Question

22-25 and Essay

22. The epidermis a) is classified as pseudostratified columnar epithelium b) allows uncontrolled water loss from the body c) might include keratinocytes, melanocytes, Merkel cells and Langerhans cells d) All the above (a, b and c) are correct 23. Cartilage a) does not contain blood vessels b) is highly negatively charged because of sugars and sulfate groups attached to sugars e) absorbs large amounts of water which acts as a "shock absorber when pressure is applied to the tissue d) All the above (a, b, and c) are correct 24 Steroid hormones that activate a cel a) generally easily cross plasma membranes b) bind to specific cytoplasmic receptors on target cells e) tum on a gene to produce a new protein to effect a change in the cell 25. Comparison of the ion concentrations of cell cytoplasm with the extracellular fluid would show that a) Potassium concentration inside the cell is the same as outside b) Sodium concentration inside the cell is lower c) Calcium concentration inside the cell is much higher d) All the above (a, b, c) are correct ESSAY. Deseibe the structure of a generalized plasma membrane. Include the major components (lipids, proteins, glycolipids, polysaccharides) Describe transport mechanismis by which materials move into and out of cells. (25 pts)

Answer 1

22. The epidermis a) is classified as pseudostratified columnar epithelium b) allows uncontrolled water loss from the body )might include keratinocytes, melanocytes, Merkel cells and Langerhans cells All the above (a, b and c) are correct Epidermis consists of keratinized, stratified squamous epithelium. It allows loss of water from the body in a controlled manner. It includes keratinocytes, melanocytes, Merkel cells, and Langerhans cells 23. Cartilage a) does not contain blood vessels b) is highly negatively charged because of sugars and sulfate groups attached to sugars c) absorbs large amounts of water which acts as a "shock absorber when pressure is applied to the tissue d) All the above (a, b, and c) are correct Cartilage is a rigid connective tissue that provides structural support, protects the organs underlying it, forms attachments and frameworks. Cartilage is made of cells known as "chondrocytes." Cartilage do not receive blood supply, and its structures trap a large amount of water that helps it to serve as a "shock absorber." The sulfate groups (negatively charged) attached the sugar molecule makes it negatively charged. 24 Steroid hormones that activate a cell a) generally easily cross plasma membranes b) bind to specific cytoplasmic receptors on target cells turn on a gene to produce a new protein to effect a change in the cell jAll the above (a, b, and c) are correct Steroid molecules are lipophilic structures, so they can cross through the plasma membrane and bind to the cytoplasmic or nuclear structures. They cause cellular changes at the genetic evel.