Chapter 9, Problem 32A

Summary Introduction

Introduction:

The timing and rate of cell division are very important to the well- being of an organism. The rate of cell division varies depending on the type of cell. There is mechanism involving proteins and enzymes that control the cell cycle. A combination of these two substances is required to signal the cellular reproduction processes.

Answer to Problem 32A

Correct answer :

The correct answer is option C. proteins and enzymes

Explanation of Solution

Explanation/justification for the correct answer:

Option C. proteins and enzymes−Cell cycle is controlled by a mechanism involving certain proteins and enzymes. Proteins called cyclins bind to enzymes called cyclin- dependent kinases (CDK) during the stages of interphase and mitosis to signal the cell to start the process of cell cycle. Different cyclin and CDK combinations control different activities at different stages of cell cycle.

Hence this is the correct option.

Explanation for incorrect answer:

Option A. fats and proteins−Cyclins are proteins andcyclin- dependent kinases are enzymes. Hence this is not the correct option.

Option B. carbohydrates and proteins- Proteins called cyclins bind to enzymes called cyclin- dependent kinases (CDK) during the stages of interphase and mitosis to signal the cell to start the process of cell cycle. Hence this is not the correct option.

Option C. fats and enzymes- Proteins called cyclins bind to enzymes called cyclin- dependent kinases (CDK) during the stages of interphase and mitosis to signal the cell to start the process of cell cycle. Hence this is not the correct option.