BIOCHEM CHAP 6 UNIT TEST

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

'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.

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?

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.

How many ATP are produced in the muscle cell when glucose is broken down and how many ATP are consumed in the liver when glucose is regenerated?

2 ATP are generated when glucose is broken down in the muscle cell (through glycolysis) and 6 ATP are consumed when ATP is regenerated in the liver (through gluconeogenesis).

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?

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.

What is anaerobic metabolism?

ATP production using only substrate-level phosphorylation

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

Aerobic respiration creates 30 ATP while anaerobic respiration creates 2 ATP.

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

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

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

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

What is the main purpose of fermentation?

Fermentation enables the regeneration of NAD+ so that glycolysis can still occur in anaerobic conditions.

What happens to glucose under anaerobic conditions?

Glucose undergoes glycolysis to produce pyruvate-The first step of glucose metabolism in anaerobic and aerobic conditions is to convert glucose to pyruvate.

What molecules undergo anaerobic metabolism?

Glucose, some amino acids, and glycerol

A patient with advanced cancer has not been able to eat a full meal for the past three months, and his intake has gradually diminished over the last month such that his entire intake in the prior three days consists solely of water. Which of the following is most likely?

He is likely to have lost adipose tissue and muscle mass

Billy is a 26-year-old male currently on his 12th day of a hunger strike to protest "government stuff." How can Billy keep going long after his glycogen supply has been used up? (Note: The brain requires a constant supply of glucose to function.)

He uses glycerol, some amino acids, and other molecules to create new glucose'. Fatty acids are not used to create new glucose. Instead they are used to build triglyceride a stored form of fat.

A woman is about to begin her ascent of Mount Everest and is preparing for Day 1 of the climb. Approximately 6 hours before the hike begins, she and her climbing team eat a meal containing 80% complex carbohydrates. What is the physiological benefit of this approach?

Improving glycogen stores in liver and muscle

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

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

Katrina is an 18-year-old female at Southwest High. Her high school is raising money by hosting a marathon pledge drive. She was advised to carb load before the big race. Why would this be recommended?

Loading on carbohydrates will increase glucose levels. Under high glucose conditions, cells perform glycogenesis, a process of building glycogen from glucose molecules. Glycogen can then be broken down rapidly into individual glucose units when glucose is low, such as during a marathon.

Jason is a 17-year-old male with a glycogen storage disease. He is also planning on running the high school marathon. Should Jason consume a diet that is low in a) fats, b) protein/amino acids, or c) carbohydrates/glucose? Explain.

Low carbohydrate because he is unable to use stored glycogen for a quick source of energy.

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

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.

Which of the following occur during aerobic respiration?

NADH and FADH2 are produced from NAD+ and FAD during the citric acid cycle-The citric acid cycle uses the NAD+ and FAD to produce NADH and FADH2.

A type II diabetes patient who has been on metformin treatment along with making some lifestyle changes for over two months now has a current A1C level reading of 7% . Which of the following statements best describes his response to the treatment and management of the condition?

No, the patient is not responding to the treatment since the normal range of A1C levels in healthy individuals is 0-5%

What is the fate of pyruvate when oxygen is absent?

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.

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?

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.

Why is the Cori Cycle important for red blood cells?

Red blood cells have no mitochondria. Red blood cells contain no mitochondria and therefore cannot carry out aerobic respiration involving the citric acid cycle.

A two year old boy is found to have an autosomal recessive glycogen storage disease that prevents him from being able to fully metabolize glucose. On examination, he has an enlarged liver and bulky appearing muscles. Biopsy of both the liver and the muscles shows markedly increased amounts of glycogen compared to normal. Which of the following is TRUE?

Since glucose can be partially but not fully metabolized, there is an increased concentration of the intermediate compounds and this causes a shift in enzymatic reactions, favoring the production of glycogen-Excessive glycogen will accumulate in the liver/muscles, increasing their size while worsening their function.

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

Substrate level phosphorylation (glucose is the substrate)

Glycolysis produces two ATP molecules through which process?

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

What best describes the role of ATP synthase?

TP 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.

What is the net ATP in the Cori Cycle?

The Cori cycle has a net loss of 4 ATP: 2 made during glycolysis and 6 used during gluconeogenesis.

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

The amount of lactate increases because lactate produced in muscles anaerobically must travel to the liver via the blood.

Which of the following is an accurate statement about glycolysis?

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

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

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. Because the FADH2 will no longer be used in the Electron Transport Chain and therefore will accumulate, not FAD.

What differentiates aerobic from anaerobic cellular metabolism?

The utilization of O2 as an electron acceptor

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

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

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

True-Glucose that is phosphorylated after entering the cell cannot move through GluT transporters.

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?

Type II diabetes-"Insulin Resistant"

GluT transporters aid in glucose transport into a cell __________

by acting as a channel to allow transport of glucose into the cell-Glut4 is a channel which transports glucose into the cell and is regulated by the insulin.

Insulin signaling results in an increased transport of ________ into cells, which allows the cell to subsequently increase ______ synthesis and store energy in the form of ______ in the liver and ______ in the adipose.

glucose, protein, glycogen, triglycerides-insulin has several effects on metabolism. It stimulates uptake of glucose into the cell. It also increases protein synthesis, glycogen synthesis and fatty acid synthesis and storage in the form of triglycerides.

Where does lactic acid fermentation occur?

in the cytosol during anaerobic metabolism

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.

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