biomedical sub test[kalplan 2001] Discussion is welcome!

樱桃小丸子/丸丸UID：2160265

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zhangheng1020UID：2130513

A couple brings in their 6-month-old child because they are concerned about the child's inability to sit without support. The physician interviews the parents and ascertains that they are both Ashkenazic Jews. The doctor        should inform them that, because of their heritage, their child may have an increased risk of which of the following disorders?
                A. Albinism and galactosemia
                B. Cystic fibrosis and Lesch-Nyhan disease
                C. Gaucher's disease and Tay-Sachs disease
                D. Krabbe's disease and Niemann-Pick disease
                E. Metachromatic leukodystrophy and phenylketonuria

樱桃小丸子/丸丸UID：2160265

对不

樱桃小丸子/丸丸UID：2160265

显示关于Lineweaver- 的酵素运动数据Burk 密谋

这个最佳的方式分析酵素运动数据将适合数据 直接地对Michaelis-Menten 等式使用非线性海退。在非线性海退是 可得到的之前, 调查员必须变换弯曲的数据成直线, 如此他们能分 析与线性海退。

单程做这是与Lineweaver-Burk 剧情 。采取Michaelis-Menten 等式的反面和简化:



忽略 实验性错误, 1/V 剧情对。1/S 是线性, 与Y 拦截1/Vmax 和倾斜 相等与Km/Vmax 。X 拦截均等?1/Km.



使用 Lineweaver-Burk 剧情只显示你的数据。别使用一条线性海退线的 倾斜和截住确定价值为Vmax 和公里。如果你做这, 你不会得到最准 确的价值为Vmax 和公里。这个问题是变革(reciprocals) 变形这个 实验性错误, 如此双重相互剧情不服从线性海退的圣母升天节。用 途非线性海退获得最准确的价值的公里和Vmax (参见 避免Scatchard, Lineweaver- Burk 并且相似变换 。

决巧你应该分析酵素运动数据与非线性海退, 不是与Lineweaver-Burk 剧情。用途Lineweaver-Burk 密谋显示数 据, 不分析数据。

创造Lineweaver-Burk 剧 情与棱镜, 开始从X 是基体浓度和Y 的桌是速度。点击分析, 和选 择镶入式分析。然后选择变革从数据操作的名单。检查选择箱子变 换两X 是1/X, 并且Y 是1/Y. 肯定检查这个选择创造结果的一张新 图表。

从那张图表, 点击分析和选择线性海 退叠加海退线。这条线性海退线不应该被使用获得价值Vmax 和公里 。X 拦截海退线是附近-1/KM, 并且这个倾斜的消极反面是在Vmax 附近。然而, Vmax 和公里价值确定直接地与非线性海退是比较准确 的。比较最好画对应于非线性海退拟合的线

创造Lineweaver-Burk 线对应于非线性海退拟 合, 跟随这些步:

1 。创造一张新数据桌, 与数字X 价值和唯一Y 价值。

2 。列1 加入 X = -1/KM (由非线性海退早先确定), Y=0.

3 。 列2 输入X=1/Smax (Smax 是最大的价值的[ 基体] 你想包括在这张 图表) 并且Y=(1/Vmax)(1.0 + KM/Smax) 。

4 。 注意这张数据桌名字。或许改称它对适当事。

5 。去Lineweaver-Burk 图表。

6 。按变动, 然后关于图表的数据。

7 。增加新数据桌来这张图表。

8 。按变动, 然后标志和线。

9 。 滴下在数据集的名单下, 和选择那个你注意在步骤4.10 。别选择密 谋标志, 但连接用线。



Allosteric 酵素





所有内容版权. 1999 年由 GraphPad Software, Inc. 版权所有。

樱桃小丸子/丸丸UID：2160265

JJ 能聊聊马

樱桃小丸子/丸丸UID：2160265

在QQ上

樱桃小丸子/丸丸UID：2160265

好强阿

zhangheng1020UID：2130513

Explanation:
         The correct answer is C. You should associate Ashkenazic (Eastern European) Jews with two diseases: Tay-Sachs disease and Type I Gaucher's disease. Both of these diseases are sphingolipidoses. Tay-Sachs disease is the more devastating of the two, and is characterized by progressive neurologic (including visual) eterioration beginning at about 6 months of age and leading to death by age 3. In contrast, Type I Gaucher’s disease is compatible with a normal life span and causes hepatosplenomegaly with CNS involvement. (The infantile Type II and the juvenile Type III forms cause more serious disease but are not seen with increased   incidence in Ashkenazic Jews.) None of the other conditions listed occur with greater frequency in Ashkenazic Jews. In this case, also note that many perfectly normal children cannot sit without support at 6 months of age, so the child may well be healthy.

