Lecture 5

Question 1

development

Answer 1

the process by which multicellular organisms grow and differentiate tissues and organs

starts with one undifferentiated cells

Question 2

animal development differs from humans because …

Answer 2

they may have these two features:
regeneration- reactivation of development later in life
metamorphosis- changes through stages approaching adulthood

Question 3

Cleavage

Answer 3

cell division by mitosis

Question 4

animal developmental stages

Answer 4

zygotes undergoes mitosis
produces blastula: multicellular stage of the embryo
gastrulation: one end of the embryo folds in to form two tissue layers, the ectoderm (outer layer) and endoderm (inner layer)

Question 5

Common developmental processes in plants and animals

Answer 5

cell division
cell differentiation
morphogenesis

Question 6

model organisms

Answer 6

species chosen because they can be well studied in the lab

Question 7

regulation of development

Answer 7

activity of cells is controlled by genes

hence regulation of development is regulation of gene activity

Question 8

Gene expression

Answer 8

the output of gene products

Question 9

Gene regulation

Answer 9

is the control of gene expression

by turning genes on and off

Question 10

differential gene expression

Answer 10

when in time genes are expressed during growth and development

or where in space gene products are produced in an organism

Question 11

homeotic genes

Answer 11

are regulatory genes controlling pattern formation in eukaryotes: the development of spatial organisation

Question 12

morphogens

Answer 12

pattern formation involves morphogens

biochemical substances whose spatial distributions or gradients establish differential gene activity in cells

Question 13

Bicoid protein in flies

Answer 13

a morphogen that forms an anterior-posterior gradient

regions with high bicoid develop the anterior end of the fly

Question 14

The French flag model

Answer 14

a simple conceptual model of how morphogens can function

each cell could develop in a number of different way

the concentrations of a morphogen that a cell receives controls the colour of the cell according to a series of thresholds

the highest concentration causes a cell to. become blue, the next causes white and the lowest red

Question 15

there are three 3D body axes

Answer 15

Anterior-posterior

left-right

dorsal-ventral

Question 16

hox code

Answer 16

a given combination of genes maps to or encodes a give structure

Question 17

nested spatial expression

Answer 17

homeotic genes show nested spatial expression

they are expressed in certain regions along a body axis which may overlap each other

the combination of overlaps determines which body segment develops

Question 18

apoptosis

Answer 18

programmed cell death

Question 19

Evodevo

Answer 19

evolutionary developmental biology is the study of the evolution of developmental processes

study of how very different organisms can share very similar developmental genes but show striking differences in form due to small differences in gene sequence or regulation