Download The Cell Cycle

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WORKSHEET 11A
Chapter 11 Worksheet Packet
Section 11.1: How do cells reproduce?
1. What is the Cell cycle?
A series of events from the time a cell forms until its cytoplasm divides
2. Fill in the steps in the Cell cycle
Interphase
G1
s
G2
Cell division (first 4
are mitosis)
3. Briefly discuss what occurs in each stage of the Cell cycle.
a. Gap 1 (G1) –Growth of the cell; normal functions
46 chromosomes at this point
b. Synthesis (S) – Duplication of the cell’s DNA
92 chromatid at this point
c. Gap 2 (G2) – Growth and production of proteins necessarily for cell division
Still 92 chromatids
d. Mitosis (M) – Division of the cell’s nucleus
Two daughter cells are formed; each have 46 chromosomes
4. What is the purpose of mitosis and cytoplasmic division?
To create two identical daughter cells to help multicellular organisms increase in cell number, remodel
tissues, and repair/replace dead/damaged cells
5. Go back to section 4.1. What limits the size of cells? Why can’t they just keep getting bigger and
bigger?
Decrease of nutrient exchange
6. Look at Figure 4.2: What do you notice happens as the cell gets larger to its ratio of surface area to
volume?
The volume increase much faster than the surface area, so the ratio decreases
7. Circle the ideal size for a cell.
8. Why is mitosis considered to be asexual reproduction?
There is only one parent; there is no exchange of genetic information; the daughter cells are identical to
the parent and each other
9. Where does each of our diploid chromosomes come from?
Our parents (one copy of chromosome 1 from mom, one copy of chromosome 1 from dad…)
10. What are homologous chromosomes? What step of the cell cycle are they formed?
Chromosomes that have the same size, shape, and gene coding sequences
They are formed during the S phase of the cell cycle when the DNA replicates
11. Give two examples of control over the cell cycle.
Checkpoint proteins
Specific example: cyclins
WORKSHEET 11B
Section 11.2 & 11.3: What is the sequence of events during mitosis? How does a eukaryotic cell divide?
1. In interphase, the DNA condenses. Revisit Figure 8.7 and label the structures associated with the
condensation of DNA
Histone
Sister
Chromatids
DNA
Chromatin
Chromosome
Centromere
2. What can you tell me about the genetic material on each chromatid?
Identical
3. Discuss the main events of each of the following stages of the cell cycle:
a. Interphase: G1, S, and G2; cell is growing to hit critical SA:V ratio, doubles its DNA, and
creates proteins necessary for division
b. Prophase:
i. DNA: condensing into chromosomes
ii. Nuclear membrane/ nucleus/ nucleolus : disappearing
iii. Nucleolus: disappearing
iv. Centrosome: forming and doubling
v. Spindle fibers: not present; may start forming
c. Metaphase:
i. DNA: chromosomes lining up in the middle/center/equator of the cell
ii. Nuclear membrane/ nucleus/ nucleolus : absent
iii. Nucleolus: absent
iv. Centrosome: each is on an opposite end of the cell
v. Spindle fibers: connected to the centrioles and the center of the chromosomes
d. Anaphase:
i. DNA: chromatids are separating to becoming unpaired chromosomes
ii. Nuclear membrane/ nucleus/ nucleolus : absent
iii. Nucleolus: absent
iv. Centrosome: opposite end of the cell
v. Spindle fibers: shortening to pull sister chromatids apart into individual chromosomes
e. Telophase
i. DNA: loosening back into chromatin
ii. Nuclear membrane/ nucleus : reforming
iii. Nucleolus: reforming
iv. Centrosome: only 1 set again
v. Spindle fibers: absent
4. How does cytokinesis differ in plants and animal cells? Sketch each out below
WORKSHEET 11C
CELL CYCLE DIAGRAMS
Sister chromatid
(specifically the
half)
Label the diagrams shown below of the Cell Cycle in Detail.
centriole
nucleolus
Nuclear envelope
Chromatin
Prophase
Interphase
Spindle Fibers
Metaphase
Anaphase
Telophase
WORKSHEET 11D
The Cell Cycle
Below are diagrams illustrating the Cell Cycle, including Interphase and the stages of Mitosis. According to what
you have read in your book, assign a phase to each diagram. Some of the stages could be in an early or late
part of the particular stage.
Interphase
Early Prophase
Early Metaphase
Metaphase
Early Anaphase
Telophase
New interphase
Late Anaphase
Late Prophase
Match the phase of the Cell Cycle to the event in the cycle of an animal cell
1. __B__Sister chromatids pair together
A. Interphase
2. __C__Sister chromatids line up on the equator
B. Prophase
3. __F__Pinching in of the cell membrane occurs(Cyto)
C. Metaphase
4. __D__Sister Chromatids separate
D. Anaphase
5. __A__DNA is replicated (S)
E. Telophase
6. __F__The cytoplasm is split between the daughter cells
F. Cytokinesis
WORKSHEET 11D
7. __A__The two new daughter cells grow
8. __B__The nuclear envelope and nucleolus break down
9. __E__The nuclear envelope and nucleolus reassemble
10. __B__Spindle fibers form and attach to the sister chromatids
11. __D__Separate chromosomes migrate to opposite poles
12. __B__Chromosomes start to coil up on histones & shorten up
13. __A__Chromatin is found in the nucleus
14. __B__Centrioles reach the opposite poles
15. __E__Chromosomes uncoil and become chromatin again
Observe the diagrams shown above of the Cell Cycle in plants. Identify 3 differences between the plant cell
cycle and the animal cell cycle.
1. ___Plants—cell wall (animals only have a cell membrane) ____________________
2. ___Plants—no centrioles (animals cell has these for division) __________________
3. ___Plants—a cell plate forms that creates a new cell wall that separates the two daughter cells
WORKSHEET 11 E
Section 11.5 & 11.6: What happens when control over the cell cycle is lost? Henrietta’s immortal cells
1. What actually does the term “cancer” refer to?
The disease state that results from malignant neoplasms
2. How do cancer cells differ from healthy cells?
No regulation in regards to the cell cycle
3. What is the difference between a benign and a malignant tumor?
Benign tumor grows in place
Malignant tumors spread
4. What causes cells to become cancerous? Use the terms oncogene, growth factors, tumor suppressors,
and proto-oncogenes in your answer.
A mutation in a proto-oncogene can turn it into an oncogene, which, when expressed, will turn
normal cells into cancerous cells. Mutations in growth factors (like EGF) are like cars with a gas
pedal that is stuck “down”, so the cell keeps dividing. Mutations in tumor suppressors (like BRCA)
are like cars with brakes that don’t work, so the cell can’t stop dividing.
5. Name some carcinogens.
Radiation (UV, X)
Chemicals (those found in cigarette smoke, industrial chemicals)
6. What is so special about the HeLa cells from Henrietta Lacks?
They are immortal (can divide infinitely as opposed to 40-50 times like normal cells)
7. Based on the diagram below, what is the difference between benign and malignant cancer?
Benign cells
stay in place
Malignant
cells (lead to
metastasis)
lose adhesion
junctions and
become
migratory, so
they spread