Making eggs

Question 1

The oocyte population ____________ steadily after birth

Answer 1

Declines

Question 2

What are the layers of the oocyte, from center to the exterior?

Answer 2

Oocyte, zona pellucida, granulosa cells, theca cells

Question 3

Where are theca cells located?

Answer 3

Outside the basement membrane

Question 4

The primordial follicle consists of the _____________

Answer 4

Oocyte

Question 5

The primary follicle consists of the oocyte and the ____________ cells

Answer 5

Granulosa

Question 6

The antral follicle consists of the oocyte, the granulosa cells and the ___________

Answer 6

Antrum

Question 7

The pre-ovulatory follicle consists of two groups of granulosa cells. What are they?

Answer 7

Mural and cumulus granulosa cells

Question 8

During which period are LH (luteinizing hormone) and FSH (follicle-stimulating hormone) the highest?

Answer 8

Fertile period

Question 9

When do primordial follicles enter into growth?

Answer 9

Every month

Question 10

Where do all the oocytes go?

Answer 10

Oocytes grow and are ovulated
Oocytes begin but do not complete growth and are not ovulated
Oocytes do not grow and are eventually degraded

Question 11

What is the shape of the primordial granulosa cell?

Answer 11

Squamous

Question 12

What is the shape of the primary granulosa cell?

Answer 12

Cuboidal

Question 13

Which cells signal to the oocyte to grow?

Answer 13

Granulosa cells

Question 14

What initiates the growth by granulosa cells?

Answer 14

Growth factor binds to its receptor (Receptor tyrosine kinase) and leads to signaling pathways that trigger the increase of protein synthesis

Question 15

How does local relaxation of the ovarian stoma activate primordial follicles?

Answer 15

Dense matrix exerts pressure that flattens cells and prevents them from growing
When pressure is released, granulosa cells become cuboidal and send a signal to the oocyte to grow cells

Question 16

What is the size of the pre-ovulatory follicle?

Answer 16

100 microns in diameter

Question 17

How is mRNA synthesized and stored for the growth of oocytes?

Answer 17

mRNA acquires poly-A tail in the nucleus
Message is transcribed and sent out into the cytoplasm for translation
Deadenylation shortens the poly-A tail, the product is not translated and stored

Question 18

What is the function of CPE in the cytoplasmic deadenylation element?

Answer 18

Determines the silence of the sequence

Question 19

What is the relation between oocyte diameter and mitochondria?

Answer 19

The larger the oocyte, the more mitochondria will be made

Question 20

The volume of an oocyte increases ________ fold

Answer 20

100

Question 21

What is needed for the growth of the oocyte?

Answer 21

Gap junctional communication between oocytes and granulosa cells

Question 22

What can be transported through the gap junctions?

Answer 22

Small molecules such as amino acids and glucose

Question 23

The zona pellucida is composed of three or four _______________

Answer 23

Glycoproteins

Question 24

Filopodia termed transzonal projections (TZPs) extend from the _____________ cells to the oocyte

Answer 24

Granulosa

Question 25

Thecal cells synthesize testosterone from _____________

Answer 25

Cholesterol

Question 26

Granulosa cells convert testosterone to _____________

Answer 26

Estradiol

Question 27

What is the difference between FSH and LH?

Answer 27

They both have different subunits for the beta unit

Question 28

Where are FSH and LH produced?

Answer 28

Pituitary gland

Question 29

The final stage of follicular growth occurs during the _______________ cycle and requires ______________

Answer 29

Ovulatory; FSH

Question 30

FSH is required for the __________ stage of the follicle

Answer 30

Antral

Question 31

Most pre-antral follicles die owing to insufficient ___________

Answer 31

FSH

Question 32

What inhibits the production of FSH?

Answer 32

Estrogen produced by growing follicles

Question 33

Treatments to raise __________ increase the number of ______________ for assisted reproduction

Answer 33

FSH; oocytes

Question 34

What triggers the first meiotic division in the final stage of oocyte development?

Answer 34

LH

Question 35

What are the differences in meiosis in males and females?

Answer 35

Males: Meiosis I and II happens during gametogenesis Females: Meiosis I happens during maturation and meiosis II happens after fertilization, creating two polar bodies

Question 36

Place these events of meiotic maturation in order: GVBD, spindle migration, first polar body extrusion, spindle formation, metaphase II arrest

Answer 36

GVBD, spindle formation, spindle migration, first polar body extrusion, metaphase II arrest

Question 37

What is the role of LH in the oocyte?

Answer 37

LH binds to its receptor on mural granulosa cells and activates signaling pathway It signals to EGFR ligands which inhibit cGMP to initiate maturation High cGMP triggers maturation inhibition

Question 38

What is the mechanism behind cGMP keeping cAMP levels high?

Answer 38

High cGMP -> PDE3A inhibited, high cAMP, active PKA, CDC25B and CDK1/cyclin B1 complex inactive Low cGMP -> PDE3A activated, low cAMP, PKA inactive, CDC25B active and CDK1/cyclin B1 active

Question 39

True or false: The fertility of a woman declines with time

Answer 39

True

Question 40

What is an example of meiotic error related to age-dependent fertility of women?

Answer 40

Trisomy 21

Question 41

What is the role of cohesins in chromosome segregation?

Answer 41

Cohesins hold the chromosomes together and need to be broken apart by separase for chromosome segregation

Question 42

What was the experiment to show that cohesins were vital in preventing meiotic disorders?

Answer 42

Remove cumulus-oocyte complex from pre-ovulatory follicle -> inject cohesins into oocyte -> permit meiotic maturation in vitro -> fertilize egg

Question 43

Which of these is not a key event of cytoplasmic maturation? a) Redistribution of mRNA b) Changes in protein synthesis c) Redistribution of ER d) Accumulation of cortical granules at the cortex

Answer 43

a)

Question 44

When does transcriptional activity stop in oocytes?

Answer 44

When the oocytes have matured

Question 45

When does the repressed mRNA bearing CPE become translationally activated?

Answer 45

When cytoplasmic maturation occurs