General Concepts & Definitions Flashcards
What is descriptive embryology?
A field that documents and describes the process & stages of embryonic development in detail
Aims to establish a timeline and morphological understanding of how an embryo develops (e.g. which cells form specific tissues or organs)
Focuses on what happens during development
What organism is commonly studied in descriptive embryology?
Xenopus laevis.
What is a fate map?
A representation of the cell lineage and fates during development.
What is the experimental embryology approach?
Focuses on how & why developmental processes occur
Involves manipulating embryos to investigate the mechanisms and factors underlying development
Aims to uncover the causal relationship, genetic controls and signalling pathways involved in development
What determines cell fate in developmental biology?
Inheritance of cell fate determinants and cell-cell communication.
Fill in the blank: The developmental biology version of the nature versus nurture question is about the influence of _______ versus _______.
who your parents are; who you hang out with
What is mosaic development?
A type of development where cell fate is determined by the distribution of specific factors (like proteins or mRNAs) during cleavage
Key features
- cell autonomy = cells have predetermined roles based on cytoplasmic determinants inherited during division
- inflexibility = if a cell is removed, the corresponding part of the organism does not develop
- relies on asymmetric distribution of molecules
What is the significance of the grey crescent in frog embryos?
It is required for normal development and is inherited during the first division.
Who conducted the famous ‘Organizer Experiment’ in 1924?
Hilda Mangold and Hans Spemann.
What is the difference between a fate map and a specification map?
Fate map assesses what a cell will become in situ, while specification map assesses what it will form if isolated.
What does ‘competence’ refer to in developmental biology?
The range of developmental potential of a cell or tissue.
True or False: Fate maps and specification maps are equivalent.
False.
What is induction in the context of developmental biology?
The process by which a cell influences neighboring cells to change their fate.
What does regulative development mean?
The ability of an embryo to adjust and regulate its development.
What is the role of the Nieuwkoop Centre in early frog development?
It induces the organizer which influences neural ectoderm and dorsal mesoderm.
What does the term ‘determined’ mean for a cell or tissue?
It will develop according to its fate regardless of its environment.
What evidence supports mosaic development in embryos?
Experiments showing that cytoplasmic determinants dictate cell fate.
What are cytoplasmic determinants?
Factors in the cytoplasm that influence cell fate during development.
What is the significance of Wilhelm Roux’s experiment on frog embryos?
It provided evidence for mosaic development.
Fill in the blank: The process of cortical rotation in frog embryos breaks _______ symmetry.
radial
What is the result of the first division in frog embryos?
It bisects the grey crescent.
What is the 4 signal model of induction events in early frog embryos?
- General mesoderm inducer from the vegetal pole
- Nieuwkoop centre in the dorsal vegetal pole induces organizer
- Organizer induces neural ectoderm and dorsalizes ventral mesoderm
- Ventral mesoderm antagonizes dorsal mesoderm
What is the main conclusion from Conklin’s statement regarding evolution?
The principal problem of evolution is understanding modifications in the germ.
What is the role of the dorsal lip of the blastopore?
It is fated to become notochord and is determined even when transplanted.
