Intro to animal development - lecture 8

Question 1

What is the ball of cells called after fertilisation has occurred?

Answer 1

Blastula stage embryo

Question 2

What does Xenopus blastula look like?

Answer 2

Dark pigmented animal pole and egg rich vegetal pole

Question 3

Which parts of the blastula divide quicker?

Answer 3

The blastomeres (cells of animal pole) divide faster than the yolk cells

Question 4

What is the radical cleavage?

Answer 4

Alternating angle divisions. Cells get smaller and smaller , no growth just division

Question 5

What is the grey Crescent?

Answer 5

When the sperm enters there is a 30 degree rotation, which exposes a wedge of cytoplasm producing a lighter coloured ‘grey Crescent’

Question 6

what does the grey crescent respond to in the future?

Answer 6

The dorsal/ back of the embryo

Question 7

What does the sperm entry respond to In future development?

Answer 7

The ventral/belly side

Question 8

What is Gastrulation?

Answer 8

Invagination of cells to generate 3 germ layers; the endoderm , mesoderm and the ectoderm

Question 9

What is the archenteron?

Answer 9

The primitive gut, invades the blastocoel

Question 10

What happens to the blastoel during gastrulation?

Answer 10

It decreases in size

Question 11

What is the epiboly in gastrulation

Answer 11

Movement of cells in which a cap of cells form epithelial monolayer on top of the embryo

Question 12

What is the gastrulation stage?

Answer 12

Beginning of formation of the interior embryo , causes tissues to fold inward. The site where the cells migrate is called the blastopore . The grey crescent makes up the Dorsal lip

Question 13

What is the neural tube formed of?

Answer 13

Ectoderm

Question 14

Which animals were the first cloning experiments done?

Answer 14

Amphibians

Question 15

What is the neural plate stage?

Answer 15

embryo after gastrulation

Question 16

what happens during Neurulation?

Answer 16

Raised neural folds appear either side of a neural groove on a neural plate, the folds move together to from a closed neural tube

Question 17

Somatic cell nuclear transplantation

Answer 17

• DNA from pigmented frog egg destroyed
• cell removed from albino blastula embryo , nucleus removed
• Nucleus put into the ‘host’ egg
• albino frog

Question 18

Can differentiated adult cells be used in cloning?

Answer 18

yes

Question 19

When was Dolly the sheep cloned?

Answer 19

Roslin institue , 1997

Question 20

what are the three key lessons we can learn from animal cloning?

Answer 20

• DNA can be reprogrammed to allow development following differentiation
• DNA is not lost during development
• gene expression must be regulated

Question 21

What is the dorsal lip?

Answer 21

just below the grey

crescent , Where cell movements start

Question 22

what does the Ectoderm form?

Answer 22

The nervous system

Question 23

what does the mesoderm form?

Answer 23

• muscles , bone, cartilage, connective tissue, organ tissue and blood

Question 24

What does the endoderm form?

Answer 24

epithelial cells of digestive and respiratory tubes

Question 25

what is Caenorhabditis elegans ( nematode work) good for?

Answer 25

Genetics , very few cells

Question 26

What is Drosophila melanogaster (fruit fly) good for?

Answer 26

Genetics , lots of mutants

Question 27

What is Danio rerio (zebra fish) good for?

Answer 27

genetics, external development , clear embryo for imaging

Question 28

What is Xenopus laevis (frog) good for?

Answer 28

external development, experimental embryology

Question 29

What is Gallus gallus domesticus (chicken) good for?

Answer 29

experimental embryology

Question 30

what is Mus musculus (mouse) good for?

Answer 30

genomics, genetic modification

Question 31

What is invagination?

Answer 31

The first step of gastrulation

Question 32

Who won the 2012 prize for medicine?

Answer 32

Sir John b. Gurdon , discovered that mature cells can be reprogrammed to be pluripotent