Organs and signalling Flashcards
define a cell
the basic unit from which living organisms are built
can be specialised for a particular function
define tissue
a group of one type of specialised cell which works together to carry out specific functions e.g. muscle tissue
define an organ
a group of different tissues (each made of a different specialised cell type) which work together to carry out one or more functions e.g. heart
define an organ system
a group of different organs (each made of different specialised cell types) working together for the same function e.g. digestive system
what can differential gene expression enable
cells that have the same genetic material to have different structures and functions
how do cells become specialised through differential gene expression
signals from the inside and outside the cell result in changes to the epigenome
the changes alter the genes transcribed at specific times and locations
epigenetic changes will bring about specialisation of the cell
how are master genes involved in early development if an organism
(what they control, what they produce an how they specialise cells)
master genes control the development of segments of an organism e.g. legs, hands
they produce mRNA that is translated into signal proteins
signal proteins switch on the genes responsible for producing the proteins needed for specialisation of cells in each segment
how do cells know how to form tissues
(what molecules used, where are they located, what they bind to)
cells use adhesion molecules (protein or glycoproteins)
they are located on the cell surface membrane
adhesion molecules are used in cellular recognition
adhesion molecules recognise and bind to complementary cells like themselves
e.g. muscle cells bind to muscle cells
what is apoptosis and how is involved in development
apoptosis is programmed cell death
healthy animal cells die during development in particular places e.g. between fingers
