FNDH 400 - Exam 2

Which of the following is FALSE? Enterocytes mature out of gastric pits. Enterocytes can be sloughed off. Uptake doesn't guarantee absorption. Absorption is when a compound reaches circulation. - correct answer False Enterocytes mature FROM STEM CELLS IN THE CRYPTS OF LIEBERKUHN Which of the following are CORRECT? -In osmosis water moves from higher solute concentration to lower solute concentration. -In osmosis water moves from lower solute concentration to higher solute concentration. -In simple diffusion and facilitated diffusion, solute moves from higher concentration to lower concentration. -In simple diffusion and facilitated diffusion, solute moves from lower concentration to higher concentration. - correct answer In osmosis water moves from LOWER solute concentration to HIGHER solute concentration. In simple diffusion and facilitated diffusion, solute moves from HIGHER concentration to LOWER concentration. Which of the following is FALSE? -Endocytosis and active carrier transport require energy -Portal vein is a vessel that drains directly to the liver -Capillary leads to lymph, lacteal to blood -GLUT transporters use active carrier transport -Monosaccharide phosphorylation maintains the concentration gradient & keeps monosaccharides from leaving the cell - correct answer Capillary leads to lymph, lacteal to blood (FALSE CAPILLARY - BLOOD, LACTEAL - LYMPH) GLUT transporters use active carrier transport (FALSE THEY USE FACILITATED DIFFUSION) Which of the following is True? -Insulin is secreted as part of the glycemic response -Insulin binding to its receptor causes GLUT4 to move to the cell surface of mainly adipose and muscle cells -Glucagon binding to its receptor causes the breakdown of glycogen in the liver -Glucagon is secreted in response to high blood glucose concentrations - correct answer Insulin is secreted as part of the glycemic response Insulin binding to its receptor causes GLUT4 to move to the cell surface of mainly adipose and muscle cells Glucagon binding to its receptor causes the breakdown of glycogen in the liver T/F In both Type 1 and Type 2 diabetes, not enough GLUT4 makes it to the cell surface. - correct answer False In both Type 1 and Type 2 diabetes, not enough GLUT4 makes it to the cell surface. (is for uptake) Absorption is the movement of the compound from the enterocyte into circulation. T/F At the top of villi are the crypts of Lieberkühn which contain stem cells, many of which differentiate to become enterocytes as they move down the villi, before ultimately being sloughed off. - correct answer False The crypts of Lieberkühn are found in the PITS BETWEEN villi which contain stem cells, many of which differentiate to become enterocytes as they move UP the villi, before ultimately being sloughed off. T/F Compounds that are taken up might not necessarily be absorbed because the enterocyte containing the compound might be sloughed off before absorption occurs - correct answer True Enterocytes are sloughed off and whatever compounds they have taken up and still contain will not be absorbed through that enterocyte Which is not a macronutrient digestion product ready for uptake? a)2-monoglycerides b)fatty acids c)glucose d)tripeptide e)sucrose - correct answer e)Sucrose Sucrose is a disaccharide that will be cleaved to the monosaccharides glucose and fructose by sucrase prior to uptake. Which is not a protein that helps move compounds through the phospholipid bilayer cell membrane? a)Carrier b)pump c)channel d)transporter e) tunnel - correct answer e) Tunnel Tunnel is not a term used for describing proteins involved in helping compounds move through a cell membrane. T/F Active transport does not require energy and moves with the concentration gradient. - correct answer False PASSIVE transport does not require energy and moves with the concentration gradient. Active transport requires energy provided by ATP and moves against the concentration gradient. T/F Cleaving a phosphate bond (dephosphorylation) generally releases energy. - correct answer True Phosphorylation is the formation of a phosphate bond and requires energy. Dephosphorylation is breaking the bond which releases energy. T/F A solute moving from lower concentration to higher concentration across a membrane is moving with its concentration gradient. - correct answer False Moving with a concentration gradient would be the solute moving from higher concentration to lower concentration to equalize the solute concentrations on both sides of the membrane. T/F In simple diffusion, a solute moves from a region with higher solute concentration across a membrane to a region with lower solute concentration. - correct answer True Simple diffusion does not use a carrier or transport protein, is passive (no energy required), and follows the concentration gradient. T/F In osmosis, water moves from a region with higher solute concentration across a membrane to a region with lower solute concentration. - correct answer False Water moves from low concentration to high concentration to dilute the higher concentration (opposite of solute movement in simple diffusion). T/F Facilitated diffusion is like simple diffusion except that a transport protein (carrier or channel) is needed to facilitate solute movement across the membrane. - correct answer True Facilitated diffusion uses a carrier or transport protein, is passive (no energy required), and follows the concentration gradient. The only difference from simple diffusion is the need for the carrier or transport protein. T/F Active carrier transport and facilitated diffusion both use a carrier or transport protein, but active carrier transport uses energy and moves with the concentration gradient. - correct answer False The statement is correct except that active carrier transport moves against the concentration gradient.