16.1 * Cell cycle: life cycle of a cell, continuous sequence of cell growth and division * Somatic cells: any of the cells of a multicellular organism except those that form gametes * Parent cell: original cell that divides to produce two new daughter cells during cell division (mitosis) * Daughter cell: any one of two cells produced from the division of a parent cell * DNA: deoxyribonucleic acid (DNA): double-stranded nucleic acid molecule that governs the processes of heredity in the cells of organisms; composed of nucleotides containing a phosphate group, a nitrogenous base (adenine, guanine, cytosine, or thymine) and deoxyribose * Chromosome: a length of DNA and is associated with proteins * Histones: protein found in chromosomes; acts as scaffold around which DNA winds, enabling it to fit within the small space of the nucleus * Chromatin: long fibers that form chromosomes and contain DNA, small amount of RNA, and various proteins; non-condensed form of genetic material that predominates for most of the cell cycle * In a drawing, these would using look like scribbles in a nuclei of a cell, like this:
* Centromere: point where two sister chromatids of a chromosome are joined together, it is the attached spindle fibres during mitosis
* Homologous chromosomes: chromosome that contains the same gene sequence as another, but they may not be made up of the same alleles; human somatic cells have 22 pairs of these, known as autosomes, and females also have homologous pair of X sex chromosomes; males have an X and a Y sex chromosomes which are not homologous * Autosomes: chromosome other than a sex chromosome, human somatic cells have 22 pairs * Sex chromosomes: X or Y chromosome that carries the genes involved in determining the genetic sex of an individual * Genes: basic unit of heredity; a specific sequence of DNA that encodes a protein, tRNA, rRNA molecule, or regulates the transcription of such a sequence; governs the expression of a particular trait and can be passed to an offspring * Locus: specific location on a chromosome * Alleles: different form of the same gene occurring on homologous chromosomes * Diploid: describing a cell that contains two pairs of every chromosome, designated as 2n; e.g., * Haploid: describing a cell containing hald the number of chromosomes (n) that the diploid (2n) parent cell contains; condition occurring in gametes, either egg(ovum) or sperm * Gametes: male or female haploid reproductive cell (ovum [f.] sperm[m.]) * Polyploid: describing a cell that contains sets of more than two homologous chromosomes * Karyotype: the particular set of chromosomes that an individual possesses * Interphase: growth stage of somatic cell, there are three phases: G1, S, and G2; ends when the cell beings the process of nuclear division (mitosis)
* G1 phase: first part of interphase, a somatic cell’s growth stage, during which cells carry out rapid and metabolic activity, AKA Growth 1 or Gap 1 * S phase: the middle part of interphase, a somatic cell’s growth stage, during which the cell’s DNA is replicated * Sister chromatin: two chromatids in a chromosome that are genetically identical and are held together by a centromere * G2 phase: the last part of interphase, a somatic cell’s growth stage, during which the cell rebuilds its reserves of energy and manufactures proteins and other molecules to prepare for division, AKA Growth 2 or Gap 2 * Mitosis: one of the two main processes in cell division: division of genetic material and the contents of the cell’s nucleus into two complete and separate sets; results in a daughter cell receiving the exact number of chromosomes and genetic make-up as the parent cell; see cytokinesis * Cytokinesis: one of the two main processes in cell division; consists of separation of cytoplasm and organelles; formation of two daughter cells
