Question 1

Which enzyme, found primarily in the liver, dictates that the gluconeogenic pathway of the Cori cycle occurs in the liver?

Accepted Answer

A)  glucose 6-phosphatase 
B)  glucokinase 
C)  glucose 6-phosphate dehydrogenase 
D)  glyceraldehyde 3-phosphate dehydrogenase 
E)  phosphoglucomutase 
A)  glucose 6-phosphatase 
B)  glucokinase 
C)  glucose 6-phosphate dehydrogenase 
D)  glyceraldehyde 3-phosphate dehydrogenase 
E)  phosphoglucomutase A

Question 2

When blood glucose is abnormally low, the pancreas releases:

Accepted Answer

A)  epinephrine. 
B)  glucagon. 
C)  glucose. 
D)  insulin. 
E)  trypsin. 
A)  epinephrine. 
B)  glucagon. 
C)  glucose. 
D)  insulin. 
E)  trypsin. B

Question 3

Provide three distinguishing characteristics between white adipose tissue (WAT) and brown adipose tissue (BAT).

Accepted Answer

White adipose tissue (WAT) and brown adipose tissue (BAT) are two types of fat found in mammals, each with distinct functions and characteristics. Here are three distinguishing features between them:

1. **Cellular Composition and Color**:
   - **White Adipose Tissue (WAT)**: WAT is composed of large, white fat cells (adipocytes) that contain a single, large lipid droplet that stores fats (triglycerides). The lipid droplet pushes the nucleus and other organelles to the periphery of the cell, giving the cell a signet ring appearance. The white color of this tissue is due to the lack of pigmented mitochondria and the abundance of stored fat.
   - **Brown Adipose Tissue (BAT)**: BAT consists of smaller brown fat cells that have multiple small lipid droplets and a high number of mitochondria containing iron, which gives the tissue its characteristic brown color. These mitochondria are responsible for the tissue's ability to generate heat through a process called non-shivering thermogenesis.

2. **Function**:
   - **White Adipose Tissue (WAT)**: The primary function of WAT is to store energy in the form of fats, which can be mobilized during periods of energy deficit. It also serves as an insulator to help maintain body temperature and acts as a cushion to protect internal organs.
   - **Brown Adipose Tissue (BAT)**: The main function of BAT is to generate body heat by burning fats, a process known as thermogenesis. This is particularly important in newborns and hibernating mammals, as it helps to maintain body temperature without the need for muscle activity (shivering).

3. **Distribution in the Body**:
   - **White Adipose Tissue (WAT)**: WAT is widely distributed throughout the body. It is found beneath the skin (subcutaneous fat), around internal organs (visceral fat), in the bone marrow (marrow fat), and in specific areas such as the buttocks, thighs, and abdomen.
   - **Brown Adipose Tissue (BAT)**: BAT is more localized and is typically found in specific areas such as around the neck, along the upper back, and near the kidneys. In humans, its prevalence decreases with age, and it is more abundant in infants and young children.

These differences between WAT and BAT reflect their unique roles in energy storage and thermoregulation, respectively.

Question 4

In an attempt to control type 2 diabetes, some people follow a high-fat, low-carbohydrate diet. Which substance(s) would NOT have an increased concentration in the blood after two weeks on this diet?

Accepted Answer

A)  fatty acids 
B)  glucagon 
C)  acetone 
D)  glucose 
E)  amino acids 
A)  fatty acids 
B)  glucagon 
C)  acetone 
D)  glucose 
E)  amino acids

Question 5

What two properties make triglycerides more efficient than glycogen for the storage of metabolic energy?

Accepted Answer

A)  They are anhydrous and less reduced. 
B)  They are anhydrous and more reduced. 
C)  They are hydrated and less reduced. 
D)  They are hydrated and more reduced. 
A)  They are anhydrous and less reduced. 
B)  They are anhydrous and more reduced. 
C)  They are hydrated and less reduced. 
D)  They are hydrated and more reduced.

Question 6

Which hormone inhibits the release of neuropeptide Y (NPY) from orexigenic neurons?

Accepted Answer

A)  leptin 
B)  ghrelin 
C)  glucagon-like peptide 1 
D)  both leptin and ghrelin 
E)  both leptin and glucagon-like peptide 1 
A)  leptin 
B)  ghrelin 
C)  glucagon-like peptide 1 
D)  both leptin and ghrelin 
E)  both leptin and glucagon-like peptide 1

Question 7

Which factor is NOT associated with exercise?

Accepted Answer

A)  activation of AMP-activated protein kinase 
B)  decreased release of insulin from the pancreas 
C)  activation of acetyl-CoA carboxylase 
D)  activation of the kinase activity of PFK-2 in skeletal muscle 
E)  inhibition of glycogen synthase 
A)  activation of AMP-activated protein kinase 
B)  decreased release of insulin from the pancreas 
C)  activation of acetyl-CoA carboxylase 
D)  activation of the kinase activity of PFK-2 in skeletal muscle 
E)  inhibition of glycogen synthase

Question 8

Briefly describe the "lipid burden" hypothesis that explains the development of type 2 diabetes.

