Chapter 11, Problem 1SQ

Your bone cells, muscle cells, and skin cells look different because

1. a. different kinds of genes are present in each kind of cell.
2. b. they are present in different organs.
3. c. different genes are active in each kind of cell.
4. d. different mutations have occurred in each kind of cell.

Summary Introduction

Introduction:

Almost all the cells in an organism are genetically identical bit different types of cells looks different result from differential gene expression. Genes are expressed by turning on and turning off its expression as a result of interaction with regulatory proteins. Each cell type contains a unique set of proteins that regulates the gene expression by controlling different levels; transcriptional level, processing level and translational level.

Answer to Problem 1SQ

Correct answer:

Eukaryotic and multicellular organism regulates gene expression to maintain different cell types during embryonic development. Therefore option c. is correct.

Explanation of Solution

Reason for correct statement:

The control of gene expression makes it possible for cells to produce specific kind of proteins that make different type of cells with the organism even if their genetic composition is same.

Option c. is given as “different genes are active in each kind of cell”.

As, in eukaryotic organisms each cell maintain differential gene expression; the bone cells, muscles cells and skin cells looks different as the differential gene expression provide them with expression of different protein responsible for particular characters. It is the right answer.

Hence, option c. is correct.

Reasons for incorrect statements:

Option a. is given as “different kinds of genes are present in each kind of cell”.

As all the cells preset in an organism contain similar genetic composition and so have identical genes. So it is a wrong answer.

Option b. is given as “they are present in different organ”.

As, different cells responsible to provide different functions to organs by expressing different genes and organs, they are not responsible for cells diversity in the body. So it is a wrong answer.

Option d. is given as “different mutations have occurred in each kind of cells”.

As, mutation is responsible for altering the function in a gene present in the cell; it cannot be associated with diversity of cells present in the organism’s whole body. So it is a wrong answer.

Hence options a., b., and d. are incorrect.

Conclusion

The bone cell, muscles cells and skins cells look different as they control their gene expression by differential expression that different kind of proteins and provide them different structure and functions.