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Embryonic Development > Cleavage > Flashcards

Flashcards in Cleavage Deck (34):
1

What are a few things that Cleavage accomplishes?

Multicellularity, regionalization, cell-cell interaction and movement, partitioning of localized determinants

2

What is different between the somatic cell cycle, and the embryonic cell division cycle?

There are no gap phases [g1 and g2] in the embryonic cleavage cycle

3

Describe the cleavage division cycle as it pertains to cyclin

Cyclins are synthesized, attached to cdc2 for MPF in the M phase, then degraded in the S phase. This repeats

4

Reductive Cleavage

Each successive cleavage does not really alter total volume of the blastula

5

What is the contractile ring mostly made of?

Actin

6

What is the role of astral microtubules during cleavage?

They align the cleavage furrow and spindle mid zone for the contractile ring

7

What precedes actin polymerization at the contractile ring?

The protein Rho

8

What happens if you block Rho?

There will be multiple nuclei, but no cleavage.

9

How can you block Rho?

With C3 transferase

10

What is the major challenge to increasing the surface area/volume ratio?

You need more membrane

11

Where is new membrane inserted?

At the furrow

12

Isolecithal

uniform, not a lot of yolk

13

Mesolecithal

moderate, slightly more yolk on one end

14

Telolecithal

Lots of yolk, usually at one end

15

Centrolecithal

yolk in the middle

16

Holoblastic Cleavage

complete cleavage

17

Mesoblastic Cleavage

incomplete cleavage

18

What are the main orientations of cleavage?

Radial, spiral, bilateral, rotational, discoidal

19

Cleavage[description,examples]: Holoblastic,Isolecithal, Radial

Echinoderms, amphioxus

20

Cleavage[description,examples]:Holoblastic,Isolecithal,Spiral

Annelids, mollusks, flatworms

21

Cleavage[description,examples]:Holoblastic,Isolecithal,Bilateral

Tunicates

22

Cleavage[description,examples]:Holoblastic,Isolecithal,Rotational

Mammals,nematodes

23

Cleavage[description,examples]:Holoblastic,Mesolecithal,Radial

Amphibians

24

Cleavage[description,examples]:Mesoblastic,Telolecithal,Bilateral

Cephalopods,molluscs

25

Cleavage[description,examples]:Mesoblastic,Telolecithal,Discoidal

fish,reptiles,birds

26

Cleavage[description,examples]:Mesoblastic,Centrolecithal,

Most insects

27

Protostome

Mouth first

28

Deuterostome

Mouth second

29

Cleavage orientation is determined by:

spindle positioning

30

If cells contain less yolk, they tend to be

smaller, and toward the animal hemisphere

31

Where does the blastocoel tend to form?

At the place with the less yolky cells

32

How does the blastocoel create a different ionic content?

Tight Junctions seal off the coel

33

What is a blastoderm?

In mesoblastic chick eggs for example, the cell sheet on top of the yolk

34

Cleavage leads to ___ partitioning

cytoplasmic