chapter 22

What causes type I diabetes?

Antibodies and leukocytes destroy beta cells.

Insulin is produced by the ________ cells of the pancreas.

beta

Which pathway is the opposite of lipogenesis?

beta-oxidation

type 1 diabetes

body cannot produce insulin

type 2 diabetes

cell does not respond to insulin, from birth

During aerobic metabolism of glucose, most ATP is produced during which group of chemical reactions?

electron transport (yielding 26-28 molecules of ATP per molecule of glucose)

The production of glucose from smaller products like lactate and amino acids

Gluconeogenesis

A process by which excess glucose is linked together and stored as glycogen in muscle and liver

Glycogenesis

The breakdown of glycogen stores from the liver to produce glucose

Glycogenolysis

The metabolic pathway that breaks down glucose into two pyruvate molecules

Glycolysis

Insulin plays a vital role in carbohydrate metabolism. What is its role?

Insulin is needed for cells to pick up glucose from the blood; without insulin, more glucose will remain in the blood.

Why is glucose present in the urine of people with diabetes mellitus?

Insulin target cells are unable to take in the glucose from the blood, resulting in hyperglycemia and saturation of kidney glucose transporters.

How does binding of insulin to its receptor cause glucose uptake from the bloodstream?

It causes insertion of GLUT4 transporters in the membrane.

The breakdown of triglycerides using lipases

Lipolysis

Body cells that respond to insulin include

Liver cells, as well as most other cells of the body.

When blood glucose levels are low

The pancreas releases glucagon, which eventually causes blood glucose levels to increase.

When blood glucose levels are high

The pancreas releases insulin.

The time between meals when the body is performing catabolic reactions in order to maintain blood glucose levels

fasted state

The time occurring right after a meal when the body is absorbing macronutrients

fed state

Which is the best example of negative feedback?

Thyroid hormone (TH) secreted into the bloodstream causes increased cellular metabolism and increased body temperature, and increased TH levels inhibit TH release.

Which hormone stimulates the breakdown of polymerized glucose?

glucagon

Which function is NOT associated with a glucagon-dominated metabolic state?

glucose oxidation

Glucose is stored in the human body as _______.

glycogen

The body's tendency to maintain relatively constant internal conditions is called

homeostasis

What happens to excess glucose in the body?

it undergoes lipogenesis

What cells in the body respond to glucagon by breaking down glycogen and releasing glucose?

liver cells

What are the products of glycolysis?

2 pyruvate molecules, 2 ATP molecules, and 2 NADH molecules

Glucose remains in the bloodstream as a result of _______.

type 1 and type 2 diabetes mellitus

A liver cell responds to insulin by

taking in glucose and converting it to glycogen.

Excess glucose can be found in the urine _______.

when the transport maximum for reabsorption in the kidney tubules is exceeded, as a result of type 1 diabetes or as a result of type 2 diabetes