lecture 1-20-16 Flashcards
- copy cellular contents
- duplicate organelles, DNA, and cytoplasm
- each new cell has the same amount as original cell
- called interphase
- G1,S,G2
preparatory phase
cell grows, makes extra cytoplasm
G1 Phase
DNA replication occurs, chromosomes
identical sister chromatids
S Phase
cell prepares for division
G2 phase
three parts of interphase __ ____ and ____
G1, S and G2
division phase includes
mitosis and cytokinesis
cytokinesis is
the division of other organelles
- chromosomes are evenly divided
- sister chromatids are separated
- centromere
mitosis
- enlarged cell splits into two cells
- each has full complement of DNA
- one parent cell into two daughter cells
cytokinesis
how do cells divide?
cytokinesis
occurs in a series of phases;
M Phase
Mitosis
phases in order
interphase
mitosis and cytokinesis
anaphase
telophase
- each chromosome is replicated in S phase, resulting in two sister chromatids connected at the centromere
- chromosomes are loosely gathered in the nucleus
interphase
- replicated chromosomes begin to coil up
- nuclear membrane begins to disassemble
- microtubule fibers begin to form the mitotic spindle
prophase
- microtubule spindle fibers from opposite ends of the cell attach to the sister chromatids of each chromosomes
- replicated chromosomes become aligned along the middle of the cell
metaphase
-microtubules shorten pulling the sister chromatids to opposite ends of the cell
anaphase
- identical sets of chromosomes reach each pole
- microtubule spindle fibers disassemble
- nuclear membrane forms around each set of chromosomes forming the daughter cell nuclei
telophase
the structure that separates sister chromatids during mitosis
the mitotic spindle
hollow protein fibers
key components of cytoskeletons
attach the centromere on chromosome via kinetochore proteins
microtubules
following mitosis and cytokinesis, daughter cells are __________
genetically identical to each other
genetically identical to the parent cell
in the cell cycle, DNA is replicated during ______
the S phase
during ____in animal cells the cell membrane pinches in to separate the daughter cells
cytokinesis
which of the following processes require normal cell division?
all of the above
1. embryonic development
2. wound healing
3.
during which stage of the cell cycle do sister chromatids separate from each other ?
anaphase
cytokinesis in plant cells involves the synthesis of a ___________ between the daughter cells
cell wall
during which stage of the cell cycle are sister chromatids initially produced
interphase
most chemotherapy drugs target cell cycle they _____
interfere with DNA replication, chromosome separation
look to plants as source of drugs
the pacific yew is one species of a family of related evergreen trees
taxus brevifolia
taxus brevifolia
extract from bark kills cancer cells
taxol
- interferes with the normal organization of microtubule
- prevents microtubules from shortening
- chromatids not separated
taxol
- cellular mechanisms
- regulate cells progression through cell cycle
- ensures each stage is completed accurately
cell cycle checkpoint
either repair damage or
direct cell to commit suicide (apoptosis)
cell cycle checkpoints
when a normal cell sustains irreparable damage, it undergoes programmed cell death. this cellular suicide prevents cells from producing more damaged daughter cells
apoptosis
cells divide uncontrollably
cancer
if there’s enough DNA damage to interfere with multiple checkpoints
Cancer
tumors
__________ divide in an unregulated manner and accumulate DNA damage and make mitotic mistakes
cancer cells
cancer kills by:
crowding out normal cells
invading other organs
secreting poisonous chemicals
most effective way to fight cancer?
surgery to remove the cancerous tumor
not effective is the cancer has metastasized
high energy radiation beams
kills dividing cells
damages DNA
triggers apoptosis
radiation therapy
drugs interfere with cell division
chemotherapy
