Essential knowledge 3.D.2:Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.

Stages of cell signaling (3 steps)

Cells communicate by cell-to-cell contact

▪ Immune cells interact by cell-cell contact, antigen-presenting cells (APCs), helper T-cells and killer T-cells.

Cell to cell communication:

▪ Plasmodesmata between plant cells that allow material to be transported from cell to cell.

Cells communicate over short distances by using local regulators that target cells in the vicinity of the emitting cell.

Examples:• Neurotransmitters• Plant immune response

Ubiquitination is a central role in cell signaling that regulates several processes including protein degradation and immunological response.[19] Much of the defense in plants relies on the destruction of defective or invaded materials within the cell, increasing the importance of functional proteasomes and protein targeting.

Other examples of short distance communication

▪ Quorum sensing in bacteria▪ http://www.ted.com/talks/bonnie_

bassler_on_how_bacteria_communicate.html

Other examples of short distance communication

▪ • Morphogens in embryonic development - Morphogens are soluble molecules that can diffuse and carry signals that control cell differentiation decisions in a concentration-dependent fashion. Morphogens typically act through binding to specific protein receptors.

Quorum sensing in bacteria

▪ Quorum sensing is a system of stimulus and response correlated to population density.

▪ Used to coordinate gene expression according to the density of their local population.

▪ Bacteria use it to coordinate certain behaviors based on the local density of the bacterial population.

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Signals released by one cell type can travel long distances to target cells of another cell type.

▪ Endocrine signals are produced by endocrine cells that release signaling molecules, which are specific and can travel long distances through the blood to reach all parts of the body.

▪ Example 1: Insulin

Signals released by one cell type can travel long distances to target cells of another cell type.

▪ Example 2: Human growth hormone

▪ HGH, produced by the pituitary gland, spurs growth in children and adolescents.

▪ Example 3: Thyroid Hormone

Goiter ▪ If there is a deficiency of dietary iodine, the thyroid will not be able to make thyroid hormone. The lack of thyroid hormone will lead to decreased negative feedback on the pituitary, leading to increased production of thyroid-stimulating hormone, which causes the thyroid to enlarge (the resulting medical condition is called endemic colloid goiter

Jokes

▪ Be careful when marketing your company on sliding van doors!!

The manliest pic you will see all day.

Dream the impossible dream!

▪ HANG ON A SECI’m texting