Virtual Lab: The Cell Cycle and Cancer 1. Open Open the the virtua virtuall lab: lab: The Cell Cycle Cycle and and Canc Cancer er 2. Click Click on the Laborat Laboratory ory Exercise Exercise link. link. 3. Click on the microscope in microscope in the lab simulation to examine the dierent sta!es o mitosis as they appear in dierent tissue samples. Three types o tissue are available or examination: lun!" stomach" and ovary. #amples o normal tissue and cancerous tissue are included. Click on the tissue box to examine dierent tissues. Examine both normal and cancerous tissue or lun! and ovary tissue type only. $ollo% the instructions to label each sta!e o the cell cycle. &. 'ecord the the number o o cells in each each sta!e o o the cell cycle cycle in Table Table 1 or normal normal tissues tissues and Table 2 or cancerous tissues. (ou must examine three dierent vie%s o each tissue type and condition ) click reset to view alternate samples o each tissue type until you have recorded the number o cells in each sta!e o the cell cycle or 3 dierent samples o each tissue. *. Calculate the avera!e avera!e +itotic ,ndex - cells dividin!/ dividin!/ and avera!e cells cells at rest or or normal tissues. 'ecord these numbers in Table 3 and & on your %orksheet. To calculate the avera!e cells at rest in normal tissue: 1. -0 cells cells in ,nterpha ,nterphase se in #ample #ample 1 0 cells in ,nterp ,nterphase hase in sample sample 2/ total total 0 cells at rest. 2. -total 0 cells at resttotal resttotal 0cells in both samples/ 4 155 avera!e cells at rest To calculate the +itotic ,ndex 6 avera!e cells dividin! 6 in normal tissue: 1. -0cel -0cells ls in mitosis mitosis in #ample #ample 1 0cells 0cells in mitosis mitosis in #ample #ample 2/2 2/2 av!. av!. 0cells 0cells dividin! 2. -av!. -av!. 0 cells dividi dividin!t n!total otal 0 cells/ cells/ 4 155 avera avera!e !e cells cells dividin! dividin! Table 1: Number of cells in each stage of the cell cycle observed in normal tissues.
Tissue Type Lun! Tissue #ample 1 Lun! Tissue #ample 2 Ovary Tissue #ample 1 Ovary Tissue #ample 2
Cells in Cells in Cells in Cells in Cells in !nterphase "rophase #etaphase $naphase Telophase 17 1 5 5 5
17
1
5
5
5
18
5
1
1
5
17
1
5
5
5
Table %: Number of cells in each stage of the cell cycle observed in cancerous tissues.
Tissue Type #tomach Tissue #ample 1 #tomach Tissue #ample 2 Ovary Tissue #ample 1 Ovary Tissue #ample 2
Cells in Cells in Cells in Cells in Cells in !nterphase "rophase #etaphase $naphase Telophase 1& 2 1 1 2
13
2
2
2
1
12
2
1
2
3
15
2
2
3
2
Table 3: #itotic !nde& 'average ( cells dividing) and $vg. ( of cells at rest
Tissue Type #tomach 6 normal
Ovary 6 normal
$vg. ( cells at rest '1*+%,)-'1*+%,)+% 1,, / *0( '12+%,)-'1*+%,)+% &1,, / *%.0(
#itotic !nde& / 1,,*0 / 0( / 1,,*%.0 / .0(
Table 4: #itotic !nde& 'average ( cells dividing) and $vg. ( of cells at rest
Tissue Type
$vg. ( cells at rest #tomach 6 cancerous '14+%,)-'13+%,)+% 1,, / 5.0( Ovary 6 cancerous '1%+%,) - '1,+%,)+% & 1,, / 00 ( $nalysis 7uestions
#itotic !nde& / 1,, 6 5.0 / 3%.0( '2+%,) - '1,+%,)+% & 1,, / 40(
1.
9hat does your data indicate about the rate o cell division in cancerous tissue compared to the rate o cell division in normal tissue 9hat data did you use to ans%er this ;uestion Cancer cells divide more rapidly and spend more time in mitosis. ! used the mitotic inde& to come to this conclusion.
2.
9ith %hat you have observed in this lab" i you %ere to compare tissue sample rom normal breast tissue and cancerous breast tissue: a.
9ould you expect to see a dierence in the rate o cell division in the cancerous breast tissue compared to the normal breast tissue Explain your ans%er.
! 8ould e&pect that cancerous breast tissue has a higher rate of cell division than normal breast tissue because cancer cells have a higher mitotic inde&.
b.
Could you make a prediction about the avera!e dividin! cells in the cancerous breast tissue Explain your ans%er.
9ifficult to be e&act but probably higher than 1,( mitotic inde& since mitotic inde& of normal cells seems to be bet8een 0.0(.
