecule?

Six.

What are the three categories of waste products mentioned in the intermediary metabolism overview?

$NH_3$/urea, $H_2O$, and $CO_2$.

The process of synthesizing glucose from pyruvate is called _____.

Gluconeogenesis.

The pathway used for the biosynthesis of pentose and other sugars is the _____ _____ _____.

Pentose phosphate pathway.

What is the term for the metabolic pathway that converts glucose into glycogen?

Glycogenesis.

What is the term for the metabolic pathway that breaks down glycogen into glucose?

Glycogenolysis.

Catabolism of glucose involves the transfer of electrons to the _____ _____ _____ to generate $ATP$.

Electron transport chain.

Which specific step in the energy-releasing phase of glycolysis involves the reduction of $NAD^+$?

The conversion of Glyceraldehyde-3-phosphate to the next intermediate.

How many molecules of pyruvic acid are produced from the glycolysis of one molecule of glucose?

Two.

Concept: Free Energy ($\Delta G$)

Definition: The amount of energy within a system that is available to perform work.

What are 'reducing equivalents' in the context of energy metabolism?

Molecules like $NADH$ and $FADH_2$ that capture and transfer electrons.

True or False: Glycolysis occurs entirely within the mitochondria.

False (it occurs in the cytosol).

What is the net result of the chemical equation for glycolysis starting with one glucose and two $ATP$?

2 pyruvate, 4 $ATP$, and 2 $NADH$.

In the Krebs Cycle diagram, how many molecules of $H^+$ are associated with the production of 6 $NADH$?

Six.

The breakdown of foodstuffs into simple units is categorized as _____ of Intermediary Metabolism.

Stage 1.

Which metabolic stage results in the 'complete oxidation of acetyl CoA'?

Stage 3.

Which intermediate in glycolysis is described as 'unstable'?

Fructose-1,6-bisphosphate.

The generation of $ATP$ using $O_2$ at the end of the metabolic pathway is known as _____ _____.

Oxidative phosphorylation.

What is the primary role of the $TCA$ cycle in Stage 3 of metabolism?

To produce a large amount of reducing power ($NADH$) for the $ETC$.

Catabolism refers to the _____ of molecules, whereas anabolism refers to their _____.

Breakdown; synthesis.

What happens to the $DHAP$ produced during the cleavage of Fructose-1,6-bisphosphate?

It is all converted into Glyceraldehyde-3-phosphate.

In the glycolysis diagram, the reaction producing $ATP$ from $ADP$ in the energy-releasing phase happens _____ times per glucose.

Four (two steps, each occurring twice).

What determines whether pyruvate enters the mitochondria or is converted to lactate?

The presence or absence of oxygen ($O_2$).

Which waste product is specifically associated with the breakdown of proteins/amino acids?

$NH_3$ (Ammonia) or urea.

Glycolysis produces a net gain of 2 $ATP$ directly; however, the slide notes a 'Net Gain' of 8 $ATP$. This accounts for the energy in _____.

$NADH$.

In terms of carbon count, glucose is a _____-carbon molecule and pyruvate is a _____-carbon molecule.

Six; three.

The Electron Transport Chain produces water by combining electrons and hydrogen with _____.

Oxygen ($O_2$).