Tissues Organs And Systems Flashcards
Describe a unicellular organism
The entire individual consists or one cell. All life functions are performed by it. e.g exchanging gas, digestion, reproduction.
Describe Multicellular organisms
More than one cell. The structure of certain cells are adapted to perform specific functions.
Describe how living organisms start life in 3 steps:
Start as a single cell known as a zygote.
To grow larger, it divides repeatedly.
Mitosis
What is mitosis?
Process of cell division that causes growth
Stages of mitosis
- Zygote
- Nucleus divides
- Cytoplasm divides
- Two identical daughter cells
- Cells enlarge
- Further divisions take place
What do repeated mitotic divisions result in?
Ball of identical cells
What happens after mitosis in a multicellular organism?
Cells in the ‘ball’ start to differentiate and take on new forms and shapes.
Define differentiation
The process that occurs when cells become different in structure. They are able to do specialized functions.
Define specialization
The process that occurs when cells take on specific functions.
Tissue
Group of structurally similar specialized cells which work together to perform specific function.e.g blood, muscle, nerves.
Cells
Smallest unit of life. Combine to form tissue.
Organ
Different tissues that work together to perform specific function.
A system
Group of organs that work together to carry out overall function. digestive system, flower.
An organism
Number of different systems necessary to keep it alive
Def. of Zygote
Single fertilized cell. All cells start life as it.
