• 犀牛首页
  • IB课程
  • AP课程
  • G5笔面试
  • AMC竞赛
  • HMMT竞赛
  • 物理碗竞赛
犀牛教育
  • IB物理真题
  • IB数学真题
  • IB化学真题
  • IB生物真题
  • IB经济真题
  • IB地理真题

IB生物真题

首页 > IB > IB生物 > IB生物真题

2011年11月IB生物SL真题下载-Paper2

2021-07-21

2011年11月IB生物SL真题下载-Paper2

1. Stem cells in the bone marrow can be forced into blood vessels in a process called mobilization.Mobilization of stem cells from the bone marrow into the blood vessels represents the basis for modern bone marrow transplantation procedures.

To test the effect of light on the mobilization of stem cells, mice were subjected to a simulated “jet lag” by advancing the light-dark cycle by 12 hours. This was done by subjecting mice to a 24-hour light period before the results shown in the graph were recorded. The results were compared to the stem cells in control mice under normal conditions of 12 hours of light (□)and 12 hours of darkness ( ▅ ).

(a) (i) State the maximum number of stem cells per ml blood in the control mice.

(ii) Determine the number of hours of light needed to release the maximum number of stem cells in blood in control mice.

(b) Distinguish between the trends shown in the number of stem cells per ml blood by the mice subjected to jet lag and the control mice.

(c) Other studies suggest that a greater number of blood stem cells for transplantation may be obtained if they are harvested during darkness. Evaluate this hypothesis.

 

One important chemical in the mobilization of stem cells is a protein, CXCL12, which maintains the stem cells inside the bone marrow. The breakdown of CXCL12 causes the mobilization of stem cells to the blood vessels.

The graph below shows the mobilization of stem cells and the production of mRNA for CXCL12 when the bone marrow is treated with two different chemicals (isoprenaline and clenbuterol).

(d) Explain how the amount of mRNA for CXCL12 gives an indication of the amount of protein CXCL12 produced.

(e) Compare the effect of isoprenaline and clenbuterol with the normal release of stem cells and the production of mRNA for CXCL12.

(f) Research is being conducted into treatment for diabetes based on stem cells. Discuss the ethical issues involved in stem cell research.

2011年11月IB生物SL真题余下省略!


你可能还关注

  1. IB生物学习内容/难点一文搞懂!哪些学生适合学IB生物?犀牛教育IB暑假班等你来! 2023-04-17   
    IB生物是IB学生必选的科目,作为很多申请生物专业学生的优势科目。IB生物学习的内容是什么?哪些学生适合学习IB生物?学习IB生物的难点有哪些?IB生物培训课程哪里找?犀牛教育IB暑假
    详情阅读
  2. 2020年11月IB生物SL真题下载-Paper3 2021-07-28   
    2020年11月IB生物SL真题下载-Paper3
    详情阅读
  3. 2020年11月IB生物SL真题下载-Paper2 2021-07-28   
    2020年11月IB生物SL真题下载-Paper2
    详情阅读
  4. 2020年11月IB生物SL真题下载-Paper1 2021-07-28   
    2020年11月IB生物SL真题下载-Paper1
    详情阅读
  5. 2019年11月IB生物SL真题下载-Paper3 2021-07-28   
    2019年11月IB生物SL真题下载-Paper3
    详情阅读

扫码免费下载真题

IB生物真题

  • IB生物学习内容/难点一文搞懂!哪些学生适合学IB生物?犀牛教育IB暑假班等你来!
  • 2020年11月IB生物SL真题下载-Paper3
  • 2020年11月IB生物SL真题下载-Paper2
  • 2020年11月IB生物SL真题下载-Paper1
  • 2019年11月IB生物SL真题下载-Paper3
  • 2019年11月IB生物SL真题下载-Paper2
犀牛国际

犀牛国际(X-NEW),由业内多名教学专家共同组建,不乏来自加州理工大学、剑桥大学、清华大学、北京大学、复旦大学、新加坡国立大学等国际一流大学。 其中有博士、硕士的学历老师众多,学术功底扎实,有的已经执教十余年,国际领域经验丰富。

国际学科

  • IB课程辅导