biology honors - cell cycle: interphase, mitosis, & cytokinesis

adenine

thymine pairs with ________

cytosine

guanine pairs with _________

chromosome

DNA that is tightly coiled up for protection because the nucleus has disappeared

chromatin

when DNA is long and stringy; takes this form when there is a nucleus present

chromatid

1 strand of DNA; 2 sister chromatids together make up an X shaped chromosome

cell cycle

aka the cell's life span

somatic cells

the cell cycle happens to which type of cells?

body cells that make up almost everything except those in reproductive organs

what are somatic cells?

- cells grow up, learn how to function, and carry out their functions

- cells decide whether or not to reproduce

what happens in G1?

they enter the G0 stage, which is where they stay the way that they are, get old and then die; can be reversed so that they can reproduce again

if cells do not decide to reproduce, what happens?

yes, they can decide to reproduce again even if they entered G0 originally

is the G0 stage reversible?

synthesis

what does the S stage stand for?

- DNA replication (DNA unwinds, unhooks, splits apart, and new nucleotides match in the correct order)

- in the nucleus

what happens in S?

2 new copies of DNA still stay attached to each other

what happens to the DNA after DNA replication occurs (in the S stage)?

centromere

the place where the 2 copies of DNA are attached together

- makes copies of organelles

- cell grows bigger

- reorganizes

what happens in G2?

prophase, metaphase, anaphase, telophase

what are the steps of mitosis in order?

- centrioles move to opposite ends of the cell and start producing spindle fibers

- DNA coils up into a chromosome; nucleus dissolves

- spindle fibers attach to the chromosomes

what happens in prophase?

prophase

what stage of mitosis is occuring in this picture?

- chromosomes line up in a single file line in the middle of the cell

- spindle fibers are fully attached to the chromosomes

what happens in metaphase?

metaphase

what stage of mitosis is occuring in this picture?

- DNA copies are pulled apart (centromere breaks) and move to opposite ends of the cell

- organelles are divided up and sent to opposite ends

what happens in anaphase?

anaphase

what stage of mitosis is occuring in this picture?

- the cell squeezes in the middle and starts to split in half

- nuclei begin to reform, DNA goes back to looking like chromatin

what happens in telophase?

telophase

what stage of mitosis is occuring in this picture?

- the 2 cells completely separate

what happens in cytokinesis?

- 2 identical cells

- 46 pieces of DNA

what is the result of cytokinesis (and the cell cycle as a whole)?

starts off with 46 and ends with 46

how many pieces of DNA does the cell cycle start off with? how many in the end result?