Lecture 1

Question 1

5 characteristic’s which make a good model organism?

Answer 1

easy to maintain, cheap to maintain, quick gestation time, known genomic sequence, easily breed.

Question 2

If a model organism is good for embryology?

Answer 2

external development of the embryo, large quantity of embryos produced, robust (healthy)

Question 3

If a model organism is good for genetics?

Answer 3

genome in which is similar to that of humans

Question 4

Other good model organism which we haven’t talked about in details ?

Answer 4

chicken, worm

Question 5

Type of division which occurs in a fertilized egg of the xenopus?

Answer 5

divisions occur only in the animal pole for the first 3 divisions. Radical cleavage occurs after the 3rd division

Question 6

Radical cleavage?

Answer 6

divisions which occur on orientation with the cell and then perpendicularly.

Question 7

animal pole?

Answer 7

top half of the fertilised egg. Pigmented

Question 8

vegetal pole?

Answer 8

denser cells (found on the bottom Half of the fertilised egg)

Question 9

blastomere

Answer 9

single cell

Question 10

where do divisions occur more and why?

Answer 10

in the animal pole as the vegetal pole is more dense ‘yolk’

Question 11

at what point does the vegetal pole begin divisions

Answer 11

3rd

Question 12

Stage one of embryogenesis in Xenopus?

Answer 12

cleavage formation?

Question 13

Dorsal Lip? Where it’s located?

Answer 13

Region just bellow the grey crescent. Where involution begins.

Question 14

2nd stage of embryogenesis in Xenopus, general name and describe how it occurs?

Answer 14

The grey crest formation. Sperm enters, opposite this point the cortical cytoplasm rotates by 30 degrees towards to point of sperm entry.

Question 15

cortical cytoplasm?

Answer 15

Specialised cytoplasm found outside the cytoplasm of the egg.

Question 16

Gastrulation?

Answer 16

Formation of the three cellular layer (mesoderm, ectoderm, endoderm)

Question 17

Blastocoel

Answer 17

Cavity which is found in embryo before gastrulation, provides the nutrients the embryo needs

Question 18

Involution?

Answer 18

Cells dragged internally inside

Question 19

3 cell layers ?

Answer 19

meso, esto, endo DERM. GERM LAYERS

Question 20

What happens to the blastocoel as gastrulation occurs?

Answer 20

degrades

Question 21

Another name for the primitive gut? When does this form?

Answer 21

archendron

Question 22

What is formed after gastrulation is complete?

Answer 22

primitive gut/ archendron

Question 23

3rd stage of Xenopus embryogenesis? What this actually is?

Answer 23

gastrulation, to form germ layers

Question 24

4th stage of embryogenesis? What this actually is.

Answer 24

neuralation, to form the neural tube

Question 25

describe the 6 steps of neurulation?

Answer 25

1. ectoderm thickens along the midline 2. a groove is formed 3. begins to form a circular structure 4. circular structure becomes dissociated 5. involution of this neural tube 6. ectoderm reformed.

Question 26

Blastula

Answer 26

Ball of cells

Question 27

dorsal

Answer 27

back

Question 28

ventral

Answer 28

belly

Question 29

somatic cell nuclear transfer method? What did it show ?

Answer 29

1. take embryo uv treat (degrade DNA) normal frog 2. Enucleate albino egg 3. insert nucleus into the uv treated egg 4. forming fully functional frog. DNA NOT LOST

Question 30

Sir John Gurdon?

Answer 30

noble prize: skin cell somatic cell nuclear transfer

Question 31

When was dolly the sheep created?

Answer 31

1997