Download Cell Division NOTES (Student) 15

Period: _____ Name: _________________________________________ Teacher: ___________________
Biology Unit
Cell Division
Review Date: _____________________
Test date: ________________________
Cell Cycle
Cytokinesis
DNA
Mitosis
Interphase
Biology
CELL DIVISION-Notes
REVIEW TERMS
Classify each of the cells below as Prokaryotic or Eukaryotic. Then identify the Kingdom it belongs to.
Prokaryotic
or
Eukaryotic?
Kingdom?
Prokaryotic
or
Eukaryotic?
Kingdom?
Prokaryotic
or
Eukaryotic?
Kingdom?
Prokaryotic
or
Eukaryotic?
Kingdom?
Prokaryotic
or
Eukaryotic?
Kingdom?
What 4 cell components do all of these organisms have in common?
Life Connections:
What is Cancer?
After reading about cancer,
explain what cancer is and
what causes cancer below:
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Biology
CELL DIVISION-Notes
Unit Focus:
Prokaryotic
cell
What is its function?
Eukaryotic
cell
Why is this unit
important?
Cell Part: What cell component are the lines labeling in the cells below?
(in 5 words or less)
Biomolecule: What type of macromolecule is it?
It is composed of which type of monomer?
Processes: Cell Cycle, DNA Replication, Mitosis
7-Characteristics of Life:
- All living things are based on a universal genetic code made of ________________.
- Cell division directly allows for which characteristic of life?
Which of the following is a reason that cancerous tumors can develop?
A The tissues in a certain area of the body are hurt.
B A foreign cell enters the body and starts to divide.
C The factors that control cell division no longer function properly.
D Using a cell phone frequently can cause development of tumors.
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Biology
CELL DIVISION-Notes
DNA Structure:
Deoxyribonucleic acid (DNA) is a nucleic acid. Nucleic acids are macromolecules composed of multiple
subunits (monomers) called nucleotides. The DNA in the nucleus of a single human cell, for example,
contains about 3 billion (3,000,000,000) pairs of nucleotides.
DNA: Nucleotides and Base Pairing
Each DNA nucleotide has 3 components:
 nitrogen base
(adenine, thymine, guanine, cytosine)
 sugar (deoxyribose)
 phosphate
Elements in a nucleotide: ____, ____, ____, ____, ____,
Nucleotide
Nucleotides can form bonds with each other between the phosphate of one nucleotide and the sugar of
the next one. The resulting chain of nucleotides is called a DNA strand.
DNA in cells is made of double strands.
DNA strand 1
DNA strand 2
A= Adenine
T=Thymine
G= Guanine
C= Cytosine
The two DNA strands are
held together because they
complement each other, as
represented in the diagram.
Below, write the
complementary base for
each nitrogen base.
A: ___
G: ___
T: ___
Base-pairing in the
DNA double strand

Which nucleotide components bridge the two strands?

Which nucleotide components form the sides?
C: ___
The double strand is twisted into a double helix, as shown in the diagram on the next page
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Biology
CELL DIVISION-Notes
DNA: Chromosomes and chromatin
The DNA of cells is such a long macromolecule that it needs to be packed tightly in order to fit in the cell.
However, not all of it is tightly packed all the time, because this would prevent the enzymes that
continually read the DNA from having access to the information that it carries.
The tightly-coiled form of DNA is called chromosome, while the loosely-coiled form is called chromatin.
The diagram below illustrates the different levels of structure of DNA.
 From small to smaller…
*
(Label the different DNA structures
marked with an asterisk, *)
Cell
*
*
Nucleus
*
*
Describe (briefly but clearly) each labeled DNA structure:

Chromosome:

Sister chromatids:

Chromatin:

Double helix:

