Chapter 09 Sexual Reproduction and Meiosis

A collection of practice flashcards to review key concepts related to sexual reproduction and meiosis, including definitions and significant processes.

What is asexual reproduction?

A form of reproduction that generates genetically identical offspring, primarily through mitosis.

What is meiosis?

A type of cell division that generates sperm and egg cells, each genetically unique, necessary for sexual reproduction.

Why is sexual reproduction considered worth the cost?

It can create or maintain genetic diversity despite the high energy required to attract a mate and produce sex cells.

What are homologous chromosomes?

Matched sets of chromosomes, one from each parent, that have the same size, structure, and genes but different alleles.

What is a diploid cell?

A cell containing two sets of homologous chromosomes, one from each parent.

What does a karyotype show?

It displays all the chromosomes in a cell, arranged into pairs, including autosomes and sex chromosomes.

What is the function of germ cells?

Specialized cells that undergo meiosis to produce gametes (sperm and egg cells), which do not divide by mitosis.

What happens during fertilization?

Gametes fuse to form a zygote, the first cell of a new organism, which is diploid and will undergo mitosis to develop.

What is the significance of haploid gametes?

They provide the correct chromosome number (23 from each parent, totaling 46 in the zygote) necessary for normal development.

How does meiosis differ from mitosis?

Meiosis consists of two rounds of division (PMAT twice), produces four genetically unique cells, and involves crossing over and independent assortment.

What is independent assortment?

The random alignment of chromosome pairs during meiosis metaphase I, resulting in many possible combinations of chromosomes.

What is crossing over?

A process during meiosis prophase I where homologous chromosomes exchange genetic material, creating new combinations of alleles.

What occurs if nondisjunction happens during meiosis?

It can lead to gametes with an incorrect number of chromosomes, resulting in abnormalities in offspring, such as Down syndrome.

What is Down syndrome?

A chromosomal condition caused by trisomy 21, characterized by specific physical features and varying degrees of developmental delay.

What is the difference between monozygotic and dizygotic twins?

Monozygotic twins are genetically identical, formed from one fertilized egg that splits, while dizygotic twins develop from two separate eggs fertilized by two sperm, resulting in unique DNA.

What distinguishes mitosis from meiosis functionally?

Mitosis produces identical cells for growth and tissue repair, while meiosis produces haploid gametes with unique genetic information.

What causes the increased risk of Down syndrome with maternal age?

As maternal age increases, the risk of errors during chromosome separation (nondisjunction) also increases.