樱桃小丸子/丸丸UID：2160265

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zhangheng1020UID：2130513

A 2-year-old retarded child is evaluated by a metabolic specialist. The child's history is significant for failure to thrive and progressive neurologic deterioration, including deafness and blindness. Physical examination is remarkable for hepatosplenomegaly, as well as a cherry-red spot on funduscopic examination. These symptoms are consistent with a diagnosis of
               A. Hunter syndrome
                B. Niemann-Pick disease
                C. Pompe's disease
                D. tyrosinosis
                E. von Gierke's disease

[ Last edited by zhangheng1020 on 2005-12-1 at 12:09 ]

zhangheng1020UID：2130513

Explanation:
         The correct answer is B. Hepatosplenomegaly accompanied by progressive neurologic deterioration should make you think of lipid storage diseases; Niemann-Pick disease is the only lipid storage disease in the answer choices. Niemann-Pick disease is due to a deficiency of sphingomyelinase, leading to an accumulation of sphingomyelin. It is most common among Ashkenazic Jews and generally results in death by age 2. The  cherry-red spot is also a characteristic of Tay-Sachs disease, but hepatosplenomegaly suggests Niemann-Pick  disease rather than Tay-Sachs.  Hunter syndrome (choice A) is a mucopolysaccharidosis, inherited in an X-linked recessive fashion. Pompe's disease (choice C) is a glycogen storage disease characterized by hypotonia and cardiorespiratory  failure. Tyrosinosis (choice D) is a rare abnormality of tyrosine metabolism that would not produce the listed symptoms.  von Gierke's disease (choice E) is a severe form of glycogen storage disease characterized by hypoglycemia, hepatomegaly, and renomegaly.

zhangheng1020UID：2130513

Which of the following enzymes is located at arrow 1 in the electron micrograph above?
             A. Carnitine acyltransferase II
              B. Fatty acyl CoA synthetase
              C. Glucose-6-phosphate dehydrogenase
              D. Hexokinase
              E. Pyruvate kinase

zhangheng1020UID：2130513

Explanation:
       The correct answer is A. Arrow 1 indicates the inner mitochondrial membrane. Carnitine acyltransferase II is located on the inner face of the inner mitochondrial membrane. It reforms fatty acyl CoA in the mitochondrial matrix (arrow 5) from acyl carnitine, thus preparing it for mitochondrial oxidation. The acyl groups on carnitine are derived from acyl CoA esters synthesized in the outer mitochondrial membrane, which are made from free fatty acids  circulating in the blood.
       Fatty acyl CoA synthetases (choice B) are located in the outer mitochondrial membrane, indicated by arrow 2. Glucose-6-phosphate dehydrogenase, the first enzyme in the pentose phosphate pathway (choice C), hexokinase, the first enzyme in the glycolytic pathway (choice D), and pyruvate kinase (choice E), which produces pyruvate from phosphoenolpyruvate in glycolysis, are all located in the cytosol, indicated by arrow 3. Arrow 4 indicates smooth endoplasmic reticulum.

zhangheng1020UID：2130513

32
A 72-year-old woman, in otherwise good health, presents with megaloblastic anemia. Careful evaluation reveals a folate deficiency as the cause of the anemia. Assuming the folate deficiency is due to dietary causes, which of the following is the most likely problem?
                 A. Lack of leafy green vegetables
                 B. Lack of milk products
                 C. Lack of red meat
                 D. Lack of yellow vegetables
                 E. Overcooked food

zhangheng1020UID：2130513

Explanation:
         The correct answer is E. Folates (pteroylglutamic acid and related compounds) are widely distributed in foodstuffs. Dietary deficiency is usually due to overcooked (folates are very labile) and old (folates rapidly decay with time) food.