Cell Specialisation and Organisation Flashcards
How are cells in an organism produced?
Produced by mitotic divisions from the fertilised egg. They all contain exactly the same genes.
How do cells become specialised?
Every cell contains the genes needed for it to develop into any one of the many different cells in an organism, only some genes are expressed, and different genes are expressed in each type of specialised cell.
What features vary between different specialised cells?
- Shape of cell.
- Number of each of their organelles
What is a tissue?
A collection of similar cells, aggregated together to work efficiently, to perform a specific function.
What are epithelial tissues?
They line the surfaces of organs with either a protective or secretory function.
What do the epithelial tissues lining the alveoli of the lungs look like?
Thin, flat cells that line the lungs for diffusion to take place through a short pathway.
What specific feature does ciliated epithelium have?
Lines ducts, such as the trachea. It is lined with cilia which are used to move mucus over the epithelial surface.
What is the role of the xylem?
They are used to transport water and mineral ions through a plant and also gives mechanical support. It occurs in plants.
What are organs?
Aggregations of tissues. A combination of tissues that are coordinated to perform a variety of functions, with one major function.
What is the role of the stomach?
An organ involved in digestion of food.
What tissues make up the stomach and what are their roles?
Muscle - churns and mixes the stomach contents.
Epithelium - Protect wall and produce secretions.
Connective tissue - Hold together other tissues.
What tissues make up the leaf organ and what are their roles?
Palisade mesophyll - made up of leaf palisade cells that carry out photosynthesis.
Spongy mesophyll - Adapted for gaseous exchange.
Epidermis - Protect leaf and allow gaseous diffusion.
Phloem - transport organic materials away from the leaf.
Xylem - Transport water and ions into the leaf.
Why are organ systems grouped together?
To perform particular functions more efficiently.
What is the role of the digestive system?
Digests and processes food. Made up of organs including the salivary glands, oesophagus, stomach, duodenum, ileum, pancreas and liver.
What is the role of the respiratory system?
Used for breathing and gas exchange. It is made up of organs including, trachea, bronchi and lungs.
