Chapter 4, Problem 1SQ

Summary Introduction

Introduction:

The cell is the basic “fundamental unit” of life. Every organism present in the environment is composed of cell. Cells perform a number of important activities that help in the survival of an organism. These activities are known as cellular activities.

Answer to Problem 1SQ

Correct answer:

All the cells have three basic structures. These are plasma membrane, cytoplasm, and DNA. Hence, the correct answer is option c.

Explanation of Solution

Reason for correct answer:

Option c. is given as “cytoplasm, DNA, and a plasma membrane.”

Every cell contains three basic structures that form a complete cellular unit. These three structures are:

• Plasma membrane:

The outer layer of cell that acts as a barrier is known as the plasma membrane. It surrounds all the cellular units and protects them from the external environment.

• Cytoplasm:

It is the middle layer of the cell. All the internal components of the cell are present in the cytoplasm.

• DNA:

DNA stands for “Deoxyribonucleic acid.” It is the genetic material present in the organisms that guide them to perform all the cellular activities.

Therefore, every cell contains these three basic units (plasma membrane, cytoplasm, and DNA).

Reason for incorrect answer:

Option a. is given as, “cytoplasm, DNA and, organelles with membranes.”

Every cell contains cytoplasm and DNA. The cell can have two types of organelles, one with membrane and other without a membrane. This indicates that it is not necessary that a cell contains an organelle with a membrane. Hence, option a. is incorrect.

Option b. is given as, “a plasma membrane, DNA, and a nuclear envelope.”

Plasma membrane and DNA are two important components that are present in every cell. However, it is not necessary that every cell has a nuclear envelope. For example, prokaryotes lack nuclear envelope but eukaryotes contain a well-defined nuclear membrane. Hence, option b. is incorrect.

Option d. is given as, “a cell wall, cytoplasm, and DNA..”

Every cell contains a cell wall and DNA. However, every cell does not contain a cell wall. For example, the plant cell has a cell wall but animal cells lack a cell wall. Hence, option d. is incorrect.

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

Conclusion

The three basic components present in every cell are cytoplasm, plasma membrane, and DNA. Thus, the correct option is c.