Development II

Question 1

Define fate map and what it tells us

Answer 1

Answers the question “if left undisturbed in the embryo, what will this cell become” ?

Part of descriptive embryology, does not invovled any cell manipulation.

Question 2

Define specification map and what it shows us

Answer 2

Specification map tells us what happens to a cell if it is isolated from its neighbours. Thus this tells us what a cell

Question 3

Define determined

Answer 3

A cell is said to be determined if it still develops according to its fate after being re-located to a new location within the cell.

Question 4

Define competence

Answer 4

Competence is the type of

Question 5

Define induction

Answer 5

Induction is the abi

Question 6

Define and explain descriptive embryology

Answer 6

descriptive embryology is allowing cells to develop and observing what structures they form.

Question 7

State three key structures of the egg

Answer 7

Ectoderm

Endoderm

Mesoderm

Question 8

What is the ectoderm

Answer 8

Skin and nervous tissue

Question 9

What is the endoderm

Answer 9

Lungs and digestive tissue

Question 10

What is the mesoderm

Answer 10

Notochord, muscles and blood.

Question 11

List the key stages in development of a embryo

Answer 11

Zygote
B cells stage
Blastula
Gastrula
Neurula

Question 12

What is the Xenopus laevis

Answer 12

Frog

Very important model organsim for developmental biologists,

Question 13

Explain the features of Xenpous Laevis that makes it such an ideal model organism for developmental biologists

Answer 13

i) Has very large oocytes

ii) frog oocyte has inherent asymmetry.

Question 14

What does the specification map show?

Answer 14

The specification map describes which cells are commited to a certain fate.

Question 15

What does the equivalency of the fate and specification map tell us

Answer 15

If the fate and specification maps match it shows that cells rely on cell-cell communication. (This is regulative development)

Question 16

Define and explain regulative development

Answer 16

Cells rely on cell-cell communication.

Question 17

Define and explain mosaic development

Answer 17

Mosaic development is the autonomous development of the cells fate. Fate is determined by cytoplasmic factors contained within the cell itself called cytoplasmic determinants.

These cells will form a fated structure even if transported to a new location

Question 18

Explain why non-equibalency of the fate map and specification map is evidence for mosaic development

Answer 18

Cells undergoing mosaic development decide their own fate due to asymmtetric distribution of cytoplasmic determinants (inside themselves). Thus these cells form fated structure even if transported to a new location. When specification maps and fate maps do not match, this means communication between cells is not required.

Question 19

When does regulative development typically occur

Answer 19

During the early gastrulation stage when cells are induced to form different structures according to cell-cell signalling interactions in a specific region of the embryo.

Question 20

Outline the Organizer experiment 1924

Answer 20

Spemann-Mangold organizer is a group of cells responsible for the induction of neural tissues during embryonic development in amphibians.

Question 21

What does the spemann mangold organizer refer too?

Answer 21

Refers to the population of cells in a frog embryo that establishes the dorsal-ventral and AP axis

Question 22

State the role of the organizer cells, and where they are located in the frog embryo

Answer 22

i) S-M organizer cells are located in the dorsal-blastopore lip.
ii) f(x) is to induce neural tissues during embryonic development.

Question 23

Dorsal

Answer 23

Towards the back and away from the stomach

Question 24

Ventral

Answer 24

Towards the stomach. Ventral surfaces include chest, abdomen, shins, palms and soles.