2.5 Cell Cycle Flashcards
What phases are included in interphase?
G1, S, and G2
Describe the cell in G1.
Cell is smallest it will ever be at the beginning of this phase
What happens during G1?
growth
What happens during S Phase?
replication of DNA
What is the S Phase referred to as?
synthetic phase
What happens to cell in G2 phase?
cell grows and makes preparations for mitosis
What happens to organelles in G2 phase?
organelles may increase in number
What happens to DNA in G2 phase?
DNA begins to condense from chromatin to chromosomes
What happens to microtubules in G2 phase?
microtubules begin to form
What is step 1 of chromatin becoming chromosomes?
DNA wraps around histones to form nucleosomes
What is step 2 of chromatin becoming chromosomes?
Nucleosomes wrap around further to form solenoids
What is step 3 of chromatin becoming chromosomes?
Solenoids group together to form chromosomes
What is step 1 of prophase?
Chromatin fibers tightly coiled to form chromosomes
What is step 2 of prophase?
Nuclear envelope disintegrates
What is step 3 of prophase?
Mitotic spindle begins to form, complete at end of prophase
What is step 4 of prophase?
Centromere of each chromosome has region called “kinetochore” that attaches to spindle
What is step 5 of prophase?
Centrosomes moves toward opposite poles of the cell due to lengthening microtubules
What is step 1 of metaphase?
Chromosomes move to middle, or equator. This area is called the metaphase plate.
What is step 2 of metaphase?
Chromosome’s centromere lies on the plate
What is step 3 of metaphase?
Movement of chromosomes is due to action of the spindle which is made of microtubules.
What is step 4 of metaphase?
Centrosomes now at opposite poles
What is step 1 of anaphase?
Usually shortest phase, begins when two sister chromatids are split
What is step 2 of anaphase?
Chromatids move to opposite poles of cell due to shortening of microtubules
What is step 3 of anaphase?
Centromeres are attached to microtubules, so they are pulled first
What is step 4 of anaphase?
At the end, each pole has identical set of chromosomes
What is step 1 of telophase?
Chromosomes are at each pole
What is step 2 of telophase?
Nuclear membrane begins to reform around each set of chromosomes
What is step 3 of telophase?
Chromosomes start to elongate to form chromatin
What is step 4 of telophase?
Nucleoli reappear
What is step 5 of telophase?
Spindle apparatus disappears
What is step 6 of telophase?
Cell is elongated and ready for cytokinesis (division)
What is number 1?
centromere
What is number 2?
chromatid
What is number 3?
kinetochore
What is number 4?
microtubules
What phase is this?
prophase
What phase is this?
metaphase
What phase is this?
anaphase
What phase is this and what is number 1?
telophase and cytokinesis, cleavage furrow
