Question 1

During fasting,blood glucose level is maintained through several sources.The first source of stored energy to be mobilized for blood glucose is:&#10;A)Adipose triglyceride.&#10;B)Hepatic ketone bodies.&#10;C)Skeletal muscle glycogen.&#10;D)Skeletal muscle protein.&#10;E)Hepatic glycogen.

Accepted Answer

During fasting, the immediate source of stored energy to be mobilized for blood glucose is hepatic glycogen. The liver stores glycogen as a means of maintaining blood glucose levels when food intake is limited. Glucose is released from hepatic glycogen through glycogenolysis, which is stimulated by hormones such as glucagon and adrenaline. When hepatic glycogen stores become depleted, the liver switches to gluconeogenesis (the synthesis of glucose from non-carbohydrate sources such as amino acids and glycerol) as a means of maintaining blood glucose levels.

Question 2

The hormone released by adipose tissue that decreases appetite is called: Type  melanocyte-stimulating hormone (-MSH).
B)Adiponectin.
C)Neuropeptide Y.
D)Leptin.
E)Insulin.

D

Accepted Answer

Leptin is the hormone released by adipose tissue that decreases appetite.

Question 3

Levels of circulating FFAs (associated primarily with albumin)are often elevated in the prediabetic and diabetic states.This is due to:&#10;A)Elevated levels of hormone-sensitive lipase.&#10;B)Elevated levels of lipoprotein lipase.&#10;C)Elevated levels of hepatic lipase.&#10;D)Elevated rate of very-low-density lipoprotein (VLDL)formation.&#10;E)Reduced expression of low-density lipoprotein (LDL)receptor.

Accepted Answer

Elevated levels of hormone-sensitive lipase, which promotes the breakdown of stored triglycerides in adipose tissue, can result in increased levels of circulating FFAs. This is commonly seen in individuals with prediabetes or diabetes.

Question 4

The insulin receptor belongs to which family of receptors?&#10;A)Tyrosine kinase receptors&#10;B)Steroid receptors&#10;C)Cytokine receptors&#10;D)G protein-coupled receptors&#10;E)LDL receptors

Accepted Answer

The insulin receptor belongs to the tyrosine kinase receptors family.

Question 5

Insulin stimulates triglyceride storage in adipose tissue.Which of the following enzymes plays an important role in this?&#10;A)Phosphoenolpyruvate carboxykinase (PEPCK).&#10;B)Glucokinase.&#10;C)Hormone-sensitive lipase.&#10;D)Lipoprotein lipase.&#10;E)Thiolase.

Accepted Answer

Lipoprotein lipase is an enzyme that breaks down triglycerides in chylomicrons and VLDLs, releasing free fatty acids and glycerol. Insulin stimulates the activity of lipoprotein lipase, thereby promoting the uptake and storage of triglycerides in adipose tissue.

Question 6

During his annual physical examination,a 55-year-old man is noted to have a body mass index of 33 (>30 indicates obesity)and high blood pressure.His blood chemistry profile indicates hyperlipidemia,hypertriglyceridemia,and hypercholesterolemia.Furthermore,his fasting blood glucose level is 120 mg/dL (elevated).His physician suspects type 2 diabetes and orders a glucose tolerance test.The patient drinks 75 g of glucose and then has his blood glucose measured 2 hours later.The 2-hour glucose level is 190 mg/dL (high end of glucose intolerance range; for the diagnosis of diabetes,the level is 200 mg/dL or higher).The most likely reason for this patient's glucose intolerance is:

A)Autoimmune destruction of the β cells.
B)Impairment of adenosine triphosphate (ATP)-sensitive potassium channel.
C)Insulin resistance.
D)Low leptin levels.
E)Impairment of glucose transporter 2 (GLUT-2)function.

Accepted Answer

The patient's high body mass index, hyperlipidemia, high blood pressure, and elevated fasting glucose all suggest insulin resistance, which is a common cause of type 2 diabetes. The glucose tolerance test result of 190 mg/dL at 2 hours confirms glucose intolerance, which is also indicative of insulin resistance. Option A is incorrect because autoimmune destruction of the β cells is the cause of type 1 diabetes. Option B is incorrect because impairment of ATP-sensitive potassium channel causes a rare form of diabetes called neonatal diabetes. Option D is incorrect because low leptin levels result in increased appetite and obesity, but not necessarily glucose intolerance. Option E is incorrect because impairment of GLUT-2 function causes a rare form of diabetes called Fanconi syndrome.

