What is a cell? According to Genetic Home Reference, “cells are the basic building blocks of all living things.” There are two main branches into which a cell can be classified. These branches are prokaryotes and eukaryotes. In the category of prokaryotes there are bacteria; in the category of eukaryotes there are plants and animals. While plant and animal cells have many differences, they also have a fair amount of similarities. For example, an animal cell has a centrosome, but so does a plant cell. An average animal cell consists of centrioles, cytoplasm, endoplasmic reticulum (smooth ER and rough ER), Golgi complex, lyosomes, microtubules, mitochondria, nucleus, nucleolus, necleaopore, and ribosomes. Centrioles in an animal cell are made to organize microtubules during the mitosis (cell division) phase. The cytoplasm helps move things around the cell and also dissolves cellular waste. The rough endoplasmic reticulum produces fluid-like membranes and proteins. The smooth endoplasmic reticulum has many tasks such as the synthesis of carbohydrates and lipids. Then there is the Golgi complex, which is responsible for producing, storing and shipping certain cellular products. Lysosomes are responsible for breaking down cellular macromolecules. Microtubules have the main job of helping to support and shape the cell. Mitochondria are what I like to call "energy centers"; they are the energy producers in an animal cell. After the mitochondria is the nucleus which, according to Regina Bailey, "contains the cell's hereditary information and controls the cell's growth and reproduction." Inside the nucleus is the nucleolus which helps in the synthesis of ribosomes. The nucleopore allows nucleic acids and proteins to move freely. Last but not least are ribosomes. Ribosomes are responsible for collecting proteins into the cell. An average plant cell consists of a cell membrane, cell wall, chloroplasts, cytoplasm, cytoskeleton, endoplasmic reticulum (smooth ER and rough ER), Golgi complex, microtubules, mitochondria, nucleus, nucleolus, nucleopore, peroxisomes, plasmodesmata, ribosomes, and vacuole. The cell membrane in a plant cell supports the cell and helps maintain its shape. The cell membrane can also control which substances can enter and leave a cell. The cell wall also protects the cell and gives it its shape. Chloroplasts absorb energy from sunlight. The main job of the cytoplasm is to move substances within a cell and dissolve cellular waste. The cytoskeleton of a plant cell is similar to that of a cell wall because it helps maintain the cell's shape and provides support to the cell.