All living organisms are made up of units called cells. A cell is the basic structural, fundamental and functional unit of life. Understanding and learning about cells supports the learning of other biological processes. In this chapter, you will learn about the concept of cytology, Cell theory, organelles and biological molecules. The competences developed will enable you to appreciate the importance of cells and their role in living organisms.
Cytology is the branch of biology that deals with the study of the structure and function of the cells. The cell is the basic structural and functional unit of all organisms. All living organisms may be composed of a single or many cells. The unicellular organisms consist of a single eell while multicellular organisms consist of multiple cells. For multicellular organisms, the cells are differentiated and organised into groups to form different structures that perform various functions. Robert Hooke, who is also known as the father of cytology, was the first scientist to study the cell structure using a primitive microscopc. In 1665, he cxamined a cross-section of the bark of a cork tree and observed its structure (Figure 1.1).
He found that the cork was made up of small chambers surrounded by walls; he gave the spaces the name "cell" meaning "little room" or "cavity". He thought the objects he had discovered looked like the individual rooms in a monastery, which
were known as cells. The cells observed by Hooke gave no indication of the nucleus and other organelles found in most living cells. However, in his invention, Hooke did not discover the true biological function of cells.
TOPICS
TOPIC 1: CYTOLOGY
TOPIC 2: PRINCIPLES OF CLASSIFICATION
TOPIC 3: NATURAL GROUPS OF ORGANISMS
TOPIC 4: COORDINATION
TOPIC 5: NUTRITION
TOPIC 6: GASEOUS EXCHANGE AND RESPIRATION
TOPIC 7: REGULATION (HOMEOSTATIS)
Cytology is the branch of biology that deals with the study of the structure and function of the cells. The cell is the basic structural and functional unit of all organisms. All living organisms may be composed of a single or many cells. The unicellular organisms consist of a single eell while multicellular organisms consist of multiple cells. For multicellular organisms, the cells are differentiated and organised into groups to form different structures that perform various functions. Robert Hooke, who is also known as the father of cytology, was the first scientist to study the cell structure using a primitive microscopc. In 1665, he cxamined a cross-section of the bark of a cork tree and observed its structure (Figure 1.1).
He found that the cork was made up of small chambers surrounded by walls; he gave the spaces the name "cell" meaning "little room" or "cavity". He thought the objects he had discovered looked like the individual rooms in a monastery, which
were known as cells. The cells observed by Hooke gave no indication of the nucleus and other organelles found in most living cells. However, in his invention, Hooke did not discover the true biological function of cells.
TOPICS
TOPIC 1: CYTOLOGY
TOPIC 2: PRINCIPLES OF CLASSIFICATION
TOPIC 3: NATURAL GROUPS OF ORGANISMS
TOPIC 4: COORDINATION
TOPIC 5: NUTRITION
TOPIC 6: GASEOUS EXCHANGE AND RESPIRATION
TOPIC 7: REGULATION (HOMEOSTATIS)
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