Download Answers to the Cell Cycle Study Guide

Study Guide: Cell Cycle/ Mitosis/ Meiosis
Remember some of this information we have not covered in class yet!
What is DNA? DNA is the genetic (heredity) material that contains all the instructions for an organism
to develop.
What are chromosomes? Chromosomes are the DNA when it condenses around the histones
(proteins) and becomes visible.
What is the difference between chromatin and chromosomes? Chromatin is DNA (pasta) that is not
condensed and can’t be see easily especially during Interphase. Chromosomes are DNA that can be
seen because they wind around histones and condense.
Prokaryotes (bacteria) reproduce differently than eukaryotic cells. What is the process called when
bacteria split into 2? Bacteria reproduce asexually by binary fission, they produce two identical cells.
They do NOT go through mitosis or meiosis.
Explain how viruses reproduce. How is this different from prokaryotic cells? How is this different from
eukaryotic cells? Viruses reproduce by taking over a living cell, they can’t reproduce on their own like
prokaryotic or eukaryotic cells. Viruses are NOT considered to be living both prokaryotes and
eukaryotes are living organisms.
Using your notes on cell cycle and mitosis answer the following questions:
Why is the cell cycle process important? Cell cycle is important because it allows cells to grow,
develop, reproduce and repair old and worn out cells.
What are the 3 main stages of the cell cycle?
a. Interphase
b. Mitosis
c. Cytokinesis
What happens in each of the following phases of interphase? Explain in detail what is happening.
G1 cell performs its function (job), cell continues to grow, cell stores up ATP, organelles multiply and
produces proteins.
S synthesis of DNA (DNA is copied)
G2 cell grows, stores more ATP, does function, cytoskeleton prepares for mitosis
What is the main purpose of mitosis? The process of mitosis assures that each cell will receive the
correct amount (or number) of chromosomes. Mitosis is the division of the nuclear material to each
daughter cell.
Below identify the four main phases of mitosis. Explain what happens in each phase. Identify each stage
below with a diagram.
a. Prophase: chromosomes become visible, centrioles start to move, spindle fibers begin
forming, nuclear membrane starts to break down and the nucleolus disappears
b. Metaphase: chromosomes move to the center of the cell (metaphase plate or equatorial plate)
and line up.
c. Anaphase: the sister chromatids separate by the action of the spindle fibers, chromatids move
to opposite sides (poles) of the cell
d. Telophase: two nuclei start to reform in ONE cell, spindle fibers disappear, centrioles move
back to same side of cell, nuclear membranes start to reform, nucleolus will reform and the cell
may start to cleave (pinch off)
What is cytokinesis? Division of the cell’s cytoplasm into two cells
Explain how cytokinesis is different from mitosis. Mitosis is division of the nuclear material,
(chromosomes) cytokinesis is division of the cell’s cytoplasm.
When a cell reproduces, how does the number of chromosomes in the parent cell compare to the
daughter cells? Explain your answer. The number of chromosomes in both daughter cells is identical
to the parent cell. This insures that both cells will be able to grow through the cell cycle themselves.
What is a karyotype? Karyotype is a picture of an organisms chromosomes from one cell.
What are karyotypes used for? Karyotypes are used for identifying or diagnosing genetic disorders.
A.
B.
What is the difference between the two karyotypes shown above? Karyotype B shows a person who is
suffering or diagnosed with Trisomy 21. Down syndrome. Karyotype A is a normal male.
How would you write the karyotype notation for the individual above in picture A?
46, XY
(normal male)
How would you write the karyotype for the individual in picture B?
47, XY,+21
Label the cells 1-5 in the order they would complete mitosis.
5
Telophase
2
Prophase
1
Interphase
3
Metaphase
4
Anaphase
Identify each of the following cells as being in interphase, prophase, metaphase, anaphase, telophase or
cytokinesis. Each term may be used more than one time or not at all.
Metaphase
Anaphase
Telophase
Telophase
Metaphase
Prophase
Prophase
Interphase
What is the difference between somatic cells and gametes? Somatic cells are body cells (diploid) and
gametes are sex cells (haploid)
1. What is cancer? The disease caused by an uncontrolled division (problems with the cell cycle)
of abnormal cells in a part of the body.
2. A malignant growth or tumor resulting from uncontrolled division of cells.
What are some causes of cancer? Chemicals, uv radiation, mutations in DNA and different types of
viruses.
What is the process of meiosis? Is the process by which ”gametes” (sex cells) , with half the number of
chromosomes, are produced. Gametes are genetically different (diverse) from each other.
Why is meiosis important to the survival of sexually reproducing organisms? If Meiosis did not occur
the chromosome number in each new generation would double. The offspring would die.
Example: sperm (46) + egg(46)= zygote (92) organism would NOT develop.
Complete the chart below:
Organism
Number of chromosomes
in somatic (body) cells
Diploid (2n)
Number of chromosomes
in gametes (sperm and
egg) Haploid (n)
Cat
38
19
Goat
60
30
Horse
32
16
Dog
78
39
Meiosis
4 haploid daughter cells
Mitosis
2 diploid daughter cells
Mitosis (4 steps prophase,
metaphase, anaphase and
telophase)
Types of Reproduction
Meiosis I and Meiosis II
Prophase I, metaphase I,
anaphase I and telophase I then,
Prophase II, metaphase II,
anaphase II and telophase II
Sexual
Genetically
Different (diverse)
identical
Cytokinesis
After telophase
Number of Divisions
Occurs after telophase I and
telophase II
2
Function
Produce gametes
Produce somatic cells
Chromosome Number
Haploid
Diploid
Crossing Over
No
Anaphase
Number of Daughter Cells
Yes, during prophase I when
homologous chromosomes form a
tetrad
Anaphase I, split the homologous
chromosomes, Anaphase II split
sister chromatids
4
Creates
Gametes, sex cells
Somatic cells, all other cells
Produces
Steps
Centromeres Split
Asexual
1
2
What is crossing over? When homologous chromosomes (example: shoes) pair up and form a tetrad,
some of the genetic information from one chromosome and swap genetic material with the other
chromosome.
Why is crossing over considered positive or a good type of change? Because it allows chromosomes to
change (genetic variation) and may give the organism a better chance at survival.
Define the following terms:
Mutations: change in DNA sequence
Inversion: when a piece of material breaks off and reattaches in the opposite direction
Deletion: piece of the DNA breaks off the chromosome
Translocation: pieces of DNA from one chromosome switch with another non-homologous
chromosome. This involves TWO different chromosomes.
Duplication: a section of a chromosome as double the amount of information.
Nondisjunction: when homologous chromosomes do NOT separate properly. A cell can end up with
an extra chromosome or not enough chromosomes.