Accepted Answer

The "lipid burden" hypothesis, also know

Question 9

What would likely be the consequence of a biochemical defect in which insulin was secreted in excess?

Accepted Answer

A)  muscular fatigue due to lactic acidosis 
B)  inhibited glycolysis in the liver resulting in enhanced glycogen stores 
C)  lowered concentrations of glucose circulating in the blood stream 
D)  depressed rate of fatty acid synthesis in the liver 
E)  enhanced rate of gluconeogenesis in hepatocytes 
A)  muscular fatigue due to lactic acidosis 
B)  inhibited glycolysis in the liver resulting in enhanced glycogen stores 
C)  lowered concentrations of glucose circulating in the blood stream 
D)  depressed rate of fatty acid synthesis in the liver 
E)  enhanced rate of gluconeogenesis in hepatocytes

Question 10

Which statement is TRUE regarding the protein leptin?

Accepted Answer

A)  Leptin is a hormone made primarily by hepatocytes that functions to regulate energy balance by curtailing appetite. 
B)  Leptin makes hepatocytes and myocytes more sensitive to insulin. 
C)  Leptin is also involved in regulating the sympathetic nervous system, resulting in a decrease in blood pressure, heart rate, and thermogenesis. 
D)  The amount of leptin released by adipose tissue is independent of the number and size of adipocytes; rather, it is strictly correlated with ingestion of food. 
E)  Leptin causes the release of orexigenic peptides that act in the brain to inhibit appetite. 
A)  Leptin is a hormone made primarily by hepatocytes that functions to regulate energy balance by curtailing appetite. 
B)  Leptin makes hepatocytes and myocytes more sensitive to insulin. 
C)  Leptin is also involved in regulating the sympathetic nervous system, resulting in a decrease in blood pressure, heart rate, and thermogenesis. 
D)  The amount of leptin released by adipose tissue is independent of the number and size of adipocytes; rather, it is strictly correlated with ingestion of food. 
E)  Leptin causes the release of orexigenic peptides that act in the brain to inhibit appetite.

Question 11

Which effect is NOT mediated by the protein leptin?

Accepted Answer

A)  increased synthesis of uncoupler protein thermogenin 
B)  decreased activity of the enzyme 5´-AMP-activated protein kinase (AMPK) 
C)  increased activity of the sympathetic nervous system 
D)  increased $\beta$ oxidation 
E)  decreased desire to eat 
A)  increased synthesis of uncoupler protein thermogenin 
B)  decreased activity of the enzyme 5´-AMP-activated protein kinase (AMPK) 
C)  increased activity of the sympathetic nervous system 
D)  increased $\beta$ oxidation 
E)  decreased desire to eat

Question 12

An elevated insulin level in the blood:

Accepted Answer

A)  inhibits glucose uptake by the liver. 
B)  inhibits glycogen synthesis in the liver and muscle. 
C)  results from a below-normal blood glucose level. 
D)  stimulates glycogen breakdown in liver. 
E)  stimulates synthesis of fatty acids and triacylglycerols in the liver. 
A)  inhibits glucose uptake by the liver. 
B)  inhibits glycogen synthesis in the liver and muscle. 
C)  results from a below-normal blood glucose level. 
D)  stimulates glycogen breakdown in liver. 
E)  stimulates synthesis of fatty acids and triacylglycerols in the liver.

Question 13

In a well-fed individual, which factor does NOT contribute to the synthesis of fatty acids and triacylglycerols in the liver?

Accepted Answer

A)  dihydroxyacetone phosphate 
B)  carbon skeletons derived from amino acids 
C)  carnitine. 
D)  HCO3- 
E)  citrate 
A)  dihydroxyacetone phosphate 
B)  carbon skeletons derived from amino acids 
C)  carnitine. 
D)  HCO3- 
E)  citrate

Question 14

Which condition is NOT typically associated with metabolic syndrome?

Accepted Answer

A)  hypotension 
B)  elevated fasting plasma glucose 
C)  elevated serum levels of LDL 
D)  abdominal obesity 
E)  reduced serum levels of HDL 
A)  hypotension 
B)  elevated fasting plasma glucose 
C)  elevated serum levels of LDL 
D)  abdominal obesity 
E)  reduced serum levels of HDL

Question 15

Long-term maintenance of body weight is regulated by the hormone:

Accepted Answer

A)  adiposin. 
B)  hypothalmin. 
C)  leptin. 
D)  obesin. 
E)  testosterone. 
A)  adiposin. 
B)  hypothalmin. 
C)  leptin. 
D)  obesin. 
E)  testosterone.

