Chapter 12 Flashcards
how do unicellular organisms reproduce?
the division of one cell reproduces the entire organism
what is the cell cycle?
the life of a cell from formation to its own division
what does cell division result in?
most cell division results in daughter cells with identical genetic information or DNA
what is an exception in cell division?
meiosis: a special type of division that can produce sperm and cell eggs; the daughter cells are not genetically identical
what is a genome?
all the DNA in a cell constitutes the cell’s genome; can consist of a single DNA molecule (prokaryotic) or a number of DNA molecules (eukaryotic)
what is chromatin? what consists of chromatin?
eukaryotic chromosomes consist of chromatin
- chromatin is a complex of DNA and protein that condenses during cell division
what are somatic cells:
somatic cells are non-reproductive cells that have two sets of chromosomes
what are gametes?
gametes are reproductive cells (sperm and eggs) that have half as many chromosomes as somatic cells
what happens in preparation for cell division?
Dna is replicated and chromosomes condense, each duplicated chromosome has sister chromatids (joined copies of the original chromosome), and the centromere is the waist where two chromatids are most closely attached
what happens to sister chromatids during cell division?
the two sister chromatids of each duplicated chromosome separate and move into two nuclei, once separate they are called chromosomes
what does eukaryotic cell division consist of?
mitosis: the division of the genetic material in the nucleus
cytokinesis: the division of the cytoplasm
how are gametes produced?
gametes are produced by a variation of cell division called meiosis
what does meiosis yield?
meiosis yields nonidentical daughter cells that have half as many chromosomes as the parent cell
what are the phases of the cell cycle?
- the mitotic (M) phases: mitosis and cytokinesis
- interphase: cell growth and copying of chromosomes in preparation for cell division
how can interphase be divided into subphases?
- G1 phase (first gap)
- S phase (synthesis); cells are duplicated only in this phase
- G2 phase (second gap)