Chapter 4 Cell division and Reproduction (Defs.) Flashcards
A plant or animal cell that forms the body of the organisms; excludes reproductive cells.
Somatic cell
A structure in the nucleus that contains DNA.
Chromosome
One of two chromosomes that are genetically identical and held together at the centromere.
Sister chromatid
The region where two sister chromatids are held together in a chromosome.
Centromere
A microtubule structure that facilitates the movement of chromosomes within a cell.
Spindle fibre
A structure that helps to form the spindle fibres.
Centrosome
The stage of mitosis during which the cell’s chromatin condenses into chromosomes.
Prophase
The stage of the cell cycle during which a cell carries out its normal functions, grows, and makes copies of its genetic material in preparation for the next stage of the cycle.
Interphase
The stage of mitosis during which spindle fibres from opposite poles attach to the centromere of each chromosome, guiding the chromosomes to the equator of the cell.
Metaphase
Stage of mitosis during which each centromere splits apart and the sister chromatids separate from each other.
Anaphase
Stage of mitosis during which the chromosomes start to unwind into strands of chromatin, the spindle fibres break down, the nuclear membrane forms around the new set of chromosomes, and a nucleolus forms within each new nucleus.
Telophase
Stage of the cell cycle that begins near the end of mitosis and involves the division of the cell cytoplasm and the creation of a new cell.
Cytokinesis
Stage of cell cycle during which a cell’s nucleus and genetic material divide.
Mitosis
A structure that forms between the two daughter nuclei during the process of cytokinesis in plant cells; cell walls then form on either side of the cell plate.
Cell plate
A spiral shape formed by a DNA molecule.
Double helix
The individual units of each strand of DNA; composed of a phosphate group, a sugar group, and a base - either adenine, guanine, thymine, or cytosine.
Nucleotides
Nucleotide bases on opposite strands of the DNA backbone that interact in a DNA molecule; adenine pairs with thymine and guanine pairs with cytosine.
Complementary base pairs
A permanent change in the genetic material of an organism; the only source of new genetic variation.
Mutation
The complete DNA sequence of an organism.
Genome
Describes a method of DNA replication that conserves half of the original DNA molecule when producing a new molecule of double-stranded DNA.
Semi-conservative
An X or Y chromosome, which determines the genetic sex of an organism.
Sex chromosome
A chromosome that is not involved in determining the sex of an organism.
Autosome
A chromosome that contains the same sequence of genes as another chromosome.
Homologous chromosome
A part of a chromosome that governs the expression of a trait and is passed on to offspring; it has a specific DNA sequence.
Gene
One of two or more forms of a gene.
Allele
A photograph of pairs of homologous chromosomes in a cell.
Karyotype
Reproduction that requires only one parent and produces genetically identical offspring.
Asexual reproduction
Reproduction that requires two parents and produces genetically distinct offspring.
Sexual reproduction
A male or female reproductive cell.
Gamete
A cell formed by the fusion of two gametes.
Zygote
In humans, the joining of male and female haploid gametes.
Fertilization
A cell that contains half the number of chromosomes as the parent cell.
Haploid
A cell that contains pairs of homologous chromosomes.
Diploid
The cellular process that produces cells containing half the number of chromosomes as the parent cell.
Meiosis
The aligning of homologous chromosomes during prophase I in meiosis I.
Synapsis
The process of producing male gametes (sperm) in mammals.
Spermatogenesis
The process of producing female gametes (eggs) in mammals.
Oogenesis
The exchange of chromosomal segments between a pair of homologous chromosomes.
Crossing over
The failure of homologous chromosomes pairs or sister chromatids to separate during meiosis.
Non-disjunction
The loss of a chromosome as a result of non-disjunction.
Monosomy
The gain of a chromosome as a result of non-disjunction.
Trisomy
The process of breeding plants and animals for desirable traits.
Selective breeding
The process by which sperm are collected and concentrated before being introduced into the female’s reproductive system.
Artificial insemination
The process by which an egg that has been fertilized artificially is transferred into a recipient female’s uterus.
Embryo transfer
The technique used to fertilize egg cells outside the female’s body.
In vitro fertilization
A process that produces identical copies of genes, cells, or organisms.
Cloning
The use of DNA manipulation techniques to produce multiple copies of a single gene or segment of DNA.
Gene cloning
A molecule of DNA that includes genetic material from different sources.
Recombinant DNA
The process of replacing an egg cell’s nucleus with the nucleus from a somatic donor cell to produce a cell line of genetically identical cells.
Therapeutic cloning
The process of producing genetically identical organisms.
Reproductive cloning
An undifferentiated cell that can develop and become specialized into different cell types of the body.
Stem cell
Describes an organism whose genome has been altered by the insertion of a gene from another organisms; a type of genetically modified organisms.
Transgenic
An organism whose genome has been altered.
Genetically modified organisms (GMO)
