1. Provide a suitable reason for each of the following:
A. Cell walls are tough and rigid structures.
B. The nuclear membrane is provided with pores.
C.The nucleus is also called the 'brain of the cell'.
D. DNA makes a copy of itself before cell division.
Answers
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism.
The nuclear pore is a protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm. In eukaryotic cells, the nucleus is separated from the cytoplasm and surrounded by a nuclear envelope. This envelope safeguards the DNA contained in the nucleus.
The nucleus is called the "brain" of the cell because it holds the information needed to conduct most of the cell's functions. Other molecules make proteins from that information on a regular basis - each moment of our lives.
DNA replication is the process by which DNA makes a copy of itself during cell division. ... The separation of the two single strands of DNA creates a 'Y' shape called a replication 'fork'. The two separated strands will act as templates for making the new strands of DNA.