Control of development Flashcards Preview

Animal Physiology, Reproduction and developement > Control of development > Flashcards

Flashcards in Control of development Deck (34)
Loading flashcards...
1

What are the key stages of developement?

Fertilisation
cleavage
gastrulation
organogenesis
morphogenesis

2

What controls developement?

cytoplasm
genes
external environment

3

What does Nuclear DNA usually do that doesn't occur in early developement?

Makes proteins by transcription, in early developement it only replicates

4

Where do proteins and enzymes come from in early development?

Provided for by the cytoplasm

5

Where does zygotic cytoplasm come from?

The mother, so early development under maternal control

6

What is genomic activation?

The transition from maternal control to embryo control

7

Timing of genomic activation varies among species, when does it occur for:
pigs?
humans?
frogs?

Pigs = in 4-8 cell embryo
Humans = 8 cell embryo
Frogs = 3000-4000 cell embryo

8

What are cells called prior to determination?

Totipotent

9

What causes differentiation to occur?

results from differential gene expression, which is influenced by the cytoplasm and extracellular environment

10

What is genomic equivalence?

Each cell in the body has same genetic material and therefore all the information necessary to create a complete organism

11

What controls the fate of the nucleus?

The cytoplasm

12

What is cytoplasmic segregation?

Occurs in division. Dividing cells receive a factor that is unequally distributed in the cytoplasm and ends up in some daughter cells but not others, causes differentiation on cells

13

What is induction?

A factor is secreted by some cells to induce other cells to differentiate

14

What are the processes of primary induction amphibians?

Cells moving over the dorsal lip of the blastopore (Spemann organiser) induce overlying ectoderm to form neural tissue

15

What are the processes of primary induction in birds?

Cells moving over Hensen’s node are induced to form the Central Nervous System

16

What is secondary induction?

Occurs after primary, includes the development of control in the vertebrate eye

17

What is a morphogen?

A chemical agent able to cause or determine morphogenesis

18

When is a signal called a morphogen?

When it directly affects a target cell or when different concentration cause different effects

19

Describe the process of limb formation

The cells that become the bones and muscles of a limb receive positional information, then organise appropriately. Cells at the bud make the morphogen BMP2

20

how does BMP2 control limb developement?

The gradient determines anterior-posterior axis, A high dose lead to thumbs, a low dose leads to the little finger

21

What is genomic imprinting?

Some genes are only active if they come from the sperm, some are only active if they come from the egg, which means male/male or female/female zygotes can't form

22

What is Prader-Willi syndrome?

Deletion on the paternal chromosome 15

23

What is angelman syndrome?

Deletion on the maternal chromosome 15

24

What do segmentation genes do?

influence the number, boundaries and polarity of body segments

25

What do gap genes do?

Organise large areas along the anterior-posterior axis

26

What do pair rule genes do?

Divide the embryo into units of two segments each

27

What do segment polarity genes do?

determine segment boundaries

28

What do homeotic genes do?

expressed along the length of the body and determine what segments will become

29

What are hox genes?

A subset of homeotic genes that control the body plan of an embryo along the head-tail axis

30

What apoptosis?

Programmed cell death, cause by the activation of 'death' genes