Growth And Differentiation Flashcards
What is growth
Growth is defined as the irreversible increase in the dry mass of an organism. It is brought about by an increase in cell size or number.
What is differentiation
Differentiation is the process of cells becoming specialised. Most types of animal cells differentiate at an early stage. They become specialised for a particular function and cannot change into different types of cells. In mature animals, cell division is mainly restricted to replacement and repair. On the other hand, many plant cells keep the ability to differentiate.
Cloning plants
People may want to clone a plant deliberately. Cloning of plants has many important commercial implications. It allows a successful variety of a plant to be produced commercially and cheaply, on a massive scale in a short space of time.
Cuttings
The simplest way to clone a plant involves taking a cutting. A branch from the parent plant is cut off, its lower leaves are removed, and the stem is planted in damp compost. Plant hormones are often used to encourage new roots to develop. The cutting is usually covered in a clear plastic bag at this stage to keep it moist and warm. After a few weeks, new roots develop and a new plant is produced. The method is easy enough for most gardeners to do successfully.
Tissue culture
Another way of cloning plants is by tissue culture, which works not with cuttings but with tiny pieces from the parent plant. Sterile agar jelly with plant hormones and lots of nutrients is needed. This makes tissue culture more expensive and difficult to do than taking cuttings.
Differentiation in animal cells
Most types of animal cells differentiate at an early stage - they become specialised for a particular function and cannot change into different types of cell. In mature animals, cell division is mainly restricted to replacement and repair. However, many plant cells keep the ability to differentiate.
Differentiation in plant cells
During plant cell development cells become specialized for a particular function. This process is called plant cell differentiation. During plant development cells adopt a cell fate according to their developmental context. The plant epidermis is the single-celled outermost layer.
