Cells and Tissues

Cells and Tissues  

 Cells are composed of their cytoplasm, which includes the cytosol and organelles;  

the nucleus and the surrounding plasma membrane. You should know that the  

plasma membrane is a double layer of phospholipid molecules and that these mol- 

ecules have a hydrophilic end and a hydrophobic end. The plasma membrane con- 

tains proteins including the ATPase (the sodium-potassium pump) which moves  

sodium ions out of the cell while moving potassium ions into the cell. You should  

know the names and function of some of the organelles. For example you should  

know that mitochondria produce ATP and that ribosomes synthesise proteins from  

amino acids.  

 You will become familiar with the names of many cells. Often a word can be  

recognised as the name of a cell because it ends in “-cyte” or, if it is an immature  

cell, by ending in “-blast”. Four major types of tissue are identifi ed in the body:  

epithelial, connective, muscle and neural tissues. Of course there are many sub- 

types within these categories. For example epithelial tissue may be squamous,  

cuboidal, columnar or glandular. Muscle may be skeletal, smooth or cardiac.  

Connective tissue is quite varied and you should be aware of the many different  

examples of tissue that are categorised as “connective”. For example, blood, bone,  

dermis, cartilage and tendon are all connective tissue.