Nucleotide base pairs:
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Biology
CELL DIVISION-Notes
DNA: Genes
The main purpose of DNA is to store genetic information. In other words, it is the cell’s main library for
protein-building instructions.
Genes are segments of DNA
encoding instructions for
assembling proteins.
Proteins determine an
organism’s traits, such as hair
color and blood type.
A typical organism’s DNA contains
thousands of genes.
Genes are inherited as
chromosomes are replicated
and passed on from a cell to
each of its daughter cells during
cell division.
Every cell in an organism
contains exactly the same DNA sequence (all the genes for that organism), no matter if the cell
is a brain cell, a skin cell, or a white blood cell. Why?
Look at the illustration to the left
and explain (in this box) why is the
genetic information the same in
all different cells of an organism?
(use the terms “cell division”, and
“stem cell”)
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Biology
CELL DIVISION-Notes
DNA Structure: Summary
1. List the following terms in order of size, from largest to smallest: Nucleotide, Gene, Nitrogen Base,
Chromosome.
2. Based on the base-pairing rules for the deoxynucleotides adenine, thymine, guanine, and cytosine,
write the complementary nucleotide sequence corresponding to the sequence shown below:
A – C– A– G – A– T – G – G – C – G – T – G – A– C – C – T – A – T – A – G – C – G – G – T
3. How many nucleotides of each kind are there in the two strands above?
Count and record them in the table below.
Nucleotide
Adenine
Guanine
Thymine
Cytosine
Number
4. What pattern do you notice from the results of question #3?
5. What is the connection between gene and trait?
Below, write your own summary of the concepts that you think are most important in the section on “DNA Structure”.
My Summary
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Biology
CELL DIVISION-Notes
The Cell Cycle
Cell life, including division, occurs in a cyclic manner, as it normally repeats the same process many
times, starting again in each new “baby” cell that resulted from a previous division.
The diagram above depicts different stages of the cell cycle. Observe the changes, starting at stage I.
* What happens in step 0?
* What has happened in step 5?
Why do cells in an organism divide? (List 3-4 purposes)
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Biology
CELL DIVISION-Notes
The cell cycle is divided into three distinct phases:
 Interphase (I)
 Mitosis (M)
 Cytokinesis (C)
The pie chart on the right depicts the proportion of the cell’s life spent in
each phase of the cycle.

