Quiz

30 Questions

Which one of these disaccharides is a reducing sugar?

Lactose

Which one of these disaccharides is a non-reducing sugar?

Sucrose

Which one of these sugars can be oxidized at the aldehyde carbon to form an acid?

Glucose

Which one of these sugars is a polyol?

Sorbitol

Which monosaccharide is absorbed from the intestinal lumen to blood via facilitated diffusion?

Fructose

Which transporter is responsible for the absorption of glucose and galactose against their concentration gradient?

SGLT1

Which transporter is responsible for the absorption of glucose, galactose, and fructose into the blood?

GLUT2

Which GLUT transporter is present in extremely high concentrations in red blood cells?

GLUT1

Which of the following is a characteristic of homopolysaccharides?

They consist of one type of monosaccharide.

Which of the following is a characteristic of amylopectin?

It consists of branched chains.

Which of the following is a characteristic of glycogen?

It is the reserve carbohydrate of animals.

Which of the following is a characteristic of cellulose?

It is the principal structural component of the plant cell wall.

Which enzyme hydrolyzes internal $\alpha$-1,4-bonds between glucosyl residues at random intervals in the polysaccharide chains?

Salivary $\alpha$-amylase

Where is the activity of glucoamylase highest?

Ileum

Which enzyme breaks the $\alpha$-1,4-bonds and $\alpha$-1,6-bonds?

Sucrase

Which type of intolerance is caused by bacterial fermentation of lactose in the colon?

Secondary intolerance

Which of the following is NOT a function of carbohydrates in the body?

Serving as structural components of organisms

Which of the following is NOT a major monosaccharide found in the human body and diet?

Sucrose

Which of the following is the correct diagram of how glucose is transported across intestinal epithelial cells and into the bloodstream?

Diagram A

Which of the following is the correct role of glucose transporters (GLUTs) in the transport of glucose into and out of cells?

GLUTs transport glucose into cells and out of cells

Which of the following is true about monosaccharides?

They can be oxidized at the aldehyde carbon to form an acid

Which of the following is true about aldoses and ketoses?

Aldoses and ketoses differ in the position of the hydroxyl group on one or more of their asymmetric carbons

Which of the following is true about D-sugars and L-sugars?

D-sugars have the -OH group on the right of the penultimate carbon

Which of the following is true about ring structures of monosaccharides?

Ring structures of monosaccharides are called furanose and pyranose

Which of the following is true about the Vmax for glucose transport into the brain?

The Vmax for glucose transport into the brain is lower than the rate of glucose utilization by the brain.

Which of the following is true about the transport of glucose in muscles and adipose cells?

The transport of glucose is greatly stimulated by insulin in muscles and adipose cells.

Which of the following is true about the stimulation of glucose transport by insulin in adipose tissue?

The stimulation of glucose transport by insulin in adipose tissue increases its availability for the synthesis of fatty acids and glycerol.

Which of the following is true about the stimulation of glucose transport by insulin in skeletal muscle?

The stimulation of glucose transport by insulin in skeletal muscle increases its availability for glycolysis and glycogen synthesis.

Which of the following is true about the release of insulin from beta cells of the pancreas?

Phosphorylated glucose is trapped in beta cells.

Which of the following is true about the stimulation of insulin release from beta cells of the pancreas?

Elevated concentrations of glucose in blood stimulate release of insulin from beta cells.

Study Notes

Carbohydrates

Sucrose is a non-reducing sugar.
Lactose is a reducing sugar.
Sucrose can be oxidized at the aldehyde carbon to form an acid.
Sorbitol is a polyol.

Absorption of Sugars

Galactose is absorbed from the intestinal lumen to blood via facilitated diffusion.
Glucose and galactose are absorbed against their concentration gradient by the transporter SGLT1.
Glucose, galactose, and fructose are absorbed into the blood by the transporter GLUT2.

GLUT Transporters

GLUT1 transporter is present in extremely high concentrations in red blood cells.

Polysaccharides

Homopolysaccharides are composed of a single type of monosaccharide.
Amylopectin is a branched polysaccharide.
Glycogen is a branched polysaccharide stored in liver and muscle cells.
Cellulose is a linear polysaccharide.

Enzymes

α-Amylase hydrolyzes internal α-1,4-bonds between glucosyl residues at random intervals in the polysaccharide chains.
Glucoamylase has highest activity in the small intestine.
Amyloglucosidase breaks the α-1,4-bonds and α-1,6-bonds.

Lactose Intolerance

Lactose intolerance is caused by bacterial fermentation of lactose in the colon.

Functions of Carbohydrates

Carbohydrates provide energy, spare protein, and are components of nucleic acids, glycoproteins, and glycolipids.

Monosaccharides

The major monosaccharides found in the human body and diet are glucose, galactose, fructose, and ribose.

Transport of Glucose

Glucose is transported across intestinal epithelial cells and into the bloodstream via GLUT2 and SGLT1 transporters.

Glucose Transporters (GLUTs)

GLUTs facilitate the transport of glucose into and out of cells.

Monosaccharide Characteristics

Monosaccharides can be classified as aldoses or ketoses.
D-sugars are found in nature, while L-sugars are not.
Monosaccharides can exist in ring structures.

Glucose Transport in Cells

Glucose transport into the brain is not saturated, meaning it can be increased with increased GLUT transporters.
Glucose transport in muscles and adipose cells is stimulated by insulin.
Insulin stimulates glucose transport in adipose tissue by increasing GLUT4 transporter activity.
Insulin stimulates glucose transport in skeletal muscle by increasing GLUT4 transporter activity.

Insulin Release

Insulin release from beta cells of the pancreas is stimulated by high glucose levels.

Test your knowledge on the absorption of dietary carbohydrates with this quiz. Learn about the main monosaccharides that are absorbed from the intestinal lumen to blood, including glucose, galactose, and fructose. Explore the process of secondary active transport and enhance your understanding of this topic.

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