- Question 11 In Plants Floral Organs Develop From Concentric Rings Of Tissue Called Whoris Beginning From The Most Outs 1 (85.97 KiB) Viewed 245 times
QUESTION 11 In plants, floral organs develop from concentric rings of tissue called whoris. Beginning from the most outside ring, whorl 1 develops into sepals, whorl 2 develops Into petals, whorl 3 develops into stamens, and whorl 4 develops into carpels. Analogous to the homeotic mutants of Drosophila, recessive mutations were found in genes that encode transcription factors. These mutants change the organ identity of a given whorl to the identity of a different whorl. The following table shows the mutant phenotypes caused by various floral organ mutations found in the genetic model plant, Arabidopsis. Genotype Whort 1 2 3 4 petals stamens wild-type ap2 lap2 sepals carpels sepals starrens stamons carpels carpels carpels sepals sepals carpels ap3/ap3 ag/ag sepals petals petals Based on the table above, which whorls require a functional AP2 gene. O whorls 3 and 4 O whorls 1 and 2 O All four whorls O whorls 2 and 4 O 3 whorls 2 and 3 QUESTION 12 Which of the following are ways in which transcriptional repressors can function in eukaryotes? (Mark all correct answers) Recruit co-repressors that prevent the RNA Pol Il complex from binding the promoter Competition with an activator for binding to an enhancer Recruit co-repressors that cause heterochromatin formation Sequester activators outside of the nucleus QUESTION 13 A variety of sheep called "Belgian Texel carry a mulation that creates increased muscle mass. The mutation was identified and found to mutate the myostatin gene such that the myostatin mRNA has become a target for a muscle- specific miRNA. Based on the general role of miRNAs in gene expression, what would you predict is the normal role for myostatin? O An activator of muscle development O An inhibitor of muscle development O An oncogene