Module 6: Interactions Between Cells and Their Environment Flashcards
What is the current understanding regarding the origin of multicellular organisms, and how has recent research shed light on this topic?
The origin of multicellular organisms remains unclear. Recent experiments using yeast have provided some insight into the emergence of multicellular organisms. These experiments suggest that the transition from unicellular to multicellular life may not have been as difficult as previously thought.
How are most cells in a multicellular organism organized, and what are some examples of different tissues in these organisms?
Most cells in a multicellular organism are organized into clearly defined tissues. Examples of different tissues include nervous tissue (found in the brain and spinal cord), connective tissue (present in joints), epithelial tissue (comprising the skin and airways), and muscle tissue (found in the heart).
What are the roles of Fibroblast of the dermis?
They have receptors that mediate interactions and transmit messages
What role do extracellular materials outside the plasma membrane play in a cell’s life, and how do cells interact with their extracellular environment?
Extracellular materials outside the plasma membrane play a crucial role in a cell’s life. Cells interact with their extracellular environment through processes such as cell-cell interactions and cell-extracellular matrix (ECM) interactions. These interactions are essential for cell communication, adherence, and tissue organization.
What is the glycocalyx, and what roles does it play in cellular functions?
The glycocalyx consists of carbohydrate projections on the outer surface of the plasma membrane.
- It serves several important roles, including mediating cell-cell and cell-substratum interactions, providing mechanical protection, acting as a barrier to molecular movement toward the plasma membrane, and serving as a regulatory factor binding site.
What is the basement membrane, and where is it found in the body?
The basement membrane is a well-defined extracellular matrix (ECM) that surrounds muscles, nerves, and fat cells. It is found underlying various tissues, including the epidermis of the skin, the digestive and respiratory tracts, and the lining of blood vessels.
What are some key components of the extracellular matrix (ECM), and how does the ECM provide support and determine cell shape and activity?
Key components of the ECM include collagen, proteoglycans, fibronectin, and laminin. Collagen provides the insoluble framework that determines many mechanical properties of the matrix, while proteoglycans contribute to the gel-like properties of the ECM. Fibronectin and laminin are involved in cell adhesion, migration, growth, and differentiation, as well as strengthening the basement membrane.
What does decellularization do?
Decellularization of organs maintains their structure.
What does recellularization do?
Acts as a potential therapeutic approach for transplantation.
What are collagens comprised of?
They are comprise a lage family of fibrous glycoproteins present only in the EMC.
What is the collagen l molecule?
- Consists of triple helix of three helical alpha chains.
- Single most abundant protein in the human body.
- Produced by fibroblasts, smooth muscle, and epithelial cells.
- 28 fiber types, often mixed in ECM.
- Large amount of proline residues.
- Proline and lysine residues are hydroxylated –post translational modification– to maintain the stability
of the collagen fiber.
What is collagen lV molecule?
- Restricted to basement membranes.
- Contains non-helical segments interspersed along the molecule and globular domains at each end.
- Non-helical segments provide flexibility while the globular ends serve as sites of interaction giving its lattice-like character.
What is the corneal stoma?
Layers of collagen fibrils of uniform diameter and spacing arranged at right angles.
What is proteoglycans?
Protein- polysaccharide complex, with a core protein attached to glycosaminoglycans (GAGs).
- Common in basement membranes and cartilage.
What is Fibronectin?
- Fibronectin consists of a
linear array of 30 Fn domains
to give a modular
construction. - Fn-type domains are also
found in blood clotting
factors and membrane
receptors. - Fibronectin binds to
numerous ECM components. - Binds to cell surface
receptors to attach cell to
ECM. - Several organs (e.g., salivary gland,
kidney, and lung) are formed by a
process of branching/cleft formation. - Cell adhesion and shape
determination also fibronectin-
dependent.
