Chapter 34, Problem 2Q

Summary Introduction

To review:

The bursting of the oocytes injected with tonoplast injecting protein (TIP) when they are placed in hypotonic environment and the outcome of the same happening if plant cells are injected with TIP messenger ribonucleic acid (mRNA).

Given:

Researchers took the oocytes of the frog Xenopus laevis and injected them with the mRNA of plant TIP. These cells are taken as they are large in size with a low osmotic cell permeability. Also, in the second case, researchers kept the oocytes uninjected. In the third case, however, mRNA of a nontransport protein is injected into the oocytes. The cells were observed after incubating them for 2 days in isotonic medium and treatment with hypotonic solution.

The following graph of changes in relative volume versus time was plotted by the researchers:

The researchers observed that oocytes having TIP mRNA bursts when kept in hypotonic solution while others do not. There was significant changes in the volume of TIP injected oocytes and a very small change in the volume of the oocytes which were remained uninjected or injected with some other nontransport protein.

Researchers observed and created the following table which depicted the osmotic water permeability of the three conditions.

Introduction:

TIP also known as tonoplast intrinsic proteins are present in the vacuoles of the plant cells and often used as marker proteins. They help in the transport of molecules in and out of the cell. The oocytes of X enopus species are usually taken for the experimental studies by the researchers for the work related to molecular biology and cell biology. Plant cells would behave in a different manner if they are injected with TIP mRNA and kept in the hypotonic solution.