Cells and DNA How they work By Marco Helson

Whats in a cell?

Cytosol Cytoplasm refers to the jelly-like material with organelles in it. If the organelles were removed, the soluble part that would be left is called the cytosol. It consists mainly of water with dissolved substances such as amino acids.

The Nucleus The nucleus is the control center or mother board of the cell. It is the largest organelle in the cell and it contains the DNA of the cell. The DNA of all cells is made up of chromosomes. DNA contains all the information for cells to perform their functions and reproduce. Inside the nucleus is another organelle called the nucleolus. The nucleolus is the organelle responsible for making ribosomes. The light circles on the surface of the nucleus are the nuclear pores. These are where ribosomes and other materials move in and out of the cell.

Mitochondria Mitochondria are membrane-enclosed organelles distributed through the cytosol of almost all eukaryotic cells. Their main job is the conversion of the potential energy of food molecules into ATP. ATP serves as the primary energy currency of the cell Every type of cell has a different amount of mitochondria. There are more mitochondria in cells that have to perform lots of work, for example- your leg muscle cells, heart muscle cells etc. Other cells that use less energy to do their work and have less mitochondria.

Endoplasmic reticulum Endoplasmic reticulum is a network of membranes throughout the cytoplasm of the cell. There are two types of ER. When ribosomes are connected it is called rough ER and smooth ER when there are no ribosomes connected. The rough endoplasmic reticulum is where a lot of protein synthesis happens in the cell. The function of the smooth endoplasmic reticulum is to synthesize lipids in the cell. The smooth ER also helps in the detoxification of harmful/foreign substances in the cell.

the Golgi complex The golgi complex is an organelle in the cell that is responsible for sorting and correctly sending the proteins produced in the ER. The proteins produced in the ER, should be correctly sent to the places that need proteins to function. In the cell, shipping and sorting is done by the Golgi complex. It is a very important step in protein synthesis. If the Golgi complex makes a mistake in sending the proteins to the right place, certain functions in the cell may stop.

Ribosomes Ribosomes are organelles that help in the synthesis of proteins. Ribosomes are made up of two parts that are called subunits. They get their names from their size. One unit is larger than than the other so they are called large and small subunits. Both of these subunits are important for protein synthesis in the cell. When the two units are put together with a special information unit called messenger RNA, they make proteins. Some ribosomes are found in the cytoplasm, but most are connected to the ER. While attached to the ER, ribosomes make proteins that the cell needs and also ones to be exported from the cell to work elsewhere in the body.

How do cells and DNA relate? DNA contains the instructions for a cell's structure and function. It is the blueprints for how the cell runs, reproduces, builds and repairs itself, and every other function necessary for cell life.

DNA controls the of a cell The working of the cell is the result of making proteins. Proteins and enzymes take up a large portion of the normal protoplasm. DNA molecules determine what proteins are made in each cell and how they are made. Therefore by controlling the proteins being made, the DNA controls both the structure and working of the cell. A gene is the part of the DNA molecule which controls the making of a certain protein. RNA stands for Ribose Nucleic Acid. It carries the information from the DNA to the ribosomes where the proteins are actually made.

DNA holds hereditary information DNA remains unchanged and has the remarkable ability of make exact copies of itself. When an organism is created it receives a complete set of genes, in order to work properly, all the cells must have the same protoplasm and enzymes. Life wouldn't be possible if DNA information were not constant.