Question

TRUE OR FALSE 1. Claudins are the proteins associated with the establishment of the paracellular barrier between cells. The charged amino acids of the extracellular loop are thought to form ion-selective pores that allow the passage of specific ions through the barrier. By changing the charged amino acids to nonpolar ones, a hydrophobic region is created that excludes polar molecules (including ions) while allowing the passage of nonpolar substances. This would obviously affect the function of the tissue in which this happened and compromise the viability of the organism.

2. A genetic screening by amniocentesis reveals a defective L1-CAM gene. During embryogenesis N-CAM and L1-CAM function in the outgrowth and the bundling of neurons. Individuals with this genetic defect will have defects including the lack of innervation of organs.

3.Cancer cells metastasize due to a variety of interactions with cell adhesions, cell junctions, and ECM. Cells stop producing E-cadherin or other cadherins; the inability to synthesize fibronectins, resulting in a loss of shape and detachment from the ECM; focal adhesion unresponsiveness β-catenin function in the Wnt signalling pathway associated with cancer.

Answer 1

1.false

2True

3true

Amniocentesis is a diagnostic test that may be recommended by your health care provider following an abnormal triple test result. Inherited or genetic concerns lead some parents to choose amniocentesis to determine if specific genetic disorders may be present in their baby.

The L1 protein plays a role in the movement (migration) and organization of neurons and the outgrowth of axons, which are specialized extensions of neurons that transmit nerve impulses. The protein also plays a role in the formation of the protective sheath (myelin) that surrounds certain neurons and the formation of junctions between nerve cells (synapses), where cell-to-cell communication occurs. These neuronal functions contribute to brain development, thinking ability, memory, and movement.

Metastatic cancer is a cancer that has spread from the part of the body where it started (the primary site) to other parts of the body. When cancer cells break away from a tumor, they can travel to other parts of the body through the bloodstream or the lymph system.

The metastatic cascade can be broadly separated into three main processes: invasion, intravasation and extravasation. The loss of cell-cell adhesion capacity allows malignant tumor cells to dissociate from the primary tumor mass and changes in cell-matrix interaction enable the cells to invade the surrounding stroma; the process of invasion. This involves the secretion of substances to degrade the basement membrane and extracellular matrix and also the expression/ suppression of proteins involved in the control of motility and migration.