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DNA & Mitosis Unit Cover Page
Page | 245
DNA & Mitosis Unit Front Page
At the end of this unit I will be able to:
 Explain why cells have a large surface area to volume ratio.
 Identify the key roles of cell division.
 List and describe the phases of mitosis.
 Describe the structure and function of DNA.
 Identify important scientific experiments that led to the
discovery of DNA’s structure.
 Give details about how DNA replicates.
Roots, prefixes, and suffixes I will understand are:
 Mitosis: Ana-, centr-, chromo-, cyto-, hist-, inter-, -mere, meta-, nucelo-, -osis, -phase, pro-, -some,
telo DNA: -ase, heli-, -ine, lig-, poly-, transThe terms I will be able to clearly define are:
 Mitosis: Anaphase, cell cycle, centromere, chromatin, chromosome, cytokinesis, gamete, histone,
interphase, metaphase, mitosis, nucleosome, prophase, ratio, sister chromatids, somatic cell,
surface area, synthesis, telophase, volume
 DNA: Adenine, complementary, Cytosine, DNA, DNA polymerase, Guanine, helicase, helix, ligase,
nitrogenous base, nucleic acid, pentose 5-c sugar, phosphate backbone, phosphate group,
proofreading enzyme, replication, RNA, semi-conservative, template, Thymine, transcribe,
transformation, translate, Uracil
The assignments I will have completed by the end of this unit are:
 Diffusion and Cell Size Activity (page 247-252)
 Warm Up: Designing a Cell (page 253)
 Cell Cycle Notes (page 254-257)
 Timing the Cell Cycle Activity (page 262-263)
 Onion Root Tip Lab (page 264-265)
 Your Body is Younger than You Think (page 266-233)
 20 Things you Didn’t Know About DNA (page 269)
 DNA: Coloring & Reading (page 272)
 Organic Compounds (page 274)
 Building a DNA Model (page 275)
 Nucleic Acid & DNA Notes (page 277, 279, 281)
 The Race to Discover DNA Review Sheets (page 276, 278, 280)
 DNA Replication Notes (page 282-282)
 DNA Extraction Lab (page 287-288)
Page | 246
Common Core Practice: Diffusion
Watch the animation, “Random Motion and Diffusion,” then answer the following questions based on the
animation. Support your responses using direct observations from the animation or background
knowledge from previous notes presented in biology.
1. How does random motion of molecules affect rates of diffusion?
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_______________________________________________________________________________________________________________
2. The double lines in the animation represent bi-lipid phospholipid membrane of a cell. Should
diffusion rates increase or decrease with increased surface area? First define surface area then
defend your answer about the relationship between surface area of the membrane and
diffusion rates, using your knowledge about phospholipid membranes.
_______________________________________________________________________________________________________________
_______________________________________________________________________________________________________________
_______________________________________________________________________________________________________________
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Page | 247
Diffusion and Cell Size Activity Flowchart
(see directions on page 16)
Page | 248
Diffusion and Cell Size Activity
Abstract:
Pre-activity questions:
1. Why do you think cells are so small? Be specific in your response.
2. Define surface area in your own words:
3. Define volume in your own words:
Page | 249
Diffusion and Cell Size Activity
Purpose: To determine why cells are small and what role diffusion has in cell size.
Problem: ____________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
Background: Cells from different organisms vary greatly in size from one another. Eukaryotic cells
tend to be larger than prokaryotic ones. For example, the largest known cell is a giraffe nerve cell and
the smallest known cells are bacteria (prokaryotes).
Procedure: In this lab, you will investigate how the size of a cell is related to its ability to get molecules
and other substances in and out. Using two different sized marshmallows to represent cells, you will
measure the amount of diffusion that occurs in each marshmallow by immersing the different sized
marshmallows in different colored fluids. By cutting open the marshmallows and looking at the color
change to the interior of the marshmallows, you will be able to determine how much diffusion has
occurred and if size of the marshmallow is a factor in diffusion rates.
Page | 250
Diffusion and Cell Size Activity
Observations:
Before
After
Analysis Questions:
1. Based on your understanding of random motion, explain or sketch what you believe was
happening at the molecular level.
2. In the graphic to the right of two different size spheres,
approximately how many times larger are the radii?
The surface areas?
The volumes?
Connect the graphic to what you have learned from the
experiment and explain how they are related.
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Diffusion and Cell Size Activity
Analysis Questions (continued):
3. Bryophytes are a phylum of the plant kingdom that lacks a vascular system. They have no
specialized tubes for transporting water and organic products of photosynthesis. Instead, they
rely upon diffusion. Examples of bryophytes are the mosses. Explain why mosses cannot grow
tall.
4. The image to the right is a representational graphic of an idealized
small intestinal cell. What unusual feature do you notice about this
cell? One of the functions of the intestinal cell is to allow the
passage of digested nutrients from the interior of the small
intestine to the blood capillaries. One of the principles of biology
is: “Form follows function.” Explain how this is illustrated in the
intestinal cell.
5. Infer what other organs or organ systems may need to have an increased diffusionary surface
area in order to properly function.
Page | 252
Warm Up: Designing a Cell
Notice how both cells (above) have the same surface area to volume ratio. Cells have many adaptations
that increase the surface area to volume ratio. In the space provided below, draw a cell with a high
surface area to volume ratio. Include the organelles, as it has to be functional.
Page | 253
Cell Cycle Notes
Page | 254
Cell Cycle Notes
What is the cell
cycle?
What is
“interphase”?
Cells reproduce by a cycle of ________________________ and ________________________
called _____________________________________________________.

