Module 6 quiz questions

'Decreased levels of ATP'. - Since the citric acid cycle is no longer working, then there will be no production of NADH and FADH2, therefore levels of NADH would decrease. These molecules are required in order to generate ATP. Without these molecules transporting electrons to the electron transport chain, ATP levels will decrease. - Acetyl-CoA is used in the citric acid cycle. If the citric acid cycle is stopped, the acetyl-CoA levels would increase.

A defect in an enzyme in the citric acid cycle causes the cycle to stop functioning. What is a possible consequence?

True. Anabolism creates larger molecules from smaller molecules and Catabolism breaks down larger molecules into smaller molecules.

Anabolic pathways result in larger molecules being made from smaller molecules and Catabolic pathways result in larger molecules being broken down into smaller molecules. T/F

Pyruvate -Acetyl-COA is produced from the breakdown of pyruvate after glycolysis.

During aerobic metabolism, acetyl-CoA is produced from which molecule?

6 -It takes 6 ATP molecules to produce glucose through gluconeogenesis.

During gluconeogenesis, how many ATP molecules are consumed for each glucose molecule produced?

Pyruvate is transformed to lactate. -In order for the glycolysis portion of anaerobic metabolism to continue, pyruvate is converted to lactate during fermentation. This process regenerates the NAD+ needed for glycolysis.

During periods of strenuous exercise, the muscle cells can become anaerobic. Without oxygen, the electron transport chain cannot continue and the citric acid cycle slows down. When this occurs, how do cells make ATP?

'I, III, & IV; intermembrane space'. - During the reactions of the Electron Transport Chain, hydrogens are pumped by complexes I, III, & IV and move from the matrix to the intermembrane space. Complex II does not directly pump electrons into the intermembrane space, instead, it pumps electrons to Coenzyme Q10 which passes them to complex III, which then pumps them across the membrane.

During the reactions of the Electron Transport Chain, hydrogens are pumped by complexes _________ and move from the matrix to the _________.

by acting as a channel to allow transport of glucose into the cell.

GluT transporters aid in glucose transport into a cell __________

True

Glucose that is phosphorylated after entering the cell cannot move through GluT transporters. T/F

Catabolic - During glycolysis, a 6-carbon glucose molecule is split into two, 3-carbon pyruvates. Reactions that involve breaking molecules down are catabolic reactions.

Glycolysis is the conversion of glucose to pyruvate. Is this a catabolic process or an anabolic process?

Substrate level phosphorylation -During glycolysis, substrate level phosphorylation transfers a phosphate group from an intermediate of glycolysis directly to ADP to create ATP.

Glycolysis produces two ATP molecules through which process?

Substrate-level phosphorylation is the only way ATP can be made without oxygen.

Glycolysis produces two ATP molecules. Through what process are these ATP molecules made?

The concentration of protons in the intermembrane space is higher than the concentration in the matrix. -The intermembrane space of mitochondria has a high concentration of protons (H+) compared to the matrix.

How does the proton gradient affect the pH of the mitochondrial matrix and the intermembrane space?

'30'. Since the patient has normal oxygen levels, their cells will undergo aerobic respiration. 30 ATP is generated per 1 glucose molecule as a result of aerobic respiration. 2 ATP are produced as a result of glycolysis, however, this patient has normal oxygen levels, which would indicate an aerobic process. If oxygen levels were low, then glycolysis only may be utilized to generate only 2 ATP per glucose.

If a patient is healthy and has a normal oxygen concentration in her blood, approximately how many ATP are produced for every molecule of glucose that enters the process of metabolism?

'The amount of lactate increases because lactate produced in muscles anaerobically must travel to the liver'. - During anaerobic conditions, ATP is produced during glycolysis and lactate is produced as a product of fermentation. Lactate produced during anaerobic metabolism leaves the muscle cells and travels to the liver via the blood.

In the absence of oxygen in the exercising muscle, why does the amount of lactate in the blood change?

'Aerobic respiration creates 30 ATP while anaerobic respiration creates 2 ATP'. - Aerobic metabolism of glucose creates 30 ATP after glycolysis and oxidative phosphorylation. Anaerobic metabolism only creates 2 ATP from glycolysis.

Starting with one molecule of glucose, compare the amount of ATP made in aerobic vs anaerobic respiration.

Type II diabetes -Diabetes results from a decreased ability to produce insulin or a decreased sensitivity of cells to the insulin produced by the body (type I and type II, respectively). This leads to excessively high blood glucose levels that are damaging to various organs and systems in the body.

There are two types of diabetes mellitus (DM) that lead to impairment in glucose utilization. Resistance to the effects of insulin leads to which type of DM?

NAD+ is required for glycolysis to occur. - NAD+ is essential for glycolysis to occur, which is the step where the 2 ATP of anaerobic metabolism are made.

There is no energy gained (and in fact energy is required) when converting pyruvate to lactate. Why is this a necessary step?

Lactate is formed from pyruvate under anaerobic conditions by the process of fermentation.

Under anaerobic conditions in humans, which molecule is formed in the cytosol by fermentation?

'Glucose molecules linked to lipids or proteins without the need for enzymes.' -The end product of glycogenolysis is glucose.

