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What are the characteristics in Carnegie stage 4?
- -Anchoring of the blastocyst on the endometrium and interaction between the
- embryo and maternal tissue.
-Implantation of the blastocyst in the mucosa of the uterus
What are the characterisics of Carnegie stage 1?
Male and female pronucleus
Formation of the zygote
What are the characteristics of Carnegie stage 5a?
- Development of the
- bilaminar germ disk
- Genesis of the amniotic cavity and the primary yolk sac (= primary umbilical
Invasion of the trophoblasts into the uterine mucosa
What are the characteristics of Carnegie stage 2?
- Separation of the
Formation of the blastomeres (totipotent to ca. the 12-cell stage)
Compaction (8 to 16 cells)
The polarization of the blastomeres becomes slowly visible.
What are the characteristics of Carnegie stage 5b?
- Formation of the
- trophoblast lacunae and complete penetration of the embryo into the endometrium
Definitive amniotic cavity
Primary umbilical vesicle (= primary yolk sac)
What are the characteristics of Carnegie stage 3?
Hatching of the blastocyst through disintegration of the zona pellucida
Epiblast and hypoblast are formed and thereby the didermic embryonic disk.
What are the characteristics of Carnegie stage 5c?
- Erosion of the maternal
- vessels: maternal blood in the lacunae of the throphoblast
The prechordal plate is formed (see stage 6)
- Transformation of the primary into the secundary yolk sac (= secundary
- umbilical vesicle)
What are the characteristics of Carnegie stage 7?
Genesis of the blood vessel system and formation of blood
What are the characteristics of Carnegie stage 6?
- Primitive streak, Primitive
- node Primitive groove
Secundary umbilical vesicle
Primordial vessels in the embryonic body stalk
Primordial germ cells
What are the dates for each:
- Stage 1=Day 1
- Stage 2=Day 2-3
- Stage 3=Day 4-5
- Stage 4=Day 6
- Stage 5a=Day 7-8
- Stage 5b=Day 9
- Stage 5c=Day 11-13
- Stage 6=Day 17
- Stage 7=Day 19
What is transcription?
The process that turns DNA into RNA
What is translation?
The process that turns RNA into proteins.
What are the steps of transcription?
- 50 different protein transcription factors bind to promoter sites, and an RNA polymerase (enzyme), binds to the transcription factors. These open the DNA double helix.
- TheRNA polymerase "reads" one strand of DNA moving in from 3′ → 5′.
- The nucleosomes in front of the advancing RNA polymerase (RNAP II) are removed and replaced after the DNA has been transcribed and RNAP II has
- moved on.
- Asthe RNA polymerase travels along the DNA strand, it assembles ribonucleotides (supplied as triphosphates,e.g., ATP)into a strand of RNA.
- Each ribonucleotide is inserted into the growing RNA strand following the rules of base pairing
- Synthesis of the RNA proceeds in the 5′ → 3′ direction.
- As each nucleoside triphosphate is brought
- in to add to the 3′ end of the growing strand, the two terminal phosphates are removed.
- When transcription is complete, the transcript is released from the polymerase and, shortly thereafter, the polymerase is released from the DNA.
What are the rules of base pairing in RNA?
- For each C on the DNA strand, a G is
- inserted in the RNA; for each G, a C; and for each T, an A. However, each A on
- the DNA guides the insertion of the pyrimidine
- uracil (U, from uridine triphosphate, UTP). There is no T in RNA.
What is the fate of messenger RNA (mRNA)?
It is translated into a polypeptide.
What is the fate of ribosomal RNA (rRNA)?
- It is used
- in the building of ribosomes: machinery for synthesizing proteins by
- translating mRNA
What is the role of transfer RNA (tRNA)?
- molecules that carry amino acids to the growing polypeptide.
What is messenger RNA (mRNA)?
- It encodes polypeptides. Most cells produce small amounts of thousands of different mRNA
- molecules, each to be translated into a peptide needed by the cell.
Name 4 types of ribosomal RNA:
The small subunit of the ribosome is made up of?
30 different protein molecules + 18S rRNA
What makes up the large subunit of a ribosome?
45 different proteins + 28S + 5.8S + 5S rRNA
Which rRNA molecules
are produced by the processing of a single primary transcript from a cluster of
identical copies of a single gene?
Which rRNA molecules
are produced from a different cluster of identical genes?
the key regulators of embryonic myogenesis.
- MyoD, Myf5, Myogenin, and MRF4
PAX genes and the MRFs (include Mef-2) involved in embryonic muscle generation.