Biology 441 Spring 2011, Second Exam KeyEach question was worth 5 points total.
1) Circle which 3 of the following have the same symmetries A N I X Z H % * @ &
2) What is this symmetry? How many fold, what symmetry?
3) Who is this building named in honor of?
4) What was his major discovery?
5) How did he misinterpret his discovery?
6) Cancer cells of several kinds have been reported to sort out from random mixtures with normal cells of the same differentiated cell type, with the cancer cells accumulating nearer the surface of the cell aggregates, and the normal cells collecting into solid blobs in the interior: How would Malcolm Steinberg's hypothesis interpret this result? (what does it tell us about how cancer cells are abnormal?)
7) What is the symmetry of a set of four identical quadruplet armadillo embryos, after each quadruplet develops its right-left asymmetry?
8) What two hypothetical mechanisms have been proposed for breaking displacement symmetry in developing embryos?
9) If you put one chick embryo directly on top of another during somite formation,
and made time-lapse videos of when and where each embryo continued to form somites,
which theory would be supported if the somites of the embryos then became synchronized, but not spatially aligned?
And which theory would be supported by observations that locations of new somites became spatially aligned (tended to be directly over each other, even if not forming simultaneously)?
10) What are the five major families of genes that control development of fly anatomy?
11) What are two specific examples of homeotic mutants that occur in Drosophila?
12) What kinds of animals have hox genes?
13) Describe and name the remarkable, unexplained correlation that exists between the locations of effects in mutations of hox genes, relative to the locations of hox genes on chromosomes?
14) Do embryos tend to develop more symmetry as they develop, or the reverse?
Give two examples:
15) What are two examples of variables in anatomical structures that are second order tensors?
16) Sketch a sea urchin embryo early during gastrulation, and diagram the relative amounts and directions of curvatures of different parts of its anatomy at this stage.
17) The main usefulness of bioassays is?
18) Osmotic pressure belongs to which class of variables?
19) What is a meristem?
20) During the exam, time lapse videos will be shown of Dictyostelium slugs aggregating from amoebae, crawling from place to place, and then forming a fruiting body.
Axial symmetry (an infinite number of planes of reflection symmetry, along one axis)?
One plane of reflection symmetry? slug - 2 points
Dilation symmetry?slugs or fruiting bodies in groups, aggregating amoebae - 1 point for any
1 point bonus for listing all of the correct answers, and no incorrect ones