EMBRYOLOGY: PRACTICE 3

SINGLE BEST OPTION SERIES

         INSTRUCTION: SELECT THE SINGLE BEST OPTION
 

1.        Which of the following is incorrect about capacitation of sperms:
   a.       It is a period of conditioning in the female genital tract
   b.      In humans, it lasts approximately seven hours
   c.       Glycoprotein coat and seminal plasma proteins are added to the plasma membrane that overlies the acrosomal regions of spermatozoa
   d.      Only capacitated sperms can pass through the corona radiata of oocytes.
   e.      Only capacitated sperms can undergo acrosomal reaction.
   2.       Phases of fertilization is in the following order:
   a.       Penetration of corona radiata → penetration of zona pellucida → fusion of oocyte and sperm cell membranes
   b.      Penetration of zona pellucida → penetration of corona radiata → fusion of oocyte and sperm cell membranes
   c.       Fusion of oocyte and sperm cell membranes → penetration of zona pellicida → penetration of corona radiata
   d.      All of the above
   e.      None of the above.
   3.       Concerning fertilization, as soon as the spermatozoon has entered the oocyte, the egg responds in the following ways except:
   a.       Undergo cortical reaction
   b.      Undergo capacitation
   c.       Undergo zona reaction
   d.      Resumes the second meiotic division
   e.      Metabolic activation of the egg.
   4.        The major aim of cortical and zona reaction during fertilization is to:
   a.       Determine the sex of the child
   b.      Encourage acrosomal reaction
   c.       Stimulation of luteinizing hormone surge
   d.      Prevent polyspermy
   e.      Prevent developmental toxicity.
   5.       Which of the following is incorrect about sacrococcygeal teratomas?
   a.       It is a disorder associated with gastrulation
   b.      They usually contain tissues derived fromall germ layers.
   c.       they are the least common tumour in newborns
   d.      They originate from remnants of primitive streak that persist in the sacrococcygeal region
   e.      They arise from clusters of pluripotent stem cells and occasionally from primordial germ cells that fail to migrate into the gonadal ridge.
   6.       The main results of fertilization include the following except:
   a.       Restoration of the diploid number of chromosomes
   b.      Fusion of the oocyte and sperm cell membranes
   c.       Determination of the sex of the new individual
   d.      Initiation of cleavage
   e.      None of the above.
   7.       The genes responsible for establishing the right-side of the body during embryogenesis is:
   a.       PITX 2
   b.      Snail
   c.       Nodal
   d.      Lefty-2
   e.      PAX-4
   8.       Infertility in a woman may be due to the ollowing except:
   a.       Occluded uterine tubes caused by pelvic inflammatory disease
   b.      Hostile cervical mucus
   c.       Immunity to spermatozoa
   d.      Absence of ovulation
   e.      None of the above
   9.       Concerning gastrulation, which of the following is incorrect?
   a.       It begins with the formation the formation of the primitive streak
   b.      Migration of the cells of the epiblast is controlled by fibroblast growth factor 8 (FGF 8)
   c.       The epiblast is the source of the endoderm, mesoderm and ectoderm of the embryo
   d.      Invaginating cells that lie between the epiblast and the newly created endoderm forms the ectoderm
   e.      None of the above.
   10.   Concerning human embryogenesis, which of the following is incorrect?
   a.       The heart of the embryo begins to beat around the fourth week of development.
   b.      The definitive placental villous form from the differentiation of the mesodermal cells in the core of the secondary villous
   c.       By beginning of the third week of embryogenesis, the trophoblast is characterized by primary villi that consist of a cytotrophoblastic core covered by a syncytial layer.
   d.      The umbilical cord forms the connection between the placenta and embryo
   e.      None of the above
   
   
   
   
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