Chapter 28 Study Guide

What cells form at the completion of meiosis II? Are those cells haploid or diploid?

(1) Mature Ovum - Fertilized (2n) diploid cells (2) Second polar body - degenerates (doesn't finish meiosis II)

What will happen to the cells produced as a result of mitosis during oogenesis?

(1) Oogonium (2n) - Remains as stem cell to divide again (2) Primary oocyte (2n) - Cells undergo meiosis to reduce number of chromosomes

What type(s) of cells are produced in meiosis I completion (female)? Are those cells haploid or diploid?

(1) Secondary oocyte (haploid - n) - Undergoes meiosis II (split pairs) and each has 23 pairs of chromatids (2) 1st Polar Body - Eventually degenerates (does not finish meiosis)

oogonium

(2n), diploid stem cells that gives rise to oocytes

How has the number of oocytes changed by the onset of puberty?

- By the onset of puberty, # of primary oocytes has been reduced between 80,000 & 400,000 (atresia)

Understand the basic process of spermiogenesis

- Cells elongate and shed excess cytoplasm - Acrosome and flagellum develop

Upon completion of meiosis I, what types of cells are produced? Are they haploid or diploid?

- Daughter cells are secondary spermatocytes (haploid - n) - Each has pairs of chromatids (split pairs in meiosis II)

When will meiosis I begin again in females?

- Each month a primary oocyte is activated => completes meiosis I - By the onset of puberty, # of primary oocytes has been reduced

When does meiosis I begin in females?

- Meiosis I occurs between 3 - 7 months gestation in females

What triggers meiosis II to begin? At what point will it pause?

- Ovulation or fertilization of oocyte triggers the beginning of Meiosis II. - It will pause during metaphase II

At what point does this meiosis I pause in females?

- Primary oocytes begins meiosis I but pauses @ prophase I - Remains paused until the onset of puberty

What type of cell is produced during meiosis II during spermatogenesis?

- Spermatids produced and mature during spermiogenesis

What 3 processes occur during spermatogenesis?

1. Mitosis of spermatogonia 2. Meiosis (produces spermatids/immature sperm) 3. Spermiogenesis (maturation of sperm)

What is produced as a result of mitosis during spermatogenesis? Are those cells haploid or diploid?

2 (2n) daughter cells: (1) Spermatogonium - Remain as stem cells, divide again (2) Primary spermatocyte - Enters meiosis I

Approximately how many primary oocytes will be present at birth?

2 - 4 million primary oocytes present at birth

What type(s) of cells are produced as a result of mitosis during oogenesis?

2 daughter cells: (1) Oogonium (2n) (2) Primary oocyte (2n)

What does the head of the sperm contain?

Chromosomes

Acrosome

Contains enzymes that helps the sperm to penetrate oocyte during fertilization

Why is the middle piece of the sperm important?

Contains mitochondria that produces the ATP to power the tail/flagellum

spermatogonium

Diploid cell (2n) undergoing mitosis to form more spermatogonium; triggered to undergo meiosis to form sperm

at the end of mitosis, are the cells produced haploid or diploid?

Diploid to diploid (2n --> 2n)

When does meiosis II begin in females?

Each month, one secondary oocyte begins meiosis II during ovulation point

Gametogenesis

Formation of gametes (sperm and egg/oocyte)

Spermatogenesis

Formation of sperm

During the oogenesis process, when does mitosis occur?

In females, all mitotic divisions that produce oocytes will occur PRIOR to birth

Does gamete formation involve mitosis or meiosis?

Meiosis

When does meiosis II finish?

Meiosis II will not complete until ovulation or fertilization of oocyte occurs.

Are oogonia haploid or diploid?

diploid

is a spermatogonium haploid or diploid

diploid (2n)

Oogenesis

formation of oocytes

Endometrium

inner lining of the uterus