Chapter 8, Problem 8STP

Summary Introduction

Introduction:

All living organisms are composed of cells. Cells have been studied by various scientists and a theory known as the cell theory have been postulated. The cell theory reflects the various properties of living cells.

Answer to Problem 8STP

Correct answer :

The correct answer is option (C) Life forms are made up of one or more cells.

Explanation of Solution

Explanation/justification for the correct answer :

Option (C) Life forms are made up of one or more cells. According to the cell theory, living things are composed on one or more cells, which is considered as the basic and fundamental unit of life. Prokaryotes are unicellular organisms while eukaryotes may be unicellular or multicellular depending on the complexity. So, the correct answer is option (C).

Explanation for incorrect answer :

Option (A). Cells can form from proteins in the environment. Proteins are produced by specific organelles of the cell. The information for protein production is encoded in the DNA of the cell and is protein produced in the ribosomes. To produce a protein, a copy of the DNA, called as mRNA, is produced. The mRNA is then transported to the ribosomes. Ribosomes read the information encoded in the mRNA and uses it to assemble amino acids into a protein. Amino acids are the building blocks of proteins. So, this is an incorrect answer.

Option (B). Cells contain membrane bound organelles. Cells contain various organelles

That may or may not be membrane bound. Nucleus, Golgi, endoplasmic reticulum, Mitochondria are membrane bound. However, some other organelles like ribosomes, cell wall, and cytoskeleton are not membrane bound.

The cell theory does not define organelles of the cell into membrane bound structures. So, this is an incorrect answer.

Option (D). Organelles are smallest form of life. The smallest unit of life is cell and organelles are small structures that exist within the cell and performs specialized function. The cell is known as the smallest structural and functional unit of life because it can exist on its own and carry out different biological processes. However, organelles once segregated from the cell or organelles, fail to survive and is incapable of carrying out different processes. So, this is an incorrect answer.