Eukaryotic Cells
By: Geoffrey Freeman
The Nucleus: The control center
The nucleus is separated from the rest of the cell by a nuclear envelope. This is composed of two parallel membranes which are separated by a narrow space and is perforated by small pores where two membranes unite. Macromolecules are able to move through the pores into or out of the nucleus and cytoplasm. Within the nucleus is a nucleolus which stains more intently because of its RNA content. Chromosomes, made with chromatin, are large units of genetic information within the cell and are bound to Histone proteins and are too small to be seen without high magnification. Mitosis is when the duplicated chromosomes are separated equally into daughter cells and Meiosis is when sex cells are created.
Cell Passageway
The Rough and Smooth endoplasmic reticulum are tubular networks through a cell. Th RER starts in the outer nuclear membrane and extends to the cell membrane. The SER is a closed tubular network that functions in nutrient processing.
Mitochnondria
Round or elongated particles spread out through the cytoplasm. With a smooth continuous outer membrane and an inner folded membrane nestled neatly within the outer membrane
Chloroplast
Chloroplast are found in algae and plant cells that are capable of converting sunlight into energy through the process of photosynthesis.
Ribosomes
Ribosomes are scattered throughout the cell found in the cytoplasm and cytoskeleton; others are attached to the RER or mitochondria and chloroplast. These are composed of ribonucleoproteins.
Cytoskeleton
A framework which has several functions including anchoring organelles, moving RNA and vesicles, and permitting shape changes and movement in some cells. Microtubules are long hollow tubes that maintain the shape of some eukaryotic cells.