Ch+5+pt+2+FP-module 4

What is the definition of homologous chromosomes?

Chromosomes that have the same length and centromere position, with genes in the same locus.

What is the primary role of meiosis?

To reduce the number of chromosomes by half and create gametes for sexual reproduction.

How many daughter cells does meiosis produce?

Four daughter cells, each with different genetic information.

What key event occurs during Prophase I of meiosis?

Homologous chromosomes pair up (synapsis) and crossing over occurs.

What happens during Metaphase I of meiosis?

Pairs of homologous chromosomes (tetrads) line up at the metaphase plate.

What is nondisjunction?

The failure of homologous chromosomes to separate during meiosis.

What are the consequences of nondisjunction?

It can lead to monosomy or trisomy, often resulting in fatal conditions or disorders like Down syndrome.

What is the difference between sperm production (spermatogenesis) and egg production (oogenesis)?

Spermatogenesis produces millions of sperm continuously, while oogenesis produces one egg with two polar bodies during each cycle.

What is the result of crossing over during meiosis?

It leads to unique combinations of genes on the chromosomes.

What does independent assortment refer to?

The random arrangement and separation of homologous chromosomes during Metaphase I and Anaphase I.

How does random fertilization contribute to genetic variation?

Each sperm and egg combination is unique, resulting in diverse offspring even from the same parents.

What effect does meiosis have on the number of chromosomes in gametes?

It reduces the chromosome number by half (from 2n to n).

During which phase does the separation of sister chromatids occur in meiosis II?

Anaphase II.

What are the two sets of divisions required in meiosis?

Meiosis I and Meiosis II.

What type of cells undergo meiosis?

Only sexually reproducing organisms' germ cells.

What is interkinesis?

A period of time between Meiosis I and II where the cell may not divide.

How many possible gamete configurations can one human produce?

8,388,608, based on 23 pairs of chromosomes.

What typically happens if nondisjunction occurs during meiosis I?

All gametes will have an abnormal number of chromosomes.

What structural changes happen to chromosomes during Prophase II?

Chromatids are still paired but chromosomes have half the number compared to the parent cell.

What is the term for an organism that is missing one chromosome?

Monosomy.

What is the term for an organism that has an extra chromosome?

Trisomy.

What distinguishes mitosis from meiosis in terms of daughter cells?

Mitosis produces 2 identical daughter cells, whereas meiosis produces 4 non-identical daughter cells.

What is produced by cytokinesis during oogenesis?

One secondary oocyte and one polar body with uneven division.

When does oogenesis begin in a female's life?

It begins in the fetus but freezes at Prophase I until puberty.

What phase initiates sperm production during spermatogenesis?

Puberty.

During _____, homologous chromosomes exchange genetic material.

crossing over

Meiosis produces _____ with half the chromosome number of the parent cell.

gametes

The term for the random distribution of maternal and paternal chromosomes during meiosis is called _____ assortment.

independent

______ pairs of homologous chromosomes line up at the metaphase plate during Metaphase I.

Tetrads

Nondisjunction can occur during _____ I or II.

Meiosis

In females, _____ occurs once a month, releasing an egg from the ovary.

ovulation

The period between Meiosis I and Meiosis II where no DNA replication occurs is called _____.

interkinesis

A cell with three copies of a chromosome is referred to as having _____ condition.

trisomy

The process of sperm development is known as _____, which begins at puberty.

spermatogenesis

The failure of sister chromatids to separate during _____ II can lead to gametes with abnormal chromosome numbers.

Anaphase