What are the three major stages?
How many cells do we begin with?
- 2, sperm cell, egg cell.
- The point of fertilization is when sperm nucleus meets egg nucleus
- when the egg is fertilized, it beocmes a ZYGOTE
goal of cell cycle?
to create a new somatic cell which is exactly like the parent cells when the daughter cells are created form parent cells.
parts of interphase?
"G1" or gap 1 phase, s phase or synthesis phase, gap2 of G2 phase
Gap 1 phase?
- when cell growth and developement occurs
- the cell matures and becomes bigger
- does its job
- the synthesis phase. DNA replication where the chromatid is replicated into a sister chromatid (chromosome)
- synthesis occues
- when organelles needed for cell division are made (centrioles, spindle fibres)
- centrioles and spindle fibres are only found in G2 phase
what are chromatids
the two identical parts on a chromosome
what is the centromere?
the middle part of the chromosome that holds together the sister chromatids
- has four part: PROPHASE, METPHASE, ANAPHASE, TELOPHASE
- process by which the nucleus of the cell is divided into two nuclei each with the same number of chromosomes as the parent cell.
- first stage of mitosis
- lognest stage of mitosis.
- chromosomes become apparent/appear
- centrioles move to opposite ends of the cell
- nucleolus and nuclear membrane dissintergrate and break down.
- 2nd phse of mitosis
- shortest phase.
- chromosomes line up at the centre of the cell by the centromeres
- 3rd phase of mitosis
- centromeres split
- sister chromotids separate to form indivitual chromosomes
- anaphase ends whent eh movement of chromosomes stop at opposite ends of the cell
- final and fourth stage of mitosis
- chromosomes uncoil into chromatin
- nuclear membrane reforms
- spindle fibres break apart
- NOT part of mitosis
- the cytoplasm of the cell divides
- forms two daughter cells that are exactly like the parent cell (each ahve one complete set of chromosomes)