Flashcards in Mitosis Deck (69):
All cells come from other cells
The basic unit of life is a cell
What are the two main phases of the cell cycle?
Growth and division
Both phases of the cell life cycle are extremely ___?
When does cell division occur?
In what organisms does cell division occur?
When a cell is not dividing, what form is DNA in?
What is chromatin?
Thin threads of DNA and proteins
What are chromosomes?
Tightly coiled packages of DNA.
DNA is in chromosome form during what only?
How many chromosomes do humans have?
46 (23 pairs)
Why is DNA in chromosome form during cell division?
Good for moving DNA around during replication
What is a sister chromatid?
Half of one chromosome
What is a centromere?
Pinched joining site of a chromosome
Cells spend most of their life in what phase?
What are the stages of interphase?
G1, S, and G2
The amount of time a cell spends in interphase depends on what?
When a cell is in interphase, what is happening?
The cell is living, undergoing normal function
A red blood cell would spend more or less time in interphase?
An osteocyte would spend more or less time in interphase?
What occurs in G1 of interphase?
Cell doubles organelles
If a cell doesn't pass the G1 checkpoint, where does it go?
G0 or Gnot
What occurs in the S stage of interphase?
What occurs in the G2 stage of interphase?
Makes proteins needed for division
What role do proteins play in cell division?
Check DNA copy for mistakes
The mitotic (M) phase of the cell cycle includes what?
Divison of nucleus and division of the cytoplasm
What is mitosis?
Division of the nucleus
What is cytokinesis?
Division of the cytoplasm
Once a cell goes through G1, what happens?
It commits to the cell cycle/replication
At the end of G2, what is a cell ready to do?
At the end of the M phase, what is the cell ready to do?
Internal control of the cell cycle is regulated by what?
What are some examples of proteins that internally regulate the cell cycle?
Cyclins + Cdks = MPF (maturation promoting factor)
What does increased MPF trigger?
G2 checkpoint passage
What are some examples of external control factors of the cell cycle?
What are regulated growth factors?
proteins that trigger cells to divide
What is density-dependent inhibition?
peripheral proteins tell the cell when to stop dividing due to high density
What is anchorage dependence?
cells must have something to divide on, so they grow on the substratum
What makes something a hormone?
What do they trigger?
A chemical that is effective in small amounts
Produced in one part of the body but doesn't have any effect there
What is the goal of mitosis?
To produce two identical cells with identical DNA
What is the spindle made of?
What does the spindle do?
Move chromosomes around
Pull sister chromatids apart
What is the spindle-organizing center?
How many of them are there?
What is an aster?
A description of the firework arrangement of spindles
What are centrioles?
Are they present in every organism?
Rods in centrosomes
What does a cell look like in interphase?
DNA in chromatin form
DNA already duplicated
Nucleus still circular and intact
What does a cell look like in prophase?
Chromatin condenses into chromosomes
Two sister chromatids are attached at a centromere
What is a kinetochore?
What are kinetochore and non-kinetochore spindles?
Protein on chromosome
Kinetochore- attaches to chromosomes
Non-kinetochore- doesn't attach to chromosomes
How does a spindle disassemble?
Motor protein chews on microtubule and spits out spindle fragments
What does a cell look like in metaphase?
Chromosomes line up at spindle equator
Spindle fibers either attach to chromosomes (tug-of-war), or they extend past the equator and overlap
What do non-kinetochore spindle fibers do?
Overlap and work to lengthen the cell and pinch in half
What does a cell look like in anaphase?
Spindle fibers pull sister chromatids apart to opposite sides
Unattached spindle fibers lengthen the cell
Sister chromatids are only called sister chromatids when they are ___? Once they separate, what are they?
What does a cell look like in telophase?
Chromosomes de-condense to chromatin
Two nuclei re-form
Cytokinesis in an animal cell consists of what?
Cytokinesis in a plant cell consists of what?
What is cancer?
A disease of the cell cycle
Genetically messed up but not all heritable
Cancer is classified by what?
What is carcinoma?
What is sarcoma?
muscle tissue cancer
What is leukemia?
What are the five cancer characteristics?
Immortal (no cell apoptosis)
Abnormal nuclei (large, lobed) or chromosomes
Form tumors (no dependent inhibition)
What is carcinogenesis?
What is a mutation?
A genetic change
What is angiogenesis?
A tumor causes the body to grow blood vessels to the tumor to supply it
What is benign?
What is malignant?
Harmful and might spread
What are the four types of cancer treatment?
What do chemotherapy and radiation affect?
Actively dividing cells, causes physical fallout
What does hormone therapy do?
Interferes with cell communication
What are some cancer prevention behaviors?
Avoid smoking (30% of all cancer deaths)
Avoid sun exposure
Heavy drinkers more prone to particular cancers