Chapter 12: The Cell Cycle Flashcards
Cell Cycle
sequence of events in the life of a cell
(Interphase- G1, S, and G2)
(M phase- Mitosis and Cytokinesis)
Genome
the genetic material of an organism or virus
Chromosomes
One DNA molecule and associated protein molecules
Chromatin
the complex of DNA and proteins that make up eukaryotic chromosomes
Somatic Cells
Body cells, everything but gametes
Gametes
Sex Cells; haploid reproductive cells formed by meiosis
Mitosis
Cell division/replication
Cytokinesis
The cytoplasm splitting after mitosis, meiosis 1, and meiosis 2
Interphase
The stage of the cell cycle where the cell does not divide, it works and duplicates chromosomes and organelles. 90% of cell cycle
Centrosome
In the cytoplasm, micro-tubule-organizing center (produces spindle fibers)
Binary Fission
Asexual reproduction method; cell grows to twice its size and then divides into 2 cells
G0 Phase
A non dividing state occupied by cells that have left the cell cycle (sometimes reversible)
Growth Factors
A protein that must be present in the extracellular environment for the growth and normal development of certain cells
Density-dependent inhibition
the phenomenon observed in normal animal cells that causes them to stop dividing when they come in contact with each other
Anchorage Dependence
the requirement that a cell must be attached to a substratum in order to initiate cell division
Benign tumor
mass of abnormal cells with specific genetic and cellular changes such that the cells are not capable of surviving at a new site and generally remain at the site of tumor origin
Metastatic tumor
tumor that will spread away from tumor site
Metastatic tumor
tumor that will spread away from tumor site
What do Eukaryotes depend on Cell Division for?
Cell division is crucial in multicellular-eukaryotes for renewal and repair. Think of a child with a scraped knee. You clean the area, bandage it, and over the next few days a scab is formed, and voila brand new skin just the same as before. This is because of cell division. Your body replicated the tissue that was missing to repair and renew it.
Most cell division results in what? What is an exception to this?
Most cell division results in 2 identical daughter cells.
The DNA is replicated, and then split into two separate cells. The exception is meiosis, who’s two daughter cells produce 2 more daughter cells, for a total of 4 daughter cells, each with unique genetic make-up.
How is cytokinesis different in animal and plant cells?
In animal cells, cytokinesis happens quickly through a cleavage furrow formed during mitosis, along the metaphase plate. Motor proteins pull the cleavage inward like a drawstring, causing the cytoplasm to split and form two new cells.
In plant cells, their is no cleavage furrow. Instead, vesicles derived from the golgi apparatus move to the middle of the cell, where they produce a “cell-plate”. Vesicles transfer their materials (phospholipids, right?) until a new cell wall is formed and the cell is split into two daughter cells.
Discuss how the G1, G2, and M checkpoint in the cell cycle work.
G1 is the growth phase of the cell. Is the cell growing well? Any damaged DNA? (wouldn’t wanna replicate that!). Does it have the resources to move onto S phase. It grows, checks itself, and then moves to S phase where it replicates it’s DNA.
G2 is the second growth phase. It checks if the DNA was replicated correctly, if the cell is growing well enough, and does it have the resources to continue. Then it moves to M phase.
The M phase checkpoint occurs in metaphase and checks that the chromosomes are aligning properly, and attached to the spindle.
There are internal and external factors that influence cell division. What are three external factors discussed in class? Describe each and their influence on the cell cycle.
External factors influencing cell division are the “checkpoints” such as G1, G2, and M. G1 is the first checkpoint and occurs during Interphase. During this time, the cell is growing to prepare itself for mitosis. G1 is a checkpoint to ensure that the cell is growing properly and has enough energy and other resources to move on into the synthesis phase of interphase. After the cell has duplicated it’s DNA in S phase, it enters into G2, another checkpoint. G2, like g1, ensures the cell is growing adequately, but also checks for any mutations in the DNA, any inadequate DNA (like too few or too many), and if there is enough resources to move into mitosis. If the cell passes all of these checkpoints, then it moves into Mitosis, where it comes to the M checkpoint (metaphase checkpoint), which ensure that the chromosomes are aligned properly and all attached to the spindle fibers, confirming that their will be no missing or extra chromosomes in the daughter cells.
Which type of external factors on cell division do cancer cells lack? Which of these two aid cancer cells in metastasis?
Density dependent inhibition and anchorage dependence. Anchorage dependence means that the cell needs to be attached to a substrate to divide. Metastatic cancer cells do not need this because they can bind and be viable for growth at any site.
