Meiosis and Sexual Life Cycles

A set of flashcards covering key concepts of meiosis and sexual life cycles to aid in exam preparation.

What accounts for the resemblance between offspring and parents?

Offspring resemble their parents because they inherit genes, which are segments of DNA.

What is the main purpose of meiosis in sexual life cycles?

Meiosis reduces the chromosome number from diploid to haploid, allowing for sexual reproduction.

What are homologous chromosomes?

Homologous chromosomes are pairs of chromosomes containing the same genes, one inherited from each parent.

What is the significance of genetic variation in sexual reproduction?

Genetic variation contributes to the evolution of species by enhancing diversity among offspring.

How many chromosomes do humans have?

Humans have a total of 46 chromosomes.

What is a karyotype?

A karyotype is an ordered display of an individual's chromosome pairs.

What are the sex chromosomes for males and females?

Females have XX chromosomes, while males have XY chromosomes.

What is the difference between diploid and haploid cells?

Diploid cells have two sets of chromosomes (2n), while haploid cells have one set (n).

What specific locations on chromosomes are genes found?

Each gene has a specific location called a locus on a chromosome.

What occurs during fertilization?

Fertilization unites a sperm and egg, re-establishing pairs of homologous chromosomes.

What type of reproduction do single-celled eukaryotes typically undergo?

Single-celled eukaryotes typically reproduce asexually by mitosis.

What is the role of mitosis?

Mitosis produces genetically identical daughter cells for growth and repair.

What happens during Meiosis I?

Meiosis I separates homologous chromosomes into two haploid cells.

What is crossing over and when does it occur?

Crossing over is the exchange of genetic material between homologous chromosomes that occurs during Prophase I.

What is independent assortment?

Independent assortment refers to the random orientation of homologous pairs during Metaphase I.

How many possible combinations of chromosomes are there for humans due to independent assortment?

There are over 8 million possible combinations of chromosomes due to independent assortment.

What happens in Meiosis II?

Meiosis II separates sister chromatids into four genetically distinct haploid daughter cells.

What is the role of the synaptonemal complex during meiosis?

The synaptonemal complex holds homologous pairs together during Prophase I.

What is a tetrad in the context of meiosis?

A tetrad consists of a pair of homologous chromosomes, having four chromatids.

What is the function of gametes?

Gametes are haploid cells that combine during fertilization to form a diploid zygote.

What occurs during Anaphase I of meiosis?

Homologous pairs are separated and move toward opposite poles of the cell.

What are the three mechanisms contributing to genetic variation during meiosis?

Crossing over, independent assortment, and random fertilization contribute to genetic variation.

How does DNA mutation relate to genetic diversity?

Mutations in DNA are the original source of genetic diversity, creating different versions of genes called alleles.

What distinguishes meiosis from mitosis?

Meiosis reduces chromosome number and produces genetically diverse cells, while mitosis maintains chromosome number and produces identical cells.

What is the significance of the random nature of fertilization?

Random fertilization increases genetic diversity by allowing any sperm to combine with any egg, resulting in unique zygotes.

What is the outcome of meiotic cell divisions?

Meiosis results in four genetically distinct haploid daughter cells.

How do homologous chromosomes differ from sister chromatids?

Homologous chromosomes are pairs from each parent, while sister chromatids are identical copies of the same chromosome.