Chapter 18 - Organismal Stages of Development

Question 1

what are the steps for embryonic development? describe them

Answer 1

1.) fertilization = haploid (n) to diploid (2n)

2.) cleavage = division (mitosis)

3.) morphogenesis
=> gastrulation = migration
=> organogenesis = specialization

Question 2

true or false: embryos are heterogeneous

Answer 2

true

Question 3

pattern formation

Answer 3

placement of tissues/organs

Question 4

edward lewis

Answer 4

(1940s)

position of organs match corresponding genes’ position on the chromosomes

discovered that homeotic genes affect development of organs

Question 5

homeotic genes

Answer 5

master regulator (control) genes that direct the development of particular body segments or structures

Question 6

christiane nüsslein-volhard & eric wieschaus

Answer 6

(1980s)

discovered maternal effect genes

Question 7

maternal effect genes

Answer 7

mutations in the mom that affect offspring development regardless of their genotype

Question 8

pattern formation

Answer 8

placement of tissue/organs

(ex: if you place a gut tissue in brain tissue area, the gut tissue will either become brain tissue (3 hours in) or migrate back to the gut area (5 hours in)

Question 9

cytoplasmic determinants

Answer 9

maternally deposited material

unevenly distributed in egg cells so you can have a genetically identical cell but the cytoplasm will be different

Question 10

cleavage

Answer 10

cell division without growth

1 cell (zygote) => many cells (blastula)

Question 11

“coel”

Answer 11

space

pronounced as “seal”

Question 12

archenteron

Answer 12

digestive cavity of the embryo

becomes the gut

Question 13

induction

Answer 13

signals from neighboring cells

uses cell surface proteins

paracrine signals = induction

Question 14

fate map

Answer 14

used to trace the “fate” of the embryonic cells and reveals the origin of various cells

(ex: dyeing one cell and seeing what type of organ it becomes)

Question 15

control element

Answer 15

non-coding DNA sequence where regulatory transcription factors bind

Question 16

transcription factor

Answer 16

proteins that influence RNA pol binding, regulate the transcription of genes

Question 17

“myo”

Answer 17

muscle

Question 18

“blast”

Answer 18

cell

Question 19

determination

Answer 19

commitment to a development path

Question 20

differentiation

Answer 20

resulting structural/functional specialization

Question 21

determination vs differentiation

Answer 21

determination = committing to a certain cell type
=> (ex: committing to a college)
differentiation = assuming the structure, function, and biochemistry of the cell type
=> (ex: going to the college you committed to)

Question 22

what comes first determination or differentiation?

Answer 22

determination