Molecular Basis of Cellular Division: Meiosis and Oogenesis

This flashcard set covers the vocabulary and molecular mechanisms of meiosis and oogenesis, including meiotic arrests, hormonal triggers for ovulation, and specific regulatory proteins like CDK1 and CSF.

Oogenesis

The process describing the stages of growth and maturation of the mammalian oocyte.

Menopause

A biological topic involving the definition, physiology, symptoms, diagnostics, and complications of the cessation of the female reproductive cycle.

Graaf follicle

Also referred to as the Graafian follicle, it is a structure in the mature human ovary that undergoes a specific maturation process during the female reproductive cycle.

First meiotic arrest

The inhibition of meiosis occurring at the stage of prophase I, regulated by $cAMP$ concentration and the activity of $PKA$, $WEE1$ kinase, and $CDC25$ phosphatase.

$$cAMP$$

A molecule whose concentration levels influence the activation of kinases and phosphatases, such as $WEE1$ and $CDC25$, to regulate the first meiotic arrest.

$WEE1$ kinase

A kinase that undergoes phosphorylation or dephosphorylation to cause activation or inactivation, contributing to the inhibition of meiosis at prophase I.

$CDC25$ phosphatase

A phosphatase involved in the molecular regulation of the first meiotic arrest; its activation or inactivation depends on its phosphorylation state.

Prophase I

The specific stage of meiosis where the first arrest of oogenesis occurs.

Ovulation

A phase in the female reproductive cycle triggered by an increase in the concentration of a specific hormone, leading to the resumption of meiotic divisions.

$$PKA$$

A kinase whose inhibition of activity is associated with the resumption of meiotic divisions following the first meiotic arrest.

Second meiotic arrest

The inhibition of meiosis at the stage of METHAPHASE II, maintained by the presence of Cytostatic Factor (CSF).

METHAPHASE II

The stage of the second meiotic division where the oocyte remains arrested until activation occurs.

CSF (Cytostatic Factor)

A factor that maintains the second meiotic arrest at METHAPHASE II and undergoes gradual inactivation during oocyte activation to allow progression to anaphase II.

$$CDK1$$

A cyclin-dependent kinase that forms a complex with Cyklina B to regulate meiotic arrest and progression.

Cyklina B

A regulatory protein that associates with $CDK1$; its degradation via ubiquitination ($Ub$) is linked to the inactivation of CSF and the completion of meiosis.

Anaphase II

The stage of meiosis reached after oocyte activation and the inactivation of the Cytostatic Factor (CSF).