Development

Question 1

development

Answer 1

process where an organism undergoes successive changes from a single cell to a mature adult - begins with fertilization

Question 2

4 stages of development

Answer 2

determination, differentiation, morphogenesis, growth

Question 3

determination

Answer 3

what type of cell it will become; occurs before distinctive features show

Question 4

differentiation

Answer 4

processes that give rise to different cell types

Question 5

morphogenesis

Answer 5

when differentiated cell types get recognized in the multicellular body of the organism

Question 6

growth

Answer 6

increase in size by cell division or enlargment

Question 7

most important point of gene regulation during development

Answer 7

transcriptional regulation

Question 8

different cell types express different

Answer 8

regulatory transcription factors

Question 9

what causes initial differences in gene expression

Answer 9

location of cell within the organism

Question 10

stem cell becomes specific cell type when

Answer 10

determination and differentiation have occurred due to activation of different transcription factors

Question 11

transcription factors in a stem cell determined by

Answer 11

external chemical signals (environment or other cells) and differential gene expression already occurring in the cell

Question 12

what experiment shows that cell fate is determined early in development

Answer 12

tissue transplantation in early embryo results in normal development, but in late embryo the tissue develops as if it were in its original location

Question 13

cell potency

Answer 13

the potential/capacity to differentiate

Question 14

totipotent

Answer 14

cell can become any cell type including more stem cells (early embryo)

Question 15

pluripotent

Answer 15

cells can develop into most types but can’t become a new embryo

Question 16

multipotent

Answer 16

can differentiate into limited but related cell types (different connective tissues)

Question 17

unipotent

Answer 17

can only produce own cell type - most cells in mature organism

Question 18

whats special about plant cell differentiation

Answer 18

most plant cells can dedifferentiate under certain environmental conditions (can easily be cloned)

Question 19

what do animal cells require for cloning

Answer 19

cytoplasmic environment of totipotent cell (can fuse extracted nucleus into cytoplasm)

Question 20

gastrulation in animals

Answer 20

cells move and organize into 3 layers

Question 21

gastrulation in plants

Answer 21

differential cell expansion

Question 22

apoptosis

Answer 22

regulated cell death which can lead to developmental abnormalities if disrupted

Question 23

what do plants have instead of apoptosis

Answer 23

autophagy

Question 24

differentiation in drosophila begins when

Answer 24

signals tell cells position in time and space (ant/post, dorsal/ventral, right/left planes)

Question 25

drosophila body plan

Answer 25

head, 3 thoracic segments, 8 abdominal segments

Question 26

drosophila embryo until the 13th cell division

Answer 26

multinucleated, no cytokineses occurs - molecules can diffuse freely to establish segmentation and developmental axes

Question 27

morphogen

Answer 27

molecule that exists in a concentration gradient and gives positional info about development

Question 28

bicoid

Answer 28

protein that leads to development of anterior structures

Question 29

bicoid mRNA gradient

Answer 29

anterior to posterior

Question 30

bicoid protein gradient

Answer 30

anterior to posterior

Question 31

bicoid transcribed

Answer 31

maternally in nurse cells and deposited into eggs before fertilization

Question 32

nanos

Answer 32

protein that leads to development of posterior structures

Question 33

nanos mRNA gradient

Answer 33

posterior to anterior

Question 34

nanos protein gradient

Answer 34

posterior to anterior

Question 35

nanos transcribed

Answer 35

maternally

Question 36

hunchback

Answer 36

required for anterior structure formation

Question 37

hunchback mRNA gradient

Answer 37

diffuse throughout embryo

Question 38

hunchback protein gradient

Answer 38

anterior to posterior, nanos inhibits translation of hunchback

Question 39

what method is used to locate mRNA

Answer 39

in situ hybridization

Question 40

what cellular structure aides in establishment of gradients

Answer 40

microtubules

Question 41

maternal effects genes

Answer 41

maternally transcribed genes that determine ant/post axis and induces 3 classes of segment genes

Question 42

gaps genes

Answer 42

maternal or embryo transcribed genes that define broad areas and regulate pair rule genes

Question 43

pair rule genes

Answer 43

embryonically transcribed genes that refine location of pairs of segments and regulates hox genes and segment polarity genes

Question 44

hox genes

Answer 44

define segment roles (which structure grows where)

Question 45

segment polarity genes

Answer 45

determine boundary and anterior/posterior orientation of each segment

Question 46

how does orientation of hox genes determine development

Answer 46

order of hox genes on chromosome is same order os position of expression in embryo

Question 47

homeotic mutations

Answer 47

structure formation in wrong segment

Question 48

what do homeotic mutations indicate

Answer 48

hox genes direct segment identity

Question 49

evo devo

Answer 49

studies how changes in expression of development genes can lead to phenotypic diversity and formation of new species

Question 50

tool kit genes

Answer 50

direct pattern formation (ie hox genes)

Question 51

genetic switches

Answer 51

regulate tool kit genes (DNA regulatory regions, transcription facotrs, signal tranduction molecules)

Question 52

modularity

Answer 52

independence of developmental processes (one thing can change independently of the whole organism)

Question 53

heterometry

Answer 53

changing amount of tool kit gene expression

Question 54

heterochrony

Answer 54

changing time of expression

Question 55

heterotopy

Answer 55

changing location of expression

Question 56

Sonic hedgehog and ZRS

Answer 56

ZRS is the enhancer (genetic switch) for morphogen Shh - limb development