Organelles that Create Boundaries
Cell Wall
Cell walls are found only in plant cells. The main functions of the cell wall include supporting, protecting, and maintaining the shape of the plant cell. The cell wall is the outermost layer of the plant cell. Cell walls are porous to allow water, carbon dioxide, and other substances to pass through.
Cell Membranes
Cell Membranes can be found in both plants and animals. In plants, a cell membrane is the second layer protecting the cell, and, in animals, it is the outermost layer. Cell membranes are made of lipids and mainly serve to regulate what enters and leaves the cell, and to protect and support the cell. Cell membranes are important parts in the life processes called absorption and secretion.
Cytoplasm
Cytoplasm is a jelly-like substance made mostly of water, and dissolved substances that holds all of the organelles in place. Everything inside the cell "floats" in the cytoplasm. Both plants and animals contain cytoplasm in their cells to hold everything in place!
The Nucleus and ALL its Parts!
Often referred to as the cell's "control center," the nucleus is a boundary in which the cell's chromatin is contained. Chromatin is a thread-like substance, also known as DNA. The nucleus and chromatin are both involved in the the process of reproduction. Both plants and animals have a nucleus and all parts inside the nucleus.
The nuclear envelope is the boundary to the nucleus. The nuclear envelope protects the organelles inside the nucleus and is covered with thousands of nuclear pores. Nuclear pores are small holes used for letting materials, such as proteins and RNA, in and out of the nucleus. The envelope is involved in the process of absorption, while the pores are used for transport.
Also inside the nucleus is the nucleolus, a small dense, region shaped like a sphere. The nucleolus is necessary in the process of synthesis, specifically the synthesis of ribosomes. Synthesis means to make; ribosomes are made in the nucleolus.
The nuclear envelope is the boundary to the nucleus. The nuclear envelope protects the organelles inside the nucleus and is covered with thousands of nuclear pores. Nuclear pores are small holes used for letting materials, such as proteins and RNA, in and out of the nucleus. The envelope is involved in the process of absorption, while the pores are used for transport.
Also inside the nucleus is the nucleolus, a small dense, region shaped like a sphere. The nucleolus is necessary in the process of synthesis, specifically the synthesis of ribosomes. Synthesis means to make; ribosomes are made in the nucleolus.