1.5 a) The Cytoskeleton and the Cell Cycle Flashcards
what is the cytoskeleton?
a network of protein filaments in the cytoplasm
The eukaryotic cell has a network of ___ ___ extending throughout the ___, called the cytoskeleton.
protein filaments, cytoplasm
What two things does the cytoskeleton provide to cells?
mechanical support and shape
The cytoskeleton consists of different protein structures such as ___, which are found in ___ cells.
microtubules, eukaryotic
Microtubules are ___ and comprised of a protein called ___.
hollow, tubulin
Microtubules radiate out of the ___ ___ ___ (___), aka the ___.
microtubule organising centre (MTOC), centrosome
Name two things that microtubules control the movement of.
chromosomes, membrane-bound organelles
Cell division requires ___ of the cytoskeleton.
remodelling
What do microtubules form that plays a key role in cell division?
spindle fibres!
Microtubules are ___ of tubulin.
polymers
The formation of microtubules involves ____ of tubulin.
The breakdown/shortening of microtubules involves ___ of tubulin.
polymerisation, depolymerisation
The cell cycle is divided into which two sections?
Interphase, the Mitotic Phase
Which steps is the Interphase divided into?
G1, S and G2
Which steps is the Mitotic Phase divided into?
Mitosis and Cytokinesis
Mitosis is divided into PMAT. (Prophase, Metaphase, Anaphase, Telophase.)
What happens in G1?
G1 is the first growth phase where proteins and organelles are synthesized
What happens in the S phase?
In the S phase, the cell continues to grow and copies its chromosomes in preparation for mitosis through DNA replication
What happens in G2?
G2 is another growth phase
Mitosis is the separation of ___ ___ by the ___ ___.
sister chromatids, spindle fibres (spindle microtubules)
(1/4)
Name the three things that happen in the Prophase of Mitosis.
Chromosomes condense,
Nuclear membrane breaks down,
Spindle microtubules extend from the centrosome and attach to chromosomes via their kinetochores (at the centromere)
(2/4)
What happens in the Metaphase of Mitosis?
Chromosomes line up along the metaphase plate (aka the equator of the spindle)
(3/4)
What happens in the Anaphase of Mitosis?
Spindle microtubules shorten by depolymerisation, pulling the sister chromatids apart to opposite poles of the cell (once separated, chromatids are called chromosomes)
(4/4)
What happens in the Telophase of Mitosis?
Chromosomes decondense,
new nuclear membranes form around the chromosomes
Cytokinesis is the ___ of the ___ into two ___ ___.
division, cytoplasm, daughter cells
At the start of Meiosis, and Mitosis (prophase), the chromosomes ___.
condense.
(they decondense in the telophase)
