Hierarchy of Structure and Cell Specialisation Flashcards
What are some examples of unicellular organisms?
Bacteria, amoeba, algae, yeast.
Describe unicellular organisms.
- Body made up of a single cell.
- The single cell can do everything it needs to do to survive.
- The cell body is exposed to the environment on all sides.
- An injury of the cell can cause death of the organism.
- Lifespan is short due to heavy work load.
Describe multicellular organisms.
- Body is made up of numerous cells.
- Different cells are specialised to perform different functions.
- Only outer cells are specialised to face the environment.
- Injury or death of some cells does not affect the organism because they can be replaced by new ones.
- Lifespan is longer because work is divided among different cell types.
What are some examples of multicellular organisms?
Humans, plants, animals, fungi.
Describe the structures of a parameceum.
- Unicelular
- Kingdom: Protista
- Simple structured
- Eukaryotic
- Live in stagnant or slow moving freshwater.
- Each organelle contributes to the overall function of the cell, e.g. cilia for movement and sweeping food towards the gullet.
What are the pros of multicellular organisms?
- Highly efficient due to division of labor.
- Multicellular organisms can grow a lot larger than single celled organisms because they can increase the number of cells to increase the surface area to volume ratio.
- Can maintain a longer life span.
What are the cons of multicellular organisms?
- Requires communication and coordination between cells.
- Specialised cells are dependent on other specialised cells to perform the task they can’t.
Why is the surface area to volume ratio important?
To ensure the exchange of substance happens quick enough.
What is cell specialisation?
- All of the cells in body have the same DNA but not every cell reads and acts on the same sections of DNA.
- Genes can be regulated (switched on and off) so that cells only use the genes that are specific to their function.
What is differentiation?
The process by which something is specialised.
Describe the levels of hierarchy of structure.
cells make up tissues, tissues make up organs, organs make up systems, systems make up multicellular organisms.
Describe the hierarchy of structure.
Specialisation brings about the need for communication and coordination between cells.
Specialised cells are totally dependent on the activities of other cells to perform tasks that they cannot.
Describe an example of how different specialised cells work together to perform functions.
Nerve cells, effectively transport nerve impulses, but they rely on red blood cells to deliver oxygen, heart muscles to pump the oxygenated blood to them and other cells to provide nutrients and to remove their wastes.
If a nerve cell is isolated from the organism of which it is part, unlike a unicellular organism, it is not able to function on its own and it dies.
What are the 4 different types of tissues?
Nervous, connective, muscle and epithelial.
Describe nervous tissue.
- Provides a means of communication between all body structures.
- Includes neurons that transmit nerve impulses.
