Mitosis Nuclear Division Flashcards
what is mitosis
a process that produces new somatic cells for development, growth, and repair
what is a nucleosome
bead like structure with DNA wrapped around histones
what is the function of histones
to allow DNA to spool around
what are nucleotides
the genetic code (sugar, base, phosphate)
what is nucleic acid
chain of nucleotides
what is DNA
double stranded, double helix with hydrogen bonds between strands
what is chromatin
- DNA strands and histones
- strings of beads
when are sister chromatids formed
formed prior to mitosis when a double helix is replicated
where do two copies of each chromosome come from
one from each parent (diploid)
what happens in interphase G1
- cell makes new molecules and enzymes and grows larger
what affects the length of G1 phase
can be long or short depending on the type of cell and the health of an organism
What happens in interphase S phase
- synthesis of more DNA
- the chromatin are replicated
what does the nucleus look like during interphase
the nucleus looks like a dark blob and the individual chromosomes are not visible
what happens in interphase G2
- the cell synthesizes more molecules
- duplicates its organelles and grows larger
what are the different phases of interphase
- G1 phase
- S phase
- G2
what happens during prophase
- DNA condenses and becomes chromosomes
- nuclear membrane dissolves
- centrioles migrate to opposite poles
- spindle fibre forms
what happens during metaphase
- spindle fibres attach to centromeres
- chromosomes line up at the midline of the cell
what happens during anaphase
- spindle fibers pull apart chromosomes
- one chromatid goes to each centriole (look like V’s)
what happens during telophase
- chromatids reach centrioles
- mitosis ends when new nuclear membranes form
- some evidence of cell dividing
- start of the cleavage furrow
what happens during cytokinesis
- in animal cell the cleavage furrow causes the cell to split into two new daughter cells
- in plant cells the cell plate forms the new cell wall between the two new daughter cells
- DNA becomes chromatin
- daughter cells enter G1 period of interphase
what is a cleavage furrow
the pinching on the cell membrane
what is a centriole
cylindrical paired organelles found in animal cells involved in development of spindle fibres
what is a centrosome
organelle containing both centrioles
what is a centromere
constricted region of chromosome where spindle fibres attach
what is a kinetochore
complex of proteins associated with centromere to which spindle fibres attach
