3.5 cell specialisation and organisation Flashcards
How are cells, tissues, organs and organ systems related
A group of similar cells performing. a specific function group together to form a tissue
A group of tissues group together into an organ
A set of organs group into an organ system
Why are the cells in organelles specialised in different ways to perform particular roles
. All cells in a multicellular organism perform basic functions but no one cell can provide the best conditions for all functions
Each specialised cell has evolved more or fewer of certain organelles and structures to suit the role it carries out
When do the cells specialise
. In an embryo they are all identical
. However as it matures each cell takes on its individual characteristics that make it suitable for the function it will perform when it matures
How do cells specialise
. All cells in organisms are produced by mitotic divisions from the fertilised egg, so they all contain the same genes needed for it to develop into any one of the many cells in an organism
. However, different genes are switched on in each type of specialised cell, and the rest of the genes are switched off
What varies between different cells
give examples
. The shape of them
. The numbers of each of the organelles:
Eg muscle or sperm cell contain a large amount of mitochondria for energy whilst a bone cell contains very few
. White blood cells have many lysosomes whilst muscle cells have very few
What is a tissue
Cells are aggregated together for working efficiency, so a group of similar cells performing a specific function is known as a tissue
What are epithelial tissues, where are they found and what do they do
What are 2 types
Found in animals
Consist of sheets of cells
They line the surface of organs and often have a protective or secretory function
. Some are made of thin, flat cells that line organs where diffusion takes place eg alveoli of the lungs
. Ciliated epithelium line the trachea and sweep mucus out of the lungs to the mouth
What are xylem tissues, where are they found
. Occur in plants and is made up of a number of similar cell types
. It is used to transport water and mineral ions throughout the plant
Also gives mechanical support
What are organs
. Tissues are aggregated into organs
So an organ is a group of tissues that work together to perform a variety of functions , but they usually have a major primary function
The stomach is an organ that is involved in the digestion of certain types of food
What 3 tissues is it made up of
. Muscle tissue to churn and mix the stomach contents
. Epithelium to protect the stomach wall and produce secretions
. Connective tissue to hold together the other tissues
A leaf is an example of an organ
What 5 tissues is it made of
. Palisade mesophyll made of leaf palisade cells that carry out photosynthesis
. Spongy mesophyll adapted for gaseous diffusion
. Epidermis to protect the leaf and allow gaseous diffusion
. Phloem to transport organic materials away from the leaf
. Xylem to transport water and ions into the leaf
Out of blood capillaries, arteries and veins which ones are organs and which is a tissue
What is the function of them all
Arteries and veins are organs
Capillaries are tissues
They all have the same major function: the transport of blood
However capillaries are made of one tissue which is epithelium whilst arteries and veins are made of many tissues eg muscle, epithelial etc
What is an organ system
. Organ work together as a single unit known as an organ system
These systems can be grouped together to perform particular functions more efficiently
What does the digestive system do
. It digests and processes food. It is made up of organs that include the salivary glands, oesophagus, stomach, duodenum, ileum, pancreas and liver
What does the respiratory system do
It is used for breathing and gas exchange.
It is made up of organs that include the trachea, bronchi and lungs
