devlopmnt

Question 0

What are Calcium independent cell adhesion molecules?

Answer 0

These are members of Ig superfamility of proteins.

Ex-neural cell adhesion molecules (N-CAM) & platelet endothelial cell adhesion molecules (PE-CAM)

Question 1

Mesoderm affinity is not merely due to position in embryo b/c the close associations can be restored even if they’rej disrupted

Answer 1

jj

Question 2

Ig domains are __ domains. What type of bonds form

Answer 2

protein-protein; H-bond

Question 3

What are calcium dependent adhesion molecules called? Examples include __

Answer 3

cadherins; neural cadherin (N-cadherin) & epithelial cadherin (E-cadherin)

Calcium forms a bridge between 2 cadherins on different cells

Question 4

Caderin proteins interact with other via a ___ bridge

Answer 4

Ca2+

Question 5

What are sugar mediated adhesion molecules? Examples include ___

Answer 5

Proteins on 1 cell bind to polysaccharides (sugar polymers) on another cell

selectins - found in synctiatrophoblast that is bound to wall of uterus which had GPs

It is required for implantation of embryo into uterine wall (tennis ball on Velcro)

Question 6

Cell adhesion molecules may also be linked to signaling pathways. For example, N-CAM cytoplasmic domain can be ___ & can interact iwth intracellular signaling molecules. Therefore, a cell may express ___ when bound to its identical neighbors

Answer 6

phosphorylated; express different genes

Question 7

At about 8-cell stage of development ___ is first expressed in the embryo. The cells change from being loosely attached to a very __ ball. This may be the reason that twinning can no longer occur after about __ cell stage. The cells are too firmly ___

Answer 7

E-cadherin; compact; 8; attached

Question 8

During early gastrulation, all cells of ecodermal layer express ___. When neural induction occurs, future neural cells down regulate __ & express ___

Answer 8

E-cadherin; E-cadherin; N-cadherin

Question 9

What is on the edge of the neural induction?

Answer 9

neural crest

Question 10

Initially all cells of neural plate express __. However, as neural tube starts to close, the crest at neural crest lose __ expression. These cells are now free to ___. Neural crest cells that finally contribute to ganglia __ N-cadherin so that they can interact with other neural cells

Answer 10

N-cadherin; N-cadherin expression; migrate; re-express

Question 11

Cells of inner cell mass express ____. First, multiple independent cells in blastocysts express ___. These cells move inside to form the ICM. Remember that alteration in cell adhesion can led to changes in gene expression.

Answer 11

PE-CAM; PE-CAM

Question 12

During early development, cell movement & cell shape play critical role in formation of many different strcutures

Answer 12

.

Question 13

What is intercalation?

Answer 13

“insert b/w 2 others”

This movement functions to elongate embryonic tissues & involves both cell movement & changes in cell adhesion. One of the best examples is lengehning of notochord along cranio-cadual axis.

Question 14

Intercalation makes it ___(longer/shorter)

Answer 14

longer

Question 15

The notochord can be seen to become __ & ___ as the cells intercalate

Answer 15

narrower & longer

Question 16

At a number of times during early development, cells lose their __ properties, leave a specific cell layer & becomes ___ - they become ___. EMT (epithelial-mesenchymal transition) is required for __, ___ & ___

Answer 16

adhesive; migratory; mesenchymal

gastrulation, neural crest migration & heart valve formation

Question 17

Two TF factors __ & ___ are expressed in mesenchymal cells & regulate migratory phenotype

Answer 17

snail & slug

Question 18

Expression of snail & slug in tumors is associate with increased ___ & __

Answer 18

EMT & metastasis

Question 19

Epithelial cells express intermediate filament proteins of keratin family. Keratin filaments connect to other epithelial cells through ___ contacts

Answer 19

cell-cell

Question 20

__ is a marker of mesenchymal cells - it is also a marker of __ & ___

Answer 20

Vimentin; invasive & metastatic tumor cells

Metastatic tumor cells lose their epithelial organization & express vimentin

Question 21

Cells in an epithelium can constrict either their basal or apical surfaces & change shape. In many cases, a cuboidal cell takes on ___. Coordinate shape change in cells of epithelium brings about change in shape of tissue - ex - neural tube folding

Answer 21

wedge shape

Question 22

During development some cells undergo programmed cell death. This is an integral part of certain developmental programs. It isn’t to be confused with ___ which is normal cell death due to infection/injury.

Answer 22

necrosis

Question 23

Apoptosis involves complex series of ___ & ___. In fact, chromosomes are completely fragmented so that ell has no chance of recovery.

Answer 23

protein degradation & DNA degradation events

Question 24

A remarkable examples of apoptosis occurs during development of ___. Cells in limb bud selectively apoptose to create separations b/w digits

Answer 24

digits

Question 25

What is syndactyly

Answer 25

webbed fingers or toes

1/2000 births

Question 26

Apoptosis is also found in ___ formation

Answer 26

heart valves

Question 27

Formation of mouth & anus is via ___. __ is responsible for removal of cells to make a clear opening

Answer 27

apoptosis; apoptosis

Question 28

ApoptoWhat is Treacher-Collins syndrome?

Answer 28

gene responsible has recently been identified. Loss of 1 copy of gene causes neural crest cells to apoptose - not enough cells to form facial structures completely

Question 29

After embryonic development, most crtiical role of apoptosis is ___. It’s likely that many spontaneous tumors arise in our bodies during our normal lifetimes but vast majority of these are destroyed by apoptosis. Only those cells that escape apoptosis can go onto cause cancer. Mutation in genes of apoptosis pathway commonly occur in __. Apoptosis genes function as___.

Answer 29

protection against tumors.

tumor; tumor suppressor genes