Chapter 4, Problem 1TYU

Which of the following is the most fundamental feature that enables the cell to function as a distinct entity, separate from its environment? (a) nucleus (b) ribosomes (c) nucleic acids

(d) plasma membrane (e) protein

Summary Introduction

Introduction: Cells are the fundamental unit of life. They are modified in different ways to carry out various functions. Prokaryotes are single-celled organisms, and eukaryotes are mostly multicellular organisms.

Answer to Problem 1TYU

Correct answer: The most fundamental feature that enables the cell to function as a distinct entity, separate from its environment, is plasma membrane. Hence, the correct answer is option (d).

Explanation of Solution

Reason for the correct answer:

The plasma membrane, also called selectively permeable membrane, is the rigid boundary that separates the extracellular niche and the intracellular components. It is present in both prokaryotic cells and eukaryotic cells. The plasma membrane has pores that allow the movement of molecules across the lipid bilayer from the extracellular matrix to the interior of the cell or vice versa. It is made up of phospholipid bilayer that is embedded with proteins, carbohydrates, and cholesterol. The membrane barriers present outside the cell will maintain the chemical environment inside the cell. The internal composition of the cell is maintained only when the cell is separated from the outside environment.

Option (d) is given as “plasma membrane”.

Plasma membrane is also called as selectively permeable membrane, as it allows the entry of only selected particles to move inside and outside of cell.

Hence the correct answer is option (d).

Reasons for incorrect answers:

Option (a) is given as “nucleus”.

Nucleus is a cellular organelle present within eukaryotic cells. They do not permit the cell to function as a distinct entity, separate from its environment, as they are not selectively permeable.

Hence, option (a) is incorrect.

Option (b) is given as “ribosomes”.

The ribosomes are organelles that comprise proteins and ribonucleic acid (RNA). The ribosomes are associated with the synthesis of proteins. They do not separate the cell from its external environment.

Hence, option (b) is incorrect.

Option (c) is given as “nucleic acids”.

Nucleic acids are the biochemical entities that mainly constitute RNA or DNA as the genetic material. They do not separate the cell from its external environment.

Hence, option (c) is incorrect.

Option (e) is given as “protein”.

Protein is a biomolecule that is made of repeating subunits of amino acids. They do not separate the cell from its external environment.

Hence, option (e) is incorrect.

Hence, the options (a), (b), (c), and (e) are incorrect.

Conclusion

The plasma membrane is the boundary between the cell and its outer environment.