3.5- CELL SPECIALISATION AND ORGANISATION Flashcards
What are cells specialised to do in multicellular organisms?
to perform specific functions
What are similar cells grouped into?
tissues
What are tissues grouped into?
organs
What are organs grouped into?
organ systems
Why is the grouping of cells -> tissues -> organs -> organ systems done for?
increased efficiency
Can any one cell provide the best conditions for all functions?
no
As cells cannot provide the best conditions for all functions, what do the cells do in multicellular organisms?
cells specialised in different ways to form particular role
What has specialised cells evolved?
more or fewer of certain organelles + structures to suit role it carries out
What is the first group of cells in an embryo initially?
initially identical
What happens to the cell as the embryo matures?
each cell takes on its own individual characteristics that suit it to the function it will perform when it’s mature
How are all cells in an organism, such as a human produced?
by mitotic divisions from fertilised egg
As all the cells in an organism are produced by mitotic divisions from a fertilised egg, what follows?
they all contain exactly the same genes
What do cells have for them to develop into any one of the many different cells in an organism?
every cell contains genes
How are the genes used in a cell for them to be specialised?
only some of the genes switched on (expressed) in a cell, at any one time. rest of the genes switched off
What will muscle/sperm cell have a lot of?
mitochondria
What do white blood cells have many of?
lysosomes
What is done to cells for working efficiency?
cells are normally aggregated together
What is a tissue?
collection of similar cells that perform a specific function
Examples of tissues? (2)
epithelial tissues
xylem
Where are epithelial tissues found?
in animals
What do epithelial tissues consist of?
sheets of cells
What do epithelial tissues line?
line surfaces of organs
What function do epithelial tissues often have?
protective or secretory function