Introduction to development

Question 1

What does development rely on?

Answer 1

Patterns in gene expression.

Question 2

The majority of processes in embryogenesis have been conserved across species. True or false?

Answer 2

True.

Question 3

What is experimental embryology?

Answer 3

Transplanting cells to a new location or treating an embryo with drugs/gene products to observe the effects.

Basically fucking with embryos to see what happens cuz yolo

Question 4

What is developmental genetics?

Answer 4

Looking at mutants to deduce the function of a gene.

Question 5

What are the 7 major stages in embryonic development?

Answer 5

1. Fertilisation
2. Cleavage
3. Gastrulation
4. Axis determination
5. Segmentation
6. Neurulation
7. Growth and differentiation

Question 6

In what stage are the germ layers formed?

Answer 6

Gastrulation.

Question 7

What are the 3 axes that must be established?

Answer 7

The anterior/posterior, dorsal/ventral and left/right axes.

Question 8

Both mammals and invertebrates are internally segmented. True or false?

Answer 8

False - mammals are internally and invertebrates are externally segmented.

Question 9

There are 3 stages to differentiation. What are they?

Answer 9

Commitment, specification, determination.

Question 10

If a cell is uncommitted it is essentially totipotent. When it becomes specified it becomes multipotent, and when it is determined it only gives rise to one cell type. True or false?

Answer 10

True (I think).

Question 11

You can reverse specification and determination. True or false?

Answer 11

False - certainly not in nature.

Question 12

What are the 2 methods by which cells become specified to their fates?

Answer 12

1. Conditional

2. Autonomous

Question 13

What is conditional specification?

Answer 13

Specification is induced by cell-cell signalling, it depends on the environment.

Question 14

What is autonomous specification?

Answer 14

Cytoplasmic determinants within the cell itself specify fate.

Question 15

Define delamination.

Answer 15

When cells individually migrate away from an aggregation.

Question 16

Drosophila neuroblasts are formed by the delamination of ectoderm. True or false?

Answer 16

True.

Question 17

Drosophila neuroblasts display lateral inhibition. What is this?

Answer 17

They release negative signals onto the surrounding ectoderm cells to prevent them also becoming neuroblasts.

Question 18

In drosophila what do achaete-scute mutants lack?

Answer 18

They have no neuroblasts.

Question 19

What is the function of the achaete-scute gene?

Answer 19

Neuroblast determination.

Question 20

In the notch-delta pathway, which is a) the signalling molecule and b) the receptor?

Answer 20

a) Notch

b) Delta

Question 21

If you supress notch-delta in drosophila what happens, what does this show?

Answer 21

Deactivation causes all cells to become neuroblasts, thus notch-delta is important for normal ectoderm development.

Question 22

After delamination, what kind of division do drosophila neuroblasts undergo?

Answer 22

Asymmetric division.

Question 23

What causes asymmetric division?

Answer 23

Unequal distribution of chemicals in the cytoplasm.

Question 24

What does the gene Miranda do?

Answer 24

Prevents the formation of neuroblasts.

Question 25

What kind of cell is the gene Miranda found in?

Answer 25

Ganglion mother cells.

Question 26

What are P-granules?

Answer 26

Germ cell determinants in C. elegans.

Question 27

In normal development where are the P-granules?

Answer 27

Concentrated on one side of the cell.

Question 28

What is the distribution of p-granules like in par-1 C. elegans mutants?

Answer 28

Even throughout the cytoplasm, thus the cells fail to segregate at division and no germ cells form.