Topic 3B.1 The Cell Cycle

mitosis

the process by which a cell divides to produce two genetically identical daughter cells

asexual reproduction

the production of genetically identical offspring from a single parent or organism

sexual reproduction

the production of offspring that are genetically different from the parent organism or organisms by the fusing of two sex cells (gametes)

meiosis

a form of cell division in which the chromosome number of the original cell is halved, leading to the formation of gametes

histones

positively charged proteins involved in the coiling of DNA to form dense chromosomes in cell division

nucleosomes

dense clusters of DNA wound around histones

karyotype

a way of displaying an image of the chromosomes of a cell to show the pairs of autosomes and sex chromosomes

cell cycle

a regulated process of three stages (interphase, mitosis and cytokinesis) in which cells divide into two genetically identical daughter cells

interphase

the period between active cell divisions when cells increase their size and mass, replicate their DNA and carry out normal metabolic activities

cytokinesis

the final stage of the cell cycle before the cell enters interphase again - division of the cytoplasm at the end of mitosis to form two independent, genetically identical cells

chromatid

one strand of the replicated chromosome pair that is joined to the other chromatid at the centromere

cyclins

small proteins that build up during interphase and are involved in the control of the cell cycle by their attachment to cyclin-dependent kinases

cyclin-dependent kinases (CDKs)

enzymes involved in the control of the cell cycle by phosphorylating other proteins, activated by attachment to cyclins