Question 16

The three common $\alpha$-keto acids involved in transamination reactions are:

Accepted Answer

A)  glutamate, succinate, and acetate. 
B)  glutamate, aspartate, and alanine. 
C)  succinate, fumarate, and malate. 
D)  pyruvate, oxaloacetate, and $\alpha$ ketoglutarate. 
E)  citrate, 3-phosphoglycerate, and isocitrate. 
A)  glutamate, succinate, and acetate. 
B)  glutamate, aspartate, and alanine. 
C)  succinate, fumarate, and malate. 
D)  pyruvate, oxaloacetate, and $\alpha$ ketoglutarate. 
E)  citrate, 3-phosphoglycerate, and isocitrate.

Question 17

In skeletal muscle:

Accepted Answer

A)  amino acids are an essential fuel. 
B)  at rest, fatty acids are the preferred fuel. 
C)  large quantities of triacylglycerol are stored as fuel. 
D)  phosphocreatine can substitute for ATP as the direct source of energy for muscle contraction. 
E)  stored muscle glycogen can be converted to glucose and released to replenish blood glucose. 
A)  amino acids are an essential fuel. 
B)  at rest, fatty acids are the preferred fuel. 
C)  large quantities of triacylglycerol are stored as fuel. 
D)  phosphocreatine can substitute for ATP as the direct source of energy for muscle contraction. 
E)  stored muscle glycogen can be converted to glucose and released to replenish blood glucose.

Question 18

How do hormonal cascades result in large amplification of the original signal?

Accepted Answer

Hormonal cascades result in large amplif

Question 19

In uncontrolled insulin-dependent diabetes, which pathway or reaction is accelerated, possibly resulting in toxic effects by the end product(s)?

Accepted Answer

A)  accelerated conversion of $\beta$-hydroxy $\beta$-methylglutaryl-CoA to acetoacetate 
B)  accelerated conversion of $\beta$-hydroxy $\beta$-methylglutaryl-CoA to mevalonate 
C)  acceleration of the citric acid cycle 
D)  accelerated removal of triglycerides from chylomicrons 
E)  acceleration of the pentose phosphate pathway in erythrocytes 
A)  accelerated conversion of $\beta$-hydroxy $\beta$-methylglutaryl-CoA to acetoacetate 
B)  accelerated conversion of $\beta$-hydroxy $\beta$-methylglutaryl-CoA to mevalonate 
C)  acceleration of the citric acid cycle 
D)  accelerated removal of triglycerides from chylomicrons 
E)  acceleration of the pentose phosphate pathway in erythrocytes

Question 20

Which two hormones play a crucial role in regulating short-term eating behavior?

Accepted Answer

A)  leptin and ghrelin 
B)  cortisol and leptin 
C)  ghrelin and PYY3-36 
D)  insulin and glucagon 
E)  adiponectin and PYY3-36 
A)  leptin and ghrelin 
B)  cortisol and leptin 
C)  ghrelin and PYY3-36 
D)  insulin and glucagon 
E)  adiponectin and PYY3-36

Exam 23: Hormonal Regulation and Integration of Mammalian Metabolism

Which enzyme, found primarily in the liver, dictates that the gluconeogenic pathway of the Cori cycle occurs in the liver?

When blood glucose is abnormally low, the pancreas releases:

Provide three distinguishing characteristics between white adipose tissue (WAT) and brown adipose tissue (BAT).

In an attempt to control type 2 diabetes, some people follow a high-fat, low-carbohydrate diet. Which substance(s) would NOT have an increased concentration in the blood after two weeks on this diet?

What two properties make triglycerides more efficient than glycogen for the storage of metabolic energy?

Which hormone inhibits the release of neuropeptide Y (NPY) from orexigenic neurons?

Which factor is NOT associated with exercise?

Briefly describe the "lipid burden" hypothesis that explains the development of type 2 diabetes.

What would likely be the consequence of a biochemical defect in which insulin was secreted in excess?

Which statement is TRUE regarding the protein leptin?

Which effect is NOT mediated by the protein leptin?

An elevated insulin level in the blood:

In a well-fed individual, which factor does NOT contribute to the synthesis of fatty acids and triacylglycerols in the liver?

Which condition is NOT typically associated with metabolic syndrome?

Long-term maintenance of body weight is regulated by the hormone:

The three common α\alphaα -keto acids involved in transamination reactions are:

In skeletal muscle:

How do hormonal cascades result in large amplification of the original signal?

In uncontrolled insulin-dependent diabetes, which pathway or reaction is accelerated, possibly resulting in toxic effects by the end product(s)?

Which two hormones play a crucial role in regulating short-term eating behavior?

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

The three common $\alpha$ -keto acids involved in transamination reactions are: