Question

Chapter 4: A Tour of the Cell 3. A cell's plasma membrane is described as being a because it is composed of a variety of molecules that are constantly in motion around each other. 4. Figure 4.4b on pg. 60 of your textbook indicates that membrane proteins will have both hydro- philic and hydrophobic regions. Briefly explain why a membrane protein would need both regions. Refer to the figure to aid you in answering the question. Chapter Content: The Nucleus and Ribosomes: Genetic Control of the Cell Complete the following questions as you read the chapter content-The Nucleus and Ribosomes: Genetic Control of the Cell: 1. Complete the following table regarding the nucleus. Nuclear envelope Nuclear pores Function Nucleolus Nucleus 2. The nuclear envelope has passages for substances moving into and out of the nucleus. These passages are called nuclear pores and they are made by proteins that are inserted into the plasma membrane that makes up the nuclear envelope. These proteins are assembled by: a. free-floating ribosomes b. the nucleus c. ribosomes bound to the endoplasmic reticulum d. nuclear pores

Answer 1

Since we are entitled to answer only one question at a time, I would be answering the ques. 3. If you need help with another question, then kindly repost the question and put up a new request.

Fluid mosaic model:

It is a model that describes the cell membrane structure. A flexible layer composed of lipid molecules is dispersed with the big protein molecules in this model. These molecules play a role as channels. Other molecules go through and leave the cell across these channels.

The molecules present in this membrane are proteins, carbohydrates, cholesterol, and phospholipids. The plasma membrane is also known as a fluid mosaic as most of its molecules keep floating along with the lipids.

Answer:

A cell’s membrane is referred to as a fluid mosaic as it is made up of an array of molecules that are regularly in motion around each other.