Cell Division Flashcards
what is a genome?
a cell’s total DNA
how many genes is a genome made up of?
~20,000 genes
where is prokaryote DNA found?
in a single circle called the nucleoid
small circles called plasmids
eukaryote DNA
several DNA double helices packaged into chromosomes
what form is a cell’s DNA during interphase?
is in loose form called chromatin
what happens to DNA during prophase?
condenses from chromatin to tightly coiled structure called chromosomes
what is another term for body cell?
somatic cell
how many chromosomes do human somatic cells have?
46 chromosomes
how many chromosomes do you have in a liver cell? skin cell? eye cell?
all cells in the body contain 46 chromosomes
cell division enable the genome of one somatic cell to be passed onto what?
two daughter cells
what happens during Mitosis (M phase) ?
divides the nucleus and sister chromatids and is immediately followed by cytokinesis
what happens during cytokinesis?
divides entire cell/cytoplasm
what does mitosis consist of?
prophase, metaphase, anaphase, telophase
what does mitosis and cytokinesis enable organisms to do? (2)
grow and develop
allows for tissue renewal
what happens when a unicellular organism undergoes mitosis/cytokinesis?
an entire new organism is created
what happens to the number of chromosomes during cell cycle?
chromosomes in somatic cells first make copies of themselves, so 46 becomes 92 during S phase. then it goes back to 46 per cell when the cell divided into 2 new daughter cells in the M phase
what happens during S phase?
DNA replication - helicase, polymerase, ligase etc all work
what does the cell cycle describe?
the sequence of events that occur during each phase of a cell’s life
in what phase do cells spend most of their lives in?
interphase
what is interphase made up of?
G1 (1st gap)
S (Synthesis of DNA)
G2 (2nd gap)
what happens to cells during G1 phase? (2)
grows
make proteins and organelles
what happens to cells during S phase? (3)
grow
make proteins and organelles
copy their DNA (2 sister chromatids)
what happens to cells during G2 phase? (3)
grow
make proteins and organelles
make sure the cell is ready to enter into the M phase
what happens to a cell after the M phase?
cell cycle either repeat or cell can become dormant (G0)