Question 1

During the fasting state, the body uses _____ to produce glucose.

Accepted Answer

Gluconeogenesis is the process of creating glucose from non-carbohydrate sources, such as amino acids and fatty acids, which occurs during the fasting state. Glycolysis and glycogenolysis both involve the breakdown of glucose, while lipolysis involves the breakdown of fat, not the production of glucose.

Question 2

What metabolic pathway predominates when excess glucose is present in the body and glycogen stores are filled?

Accepted Answer

When excess glucose is present in the body and glycogen stores are filled, the body will undergo lipogenesis and convert the excess glucose into triglycerides for storage in adipose tissue. This occurs primarily in the liver and can lead to weight gain and obesity if there is a continued excess of glucose in the diet. Glycolysis and glycogenolysis are pathways utilized when glucose is needed as a quick source of energy, while lipolysis is the breakdown of stored triglycerides for energy when glucose levels are low.

Question 3

Holly has type 1 diabetes. It is important that she take her insulin because without it her body’s metabolism is similar to that of someone who is _____.

Accepted Answer

Without insulin, the body's cells are unable to take in glucose from the bloodstream for energy, leading to a state similar to starvation.

Question 4

You have been stranded in a remote area for eight days with nothing to eat. The process that your body uses to produce “an alternate form of energy” under these circumstances is:

Accepted Answer

Ketogenesis is the process by which the body produces ketone bodies from stored fat in the absence of glucose (i.e. during a period of fasting or starvation). Ketone bodies can be used by the body as an alternate form of energy to sustain vital functions. Gluconeogenesis refers to the synthesis of glucose from non-carbohydrate sources, such as amino acids, which occurs mainly in the liver during periods of fasting. Proteolysis refers to the breakdown of proteins into amino acids, but this process does not directly produce energy. Lipogenesis is the process by which the body creates fat from excess glucose, which is not relevant in these circumstances.

Question 5

What the body's primary fuel source during fasting?

Accepted Answer

Fatty acids are the body's primary fuel source during fasting.

Question 6

During starvation, cells in the brain, muscles, and kidneys use _____ as a source of energy.

Accepted Answer

During starvation, the body shifts from glucose as the primary source of energy to ketones produced by the liver through the breakdown of fatty acids. Ketones can be used by the brain, muscles, and kidneys as an alternative source of energy. Glycogen stores in the liver and muscles are depleted within the first 24-48 hours of fasting, and triglycerides are broken down into fatty acids for ketone production. Glycerol may be used for gluconeogenesis to maintain blood glucose levels, but it is not a significant source of energy for these tissues.

Question 7

The time shortly after a meal is referred to as the postprandial period or the  _____ state.

Accepted Answer

The postprandial period refers to the time after a meal when nutrients are being absorbed and processed, and the body is in a fed state. This is in contrast to the postabsorptive state, which occurs when the body has finished absorbing nutrients and is in a fasting state. So, choice A (fed state) is the best answer. Choice B (postabsorptive state) is incorrect because it is the opposite of the postprandial state. Choices C (satisfied) and D (pre-hunger) are not accurate or commonly used terms to describe this physiological state.

Question 8

The anabolic process whereby glycogen is formed in liver and muscle tissue is called:

Accepted Answer

Glycogenesis is the process by which glycogen is formed in liver and muscle tissue through the anabolic pathway. Glycolysis is the process by which glucose is broken down to produce energy. Glycogenolysis is the breakdown of glycogen to release glucose. Gluconeogenesis is the formation of glucose from non-carbohydrate sources.

Question 9

James, an 18 year-old college student, just ate a very large supper. What is going on metabolically?

Accepted Answer

After eating a large meal, the body shifts towards anabolic pathways to store energy, increasing processes like glycogen and fat synthesis, while catabolic pathways decrease.

Question 10

During the fasting state, the body uses _____ for ATP production.

Accepted Answer

During the fasting state, the body relies on adipose reserves for ATP production through a process called lipolysis.

Question 11

Which of the following hormones is anabolic?

Accepted Answer

Insulin is an anabolic hormone that promotes tissue growth and storage of energy. Glucagon, cortisol, and epinephrine are catabolic hormones that promote the breakdown of energy stores.

Question 12

High rates of gluconeogenesis deplete the amount of _____.

Accepted Answer

Gluconeogenesis uses oxaloacetate as a substrate to produce glucose, depleting its levels.

Question 13

You have a tendency to overeat at buffets and have noticed an increase in your weight and clothing size. Your body has been using the excess energy to make fatty acids and triglycerides, a process called:

Accepted Answer

Lipogenesis is the process of converting excess energy into fatty acids and triglycerides, which leads to an increase in body fat and weight. Overeating, especially at buffets, can increase the amount of energy available for lipogenesis and promote weight gain. Lipolysis, on the other hand, is the breakdown of fats for energy, which would not lead to an increase in weight or clothing size. Lipophilia refers to an attraction to or preference for fatty foods or people with excess body fat, which is not relevant to this scenario. Hyperlipidemia is a condition of high levels of fats in the blood, which can be caused by a variety of factors but is not directly related to overeating or weight gain.

Question 14

When glucose enters the lipogenesis pathway, what percentage of its energy is used for the entire process?

Accepted Answer

Approximately 20%-25% of the energy from glucose is used during the lipogenesis process, which involves converting glucose into fatty acids and triglycerides.

Question 15

When oxaloacetate is depleted, acetyl-CoA is diverted to _____ production.

Accepted Answer

When oxaloacetate is depleted, acetyl-CoA is diverted to ketone production through a process called ketogenesis. This occurs primarily in the liver to provide energy for other tissues, such as the brain, during times of prolonged fasting or low carbohydrate intake.

Question 16

The availability of metabolic fuels _____.

Accepted Answer

The availability of something can fluctuate throughout the day, depending on factors such as demand, supply, and production. Therefore, it cannot be predicted or expected to peak before meals, and while changes in mood may be a result of availability, it is not a defining characteristic.

Question 17

Where does lipogenesis mainly take place?

Accepted Answer

Lipogenesis mainly occurs in the liver and adipose tissue. The liver is responsible for converting excess carbohydrates and proteins into fatty acids, which are transported to adipose tissue for storage. Adipose tissue can also synthesize fatty acids from glucose and other nutrients in the blood. Kidneys and pancreas are not major sites of lipogenesis.

Question 18

What percentage of the energy stored in dietary fatty acids is required to transform them into stored triglycerides?

Accepted Answer

The energy cost to convert dietary fatty acids into stored triglycerides is approximately 5%.

Question 19

Maria wants to try a very low-CHO diet for weight reduction. The authors of this plan advertise that you will know that it is working because your breath will have a fruity smell. What should Maria know about this “diet’?

Accepted Answer

Maria should be cautious about starting a low-CHO diet because it can cause ketosis, leading to ketoacidosis, a potentially life-threatening condition. The fruity smell of the breath is a sign of this dangerous metabolic state.

Question 20

How many hours of energy can be provided by the average person’s total supply of liver and muscle glycogen?

Accepted Answer

The answer of How many hours of energy can be...

Quiz 7: Energy Metabolism