What are advanced glycation end products (AGEs)?

GLUT4 transporters move to the surface of the cell to allow glucose to enter the cell.

What happens in the liver cells when they respond to insulin?

'Glucose undergoes glycolysis to produce pyruvate'. - This is the first step of glucose metabolism in anaerobic and aerobic conditions. The citric acid cycle only occurs during aerobic conditions and acetyl-CoA, not glucose, enters into the citric acid cycle.

What happens to glucose under anaerobic conditions?

'ATP production using only substrate-level phosphorylation'. Substrate level phosphorylation is responsible for ATP production during glycolysis. Aerobic metabolism utilizes oxygen but anaerobic metabolism occurs when oxygen is depleted.

What is anaerobic metabolism?

Pyruvate is converted to lactate and enters the Cori cycle. -During anaerobic conditions the pyruvate will be converted to lactate to allow glycolysis to continue and produce ATP. - - Gluconeogenesis can be used to convert pyruvate to glucose when there is low blood sugar.

What is the fate of pyruvate when oxygen is absent?

'Fermentation regenerates the NAD+ needed for glycolysis.' -Fermentation creates lactic acid as a product.

What is the function of fermentation during anaerobic metabolism?

A complex carbohydrate

What kind of molecule is glycogen?

lactate, glucose -During anaerobic metabolism, muscles convert pyruvate to lactate and the liver uses this lactate to create glucose.

When oxygen is low, muscle and liver cells can participate in the Cori Cycle in which the muscle cells produce _______ which is then converted to _______ in the liver.

To replenish cellular stores of glycogen -A large amount of carbohydrates can be stored as glycogen and used during exercise.

Why would a marathon runner consume a large meal full of complex carbohydrates the night before her run?

'ADP will build-up'. -Since the electron transport chain can no longer function because the electrons are blocked at complex IV, the protons cannot be pumped into the intermembrane space. As a result, ATP synthesis will drastically decrease.

Cyanide binds to complex IV of the electron transport chain, preventing electron transport. Which of the following would be the most immediate effect of cyanide consumption?

NAD+ -Fermentation regenerates NAD+ so that it can be used by glycolysis.

Which molecule is regenerated with the production of lactate during anaerobic metabolism?

Glucagon is released when blood glucose is low and causes the breakdown of glycogen into glucose to raise blood glucose levels.

Which molecule signals the liver to release glucose by breaking down glycogen?

'Glucose, some amino acids, and glycerol'. - Only molecules that can enter glycolysis can be used in anaerobic metabolism. Fatty acids cannot enter into glycolysis.

Which molecules undergo anaerobic metabolism?

'Fermentation enables the regeneration of NAD+ so that glycolysis can still occur in anaerobic conditions.' - Fermentation regenerates the NAD+ that is essential for glycolysis to occur.

Which of the following best describes the purpose of fermentation?

'ATP synthase allows protons to flow down their concentration gradient into the matrix and generates ATP'. Protons flow down their concentration gradient through ATP synthase, from the intermembrane space into the matrix.

Which of the following best describes the role of ATP synthase?

The utilization of O2 as an electron acceptor -Only aerobic metabolism depends on oxygen as the terminal electron acceptor in the electron transport chain.

Which of the following differentiates aerobic from anaerobic cellular metabolism?

'The final products of glycolysis are two molecules of pyruvate'. -Glycolysis results in the net production of 2 ATP.

Which of the following is an accurate statement about glycolysis?

The proton gradient dissipates, resulting in a dramatic reduction in ATP production that can lead to cell death. -The proton gradient will dissipate when oxygen is not present because the electron transport chain will no longer be able to transport electrons. The proton gradient is necessary for the aerobic production of ATP.

Which of the following is expected to occur when oxygen is not present?

'Lactic acid fermentation - mitochondrial matrix'. - Lactic acid fermentation occurs during anaerobic metabolism and therefore occurs in the cytosol, not the mitochondria. The citric acid cycle occurs in the matrix of the mitochondria. True: Citric acid cycle - mitochondrial matrix. Glycolysis - cell cytosol ATP synthesis - inner membrane of the mitochondrion

Which of the following is incorrectly paired?

'NADH and FADH2 are produced from NAD+ and FAD during the citric acid cycle'. - NAD+ and FAD do not donate electrons. Instead, they will accept electrons to generate NADH and FADH2 during the citric acid cycle.

Which of the following occur during aerobic respiration?

Cells do not move enough GLUT4 transporters to their cell membranes. -Cells that do not move enough GLUT4 transporters to the cell membranes will cause blood glucose levels to be high.

Why are blood glucose levels high in patients with unmanaged Diabetes Mellitus?

'Red blood cells have no mitochondria'. - Red blood cells contain no mitochondria and therefore cannot carry out aerobic respiration involving the citric acid cycle. The Cori Cycle involves the production of lactate during the anaerobic production of ATP.

Why is the Cori Cycle important for red blood cells?

Red blood cells lack mitochondria. -Red blood cells lack mitochondria and must depend upon anaerobic metabolism to produce ATP.

Why must red blood cells rely solely on glycolysis to make ATP?