Exam1_explained - The numbers on the left reflect the...

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The numbers on the left reflect the question number on Form A, B, and C respectively 1, 25, 8 If hematopoietic stem cells were transplanted into a host and it could be shown that descendents of the transplanted stem cells became neurons, that would be an example of A. apoptosis. B. canalization. C. trans-differentiation.@ D. embryonic stem cell therapy. E. normal hematopoiesis. Rationale: Hematopoietic stem are adult stem cells, thus their use cannot be an example of embryonic stem cell therapy. HSCs are normally only differentiate into blood cell, thus if HSCs could be shown to differentiate into a non-blood cell type, that would be an example of (highly controversial) transdifferentiation, as discussed in Lecture 3. 2, 26, 7 Which of the following is FALSE of telomeres? A. They are replicated by DNA polymerase. @ B. They are highly repetitious sequences of DNA base pairs. C. They are found at the ends of chromosomes. D. They determine the life span of somatic cells. E. They shorten as most cells age. Rationale: Telomeres are replicated by telomerase, which is a reverse transcriptase, not DNA polymerase. All the other foils are true statements about telomeres. 3, 27, 9 Embryonic stem cells differ from adult stem cells in that only embryonic stem cells A. are 'immortal' with respect to cell division. B. can self-renew indefinitely. C. can produce descendents that are differentiated. D. can be safely transplanted directly into a host. E. are derived from cells cultured from a blastocyst .@ Rationale: Both embryonic and adult stem cells fulfill the definition of stem cells, and are thus immortal with respect to cell division, which is another way of saying they can self-renew indefinitely. Only adult stem cells can be safely transplants directly into a host, embryonic stem cells produce a teratoma. As several slides showed in both lecture 1 and lecture 3, embryonic stem cells are typically derived from the inner cell mass of the blastocyst . 4, 28, 6 Based on the assigned reading and lecture notes on apoptosis, which of the following correctly pairs a protein molecule with its role in apoptosis? A. Caspase--controls the permeability barrier of mitochondria B. p53--directly degrades proteins during apoptosis C. Fas--receptor protein that inhibits apoptosis when activated D. Bcl-2--protects cells against apoptosis@ E. ICE-like proteases--involved in necrosis, not apoptosis Rationale: Some of these foils are derived from the reading, as suggested by the question. Lecture 1 emphasized that caspases are proteolytic enzymes, also on a review question and thus it is Caspases, not p53, that directly degrades proteins during apoptosis. Another name for Caspases is ICE-like proteases, used throughout the required reading. Fas was also discussed
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in several paragraphs in the reading as was BCL-2. Further, both Fas and Bcl-2 were mentioned, and BCL-2 specifically covered in lecture 1. 5, 29, 5
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This note was uploaded on 04/03/2008 for the course PSL 432 taught by Professor Several during the Spring '08 term at Michigan State University.

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Exam1_explained - The numbers on the left reflect the...

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