Get out homework (phases of meiosis worksheet)

Fill in Meiosis Mitosis Venn DiagramPlease try to think of at least four

differences for each and two things they have in common

How meiosis is different in males and females.

Meiosis in males, process used to create sperm

Males create four sperm cells for each single spermatogonium

Remember the original spermatogonium is diploid, while the resulting four sperm are

haploid (have half the DNA) This process occurs in the seminiferous tubules which make up the testes

Seminiferous tubules are the little tubes that curl around to create the testes

If stretched out these could reach 300 to 350 meters

Men can produce an infinite number of sperm in their life time.

They begin producing sperm at puberty because that is when the tubes become hollow

The spermatogonium starts on the outside of the tube

As it moves its way to the inner portion of the tube it undergoes meiosis

The four sperm are then released into the inside of the seminiferous tubule.

Oogenesis is meiosis in females and produces one egg cell.

Each round of meiosis creates one mature egg cell that can be fertilized and three polar bodies, which cannot be fertilized.

This process occurs in the follicles of the ocary

Each female has about 400,000 primary follicles in her ovary at birth. A female starts producing egg cells at puberty and

cannot possibly produce more egg cells than she has follicles

Most female produce about 400 mature eggs in her lifetime

During ovulation the egg is released from the ovary so it can be fertilized

Spermatogenesis Oogenesis

Creates four mature sperm

Occurs continuously Occurs throughout

entire life after puberty

Occurs in males Sperm are smaller

and motile

Creates one mature egg and three polar bodies

Occurs once a month

Stops occurring once menopause is reached

Occurs in females Egg is much larger

and not motile

Both are forms of meiosis Both create sex cells used in sexual

reproduction Both occur in the gonads Both start with a diploid cell and end up

with haploid cells. Both occur in plants (pollen or spores

and egg instead of sperm and egg) and animals

Most issues during gamete formation occur during meiosis I

As a woman gets older there become more and more genetic abnormalities in her eggs, which is why the chances of bearing a child with birth defects increase as a woman gets older.

Sometimes during meiosis the chromosomes do not separate causing the egg or sperm to either have 46 or 0 chromosomes

Sometimes only one pair of chromosomes does not separate causing the egg or sperm to have 47 or 45 chromosomes.

Sometimes sperm do not form properly

When this occurs it can lead to infertility

Even though sperm are being produced, they might be slow or not motile.

This causes them to die before they could possible reach the egg