Sexual Reproduction

These flashcards cover the fundamental concepts of sexual reproduction, cell division, and genetic variation based on the lecture notes.

What is the basic process of cell proliferation in living organisms?

It involves replicating DNA and dividing the cell in two.

How are gametes different from somatic cells in terms of chromosome number?

Gametes are haploid, containing one set of chromosomes, while somatic cells are diploid, containing two sets.

What is the outcome of the fusion of a sperm and an egg?

It produces a diploid cell called a zygote.

What does meiosis accomplish in the sexual reproduction cycle?

Meiosis halves the chromosome number to produce haploid gametes.

Why is crossing over important during meiosis?

It increases genetic variation among gametes.

What are the two types of cell divisions referred to in meiosis?

Meiotic division I (meiosis I) and meiotic division II (meiosis II).

What is a bivalent in the context of meiosis?

It is a structure formed when homologous chromosomes pair up before cell division.

What are the benefits of sexual reproduction?

It produces genetic diversity and novel combinations of chromosomes.

What is the role of chiasma during crossing over?

It is the point of contact between non-sister chromatids during crossing over.

How many cells are produced from one round of meiosis?

Four genetically dissimilar haploid cells.

What specific process occurs during Prophase I to pair homologous chromosomes?

Synapsis, where homologous chromosomes align gene-for-gene to form a bivalent.

What is independent assortment?

The random orientation of homologous chromosome pairs at the metaphase plate during Meiosis I, which creates genetic variation.

What is the primary difference between Anaphase I and Anaphase II?

In Anaphase I, homologous chromosomes are pulled to opposite poles, while in Anaphase II, sister chromatids are separated.

How does the chromosome count change from a diploid cell to a haploid cell?

The chromosome count is reduced by half, from 2n (diploid) to n (haploid).

What are germ-line cells?

Specialized cells in a multicellular organism that are set aside to undergo meiosis and produce gametes.

How many rounds of DNA replication occur for the two rounds of cell division in meiosis?

Only one round of DNA replication occurs before Meiosis I, and no replication occurs between Meiosis I and Meiosis II.

What is the function of the synaptonemal complex?

It is a protein structure that forms between homologous chromosomes during Prophase I to support synapsis and crossing over.

Why is Meiosis II often compared to Mitosis?

Because during Meiosis II, sister chromatids are separated and moved to opposite poles, similar to the process in Mitosis.