unit 5 test Flashcards
What is the cell cycle?
Cycle of cell growth and division
What is cytokineses?
when the cell actually splits
what the two main parts of the cell cycle?
interphase and mitosis
what is the purpose of interphase?
grow, replicate dna, and prepare to divide.
what are the 3 parts of interphase?
G1, S, G2
what happens is G1 (interphase)?
cellular contents including chromosomes duplicate
what happens in S (interphase)?
each of the 45 chromosomes is duplicated by the cell
what happens in G2 (interphase)?
the cell “double checks” the duplicated chromosomes for error, making any needed repairs
what is the purpose of mitosis?
growth, development, repair
where is mitosis in the cell cycle?
before cytokineses, and after G2 of interphase
how many cells are at the beginning of mitosis?
1
how many cells are there at the end of mitosis?
2
What are somatic cells?
all body cells except reproductive cells (gametes)
what type of cell does mitosis make?
somatic cells
what is chromatin?
stringy uncoiled dna
what are chromosomes?
coiled dna (packed up)
what is replicated chromosome?
chromosome with 2 identical sisters
what are homologous chromosomes?
2 chromosomes that have the same type of info but the info is not identical
what does dna appear as in interphase?
chromatin
what are the 4 phases of mitosis (division of the nucleus)
prophase, metaphase, anaphase, telophase
what happens during prophase?
chromatin condenses (smushes up) into chromosomes, spindle fiber forms (animals), nuclear membrane disappears
what happens during metaphase?
chromosomes line up in the middle of the cell (equator)
what happens during anaphase?
sister chromatids split, move to opposite sides of the cell
what happens during telophase?
2 new nuclei form, chromosomes uncoil into chromatin
what is cytokinesis?
the cell membrane and cytoplasm divide creating 2 cells with identical dna (in nucleus)
*in plants the cell makes a cell plate and then new cell walls
what happens when cells leave the cell cycle?
apoptosis
what is a centriole?
where spindle fibers come from
what is a centromere?
the center of a chromosome (bringing everything together)
do cells in interphase always have a visible nucleus?
no
what does a replicated chromosome look like?
half of a “x”
what does a replicated chromosome look like?
a “x”
what is a sister chromatid?
either of the two identical chromatids that are formed by replication of a chromosome
in MITOSIS, what is the number of chromosomes in each cell?
diploid, meaning they have 2 copies of each chromosome
*humans have 46 (23 pairs)
how many cells does meiosis make?
4 non-identical reproductive cells