Question

describe the single celled organism amoeba? what kind of protection by the cell wall in plants?
mention the funtions of the nucleous of a cell?​

Answer 1

A cell wall is a rigid, semi-permeable protective layer in some cell types. This outer covering is positioned next to the cell membrane (plasma membrane) in most plant cells, fungi, bacteria, algae, and some archaea. Animal cells however, do not have a cell wall. The cell wall has many important functions in a cell including protection, structure, and support.

Cell wall composition varies depending on the organism. In plants, the cell wall is composed mainly of strong fibers of the carbohydrate polymer cellulose. Cellulose is the major component of cotton fiber and wood, and it is used in paper production. Bacterial cell walls are composed of a sugar and amino acid polymer called peptidoglycan. The main components of fungal cell walls are chitin, glucans, and proteins.

Plant Cell Wall Structure
A section of the cell wall in a plant cell
The plant cell wall is multi-layered and consists of up to three sections. From the outermost layer of the cell wall, these layers are identified as the middle lamella, primary cell wall, and secondary cell wall. While all plant cells have a middle lamella and primary cell wall, not all have a secondary cell wall.

Middle lamella: This outer cell wall layer contains polysaccharides called pectins. Pectins aid in cell adhesion by helping the cell walls of adjacent cells to bind to one another.​
Primary cell wall: This layer is formed between the middle lamella and plasma membrane in growing plant cells. It is primarily composed of cellulose microfibrils contained within a gel-like matrix of hemicellulose fibers and pectin polysaccharides. The primary cell wall provides the strength and flexibility needed to allow for cell growth.​
Secondary cell wall: This layer is formed between the primary cell wall and plasma membrane in some plant cells. Once the primary cell wall has stopped dividing and growing, it may thicken to form a secondary cell wall. This rigid layer strengthens and supports the cell. In addition to cellulose and hemicellulose, some secondary cell walls contain lignin. Lignin strengthens the cell wall and aids in water conductivity in plant vascular tissue cells.

Answer 2

Answer:

Hello mate✌✌✌

1) Amoebae are eukaryotes whose bodies most often consist of a single cell.

2) A major function is to act as pressure vessels, preventing over-expansion of the cell when water enters.

3) Nucleus stores heredity material in the form of deoxy-ribonucleic acid (DNA) strands.Also, it stores proteins and ribonucleic acid (RNA) in the nucleolus.

Hope it helps✌✌✌