Cell specialisation Flashcards
How does the cell become specialised?
Every cell contains the genes needed for it to develop into any one of the many different cells in the organism.
But only some of these genes are switched on/expressed in any one cell, at any one time.
Different genes are switched on in each type of specialised cell. The rest of the genes are switched off.
The number of organelles also varies. Eg muscle/sperm cell will contain many mitochondria, while bone cell has few. WBC have many lysosomes while muscle cells have few.
How are cells before they are specialised?
The first group of cells in an embryo are all initially identical.
As it matures, each cell becomes specialised in structure to suit the role it will carry out.
All cells cells will in an organism are produced by mitotic divisions from the fertilised egg. They all contain exactly the same genes.
What is a tissue?
A collection of similar cells that perform a specific function is known as a tissue.
This is because of working efficiently.
What are epithelial tissues?
Found in animals and consist sheets of cells.
Like on the surface of organs and have a protective or secretory function.
There are many tupes
What are organs?
An organ is a combination of tissues that are coordinated to perform a variety of functions, although they have a predominant major function.
What are organ systems and give eg.
Organs work together as a single unit known as an organ system. These systems may be grouped together to perform particular functions more efficiently.
Eg:
Digestive system: digests and processes food. Made up of organs that include the salivary glands, oesophagus, stomach, duodenum, ileum, pancreas and liver.
Respiratory system: for breathing and gas exchange. Made up of trachea, bronchi and the lungs.
Circulatory system: pumps and circulates blood. Made up of the heart, arteries and veins.
