• University of Toronto, Mississauga

• BIO 380

 academic integrity. You are reminded that you may be charged with an academic offence for possessing any unauthorized aids during the writing of an exam. Clear, sealable, plastic bags have been provided for all electronic devices with storage, including but not limited to: cell phones, SMART devices, tablets, laptops, calculators, and MP3 players. Please turn off all devices, seal them in the bag provided, and place the bag under your desk for the duration of the examination. You will not be able to touch the bag or its contents until the exam is over. If, during an exam, any of these items are found on your person or in the area of your desk other than in the clear, sealable, plastic bag, you may be charged with an academic offence. A typical penalty for an academic offence may cause you to fail the course. Please note, once this exam has begun, you CANNOT re-write it. This exam has two parts: Part I, 55 Multiple Choice Questions (55 marks) Part II, 7 Short Answer Questions (45 marks) BIO380 2 PART I: MULTIPLE CHOICE QUESTIONS (55 marks; 1 mark each) Choose one option that best answers the question. Fill in your scantron sheet for all questions and remember to include your first and last name and student number on your scantron and your test. 1. The clock-wavefront model for somitogenesis proposes that: A) The differential expression of Hox genes along the A/P axis drives the wave of somitogenesis B) A moving boundary between gradients of FGF and retinoic acid regulates somitogenesis C) A segmentation clock involving Fgf8 signaling converts mesoderm into somites D) A wave of Shh from the notochord drives somitogenesis 2. Which of the following statements regarding somites is false? A) The newly formed somite contains 2 main compartments B) Somites form in a cranial-caudal direction C) Somites develop from the paraxial mesoderm D) The scleretome generates rib cartilage E) The myotome contributes to limb muscles 3. What do the transcription factors Id and E12 share in common? A) Both are required for muscle-specific gene activation B) Both work better when they dimerize with E12 C) Both can form heterodimers with MyoD D) Both are activated by myostatin signaling 4. Notch functions during somitogenesis to: A) Antagonize the Fgf8 morphogen gradient B) Generate somite boundaries C) Prevent the premature end of axis elongation D) Negatively regulate retinoic acid expression 5. What gene’s loss-of-function produces an overly muscular dog? A) Myostatin B) MyoD C) Myf-5 D) Myf-6 E) Myogenin 6. The rib arises from which mesodermal tissue? A) The intermediate mesoderm B) The dermatome C) The lateral plate m