Animal Cell

By Kristin Crowell

Cytoplasm

The cytoplasm is all the organelles and the cytosol. The cytosol is the liquid all the organelles are in, within the cell. The cytoplasm is the area outside the nucleus.


Nucleus

The nucleus is where the DNA and information to make proteins and other molecules are stored. It controls all the different parts of the cell. On the outside of the nucleus is the nuclear envelope. This has many small holes, called nuclear pores, the pores let material in and out of the nucleus, like little massagers, including proteins, and RNA.

Nucleolus- Inside the nucleus there is the nucleolus. the nucleolus is in charge of the start of the assembly of ribosomes.

Chromatin- Spread throughout the nucleus and made of DNA bound to protein.

Chromosomes- They are the condensed form of chromatins when cells divide. Chromosomes carry the genetic information in their threadlike structures.


Ribosomes

Ribosomes are around the nucleus in the cytoplasm and are made of RNA and protein. They follow coded orders from the nucleus to create proteins. Between the two subunits, large and small, amino acids are added to transfer RNA to create protein chains. (seen in image below rough ER)

Smooth Endoplasmic Reticulum (Smooth ER)

The smooth ER, called smooth by the look from electrum microscopy, has many different functions depending on the different cell type. The smooth ER can synthesize lipids and steroids, breakdown lipid soluble toxins in liver cells and control calcium release in muscle cell contraction. (seen in image below rough ER)

Rough Endoplasmic Reticulum (Rough ER)

This endoplasmic reticulum looks rough through electron microscopy because of the many ribosomes on the surface. The rough ER collects the proteins that were synthesized on the ribosomes and sends them throughout the cell.

Golgi

The Golgi apparatus is a stack of membrane-bound vesciles with a single membrane. It is a stack of large vesicles that are surrounded by smaller vesicles. In the smaller vesicles carbons and lipids are attached to proteins as the final touch and sent elsewhere in the cell. The Golgi packages, modifies, and sorts proteins and other materials.

Lysosomes

Lysosomes are needed for intracellar digestion. They break down lipids, charbohydrates, and proteins by releasing lysosome contents into the valuole that kills and digests bateria. Too much of the contenst in the cytoplasm can lead to cell death.

Mitochondria

This organnelle makes high energy compounds which allow the cell to move, divide, produce secretory products and other jobs. Mitochondria have a double membrane with a smooth outer membrane and the inner membrane is twisted and coiled. These folds are cristae and are where food and oxygen combine to puduce the cells major energy source.

Cytoskeleton

The cytoskeleton is a network of protein filaments, or thin strings. These filaments are microtubules, actin filaments, and intermediate fibers. The cytoskeleton is what maintains the cell structure and is also in charge of its movement.

Microtubules- They are hollow structures made up tubulins that maintain cell shape, and are important in cell division because they make mitotic which helps separate chromosomes.

Actin filaments (Microfilaments)- These are made of proteins called actins to give it a thread like structure. The microfilaments are flexible and allows the cell to move and not fall apart.

Intermediate fibers- These fibers give the cell strength.

Centrioles

Centrioles are made of microtubules in nine groups of three and are part of the cytoskeleton. Two centrioles perpendicular to each other make up the centrosome. The centrioles replicate when a cell divides and make the two centrosomes that which separate the two chromosomes into the two new cells.

Cell Membrane

The cell membrane is made up of a lipid bilayer, or a double layer of phospholipids. the bilayer is flexible and strong so it can protect the cell. Parts of the bilayer that are exposed are hydrophilic and like the water in and around the cell. The parts of the lipid bilayer that is not exposed are hydrophobic and can protect the cell from too much water. Within the lipid bilayer are proteins. The proteins allow materials in and out of the cell. The carbohydrate molecules connected to the proteins on the outside of the cell identify the materials before they enter. the proteins can bond with tastes and hormones, and control the entry and exit of ions.

How the Orgenelles Work Together

Cells come from other cells. For this to happen cells divide and the centrioles are responsible for replicating and becoming the centrosomes which then divide the chromosomes to form two new cells. A cells structure is the cytoskeleton. All the parts are held together and are able to move as a unit because of the cytoplasm. Everything in the cell is in cytosol. all the organelles float in the cytosol. The nucleus controls all the work in the cell and everything relates back to it. In the nucleus is the nucleolus which creates ribosomes. The ribosomes move to the surface of the rough endoplasmic reticulum . Protein is synthesized on the ribosomes and the rough ER sends the proteins to other sections of the cell. Some of the proteins are sent to the Golgi where they are packaged and stored in the cell. While this process happens the cell creates waste. The lysosomes break down the proteins, lipids, and carbohydrates so they can be used somewhere else in the cell. For each step to all happen the cell needs energy. The mitochondria takes the energy from stored food and converts them into compounds that the cell can use. When proteins are released, the exit through the cell membrane. The cell membrane monitors what goes in and out of the cell. All these organelles working together and sitting in cytosol make up the cytoplasm. A cell uses each part to make the basic unit of life.

A Liver Cell (Hepatocytes)

80% of the liver is made up of hepatocytes. These cells are active in protein and lipid synthesis. Hepatocytes have a greater number of rough and smooth endoplasmic reticulums and Golgis so more syntheses can occur. The cells release very density lipoproteins. hepatocytes secrete the chemicals necessary to make the chemical reactions occur that turn our food into energy. These cells help with the life process of metabolism. Metabolism mostly takes place in the liver where this type of cell is located. When food is brought to the liver, the hepatocytes synthesize the proteins and lipids so the body can use them as energy. One major particle released by these cells id glycogen. The glycogen is used as storage of energy. Each and every cell has its one organelles working together and creates a cell as a whole which then goes on to work with other cells.