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
Types of epithelial tissues? (2)
thin, flat cells
ciliated epithelium
What do thin, flat cells of epithelial tissues line and what happens here?
line organs where diffusion takes place
Example of where thin, flat cells of epithelial tissue line?
alveoli of lungs
Example of where ciliated epithelium of epithelial tissue line?
a duct i.e. trachea
What is the cilia of the ciliated epithelium of epithelial tissue used to do?
move mucus over epithelial surface
Where does the xylem occur?
in plants
What is the xylem used for? (2)
to transport water + mineral ions throughout plant
give mechanical support
What are tissues aggregated into?
organs
What is an organ?
combination of tissues coordinated to perform variety of functions although they have one predominant major function
In animals, what is the stomach organ involved in?
digestion of certain types of food
What tissues is the stomach made up of? (3)
muscle
epithelium
connective tissue
What do the muscle tissues do in the stomach?
churn + mix stomach contents
What do the epithelium tissue do in the stomach?
protect stomach wall + produce secretions
What do the connective tissue do in the stomach?
hold together the other tissues
What tissues is the leaf made up of? (5)
palisade mesophyll spongy mesophyll epidermis phloem xylem
What is the palisade mesophyll of the leaf made up of?
leaf palisade cells
What do the palisade mesophyll do in the leaf?
carry out photosynthesis
What is the spongy mesophyll in the leaf adapted for?
gaseous diffusion
What do the epidermis do in the leaf?
protect leaf + allow gaseous diffusion
What do the phloem do in the leaf?
transport organic materials away from leaf
What do the xylem do in the leaf?
transport water + ions into leaf
Are capillaries organs?
no
Are veins and arteries organs?
yes
What is the function of arteries, veins and capillaries?
transport of blood
What tissue is the capillary made up of?
epithelium
What tissues are the veins and arteries made up of?
epithelial, muscle + other tissues
What is the single unit that organs work together in called?
organ system
Why are organs grouped together?
to perform particular functions more efficiently
Examples of organ systems in humans? (3)
digestive system
respiratory system
circulatory system
What does the digestive system do?
digest + process food
What organs are in the digestive system? (7)
salivary glands oesophagus stomach duodenum ileum pancreas liver
What does the respiratory system do?
used for breathing + gas exchange
What organs are in the respiratory system? (3)
trachea
bronchi
lumps
What does the circulatory system do?
pumps + circulates blood
What organs are in the circulatory system? (3)
heart
arteries
veins