In which phase does the cell spend most of its life?
Cell Cycle: Interphase
The interphase is the major part of a cell’s life cycle, during which the cell grows and develops,
and basically does what a cell does to support the organism’s life (metabolism, homeostasis, etc.).
Besides growing, the cell uses interphase also as a time of preparation for cell division, ensuring that the
DNA is ready before mitosis begins. This preparation is a process called DNA replication.
 Why is it important to prepare the DNA?
A human cell contains 46 chromosomes (23 pairs).
1. Assume that a human skin cell divides into two “daughter” cells. How many total chromosomes does
each daughter cell have?
2. Now, imagine that each of those daughter cells divides again. How many total chromosomes would
each new daughter cell contain?
3. What is happening to the number of chromosomes in each new daughter cell?
4. How many total times could this cell division cycle be repeated before the cells could no longer split
the number of chromosomes?
5. Why do you think that real cells are able to divide over countless cell cycles without running out of
DNA to pass on to the next generation? (Think about what needs to happen in step 0, between stages I
and II, in the Cell Cycle diagram on page 7).
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Biology
CELL DIVISION-Notes
Replication
Before splitting into two new cells, a
cell must make a complete duplicate
copy of its DNA.
This process is called replication, and
occurs during interphase.
[NCBI]
Observe the two diagrams of replication shown on this page and answer the following questions.
1. What is the product? How much of it is made?
2. What reactants are used (building blocks and template/mold)?
3. What is the name of the enzyme unzipping the double helix and assembling the product?
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Biology
CELL DIVISION-Notes
Cell Cycle: Mitosis
Mitosis is a process in which the nucleus divides; it occurs before the rest of the cell divides.
The replicated DNA is separated into two sets, one for each future daughter cell.
Examine the diagram of mitosis shown above and describe what is happening in each stage (A – D). Use
the terms “chromosomes” and “sister chromatids” in your description.
A.
B.
C.
D.
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Biology
CELL DIVISION-Notes
Cell Cycle: Cytokinesis
The final phase of the cell cycle begins right after mitosis ends. Once the chromosomes have been
separated (in mitosis), the rest of the cell can begin to split into two. This process is called cytokinesis.
The cytoplasm is split in two (along with any other cell components within it) as the cell membrane
pinches in along the middle, between the two new cell nuclei.
Cell Cycle: Summary
Match the cell cycle stages in the table below to the letters/numbers on the Cell Cycle diagram on page 7.
Cell Cycle Phase
Description
Interphase
Cell growth and DNA replication
Mitosis
Letter/Number
Prophase
Spindle fibers form; nucleus disappears
Metaphase
Sister chromatids line up at middle
Anaphase
Chromosomes move to opposite ends
Telophase
The cell begins to pinch in half
Cytokinesis
The cytoplasm splits in half to form 2 new cells
Below, write your own summary of the concepts that you think are most important in the section on “Cell Cycle”.
My Summary:
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Biology
CELL DIVISION-Notes
Model Evaluation
Consider the two models of DNA shown below, and evaluate each one listing their pros and cons, as
compared to the real DNA molecule that they represent.
Model A
Model B
Practice Question 11
The diagram above shows a 2-dimensional model of DNA. This model is good
because –
A the rungs of the ladder are made up of nitrogen
bases and phosphates
B adenine is paired with guanine
C the double helix shape is illustrated
D thymine is paired with cytosine
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Biology
CELL DIVISION-Notes
Practice Question 10
Put the following pictures in order.
Practice Question 9
Which of the following describes what happens during mitosis?
A The nucleus divides and then the DNA replicates.
B The DNA breaks apart and new nucleotides match the original nucleotides.
C The cytoplasm divides completely and 2 new cells are formed.
D The original DNA and its copy are separated into 2 different nuclei.
Practice Question 8
AGGTAACTTGCG
1.If the strand of nitrogen bases above were to undergo replication, what would be the nitrogen
bases that match? Write them below in the order that they match.
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Biology
CELL DIVISION-Notes
Practice Question 7
Which of the following describes the process of replication?
A The bonds between the nitrogen bases of DNA break apart and new nucleotides pair
with each nucleotide of the original strands of DNA.
B The bonds between the deoxyribose sugars of RNA break apart and new nucleotides
pair with each nucleotide of the original strands of DNA.
C The bonds between the phosphate groups of DNA break apart and new nucleotides
pair with each nucleotide of the original strands of DNA.
D The bonds between the ribose sugars break apart and new nucleotides pair with each
nucleotide of the original strands of DNA.
Practice Question 6
What is the role of DNA replication in the process of cellular reproduction?
A DNA replication must occur so that each daughter cell has an exact copy of the DNA.
B DNA replication must occur so that more cytoplasm can be made before the cell
divides.
C DNA replication must occur so that DNA can be hydrolyzed.
D DNA replication must occur so that each resulting cell can have different combinations
of genes.
Practice Question 5
Why is the cell cycle important for growth?
A Every time a cell goes through the cell cycle, the cells get larger and larger.
B Each new cell must have chromosomes identical to the parent cell in order to do its
job.
C Each cycle, the parent cells must have three times the number of organelles for the
daughter cells.
D Cells must cycle several times to have enough cytoplasm to divide.
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Biology
CELL DIVISION-Notes
Practice Question 4
1.In which of the following organisms do you find deoxyribose, the nitrogen bases
adenine, guanine, cytosine, and thymine, and phosphate groups?
A animals, plants, and fungi, but not bacteria
B all eukaryotes
C all prokaryotes
D all eukaryotes and prokaryotes
Practice Question 3
What characteristic of DNA is responsible for the unique traits that every organism has?
A The number of nucleotides in each chromosome is the same.
B The deoxyribose sugars are arranged at the “sides” ofthe DNA ladder.
C The nitrogen bases are arranged in a specific order.
D The phosphate groups are attached to deoxyribose.
Practice Question 2
What are the components of DNA?
A DNA is made up of monomers called monosaccharides. Monosaccharides are
composed of ribose, phosphate groups, and nitrogen bases.
B DNA is made up of monomers called nucleotides. Nucleotides are composed of
deoxyribose, phosphate groups, and nitrogen bases.
C DNA is made up of monomers called amino acids. Amino acids are composed of
deoxyribose, phosphate groups, and nitrogen bases.
D DNA is made up of monomers called fatty acids. Fatty acids are composed of ribose,
phosphate groups, and nitrogen bases.
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