You Have Isolated Two Mutants of a Normally Pear-Shaped Microorganism $\quad\quad\quad\quad\quad\quad\quad\text { First cell extract }$

question 23

Essay

You have isolated two mutants of a normally pear-shaped microorganism that have lost their distinctive shape and are now round.One of the mutants has a defect in a protein that you call A and the other has a defect in a protein that you call B.First, you grind up each type of mutant cell and normal cells separately and separate the plasma membranes from the cytoplasm, forming the first cell extract.Then you set aside a portion of each fraction for later testing.Next, you wash the remaining portion of the membrane fractions with a low concentration of urea (which will unfold proteins and disrupt their ability to interact with other proteins) and centrifuge the mixture.The membranes and their constituent proteins form a pellet, and the proteins liberated from the membranes by the urea wash remain in the supernatant.When you check each of the fractions for the presence of A or B, you obtain the results given below. $\quad\quad\quad\quad\quad\quad\quad\text { First cell extract }$$\quad\quad\quad\quad\quad\text { After urea wash and centrifugation }$
$\begin{array}{lcccc}\hline&\text { Membrane }&\text { Cytosol }&\quad\quad\text {Membrane }&\text {Supernatant }\\\hline\text { Normal cells } & \text { A and B } & \text { no A or B } & \text { A } & \text { B } \\\hline \text { Mutant A } & \text { A } & \text { B } & \text { A } & \text { no A or B } \\\hline \text { Mutant B } & \text { A } & \text { B } & \text { A } & \text { no A or B }\end{array}$
Figure 11-15
Use these initial observations to classify membrane proteins A and B.What additional information can be inferred from this data set that helps you understand the mutant phenotype?

Grasp the stages of meiosis and their outcomes on the chromosome number in daughter cells.

Appreciate the importance of chromosome alignment and its outcomes during meiosis.

Understand the process and significance of meiosis in sexual reproduction.

Recognize the stages of meiosis and the key events that occur in each.

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Definitions:

Investment

The allocation of resources, such as capital or time, in anticipation of generating income or profit.

Modified Duration

A measure of the sensitivity of a bond's price to a change in interest rates, adjusting for the fact that the bond's cash flows change as yields change.

Maturity

The specific day when the core sum of a financial product, like a bond or loan, must be paid back to the investor.

Semiannually

Occurring twice a year; every six months.