Animal tissues and development Flashcards
What kind of egg was used to make Dolly the sheep?
An unfertilised one
How was genetic material removed from the unfertilised egg?
The pronucleus was removed from the unfertilised egg
How was the pronucleus removed from the unfertilised egg?
It was sucked out using a micropipette
What kind of specialised cells were cultured when Dolly the sheep was cloned?
Udder cells
What was removed from the udder cell and moved into the oocyte?
The nucleus
How was the nucleus removed from the udder cell?
An electrical current was passed through it
What was the purpose of passing an electrical current through the udder cell?
It changed the permeability of the cell
What happened to the oocyte-udder hybrid when after it divided and reached blastocyst stage?
It was reimplanted into a sheep
Was a lamb born from the oocyte-udder hybrid?
Yes
What was proved as a result of the cloning of an animal from the DNA of an udder cell?
DNA was not lost during development (of the udder cell) as a whole animal developed from its DNA
What variables are taken into consideration when choosing an animal model?
Maintenance costs, ease of breeding, general costs, experimental advantages, genome sequence, ethical considerations and animal license
What are animal models used for?
Studying things
What are the two sides of a frog egg called?
Light side and dark side
What is the vegetal pole?
The side with the yolk
What is the animal pole?
The side where fertilisation occurs
Which side is the vegetal pole (light/dark)?
Light side
Which side is the animal pole (light or dark)?
Dark side
What triggers cell division in oocytes?
fertilisation
What happens as a result of cell division?
cleavage
What do the initial dell divisions occur without?
An increase in the size of the blastula
How do the first two cleavages occur in relation to each other in radical cleavage?
At right angles to each other
How does a radical cleavage appear from a birds eye view of the cell?
A cross (+)
What happens after the first two cleavages in radical cleavage?
A third cleavage, perpendicular to the first two
What is specific about the third cleavage?
It is slightly displaced towards the animal pole
How many blastomeres do you end up with after radical cleavage?
8
What are cleavage events driven by?
mRNA in the egg
Why are early frog cell divisions rapid?
There are no gap phases
What is the grey cresent?
Grey bit between the vegetal region and the animal pole
Why is the grey crescent significant?
It is the position which starts the first movements of the embryo
What is gastrulation?
first movements of the embryo
Where does sperm enter the egg?
Animal pole
What happens to the cytoplasm on the cortical edge when a sperm enters the cell
It rotates slightly
What is cortical rotation?
The rotation of the cortical edge of the egg
What does cortical rotation result in?
Grey egg formation
What is the degree of rotation for cortical rotation?
30 degrees
What are the different types of cell in the multi-layered embryo called?
ectoderm, mesoderm, endoderm
WHat is the blastula cavity called?
blastoceal
What is the area where the cells first move into the embryo?
dorsal lip
What forms at the dorsal lip?
The blastopore
What is the second cavity that forms in the blastula?
anchenteron
What is the anchenteron?
The primitive gut
