Molecular Biology Homework: Systems, Glucose, and Insulin Production

This molecular biology assignment delves into the interconnectedness of various biological systems, focusing on the endomembrane, digestive, and circulatory systems. It examines the role of the endomembrane system, particularly the endoplasmic reticulum (ER), in insulin production and transportation, highlighting the cellular response to hyperglycemia. The assignment further explores nutrient absorption in the small intestine, emphasizing the role of microvilli and the subsequent transport of glucose to various tissues and organs via the circulatory system. The process of carbohydrate digestion, glucose absorption, and the role of insulin in regulating blood glucose levels are also discussed. Finally, the assignment touches upon the implications of hyperglycemic blood and the condition of glycosuria, linking these concepts to diabetes. The conclusion emphasizes the interdependence of these systems in maintaining homeostasis and overall life processes.

Running head: MOLECULAR BIOLOGY
MOLECULAR BIOLOGY
Name of the Student:
Name of the University:
Author note:

1MOLECULAR BIOLOGY
Introduction
The following questions and answers cover key functions and components of molecular
biology especially the digestive, endomembrane and circulatory systems.
Discussion
Question 1
The endomembrane system comprises of organelles such as the endoplasmic reticulum
(ER), lysosomes, Golgi apparatus, endosomes and secretory vesicles and granules. The function
of this system is to transport macro across extracellular and intracellular pathways. The hormone
insulin is formulated by proteins manufactured by the ER which are transported across the
endomembrane system. Insulin manufactured by ER-bound ribosomes are then bound to the
membrane. This insulin can undergo intracellular and extracellular transportation via ribosomes
and exocytosis. Thus, hyperglycemia triggers ER and ribosome functioning to stimulate insulin
synthesis and transportation. This insulin then facilitates glucose metabolism via GLUT4
transport activation and stimulation of GLUT4 mobilization of containing vesicles to the plasma
membrane (Lizák et al., 2019).
In addition to the role of villi, we learned from the lab that the gut or small intestine
facilitates protein, lipid and carbohydrate metabolism via secreting proteolytic enzymes like
trypsin and chymotrypsin and stimulate the gall bladder and pancreas to secrete bile and
pancreatic amylase.

2MOLECULAR BIOLOGY
Question 2
Increased surface area due to microvilli in the epithelium lining of the small intestine
assists in rapid nutrient absorption. Thus, glucose from the bolus via diffusion enters the blood
vessels within the villi which is then followed by circulatory transport to the various tissues and
organs of the body. The transported glucose then diffuses in to the intracellular membranes via
lymphatics. The glucose via oxidative phosphorylation can stimulate the production of ATP in
the mitochondria - which is main unit of energy and life in the body (Meng et al., 2015).
Question 3
Carbohydrates are broken to glucose via amylase enzyme in the saliva, followed by
digestion in the small intestine pancreatic amylase enzymes. The glucose is then absorbed via
diffusion into microvilli lining the gut epithelium to the blood vessels causing a rise in blood
glucose levels. High blood glucose facilitates insulin secretion via pancreatic beta cells for
glucose regulation. Glucose undergoes reabsorption by the proximal convoluted tubule (PCT) to
be recirculated prior to urine secretion. However, hyperglycemic blood does not undergo PCT-
facilitated reabsorption resulting in glycosuria – a key symptom of diabetes (Gong et al., 2017).
Conclusion
From the above paragraphs, it can thus be understood that all systems are interconnected
to each other and facilitate life and homeostasis.

3MOLECULAR BIOLOGY
Reference
Gong, S., Guo, J., Han, X., Li, M., Zhou, L., Cai, X., ... & Ma, Y. (2017). Clinical and genetic
features of patients with type 2 diabetes and renal glycosuria. The Journal of Clinical
Endocrinology & Metabolism, 102(5), 1548-1556.
Lizák, B., Szarka, A., Kim, Y., Choi, K. S., Németh, C. E., Marcolongo, P., ... & Margittai, É.
(2019). Glucose Transport and Transporters in the Endomembranes. International
journal of molecular sciences, 20(23), 5898.
Meng, Z., Le Marchand, S., Agnani, D., Szapacs, M., Ellens, H., & Bentz, J. (2017). Microvilli
morphology can affect efflux active P-glycoprotein in confluent MDCKII-hMDR1-NKI
and Caco-2 cell monolayers. Drug Metabolism and Disposition, 45(2), 145-151.