320Fall08Midterm4_key - BIO320Dr.Bushart MidtermExam#4...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
BIO 320 Dr. Bushart Print Name:___ Key ___________ Midterm Exam #4 Thursday December 4, 2008 1. The injectable filler style of cosmetic surgery is often used to hide wrinkles. It works by stretching the skin through the injected filler taking up space. Why might an equivalent mass of Restylane ® , a brand name for hyaluronan or hyaluronic acid, have a greater “filler” effect than collagen? Be specific about any relevant molecular properties of these two ECM components. Hyaluronan is a long carbohydrate, which is less flexible than proteins and also fairly hydrophilic. This means it will take up a lot of space due to its inflexibility and the attraction of water (which will generate turgor). Collagen on the other hand is a rope- like protein. While somewhat inflexible as well, it is mostly insoluble so will not attract water like hyaluronan does. So collagen should not take up as much space as hyaluronan would, making hyalyronan a better choice as a filler for wrinkles. 2. Skin is an arrangement of epithelial and connective tissues. While the specific strategies vary between these two tissue types, they work towards very similar goals. Describe one similarity between how both tissue types resist tension/pulling forces. Answers should include elements involved (intermediate filaments, collagen, fibronectin, etc) and reference BOTH tissue types. The following are the general comparisons: Both use rope-like proteins which are good at resisting pulling forces without breaking. In both tissue types the fibrous proteins are arranged in multiple directions in order to resist pulling forces from multiple directions. In both cases the fibrous proteins are networked together to impart greater strength and stability (either between themselves or other proteins). 3. Integrins have both “inside-out” and “outside-in” functionality. Integrins are also important for both epithelial cells and the fibroblasts of connective tissue. Describe one function of integrins in either tissue type and explain if your function is an example of an inside-out or outside-in usage. Integrins are important for the organization of the basal lamina by epithelial cells. They
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/18/2010 for the course BIOLOGY 320 taught by Professor Saxena during the Spring '10 term at University of Texas at Austin.

Page1 / 4

320Fall08Midterm4_key - BIO320Dr.Bushart MidtermExam#4...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online