Chapter 13: Meiosis and Sexual Life Cycles Flashcards
Heredity
Transmission of traits from one generation to the next
Genetics
The study of heredity and inherited variation
Gene
Unit of heredity made up of segments of DNA
Asexual reproduction
Single individual passes all genes to identical offspring
Sexual reproduction
Two parents pass on half of their genes to a unique offspring
Homolog (homologous chromosomes)
Members of a pair of chromosomes
Autosome
Nearly identical homologs in size and genetic composition
Sex chromosomes
X and Y chromosomes that determine the sex of an individual
Fertilization
Union of gametes (sperm and egg)
Zygote
Fertilized egg
Prophase I
Crossovers occur, genes align, sister chromatids associate
Synaptonemal complex
Protein structure that connects homologous chromosomes
Metaphase I
Pairs of homologs line up on the metaphase plate
Anaphase I
Homologous pairs separate and are pulled towards opposite poles
Telophase I
Each half of the cell has a haploid set of duplicated chromosomes, each containing two sister chromatids
Cytokinesis
Occurs simultaneously with telophase, cleaving the cell into two
Prophase II
Begins with two haploid cells, spindles form
Metaphase II
Sister chromatids (single chromosomes) arrange on the metaphase plate
Anaphase II
Sister chromatids separate, now individually chromosomes, move toward opposite poles
Telophase II
Chromosomes on opposite poles, nuclei form, chromosomes decondense
Synapsis and crossing over
Homologous chromosomes physically connect and exchange genetic information
Recombinant chromosomes
Combine DNA from each parent
