Carbohydrates & Metabolism Overview

Questions and Answers

What distinguishes anabolic pathways in metabolism?

They synthesize complex molecules from smaller ones. (correct)

They do not require any energy input.

They primarily break down complex molecules.

They produce energy in the form of ATP.

What is the primary function of glycosidases in carbohydrate metabolism?

To break down polysaccharides into monosaccharides. (correct)

To transport glucose across intestinal walls.

To synthesize complex carbohydrates.

To absorb monosaccharides into cells.

Which statement correctly describes the absorption of glucose and galactose in the intestine?

They infrequently require energy input for absorption.

They are absorbed without any transport proteins.

They utilize sodium-dependent transport proteins. (correct)

They are absorbed solely through passive transport.

Why are indigestible polysaccharides important in human nutrition?

They contribute to dietary fiber and aid digestion. Signup and view all the answers

What role does NADPH play in anabolic reactions?

It contributes reducing power for biosynthetic processes. Signup and view all the answers

Which of the following substances are the direct products of carbohydrate digestion?

Glucose, galactose, and fructose. Signup and view all the answers

What distinguishes the transport mechanism of fructose compared to glucose and galactose in the intestine?

Fructose requires a sodium-independent transporter. Signup and view all the answers

Which type of bond in cellulose makes it indigestible for humans?

Beta-1,4 glycosidic bonds. Signup and view all the answers

Study Notes

Carbohydrates

Indigestible polysaccharides are components of dietary fiber that pass through the intestines to feces
Cellulose, a type of indigestible polysaccharide, cannot be cleaved by human enzymes due to its β-1,4 bonds

Metabolism

Metabolism refers to the processing of dietary components after digestion and absorption
Anabolic pathways are synthetic processes focused on synthesizing compounds
Anabolic reactions combine smaller molecules such as amino acids to form larger molecules like proteins
These reactions are endergonic, meaning they store energy, primarily derived from ATP breakdown
The electron donor NADPH often provides the reducing power in anabolic reactions

Absorption of Glucose, Fructose, and Galactose

Glucose, fructose, and galactose are the final products of carbohydrate digestion, absorbed by intestinal epithelial cells
Galactose and glucose utilize the sodium-dependent glucose cotransporter 1 (SGLT-1) for active transport into mucosal cells
Fructose is absorbed through a sodium-independent transporter called GLUT-5

Glycosidases

Glycosidases are enzymes that act on glycosyl residues, breaking specific bonds based on structure and configuration
The end products of carbohydrate digestion are monosaccharides: glucose, galactose, and fructose, absorbed by small intestine cells

Description

This quiz covers the basics of carbohydrates, focusing on indigestible polysaccharides like cellulose and their role in dietary fiber. Additionally, it explores metabolism, particularly anabolic pathways involved in synthesizing compounds from dietary components.