Unit 2 - Cell organisation and stem cells Flashcards
Define cell
a single repeating unit of an organism
Define tissue
a collection of differentiated cells that have a common function
Define organ
a group of tissues that work together to carry out a common function
Define organ system
a group of organs that carry out a common function
Define specialised
having particular structure to serve a particular function
Define differentiated
the process by which a less specialised cell develops a distinct form and function,a cell specialising
Why do multicellular organisms need specialised cells?
-complex communication in a multicellular organism
-specialised functions need specialised cells
-maximise efficiency of processes like absorbing nutrients
What features does an red blood cell have to suit it for its function?
Biconcave disc- maximises SA to carry oxygen
No nucleus- more room for haemoglobin
Flexible- can squeeze through narrow capillaries
What features does a root hair cell have to suit its function?
Root hairs- increase surface area to maximise uptake of water/minerals from the soil
What features does a guard cell have to suit it for its function?
Cell wall thicker on inside than outside- so cell doesn’t change symmetrically as its volume changes
Gap in the centre- allows gases in and out
What are the 4 main categories of tissues in animals?
Nerve tissue
epithelial tissue
muscle tissue
connective tissue
What are stem cells?
Undifferentiated cells with the potential to differentiate into a variety of the specialised cell types of an organism
Define undifferentiated
An unspecialised cell originating from mitosis or meiosis
What are the characteristics of stem cells?
-can repeatedly undergo cell division
-not adapted to a specific function
-can give rise to specialist cells
-few epigenetic markers
What are stem cells used for in the body?
-growth
-development (of am embryo)
-tissue repair
