GLUT Transporters in Metabolism Quiz

Organic molecules primarily composed of carbon, hydrogen, and oxygen, structured like a hydrate of carbon (C‒H2O)n.

Simple sugars, like glucose and fructose, that cannot be broken down further.

Two monosaccharides linked together, like sucrose (table sugar) and lactose (milk sugar).

Polymers of multiple saccharide units connected by glycosidic bonds, including oligosaccharides and polysaccharides.

Complex carbs containing 3-10 saccharide units, often found attached to proteins or lipids in cell membranes.

Complex carbs with more than 10 saccharide units, often thousands, like starch and cellulose.

Large circular folds lining the small intestine, increasing its surface area for absorption.

Finger-like projections in the small intestine, containing enterocytes (absorptive cells) for nutrient uptake.

The brush border (also called apical) membrane is the outer layer of the enterocyte cell that faces the lumen of the gut.

Monosaccharides, like glucose and galactose, need to cross the enterocyte membrane twice - once to enter the cell and again to exit into the bloodstream.

The basolateral membrane is the inner surface of the enterocyte that faces the bloodstream. It's where absorbed nutrients exit the cell.

SGLTs are active transporters that use energy to move glucose and galactose from the gut lumen into the enterocyte. They work by coupling glucose transport with the movement of sodium ions.

GLUTs are passive transporters that help glucose and other sugars move across cell membranes down their concentration gradient. They don't require energy to function.

GLUTs are integral proteins that span the cell membrane. They form channels that allow sugars to pass through.

SGLT1 is primarily found in the brush border membrane of enterocytes and plays a key role in absorbing dietary glucose and galactose.

GLUT1 is the most common glucose transporter in the body and helps glucose cross the blood-brain barrier. It's essential for supplying energy to the brain.

A glucose transporter protein primarily responsible for supplying glucose to red blood cells, brain endothelial cells, and fetal tissues. Its deficiency leads to GLUT1 deficiency syndrome, characterized by seizures in early infancy due to insufficient glucose supply to the brain.

A low-affinity, high-capacity glucose transporter mainly found in the pancreas, liver, small intestine, and kidneys. It plays a key role in transporting glucose from the gut into the bloodstream.

A high-affinity glucose transporter that primarily supplies glucose to tissues with high energy demand, such as the brain and neurons. It's also expressed in tissues like spermatozoa and the placenta.

The primary insulin-regulated glucose transporter in muscle and adipose tissue. It facilitates glucose uptake into these tissues in response to insulin.

A fructose-specific transporter, meaning it only transports fructose. It's primarily found in the small intestine, playing a crucial role in absorbing dietary fructose.

The process of maintaining a stable blood glucose concentration, involving the coordinated effort of various organs like the small intestine, liver, kidneys, muscles, and adipose tissue.

A dietary regimen high in fat and low in carbohydrates, often used to treat conditions like epilepsy. It raises ketone body levels in the blood, providing an alternative fuel source for the brain.

Organic molecules produced during the breakdown of fats, which can be used as an energy source by the body, especially the brain.

The process by which the body removes glucose from or returns glucose to the blood. This is primarily regulated by insulin and glucagon, but also by cortisol.

The primary anabolic hormone responsible for lowering blood glucose levels. It stimulates the uptake of glucose, amino acids, and lipids for storage in muscle and adipose tissue.

The process by which glucose is stored in the liver and muscle tissue in the form of glycogen.

The primary catabolic hormone responsible for raising blood glucose levels. It stimulates the breakdown of liver glycogen and encourages fat breakdown.

The process of breaking down glycogen stores in the liver, releasing glucose into the bloodstream.

The process of creating new glucose from non-carbohydrate sources, primarily in the liver, triggered by cortisol to increase blood sugar.

A state where the body's cells become resistant to the effects of insulin, meaning insulin is less effective at lowering blood glucose levels.

Muscle hexokinase can function at maximum velocity even with normal blood glucose levels due to its low Km, meaning it efficiently uses glucose even when it's not abundant.

Glucokinase, the liver's primary hexokinase, is not inhibited by glucose-6-phosphate. This allows rapid phosphorylation of excess glucose, especially after a meal.

Glucokinase has a higher Km than muscle hexokinase, allowing it to efficiently convert glucose into its phosphorylated form when blood glucose rises significantly.

Phosphorylation of glucose by glucokinase decreases the free glucose concentration in the liver cell, creating a concentration gradient for more glucose from the blood.

GLUT2, the main glucose transporter in the liver, has a high capacity and doesn't depend on insulin, allowing the liver to actively reduce blood glucose levels.

Glucokinase is inducible by insulin, meaning its activity increases with insulin levels. This enhances glucose uptake in the liver after meals.

In type 1 diabetes, low insulin levels decrease glucokinase activity, reducing liver glucose uptake and contributing to high blood sugar.

In type 2 diabetes, glucokinase becomes resistant to insulin's effects, leading to impaired glucose uptake in the liver and further contributing to high blood sugar.

An enzyme that catalyzes the formation of UDP-glucose from glucose-1-phosphate and UTP, a crucial step in glycogen synthesis.

The main enzyme responsible for adding UDP-glucose to a growing glycogen chain, extending the glycogen molecule.

A short chain of glucose units required as a starting point for glycogen synthase to begin adding more glucose.

A branching enzyme that transfers a short oligosaccharide segment from the end of a glycogen chain to create branches, increasing its solubility and compactness.

The active form of glycogen synthase, which is dephosphorylated and readily synthesizes glycogen.

The less active form of glycogen synthase, which is phosphorylated and less efficient at synthesizing glycogen.