Chapter 13 Flashcards
A chromosome created when crossing over combines the DNA from two parents into a single chromosome.
Recombinant Chromosome
The X-shaped, microscopically visible region where homologous nonsister chromatids have exchanged genetic material through crossing over during meiosis, the two homologs remaining associated due to sister chromatid cohesion.
Chiasma
The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis.
Crossing Over
The pairing and physical connection of replicated homologous chromosomes during prophase I of meiosis.
Synapsis
(1) In the life cycle of a plant or alga undergoing alternation of generations, a haploid cell produced in the sporophyte by meiosis. A _____ can divide by mitosis to develop into a multicellular haploid individual, the gametophyte, without fusing with another cell. (2) In fungi, a haploid cell, produced either sexually or asexually, that produces a mycelium after germination.
Spore
In organisms (plants and some algae) that have alternation of generations, the multicellular diploid form that results from the union of gametes. The ________ produces haploid spores by meiosis that develop into gametophytes.
Sporophyte
In organisms (plants and some algae) that have alternation of generations, the multicellular haploid form that produces haploid gametes by mitosis. The haploid gametes unite and develop into sporophytes.
Gametophyte
A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.
Alternation of Generations
A modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cell.
Meiosis
The diploid product of the union of haploid gametes during fertilization; a fertilized egg.
Zygote
(1) The union of haploid gametes to produce a diploid zygote. (2) The addition of mineral nutrients to the soil.
Fertilization
A cell containing only one set of chromosomes (n).
Haploid Cell
A cell containing two sets of chromosomes (2n), one set inherited from each parent.
Diploid Cell
A chromosome that is not directly involved in determining sex; not a sex chromosome.
Autosome
A chromosome responsible for determining the sex of an individual.
Sex Chromosome
A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism’s father, the other from the mother. Also called homologs, or a homologous pair.
Homologous Chromosomes
A display of the chromosome pairs of a cell arranged by size and shape.
Karyotype
Any cell in a multicellular organism except a sperm or egg.
Somatic Cell
The generation-to-generation sequence of stages in the reproductive history of an organism.
Life Cycle
(1) A lineage of genetically identical individuals or cells. (2) In popular usage, a single individual organism that is genetically identical to another individual. (3) As a verb, to make one or more genetic replicas of an individual or cell.
Clone
A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from the gametes of the parents.
Sexual Reproduction
The generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, or division of the entire organism into two or more parts). In most cases, the offspring are genetically identical to the parent.
Asexual Reproduction
A haploid reproductive cell, such as an egg or sperm. ______ unite during sexual reproduction to produce a diploid zygote.
Gamete
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, for some viruses).
Gene
The scientific study of heredity and hereditary variation.
Genetics
The transmission of traits from one generation to the next.
Heredity