Question 7

A key metabolite that controls the movement of fatty acyl CoA into the mitochondria (where they are oxidized)is:&#10;A)Acetyl CoA.&#10;B)Malonyl CoA.&#10;C)Palmitate.&#10;D)Citrate.&#10;E)ATP

Accepted Answer

Malonyl CoA is known to be a regulator of fatty acid oxidation. Specifically, it inhibits the entry of fatty acyl CoA into the mitochondria via its inhibition of CPT1 (carnitine palmitoyltransferase 1), which is required for the transport of fatty acyl CoA into the mitochondria. This inhibition occurs when energy levels are high, indicating that there is an adequate supply of glucose as an energy source, and inhibiting fatty acid oxidation allows cells to prioritize glucose metabolism.

Question 8

The most important stimulus of insulin release is:&#10;A)Glucose.&#10;B)Glucagon.&#10;C)Adrenergic stimulation.&#10;D)Cholinergic stimulation.&#10;E)Amino acids.

Accepted Answer

Glucose is the primary stimulus of insulin release from pancreatic beta cells. When blood glucose levels rise, beta cells release insulin into the bloodstream to help cells uptake the excess glucose. Other factors, such as amino acids, can also stimulate insulin release to a lesser extent, but glucose is the most important stimulus.

Question 9

High circulating lipid levels are typical of the prediabetic and diabetic states.When the liver is saturated with glucose from the blood,it converts the glucose into free fatty acids (FFAs)and triglycerides.One of the enzymes involved in hepatic lipogenesis is:

A)Glucose-6-phosphatase.
B)Phosphorylase.
C)Pyruvate carboxylase.
D)Fatty acyl oxidase.
E)Acetyl coenzyme A (CoA)carboxylase.

Accepted Answer

Acetyl-CoA carboxylase is an enzyme involved in hepatic lipogenesis, which converts glucose into free fatty acids and triglycerides. Glucose-6-phosphatase and phosphorylase are involved in gluconeogenesis, while pyruvate carboxylase is involved in the conversion of pyruvate to oxaloacetate in the citric acid cycle. Fatty acyl oxidase is involved in the breakdown of fatty acids.

Question 10

A major source of stored energy for skeletal muscle during exercise is:&#10;A)Lactate.&#10;B)Triglyceride.&#10;C)Glycogen.&#10;D)Ketone bodies.&#10;E)Fatty acids.

Accepted Answer

Glycogen is a major source of stored energy for skeletal muscle during exercise. It is a polysaccharide made up of glucose molecules that can be rapidly broken down into glucose-6-phosphate and used for energy production through glycolysis. Lactate, triglyceride, ketone bodies, and fatty acids can also be utilized for energy production but are not the major source of stored energy for skeletal muscle during exercise.

Question 11

Triglycerides are extremely hydrophobic and need to be transported in lipoprotein particles.The particle involved in the transfer of triglycerides from the liver to adipose tissue is called:&#10;A)VLDL.&#10;B)LDL.&#10;C)Chylomicron.&#10;D)Intermediate-density lipoprotein (IDL).&#10;E)High-density lipoprotein (HDL).

Accepted Answer

The answer of Triglycerides are extremely hydrophobic and need to...

Question 12

A primary target of insulin in skeletal muscle is:&#10;A)Glucokinase.&#10;B)Acetyl CoA carboxylase.&#10;C)Uncoupling proteins.&#10;D)Fatty acid synthase.&#10;E)Glucose transporter 4 (GLUT-4).

Accepted Answer

The answer of A primary target of insulin in skeletal...

Question 13

Glucagon has an important counterregulatory role that prevents hypoglycemia.Which glucagon-stimulated enzyme increases hepatic glucose production and thus blood glucose levels?&#10;A)Hormone-sensitive lipase&#10;B)Lipoprotein lipase&#10;C)Fructose-1,6-bisphosphatase&#10;D)Glycogen synthase&#10;E)Fatty acyl oxidase

Accepted Answer

The answer of Glucagon has an important counterregulatory role that...

Question 14

Juvenile-onset type 1 diabetes is often suspected by parents because of which change in the child's appearance or behavior?&#10;A)Sudden increase in muscle mass&#10;B)Darkening of the skin&#10;C)Increased thirst and frequency of urination&#10;D)Puffiness around the face&#10;E)Early (precocious)pubertal growth spurt

Accepted Answer

The answer of Juvenile-onset type 1 diabetes is often suspected...

Question 15

The first action of secreted insulin is:&#10;A)Activation of lipoprotein lipase.&#10;B)Inhibition of glucagon secretion.&#10;C)Stimulation of hepatic glycolysis.&#10;D)Mobilization of GLUT-4 into myocellular membranes.&#10;E)Inhibition of appetite.

Accepted Answer

The answer of The first action of secreted insulin is:&#10;A)Activation...

Deck 39: Hormonal Regulation of Energy Metabolism