Biology is the science of life. It is the study of living organisms, including their structure, function, growth, origin, evolution, and distribution. It includes botany and zoology and all their subdivisions.
Characteristics of life
Composed of cells
Ability to grow and develop
Undergo metabolism
Maintain homeostasis
Respond to stimuli
Ability to reproduce
Ability to evolve and adapt
Cell
The lowest level of structure capable of performing all the activities of life. All organisms are made up of cells. They are the basic units of structure and function.
Robert Hooke coined the name "cell"
1665
Matthias Schleiden and Theodor Schwann recognized cells as the basic units of life
1839
Cell Theory
All living things consist of cells<|>All cells come from pre-existing cells
Cell membrane
Separates a cell from other cells and from surrounding fluids
Holds the cell together and gives its shape
Selectively permeable membrane that controls movement of substances across it
Nucleus
Control center of the cell
Contains nucleoplasm, nucleolus, chromatin, and chromosomes
Surrounded by nuclear membrane
Cytoplasm
Cell materials outside the nucleus
Contains highly organized organelles that take part in specific chemical activities
