Body plans

Question 1

Morphogenesis definition

Answer 1

The regulation of the pattern of anatomical development

Question 2

Morphogenesis is controlled by a specific group of regulatory genes…

Answer 2

Homeobox genes

Question 3

Homeobox genes

Answer 3

Ancient, highly conserved regions of DNA in animals, plants and fungi
-180 base pairs long
-code for homeodomains-protein segments that act as transcription factors (60 AA’s)
-so switch on/off so control development of body plan

Question 5

Hox genes

Answer 5

Are one specific group of homeobox genes, only found in animals

Question 5

What does ancient and highly conserved imply?

Answer 5

Means their activity is fundamental to development of a body that actually works (any mutation would be fatal)

Question 6

Symmetry of body plan

Answer 6

1.Radial symmetry- organisms have top and bottom but no left and right
2.Bilateral symmetry- organisms have top and bottom and left and right
3.Asymmetry- organisms have no lines of symmetry

Question 7

Diploblastic/Triploblastic animals

Answer 7

Animals with two primary tissue layers and animals with three primary tissue layers

Question 8

Apoptosis definition

Answer 8

Programmed cell death (removes unwanted cells and tissues)
-release chemical signals to stimulate mitosis and cell proliferation leading to remodelling of tissues

Question 9

Apoptosis step-by-step

Answer 9

1.Cell shrinkage and DNA fragmentation
2.Membrane blebbing
3.Apoptotic bodies
4.Phagocytosis of apoptotic bodies

Question 10

Factors affecting the expression of regulatory genes

Answer 10

Internal (release of hormones or psychological stress) and external (change in temp, light intensity)

Question 11

Stress definition

Answer 11

As the condition produced when the homeostatic balance within an organism is upset