Mitosis and Cell Cycle Test Review Sheet

Biology Cell Cycle and Cancer Review

1) What are three reasons why cells divide? a. to repair tissue (multicellular organisms- like us)

b. to grow (multicellular organisms- like us)

c. asexual reproduction (unicellular organisms- like bacteria)

2) Why are cells so small? Surface area to volume ratio is high when cell is small It is easier for cells to transport materials and it decreases demands on DNA

Large ratio is desired (Ex: 1,000,000/1) because lots of surface area help materials get into and out of the cell QUICKLY and little volume is desired because it slows down the movement of these materials.

3) What are three reasons why it is important for cells to stay so small a) To maintain a HIGH surface area: volume ratio

b) Avoid DNA overload

c) To make transport easier

4) What is the relationship between chromatin and chromosomes? Chromatin is thread-like DNA and is the form that DNA is usually found in a cell that is NOT dividing. When a cell is going to divide, it coils up the chromatin to form CHROMOSOMES, which are packages of DNA that are much easier to divide evenly among the 2 new cells.

5) Are cells produced from mitosis identical to parent or not? Yes- Identical

6) The parent cell contains 46 chromosomes and the daughter cells contain 46 chromosome. 7) What are the four phases of mitosis? a. Prophase b. Metaphase c. Anaphase d. Telophase (and cytokinesis)

8) During which phase of the cell cycle is DNA duplicated? S Phase

9) Why is it important that a cell’s DNA is duplicated before cell division? The DNA needs to be duplicated before the cell divides SO THAT both new cells have the SAME AMOUNT of DNA.

10) Which phase of the cell cycle does the cell spend the longest time (in normal cells) and how does this compare to the cell cycle in cancer cells?

Normal cell- Interphase (90% of the time); Mitosis (10% of time) Cancer cell- Interphase (less than 90% of time); Mitosis (more than 10% of time)

11) What part of the cell’s life is resting? G1, S, G2

12) What part of the cell’s life is making new cells? M phase (PMAT)

13) What phases are involved in cell division? PMAT

14) What biomolecules regulate the cell cycle? Proteins

15) What happens if no check points or if the checkpoints fail?

Cancer cells have escaped the checkpoint and are growing out of control and are dividing very often and can grow into tumors. Why is it a Problem?- because they are too busy dividing and not doing what they are supposed to be doing and getting in the way- disturbing normal functioning

What is apoptosis and why do cells do this? Apoptosis, is programmed cell death- the cell destructs (because you don’t want damaged cells to continue and divide.) It happens at the checkpoint between G2 and M phases.

16) What is the role of spindle fibers during cell division? To move the chromosomes evenly between the two new cells

17) LOOK AT DIAGRAM BELOW A PROPHASE B METAPHASE C ANAPHASE D

TELOPHASE/ BEGINNING CYTOKINESIS E INTERPHASE

1 CENTRIOLE 2 SPINDLE FIBER 3 SISTER CHROMATID 4 DAUGHTER CELLS 5 CHROMATIN (DNA) 6 CELL MEMBRANE 7 NUCLEOLUS 8 CENTRIOLES 9 CHROMOSOME 10 NUCLEUS

18) Write a brief explanation of each phase Interphase G1 cell size doubles, organelles double

S DNA is doubled “synthesized”

G2 Cell grows and prepares to divide Prophase Chromosomes condense and nucleus disappears- “PASTA”

Metaphase Chromosomes move into the equator of the cell “MIDDLE”

Anaphase Chromosomes are pulled away towards opposite poles of the cell “AWAY”

Telophase Nuclear membranes reappear in both poles, chromosomes unwind, starts to show 2 cells “TWO” Cytokinesis Cytoplasm divides in 2 Plants- cell plate Animals- cleavage furrow 19) Provide a brief explanation of each term Apoptosis- programmed cell death- if a cell is irregular, and cannot be repaired or fixed, then the cell will destroy the mutant cell rather than let it become cancerous.

Spindle Fibers- fibers that attach to every chromosome and assist to move them away towards opposite ends of the cell

Centromere- the middle part of chromosomes that attaches the two sister chromatids together

20) Cancer: What is cancer? The uncontrollable division of cells

What happens in the cell that leads to cancer? There must be a change in the DNA (mutation) that causes the cell to lose control of its cell cycle and constantly divide

Normal cells- mostly in interphase// Cancer cells have more cells in stages of mitosis.