19.3 body plans Flashcards
what is the body plan of an organism?
general structure of an organism
what are homeobox genes
group of genes which all contain a homeobox
what is a homeobox?
section of DNA which codes for a homeodomain
what is a homeodomain?
part of a protein which binds to DNA to control transcription to produce proteins involved in the DEVELOPMENT of the body plan
ACT AS TRANSCRIPTION FACTORS
what are hox genes?
genes which CONTROL the body plan by regulating mitosis and apoptosis
code for a transcription factor which sends signals for mitosis/aptosis to occur
responsible for the correct positioning of body parts in an animal
what are the 3 types of symmetry?
radial
bilateral
asymmetrical
what is radial symmetry?
when animal only has a top and bottom
what is bilateral symmetry?
when an animal has only a left and a right
what is asymmetrical?
no lines of symmetry
what processes are important in forming a body plan?
mitosis
apoptosis
what regulates mitosis and apoptosis?
hox genes
what is the role of mitosis in a body plan?
it increases the number of cells needed for growth and body parts
what is the role of apoptosis in a body plan?
it removes unwanted cells and tissues to model body parts
releases chemical signals to undergo mitosis to remodel the body parts
what happens to the body plan if DNA is damaged?
the wrong homeobox genes will be expressed so the wrong body plan is produced
what factors affect the expression of regulatory genes?
temperature change
light intensity
hormonal change
use of drugs
