Download Chapter 12: Mitosis (with answers)

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Week 8, Session 2
The Cell Cycle
Supplemental Instruction
Iowa State University
Kelsey
Bio 211 (5)
Dr. Holscher
10-15-09
1. What differentiates living matter from non-living matter?
Living matter is able to reproduce their own kind.
2. What is continuity of life based on?
The reproduction of cells
3. What is the function of mitosis in animal cells? (What is produced?)
To produce 2 identical daughter cells from 1 parent cell
4. In humans, ____somatic_______________ cells have 46 chromosomes, and
___reproductive___________cells have 23 chromosomes.
5. The genetic info, packaged as DNA, is called the ___genome________________.
6. Label the diagram:
centromere
sister chromatid
chromosome
7. Eukaryotic cell division consists of _mitosis_____________ and __cytokinesis_______.
8. What phase alternates with the mitotic phase of eukaryotic cell division?
interphase
9. What are the three stages of interphase?
 G1
 S
 G2
10. What is G0 stage? How do cells get here? What kinds of cells might we find in this stage?
G0 is a “no growth” stage. Cells get here by not receiving a signal during G1 to continue
growing. We would find cells in this stage that don’t divide often: muscle, skeletal, and
nerve cells are some examples.
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11. What are the five phases of the mitotic cycle? Describe each phase:
 Prophase: early mitotic spindles form
 Prometaphase: centrosomes are present at opposite ends of the cell, nuclear
envelope disintegrates
 Metaphase: all chromosomes line up at the metaphase plate
 Anaphase: chromosomes separate, cell elongates
 Telophase: chromosomes elongate/unravel, cleavage furrow forms, nuclear
envelope re-forms
12. What two regulatory proteins are involved in cell cycle control? How do they work
together?
Cyclins and cyclin-dependent kinases (CDKs). CDKs are usually present, but inactive.
CDKs become activated by binding to cyclins (thus the name cyclin DEPENDENT
kinase).
13. What are examples of external signals that control cell cycle checkpoints?
chemical signals: growth factors (PDGF) stimulate other cells to divide
physical signals: density-dependent inhibition and anchorage-dependent inhibition
14. What inhibitions do cancer cells lack?
Cancer cells lack both physical signals (density-dependent and anchorage-dependent)
15. Explain the difference between a tumor being benign and malignant.
benign: tumors are cancerous but confined to one area
malignant: tumors invade surrounding tissues and spread
16. What does it mean to metastasize?
to move/spread to other locations