Describe the process (step by step) how a glucose molecule is absorbed from the lumen of the intestine to the blood. Include what energy drives this process. Then explain how researchers like Pia Roder were able to use radioactivity to determine where and how the transporters functioned. (The answer must be in a long paragraph form) Solution Carbohydrates initially undergo chemical digestion by salivary amylases result in formation of simple monomer sugars of \"glucose\" etc finally absorbed directly into the sublingual circulation. Later mixed food material enters into the pharynx from mouth due to the peristaltic movement of the visceral smooth muscles finally enters into the stomach Disaccharidases are the enzymes secreted from the brush border cells of intestine. These enzymes are sucrase, maltase, and lactase. These enzymes acts on disachraides such as maltose, sucrose and lactose and digests them into monomer sugar units of glucose & galactose. Simple, soluble and absorbable monomer glucose molecules \"diffused\" (diffusion) into the blood portals finally food chyme enters into the large intestine for reabsorption. It has clearly observed the \"sodium -glucose symport\" enable the transport of glucose monomers after digestion into the intestinal epithelial cells via microvilli (improve absorption) finally into the interstitial space followed by movement of glucose into the blood down the concentration gradient (crossing basilar membrane). Primary active transport using Na+-K+- ATPase improves movement sodium inside and potassium outside using energy followed by building up of interstitial sodium concentration. Sodium –glucose symport has considered as secondary active transport as it is a co-transporter. P V Roder analysis of \"glucose transporter functions\" via radioactivity principle: The sodium-glucose linked transporter (SGLTs, a co-transporter) uses the energy generated by the ATPase pump through the downhill sodium ion gradient for the glucose transportation across the apical membrane (against the glucose gradient). SGLTs are an example of secondary active transport. The glucose transporters (GLUT) present in the basolateral membrane now allow the glucose transport into the peritubular capillaries. Inhibition of the Na+/K+/ATPase fails to generate energy required for the SGLT secondary transporters, which inhibits glucose uptake. Sugars such as glucose, galactose and free amino acid (alanine) uptake into the microvilli epithelial cells is based on sodium mediated cotransport whereas fructose cannot be transported by sodium mediated transport during absorption after digestion. H+ mediated oligopeptide transport is present in gut epithelium. Scientist PV Roder has analyzed the function of SGLTs and GLUTs in the apical membrane using “radiotracer glucose gavage“, in which mice was taken of two different types such as “Sglt1 expressing wild type” and ” mice with sglt1-knockout” finally C14 radioactive tracing performed for the moveme.

1. Describe the process (step by step) how a glucose molecule is absorbed from the lumen of the
intestine to the blood. Include what energy drives this process. Then explain how researchers like
Pia Roder were able to use radioactivity to determine where and how the transporters functioned.
(The answer must be in a long paragraph form)
Solution
Carbohydrates initially undergo chemical digestion by salivary amylases result in formation of
simple monomer sugars of "glucose" etc finally absorbed directly into the sublingual
circulation. Later mixed food material enters into the pharynx from mouth due to the peristaltic
movement of the visceral smooth muscles finally enters into the stomach
Disaccharidases are the enzymes secreted from the brush border cells of intestine. These
enzymes are sucrase, maltase, and lactase. These enzymes acts on disachraides such as maltose,
sucrose and lactose and digests them into monomer sugar units of glucose & galactose. Simple,
soluble and absorbable monomer glucose molecules "diffused" (diffusion) into the blood
portals finally food chyme enters into the large intestine for reabsorption.
It has clearly observed the "sodium -glucose symport" enable the transport of glucose
monomers after digestion into the intestinal epithelial cells via microvilli (improve absorption)
finally into the interstitial space followed by movement of glucose into the blood down the
concentration gradient (crossing basilar membrane). Primary active transport using Na+-K+-
ATPase improves movement sodium inside and potassium outside using energy followed by
building up of interstitial sodium concentration. Sodium –glucose symport has considered as
secondary active transport as it is a co-transporter.
P V Roder analysis of "glucose transporter functions" via radioactivity principle:
The sodium-glucose linked transporter (SGLTs, a co-transporter) uses the energy generated by
the ATPase pump through the downhill sodium ion gradient for the glucose transportation across
the apical membrane (against the glucose gradient). SGLTs are an example of secondary active
transport. The glucose transporters (GLUT) present in the basolateral membrane now allow the
glucose transport into the peritubular capillaries. Inhibition of the Na+/K+/ATPase fails to
generate energy required for the SGLT secondary transporters, which inhibits glucose uptake.
Sugars such as glucose, galactose and free amino acid (alanine) uptake into the microvilli
epithelial cells is based on sodium mediated cotransport whereas fructose cannot be transported
by sodium mediated transport during absorption after digestion. H+ mediated oligopeptide
transport is present in gut epithelium.
Scientist PV Roder has analyzed the function of SGLTs and GLUTs in the apical membrane

2. using “radiotracer glucose gavage“, in which mice was taken of two different types such as
“Sglt1 expressing wild type” and ” mice with sglt1-knockout” finally C14 radioactive tracing
performed for the movement of glucose followed by Western blot analysis. The results have
produced that intestinal glucose uptake SGLT1 glucose transporter abundance in “intestinal
apical membrane” fractions