Question

Name MULTIPLE CHOICE. question. Choose the one alternative that best completes the statement or answers the Density-dependent inhibition is explained by which of the following? AAs cells become more numerous, they begin to squeeze against each other, restriting their size and ability to produce growth factors. 1) B) As cells become more numerous, the cell surface proteins of adjacent cells bind to each other and send signals that inhibit cell division. C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. D) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism. Which of the following statements best describes how often crossing over occurs in humans? least 1-3 times per chromosome pair B) -1 time per pair of sister chromatids 2) C)-50 times per chromosome pair D) -2 times per melotic cell Use the following pedigree (Figure 11.3) for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. A slash through the symbol indicates that the individual is deceased. 44 49 20 Figure 11.3 ould be found in 3) In each generation of this family after generation I, the age at diagnosis is significantly lows than w 3) nonfamilial (sporadic) cases of this cancer (-63 years). What is the most likely reason? A) Members of this family know to be checked for colon cancer early in life This cancer requires mutations in more than this one gene. C) This is pure chance: it would not be expected if you were to look at a different family. D) Affected members of this family are born with colon cancer, and it can be detected whenever they are first tested. E) Hereditary (or familial) cases of this cancer typically occur at earlier ages than do nonfamilial forms. 4) One map unit is equivalent to which of the following values? A) 1 nanometer of distance between two genes boi Us and

Answer 1

Ans. 1

(D) There are various inhibition phenomenons to help check the physiological limits of growth. One of these is Density dependent Inhibition , which means crowding of cells stops their further growth.The cells are influenced by their neighbouring cells which restrict their growth. They do not grow because overcrowding leads to depletion of nutrients or less available signals or accumulation of metabolic waste ( as option is given) . All other options except D need contact to other cells which is defined under contact inhibition.

if these inhibitions are removed the cells will divide continuously and become tumor cells.