Lab 3 - Cleavage in Frog

Question 1

3 regions that can be seen during embryonic development of a frog

Answer 1

1. animal hemisphere
2. vegetal pole
3. grey crescent

Question 2

pigmented

Answer 2

animal hemisphere

Question 3

white

Answer 3

vegetal pole

Question 4

• no pigment
• between animal and vegetal pole

Answer 4

grey crescent

Question 5

when does zygote begin to divide

Answer 5

2-3 hours after fertilization

Question 6

repeated division in successive fashion

Answer 6

• cleavage or
• segmetation

Question 7

type of cell division during cleavage

Answer 7

mitotic

Question 8

where does cleavage bein

Answer 8

small depression at animal pole

Question 9

type of division in frogs

Answer 9

holoblastic and complete

Question 10

first cleavage

Answer 10

vertical (2-cell stage)

Question 11

second cleavage

Answer 11

vertical, right angle to first one (4-cell stage)

Question 12

cells in cleavage

Answer 12

blastomere

Question 13

third cleavage

Answer 13

horizontal, above equitorial line

Question 14

upper 4 cells toward anial pole

Answer 14

micromeres or epiblast

Question 15

lower 4 large yolk laden cells

Answer 15

megameres or hypoblast

Question 16

fourth and fifth cleavage

Answer 16

vertical (16-cell stage)

Question 17

cleavage after fifth cleavage

Answer 17

two horizontal cleavage (one each toward animal and vegatal pole)
- 32-cell stage

Question 18

result of repeated and irregular cleavage

Answer 18

morula (morula stage)

Question 19

small black and yolkless cells

Answer 19

micromeres

Question 20

fewer number of large white and yolk laden cells

Answer 20

megameres

Question 21

result of micromeres dividing more rapidly than megameres

Answer 21

small fluid-cavity (blastocoel)

Question 22

other term for blastocoel

Answer 22

segmentation cavity

Question 23

blastocoel bearing stage

Answer 23

blastula

Question 24

floor of blastocoel

Answer 24

megameres

Question 25

roof of blastocoel

Answer 25

micromeres

Question 26

entire animal pole of blastula represents what

Answer 26

presumptive ectoderm

Question 27

division of presumptive ectoderm

Answer 27

- presumptive epidermis - presumptive neural plate

Question 28

small area near vegetal pole

Answer 28

presumptive notocord

Question 29

close to presumptive notochord

Answer 29

grey crescent region = presumptive mesoderm

Question 30

vegetal region

Answer 30

presumptive endoderm

Question 31

unsegmented and enclosed tightly by transparent jelly coats

Answer 31

unfertilized eggs

Question 32

zygote that was divided into two or four equal sizes

Answer 32

2-4 cell stage

Question 33

embryo with eigth cells but only four blastomeres may be seen

Answer 33

8 cell stage

Question 34

composed of 32-64 blastomeres

Answer 34

early blastula stage

Question 35

name of the embryo during early blastula stage

Answer 35

morula

Question 36

- has more numerous but smaller cells than early blastula stage - in mid-sagital section, an eccentric cavity adjacent to animal pole can be seen

Answer 36

late blastula stage

Question 37

represented by mitosis figures or chromosomes in some cells

Answer 37

nucleus

Question 38

cleft or intended portion of the cell undergoing division

Answer 38

cleavage furrow

Question 39

- thin clear membrane around the cleaving embryos - usually torn or displaced away from the embryo

Answer 39

fertilization membrane

Question 40

animal pole cells concentrated at the peripheral region of the embyo

Answer 40

pigmented cells

Question 41

small cells in the animal pole

Answer 41

micromeres

Question 42

large cells in the vegetal pole

Answer 42

macromeres

Question 43

contains small amount of yolk

Answer 43

microlecithal eggs

Question 44

contains moderae amount of yolk

Answer 44

mesolecithal eggs

Question 45

contains enormous amount of yolk

Answer 45

macrolecithal eggs

Question 46

- has a large quantity of yolk, where the yolk is unevenly distributed all throught the cytoplasm - concentrated more towards the vegetal pole

Answer 46

telolecithal eggs

Question 47

type of cleavage in which the segmentation line passes through the entire egg

Answer 47

holoblastic equal cleavage

Question 48

hollow blastula

Answer 48

coeloblastula

Question 49

embryo produced by spiral cleavage characterized by the absence of a blastocoel

Answer 49

stereoblastula