Cell Cycle Flashcards
PMAT
Prophase, Metaphase, Anaphase, Telophase
Prophase:
Nuclear envelope dissolves, chromatin condenses to form chromosomes
Metaphase
Chromosomes are lined up down center of cell by spindle fibers
Anaphase
Sister Chromatids (double stranded chromosomes) are seperated and pulled to opposite sides of cell (double stranded become single stranded)
Telophase
Cell begins to split creating hourglass shape. Two nuclei form at opposite ends of cell
Cytokinesis
Division of Cytoplasm, everything splits, left w two daughter cells. Part of cell division but not considered part of mitosis.
Interphase
Cell prepares for mitosis, cells spend 90% in this phase. Interphase includes G1 stage, S Stage and G2 stage.
G1
Cell grows and accumulates nutrients
S stage
Synthesis phase, DNA synthesis stage to be specific, replication occurs.
G2
More growth, organelles copied, spindle fibers developed
G1 Checkpoint
Assesses for proper growth and if cell has required nutrients to continue.
G2 Checkpoint
Right before mitosis. Enzymes scan DNA for accurate replication.
Metaphase Checkpoint
Checks for proper spindle fibers attachment.
What happens if a cell fails a Checkpoint?
Cell will attempt to repair the damage, if cell cannot be repaired it will go through Cell Suicide aka Apoptosis
Chromosome
Highly condensed complex of a DNA molecule.
Chromatin
Loose uncondenaed complex of DNA and histones
Chromatin in Prophase
Chromatin coils, folds, condenses to become a chromosome
Karyotype
Visual display of chromosomes in a cell
Human Karyotype
23 homologous pairs, 43 total chromosomes
(humans) n=?
n=23, so 2n is correct making 46
Autosomes
Chromosomes 1-22 of the somatic cells, 23 is a sex chromosome
Somatic Cells
Cells of the body, diploid with 23 homologous pairs
Germ-Line
Stem cells, perform meiosis to produce gametes. Diploid, reside in testes of males and ovaries of females.
Gametes
Used in sexual reproduction, sperm and egg cells, haploid and contain half the genetic information of every chromosome. haploid is 1n.
Why do cells divide by mitosis?
Repair and growth, intestinal lining, bone marrow and skin/hair cells are always dividing. Most others don’t unless you get a wound or you are a child/adolescent.
Asexual Reproduction
Not by meiosis, it is miotic reproduction. Utilizes cloning, creates genetically identical offspring. ex: Binary fission in bacteria, strawberry runners, molds, most protists.
