History and Basic Concepts

Question 1

Define embryogenesis

Answer 1

the development of an embryo from the fertilized egg

Question 2

Define morphogenesis

Answer 2

the development of form

Question 3

Define embryology

Answer 3

the study of the development of an embryo from the fertilized egg

Question 4

Two reasons for having the model organisms that we have:

Answer 4

1. partly historical

2. partly convenient to study and amenable to experimental manipulation (or genetic analysis)

Question 5

HISTORY — in terms of the principles of heat, wetness, and solidification

Answer 5

Hippocrates

Question 6

HISTORY — 2 possibilities: performed or epigenesis

Answer 6

Aristotle

Question 7

HISTORY — preformation ideas yet he remarkably described the development of the chick embryo

Answer 7

Marcello Malpighi

Question 8

___1.___ : the discovery of cells

Answer 8

1. microscopy

Question 9

What is the Cell Theory of Life?

Answer 9

all living organisms consist of cells; cells are the basic units of life; the new cells can only be formed by the division of pre-existing cells

Question 10

HISTORY — offspring does not inherit its characteristics from the body (soma) of the parent but only from the germ cells (somatic cells and germ cells)

Answer 10

August Weismann

Question 11

___1.___ : 2 nuclei fuse resulting in a single cell (zygote)

Answer 11

1. fertilization

Question 12

HISTORY — basis for mitosis, meiosis, haploidy, diploidy

Answer 12

Gregor Mendel

Question 13

How do cells become different from one another during embryonic development?

Answer 13

according to Weismann, the nuclear determinants would be distributed unequally … “mosaic” (the fate of each cell was therefore predetermined in the egg)

Question 14

HISTORY — experiments on frog embryos (the development of a frog is based on a mosaic mechanism)

Answer 14

Wilhelm Roux

Question 15

HISTORY — experiments on sea urchin eggs (a different result), it was the first clear demonstration of the developmental process known as ___1.___

Answer 15

Hans Driesch

1. regulation

Question 16

Weismann was wrong in one crucial respect…

Answer 16

such determinants are not nuclear but cytoplasmic (cytoplasmic determinants)

Question 17

HISTORY — responsible for induction and regulation

Answer 17

Hans Spemann & Hilde Mangold

Question 18

What is induction?

Answer 18

one cell or tissue directs the development of another neighboring cell or tissue (cells communicate and interact with each other through cell-cell interactions)

Question 19

HISTORY — experiments on the fruit fly (inheritance of a mutant trait was linked to the sex of the fly)

Answer 19

T.H. Morgan

Question 20

HISTORY — genotype and phenotype

Answer 20

Wilhelm Johannsen

Question 21

Which type of mutations are more easily recognized?

Answer 21

identifying genes affected by recessive mutations is more laborious … and a carefully worked-out breeding program is needed to obtain homozygotes

Question 22

The first developmental genes were identified as ___1.___ mutations that disrupt their function and produce an abnormal phenotype (dominant, semi-dominant, or recessive)

Answer 22

1. spontaneous

Question 23

Many mutations are ___1.___ mutations! The effects of those mutations only show up when the animal is kept in a ___2.___ (e.g. temperature-sensitive mutation)

Answer 23

1. conditional

2. particular condition

Question 24

Temperature sensitivity is usually due to the ___1.___ being able to fold into a functional structure at the ___2.___ but being less stable at the ___3.___

Answer 24

1. encoded mutant protein
2. normal temperature
3. higher temperature

Question 25

What is reverse genetics?

Answer 25

working backwards to determine its function by removing the gene or blocking its function (gene knock-out, gene knock-down or gene silencing)