Movement of glucose down its concentration gradient into cells is facilitated by Select one: a. Active transport b. Diffusion across phospholipids c. Facilitated transport d. a protein that consumes ATP e. a protein that gets phosphorylated

Liver cells in culture were kept at 0°C and treated with trypsin to digest the receptors on the cell surface. The temperature was then raised to 37°C and radioactive LDL was added to the culture media. Several hours later, the labeled LDL was found to be inside the cells. This specific process of LDL uptake is A. active transport B. facilitated diffusion C. phagocytosis D. pinocytosis E. receptor-mediated endocytosis

While endocytosis and exocytosis refer to the direction in which a vesicle moves into and out of a cell respectively, it is important to think about what is being moved with and within the vesicles. To demonstrate how this process is utilized in human cells we will focus on the human body's insulin response. The purpose of the insulin response is to create a pathway for glucose entry into cells by releasing glucose transporters into the membrane. Cell Type #1- insulin producers: In humans, pancreatic B-cells create steroid insulin that can be packaged into vesicles starting at the ER. These vesicles are prepared for exocytosis so that the insulin can be released from the pancreatic B - cells and get into the bloodstream when signaled to do so. When glucose is present in the blood stream these cells will release the pre-packed insulin into the blood stream. Cell Type #2- insulin responders: Other cells do not produce insulin but instead respond when they have received the insulin signal…

Na+ moves from high to low concentration, across the plasma membrane, through a protein channel that is permenantly open. Which statement is true about this process? a. It does not require ATP b. It is a form of active transport  c. Movement is against the concentration gradient of Na+ d. The channel probably allows many different molecules and ions to cross