Problem_set_2

Problem set 2

1. 匀浆肝组织并且按图所示分离了细胞组分，每一部分保留了小的等份试样:

问题：

1) 对每一等份试样进行琥珀酸脱氢酶(SDH)的专一性酶分析，SDH 是TCA循环中的一个酶。假如细胞分离得很完全，哪一部分将被检出有SDH活性?

2) 哪一部分会有最高的SDH专一活性(单位蛋白质活性)?

3) 哪一部分有最高量的总蛋白质?

4) 分离到最后时，核糖体存在于哪一部分?

2. 5位同学总是坐在同一排，这可能是因为

1）他们真的是彼此喜欢；

2）没有其他人想坐在他们的旁边

问题：哪种解释更符合脂双层的装配机理？假定脂肪分子采用另一种方式，则脂双层的性质将会如何改变？

3. Below is a standard table of the amino acids, and the sequences of a short polypeptide that has one transmembrane domain.

MKRENDSDNHIALVVLSWLAIEGGLTAFFGFEDNIKELDNK

Underline the predicted transmembrane domain in the polypeptide above.

4. Explain two ways that we know many membrane proteins can diffuse laterally in the plasma membrane in cells.

5. You are a biochemist studying the properties of cell membranes across species of birds from around the world. The labels come off of two tubes: the first is a penguin sample (from Antarctica) and the second is from a macaw (a parrot that lives in tropical South America). As a part of your analysis, you quantitate the amount of cholesterol, saturated, and unsaturated fatty acids present in both of the membrane samples. How would you use this information to identify which samples came from which bird and why?