CORRECT ANSWERS 2025/2026
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Which of the following occurs for the first time in pachytene prophase I of meiosis? - CORRECT
ANSWER -Synapsis and crossing over occurs
Synapsis only occurs during meiosis, which of the following accurately describe this event? -
CORRECT ANSWER -Formation of a bivalent on specialized protein structure
The Tasmanian devil, Sarcophilus harrissi, has 14 chromosomes. If nondisjunction of
chromosome 5 occurs in meiosis I, which of the following best describes the n of the resulting
gametes? - CORRECT ANSWER -Two germ cells will be n=8 and two will be n=6
Above is karyotype of your patient. Which of the following BEST describes what you would tell
this patient's parents? - CORRECT ANSWER -This is a 48 XXY, two extra chromosomes
You have made a transgene that expresses green fluorescent protein (GFP) in spermatogonia
only. If you are examining a transverse section of the testes where would you expect to find GFP
positive (GFP+) cells? - CORRECT ANSWER -Associated with the Sertoli cells in the seminiferous
tubule.
The switch from mitosis to meiosis in spermatogenesis is regulated by levels of
and this is induced by . Fill in the blanks. - CORRECT ANSWER -low, glial cell derived
neurotrophic factor (GDNF), follicle stimulating hormone (FSH)
Spermatozoa nuclei are transcriptionally silent. Which of the following BEST explains this? -
CORRECT ANSWER -Replacement of histones with protamines
, Two mice were treated with Busulfan A that kills spermatogenic cells. The seminiferous tubules
of one mouse were transplanted with spermatogonia and the status of spermatogenesis was
examined in both mice one month later. What is the most likely outcome of this experiment? -
CORRECT ANSWER -Only the mouse that received spermatogonia will re-establish
spermatogenesis.
An oogonium enters embryonically and is blocked at until se
xual maturity. Fill in the blanks. - CORRECT ANSWER -meiosis: diplotene I
In the ovary, oocytes are held at metaphase II of meiosis until fertilization. How is this bloc
k released? - CORRECT ANSWER -
A Ca2+ influx induces the activity of calmodulin, which induces Camodulin dependent kinas
e (CAM PKII) and calpain and they degrade cystostatic factor (CSF).
If you have a defect that blocks the release of gonadotropin releasing hormone (GnRH) fro
m the pituitary, which of the following statements about folliculogenesis would be true? -
CORRECT ANSWER -A lack of GnRH would inhibit folliculogenesis.
During the menstrual cycle, there is an increase of midcycle, which stimulates
a surge of and induces the synthesis of progesterone by granulosa cells. Fill in
the blanks. - CORRECT ANSWER -estrogen; luteinizing hormone
Spermatozoa that are harvested directly from the epididymis for IVF in men with blockage
of their vas deferens are incompetent to fertilize eggs. What must first happen for successf
ul fertilization? - CORRECT ANSWER -capacitation
The acrosome reaction . Pick the best answer to finish the statement. -
CORRECT ANSWER -releases enzymes necessary for penetrating the zona pellucida
You think that you have identified a sea urchin sperm chemoattractant. Which of the follow
ing properties should this protein have? - CORRECT ANSWER s s -