In addition, the nucleolus of the nucleus produces the RNA that is used to make ribosomes.
Linked to the nucleus is the rough endoplasmic reticulum, which consists of compartments and these compartments are called cisternae. There are also organelles on the 'cytoplasm face' of the rough endoplasmic reticulum called ribosomes these have a small and dense structure, like a giant enzyme, plus it has two units a large and small unit joined together. Moreover the ribosomes and rough endoplasmic reticulum produces proteins and proteins enzymes. Ribosomes are the sites of translation.
The function of the ribosomes is very important as they give proteins there characteristic by controlling the amino acids order in the polypeptide chain in the primary structure, by bonding the amino acids in a certain order by peptide bonds when condensation reactions occur. Furthermore the nucleus sends out instructions and the ribosome's and rough endoplasmic reticulum send out protein or protein enzymes, the rough endoplasmic reticulum packages and transports them in a transfer vesicle.
The chemical products (proteins and protein enzymes etc.) are modified by the Golgi body. The Golgi body receives the chemical products on the forming face and modifies the chemicals e.g. protein enzymes modified from being inactive to active protein enzymes. The Golgi has flattened cavities like saucers, as they go from the forming face to the releasing face each flattened cavity gets circular around the edges, plus this is where the modified chemicals are.
Finally at the releasing face the Golgi body packages the modified chemicals in lysosomes, the lysosomes come of the round edges of the flattened cavities which also give the lysosomes a surrounding membrane. The lysosomes contain powerful digestive enzymes therefore are, involved in metabolic reactions, lysosomes secrete out of the cell via the cell membrane. Some of the lysosome remain in the cell and hydrolyses old and dead organelles or surplus organelles of the cell takes place. Furthermore the lysosomes can even be used to break down material which has entered the cell by the process of endocytosis. The tertiary structure of the protein lysosome is an anti-bacterial compound.
The nucleus/DNA information also controls what the cell membrane lets in and out. What is more, the cell membrane has a phospholipids bilayer. The phospholipids are made from two fatty acids, a glycerol and a phosphate group. The glycerol and two amino acids join by condensation reactions, and the oxygen atom is shared in the ester bonds, between the two fatty acids and the glycerol molecule.
The phospholipids has a phosphate group which ionises and gets a positive and negative charge, because of the positive and negative charge it is polar and hydrophilic and attracts water and will therefore, dissolve in water.
The phospholipids bilayer has hydrophilic heads (phosphate group and a glycerol) and hydrophobic (two fatty acids) tails. The hydrophobic tails attract each other and are in the middle of the cell membrane. The plasma membrane is so small that if you have an electron microscope at 500,000x magnification, because of the sort wavelength you can see two lines, which represent the plasma (cell) membrane.
Now I will to introduce an organelle which is playing a vital role in our cells and helping us keep alive.
The cell has a very important organelle which has evolved to work for the cell; this has been captured by the typical human cell, what more is that these are primitive cells. This organelle used to be a prokaryotic cell which is clearly identifiable when you compare the typical bacterial cell with this organelle called mitochondria.
This is because the mitochondria contain circular DNA, which is a similarity of prokaryotic cells. The mitochondrion is a rod-shaped organelle.
Furthermore the structure of a mitochondrion contains matrix (fluid in the mitochondrion), cristae (folded inner membrane) and circular DNA, ribosomes, inner membrane and an outer membrane.
The matrix (fluid) contains enzymes which catalyse reactions in the stages of respiration.
The ribosomes inside of a mitochondrion produce the mitochondrion's own protein
enzymes. What's more is that the folded inner membrane of the mitochondrion, cristae contains enzymes which are concerned with the later stages of respiration.
The great importance of the mitochondria is that it respires to give out energy to the cell, and the cell has several of these organelles respire aerobically to give out ATP energy to power active transport by using enzymes, ATP is used to make big molecules and help muscle contract this is about 1-10 micro meters in size up to 1000 in cytoplasm of each cell.
Another organelle which a typical human cell has is smooth endoplasmic reticulum. This is not connected to the rough endoplasmic reticulum. The SER also has compartments in which there are cisternae. Furthermore the SER is involved in lipid and phospholipids production. Also the synthesis of steroids takes place here as well. Sometimes this is linked to the rough endoplasmic reticulum is further away in the cell.
Hence in you can see that the typical human cells have a complex structure, when each structure does its particular function then it all adds up to carry out a particular job in a typical human cell.
