During gluconeogenesis, the three irreversible steps of glycolysis have to be bypassed. The first step is the conversion of pyruvate to phosphoenolpyruvate. Which of the following statement is false regarding the reaction step? Select one: a. Conversion of oxaloacetate from pyruvate occurs in mitochondria and shuttled into the cytosol. b. Formation of phosphoenolpyruvate requires both ATP and GTP as an energy source. c. Acetyl CoA is an activator of enzyme pyruvate carboxylase. d. This reaction involves two-step process catalyzed by pyruvate carboxylase and phosphoenolpyruvate carboxykinase

c) Some scientists debate whether it is correct to consider pyruvate as “the end of glycolysis”. Elaborate on this statement, discussing supporting and limiting facts.

In the Cori cycle, the lactate product of glycolysis in muscle is transformedback into glucose by the liver. (a) List the enzymes involved in the lactate → glucose pathway. (b) What is the net gain/loss of ATP for one round of the Cori cycle (glucose → lactate → glucose)?

When proteins are digested for fuel, they are first broken down into their amino acid components. Amino acids can be further oxidized to generate useful energy for the cell. For example, when one molecule of the amino acid tryptophan is oxidized, one pyruvate molecule and one acetyl CoA molecule are generated. One NADH molecule is also generated during the oxidation of tryptophan into one pyruvate molecule and one acetyl CoA molecule. Below is the general reaction described in the prompt: 1 tryptophan --> 1 pyruvate + 1 acetyl CoA + 1 NADH

Gluconeogenesis occurs in liver and kidney. Which is of the following enzyme are important for gluconeogenesis are expressed exclusively in these tissues? Select one: a. Glucose-6-phosphatase b. Fructose-1,6-Bisphosphatase c. Phosphoenolpyruvate carboxykinase d. Pyruvate carboxylase

Propose a pathway for the following compound to enter gluconeogenesis / glycolysis. In your pathway, include enzymes (you can use E1, E2, etc.) as well as any necessary cofactors.

Pyruvate, labeled with 14C at C-1, is incubated with 13C labeled bicarbonate and added to intact yeast cells (yeast can perform gluconeogenesis).   What and where will these labels appear on the resulting glucose produced through gluconeogenesis?   What and where will these labels appear on ethanol produced through fermentation?

The first step of gluconeogenesis involves the carboxylation of pyruvate and has a large negative delta G (i.e very exergonic). Explain how it is possible that this step can be exergonic if we know that adding CO2 onto molecules is fundamentally a destabilizing phenomenon?

Glucose 6-phosphate is also a precursor for the synthesis of nucleotides that are used to build DNA and RNA. The first step of this pathway is catalyzed by an enzyme called glucose 6-phosphate dehydrogenase. Assume that reactions in this pathway with double arrows are reversible under cellular conditions, while those with single arrows are effectively irreversible. Which of the following enzymes, if present in your fructose-6-phosphate solution, would most substantially decrease the amount of 6-phosphogluconolactone you produce? Phosphoglucomutase G6P Dehydrogenase G6P Isomerase Hexokinase PFK-1

Which of the following statements are True as to the location in pyruvate of labeled carbons if glucose molecules labeled (in separate experiments) with 14C (radioactive carbon) at each position of the carbon skeleton proceed through the Glycolytic pathway. Multiple answers:Multiple answers are accepted for this question   a The carboxyl carbon of pyruvate derives from carbon 3 of glucose.  b The keto carbon of pyruvate derives from carbon 2 of glucose.  c The methyl carbon of pyruvate derives from carbon 1 of glucose.  d The carboxyl carbon of pyruvate derives from carbon 4 of glucose. e The keto carbon of pyruvate derives from carbon 5 of glucose.  f The methyl carbon of pyruvate derives from carbon 6 of glucose.  g The carboxyl carbon of pyruvate derives from carbon 2 of glucose.  h The keto carbon of pyruvate derives from carbon 3 of glucose.  i The methyl carbon of pyruvate derives from carbon 4 of glucose.