microbiologymultichoice2

The cytotrophoblast is the inner layer of the trophoblast, interior to the syncytiotrophoblast in an embryo. It serves to anchor the embryonic chorion to the endometrium. These cells invade maternal uterine tissue and thus are in direct contact with maternal stroma and immune cells.

Gastrulation is a phase early in the development of embryos, during which the morphology of the embryo is dramatically restructured by cell migration Gastrulation occurs after implantation, around day 16 after fertilization in human embryogenesis. It essentially changes the embryo so it is protected via the fluid in the amnion layer, and is able to produce its own blood cells, through the yolk sac of the hypoblast.

Created by: troy
  1. which of the following reagents is not used in the PCR amplification reactions
  2. which of the following statements about PCR primers is true
  3. PCR amplification from template DNA by thermophilic DNA polymerase is dependent on
  4. which of the following factors does not affect the annealing temperature of PCR primers?
  5. which one of the following statements is false
  6. PCR can be used in the following applications
  7. which of the following statements concerning overlap extension PCR (OEPCR) is incorrect
  8. Oligonucleotide primers are synthesised by which one of the following methods
  9. The most important role of the prokaryotic cell wall is to:
  10. Which one of the following statements characterises cell wall complexes of Gram positive bacteria?
  11. The outer membrane of Gram negative cells is more permeable than the plasma membrane because:
  12. The third amino acid in the peptidoglycan cross-linking chain is either diaminopimelic acid or lysine. These di-amino amino acids are in this position because this amino acid must:
  13. Fimbriae (often called pili):
  14. Which one of the following statements best describes the purpose of endospores produced by bacteria belonging to the genera Bacillus and Clostridium?
  15. Which of the following treatments does not kill bacterial endospores?
  16. A bacteriologist obtained the following results from a plate count of bacteria in a sample. Sixty four (64) colonies grew on a nutrient agar plate inoculated with 0.1 ml of sample withdrawn from a solution diluted 1 in 104 in a standard plate count procedure. How many cells were in the original sample?
  17. In order for a polypeptide to be secreted across the cell membrane of a bacterium via the Sec dependent pathway, the peptide must include a sequence of amino acids called a signal (or leader) peptide. Which one of the following is NOT a property of signal peptides?
  18. Which of the following statements relating to restriction endonucleases is correct:
  19. which one of the following statements about the prokaryotic cell wall is correct
  20. which one of the following statements characterises cell wall complexes of gram positive bacteria

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