Germ Cells and Meiosis Quiz

Germ cells

• Germ cells give rise to gametes (sperm and egg)
• Germ cells are diploid (2n), containing two sets of chromosomes.
• Germ cells undergo meiosis to produce haploid (1n) gametes with one set of chromosomes.
• This reduction in chromosome number is essential for sexual reproduction, ensuring the correct diploid number in the zygote.

Somatic cells

• Somatic cells include all cells besides germ cells and gametes.
• They are responsible for body growth, development, and maintenance.
• Somatic cells undergo mitosis, producing identical daughter cells.

Meiosis

• Occurs in specialized germ-line cells located in the gonads: testes in males and ovaries in females.
• Reduces the number of chromosomes in gametes by half.
• Ensures the correct chromosome number in the zygote after fertilization.
• Increases genetic diversity through crossing over and independent assortment.

Sexual Reproduction

• Involves the fusion of two gametes (sperm and egg).
• Is the primary mechanism for generating genetic diversity in offspring.
• Gametes are produced through meiosis.

Crossing Over

• Occurs during prophase I of meiosis.
• Homologous chromosomes exchange segments of DNA.
• This exchange creates new combinations of alleles on chromosomes.
• Ensures each gamete receives a unique combination of genetic material from both parents.

Independent Assortment

• Occurs during metaphase I of meiosis.
• Homologous chromosome pairs align randomly at the metaphase plate.
• Each pair's orientation is independent of others, leading to random distribution of maternal and paternal chromosomes to daughter cells.
• Creates a vast number of possible chromosome combinations in gametes, further increasing genetic diversity.

Genetic Variation

• Mutations, changes in DNA sequence, can introduce new genetic variations.
• Can occur during DNA replication in the S phase before meiosis.
• Mutations can be beneficial, harmful, or neutral.
• Beneficial mutations contribute to a species' adaptation, while harmful ones can lead to disease.

Somatic Cells

• Also known as body cells.
• Include all cells in the body besides gametes, germ cells, and stem cells.
• Found in tissues and organs like skin, heart, muscle, bones, and blood.
• Are diploid (2n) with two sets of chromosomes.

Mitosis

• Produces new cells for growth, repair, and maintenance.
• Daughter cells have the same number of chromosomes as the parent cell.
• Each daughter cell receives a complete set of genetic information from the parent cell.
• Essential for growth, development, and repair in multicellular organisms.

Mitosis and Growth

• Living organisms grow by producing more cells through mitosis.
• Responsible for the rapid growth of tissues and organs during embryonic and childhood development.

Mitosis and Repair

• Necessary for repairing damaged tissues.
• Mitosis creates new cells to replace damaged or lost cells.

Mitosis and Regeneration

• Involved in regenerating lost body parts in some organisms.
• Plays a role in skin cell regeneration after a wound.

Meiosis II

• Similar to mitosis, involves sister chromatids separating.
• Starts with a haploid cell.
• Produces four haploid daughter cells, each genetically unique due to crossing over and independent assortment.