Zygotic gene activation II

Question 1

What type of division do sea urchins have

Answer 1

Holoblastic

Question 2

What does stereotypical division mean for an animal?

Answer 2

Same in all of that species

Question 3

What kinds of divisions are divisions 1 and 2 in sea urchins?

Answer 3

meridional

Question 4

What does meridional mean?

Answer 4

pass through animal and vegetal poles

Question 5

What kind of division is division 3 in sea urchins?

Answer 5

equatorial

Question 6

What kind of division is division 4 in sea urchins?

Answer 6

cells of animal tier divide meridionally

Question 7

Size of the cells at blastula stage of sea urchin?

Answer 7

All the same size

Question 8

What cell stage can the sea urchin cell fates be determined?

Answer 8

60 cell stage

Question 9

First step in vegetal pole of sea urchin?

Answer 9

Autonomous–> maternal factors in large micromeres form an exoskeleton

Question 10

Second step in vegetal pole of sea urchin?

Answer 10

large micromeres then secrete paracrine factors to induce endoderm

Question 11

WHat germ layer does the sea urchin animal pole become?

Answer 11

Ectoderm

Question 12

What regulates sea urchin development?

Answer 12

transcription factor (TF) circuits

Question 13

What is meroblastic cleaage?

Answer 13

Division plane doesnt pass through the whole cell

Question 14

What does karyokinesis occur without in drosophila?

Answer 14

Cytokinesis

Question 15

What is karyokinesis?

Answer 15

Nucleus division

Question 16

How does the cleavage in drosophila work when there is nuclei dividing?

Answer 16

partial cleavage: restricted to periphery (yolk in centre)

Question 17

What is a syncytium?

Answer 17

Many nuclei, one cytoplasm

Question 18

When does embryonic transcription begin in drosophila?

Answer 18

mid-blastula transition (MBT)

Question 19

What is mid-blastula transition (MBT) equivalent to in mammals?

Answer 19

EGA

Question 20

What cycle does mid-blastula transition (MBT) occur in drosophila?

Answer 20

13

Question 21

What happens to maternal mRNAs in the mid-blastula transition (MBT) in drosophila?

Answer 21

They are degraded

Question 22

How many cells are there in the drosophila cellular blastoderm?

Answer 22

~6000

Question 23

What kind of embryonic cleavage do zebrafish undergo?

Answer 23

Meroblastic

Question 24

How are the eggs in zebrafish?

Answer 24

telolecithal: mostly occupied by yolk

Question 25

What is zebrafish embryonic cleavage restricted to?

Answer 25

thin region of animal pole: blastodisc

Question 26

When does mid-blastula transition begin in zebrafish?

Answer 26

Cell cycle #10

Question 27

What are the germ layers in the fish embryo fate map?

Answer 27

Ectoderm, mesoderm, endoderm

Question 28

How does xenopus cleavage occur?

Answer 28

holoblastic cleavage with radial animal-vegetal symmetry

Question 29

Mesolecithal division in xenopus?

Answer 29

radial egg division displaced by moderate yolk

Question 30

Which region is fertilised by sperm in xenopus?

Answer 30

Animal pole

Question 31

What is unique ab the animal pole in xenopus?

Answer 31

It is more heavily pigmented

Question 32

Effect of yolk on animal pole cleavage in xenopus?

Answer 32

It stops it

Question 33

Relationship between first two divisions in xenopus?

Answer 33

second division starts in animal region before first division is complete