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Biochemistry Unit 6

Terms in this set (52)

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.
The image shown provides a general schematic of how the food we eat can be broken down to provide energy. Which answer choice correctly identifies the metabolites A, B, and C in the schematic?
a. A. Fatty acids
B. Amino acids
C. 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?
30
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
Which of the following best describes the role of ATP synthase?
ATP synthase allows protons to flow down their concentration gradient into the matrix and generates ATP.
Which of the following occur during aerobic respiration?
NADH and FADH2 are produced from NAD+ and FAD during the citric acid cycle.
Glycolysis is the conversion of glucose to pyruvate. Is this a catabolic process or an anabolic process?
Catabolic
Which of the following is an accurate statement about glycolysis?
The final products of glycolysis are two molecules of pyruvate.
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
True or False:
Glucose that is phosphorylated after entering the cell cannot move through GluT transporters.
True
During the reactions of the Electron Transport Chain, hydrogens are pumped by complexes _________ and move from the matrix to the _________.
I, II & IV; intermembrane space
What is the fate of pyruvate when oxygen is absent?
Pyruvate is converted to lactate and enters the Cori Cycle.
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.
Glycolysis produces two ATP molecules through which process?
Substrate level phosphorylation
Under anaerobic conditions in humans, which molecule is formed in the cytosol by fermentation?
Lactate
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
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.
What happens to glucose under anaerobic conditions?
Glucose undergoes glycolysis to produce pyruvate.
Why is the Cori Cycle important for red blood cells?
Red blood cells have no mitochondria.
The figure of the Cori Cycle demonstrates how glucose is consumed in the muscle cell and regenerated in the liver. 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 and 6 ATP are consumed when glucose is regenerated in the liver.
True or False: 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
Fill in the missing numbers of ATP molecules in the diagram of the Cori Cycle shown.
A= 2 ATP
B= 6 ATP
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.
Starting with one molecule of glucose, compare the amount of ATP made in aerobic vs anaerobic respiration.
Aerobic respiration created 30 ATP while anaerobic respiration creates 2 ATP.
What is anaerobic metabolism?
ATP production using only substrate-level phosphorylation.
Which molecules undergo anaerobic metabolism?
Glucose, some amino acids, and glycerol.
Glycolysis produces two ATP molecules. Through what process are these ATP molecules made?
Substrate level phosphorylation
Which of the following differentiates aerobic from anaerobic cellular metabolism?
The utilization of O2 as an electron acceptor
Which of the following is incorrectly paired?
Lactic acid fermentation - mitochondrial matrix
Which of the following best describes the purpose of fermentation?
Fermentation enables the regeneration of NAD+ so that glycolysis can still occur in anaerobic conditions.
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.
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
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
GLUT transporters aid in glucose transport into a cell __________
By acting as a channel to allow transport of glucose into the cell.
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%.
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.
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.
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
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.
During gluconeogenesis, how many ATP molecules are consumed for each glucose molecule produced?
6
Which molecule signals the liver to release glucose by breaking down glycogen?
Glucagon
Which molecule is regenerated with the production of lactate during anaerobic metabolism?
NAD+
During aerobic metabolism, acetyl-CoA is produced from which molecule?
Pyruvate
Why would a marathon runner consume a large meal full of complex carbohydrates the night before her run?
To replenish cellular stores of glycogen
Why must red blood cells rely solely on glycolysis to make ATP?
Red blood cells lack mitochondria
What are advanced glycation end products (AGEs)?
Glucose molecules linked to lipids or proteins without the need for enzymes
Why are blood glucose levels high in patients with unmanaged Diabetes Mellitus?
Cells do not move enough GLUT4 transporters to their cell membranes
What kind of molecule is glycogen?
A complex carbohydrate
What happens in the muscle cells when they respond to insulin?
GLUT4 transporters move to the surface of the cell
What is the function of fermentation during anaerobic metabolism?
Fermentation regenerates NAD+ needed for glycolysis
How does the proton gradient affect the pH of the mitochondrial matrix and the intermembrane space?
The concentration of proteins in the intermembrane space is higher than the concentration in the matrix.
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