__________________________ stage of cell cycle (______ %)

___________________ is ________________

Cell is ___________________ during _____ and _____and ________ is being
replicated during ______
G1: ___________________________________________________________________________________
What is happening
at each of the 3
phases during
interphase?
S: ___________________________________________________________________________________
______________________________________________________________________________________
G2: ___________________________________________________________________________________
______________________________________________________________________________________
Calculate the SA/V
ratio for each
example provided:

What is the
problem with a low
surface to volume
ratio?
There are ___________________________________________________
__________________________________________ to meet its demands

Materials have _______________________________________________
_________________________________________________________________

The cell can’t ________________________________________________
________________________________ to meet the demands of the cell.
Page | 255
Cell Cycle Notes
Page | 256
Cell Cycle Notes
Cell division functions in:
 ___________________________________ for some organisms
What are the key
roles of cell
division?

_______________________ of an organism from a fertilized egg

_______________ of cells that die from normal wear and tear or accidents
Cell division distributes _____________________________________________________________
_________________________________________________________________________________________
What are somatic
cells and gametes?
How many
chromosomes are
in each gamete or
somatic cell?
What are
chromosomes
made of?
What is a histone?
What are
nucleosomes?
DNA molecules are packed into _____________________________________.
Human
chromosomes
Human
(body cells) have _________
______ (sperm or eggs) have ________ chromosomes
Chromosomes are made of a material called ____________________________.
Chromatin is composed of
________ and
___ ___ ___ is supercoiled around proteins called
.
________
.
Together the __ __ __ and ________________ protein form bead-like structures
called
Page | 257
Mitosis Notes
Page | 258
Mitosis Notes
When are
chromosomes
duplicated?
What are sister
chromatids?
How are they
connected?
The chromosome is duplicated during ________ in ______________________________.
Each duplicated chromosome consists of two
_______________________________.
These are connected by a
.
The “M phase” of the cell cycle contains two parts:
___________________________ and __________________________________________.
What are the 4
phases of Mitosis?
Mitosis has four parts:
P
M
A
T
Page | 259
Page | 260
Mitosis Notes
Describe late
interphase (before
mitosis begins)
Describe Prophase
Describe Metaphase
Describe Anaphase
Describe Telophase
What happens in
cytokinesis?
What is the end
product?
Two ________________________________________________________________ ready to start
the cycle again… or not.
Some cells (like ________________________________________________________________)
do not undergo division
Page | 261
Timing the Cell Cycle Activity
Abstract:
Introduction:
How long do onion root tip cells spend in each phase of the cell cycle? In this computer lab you will
identify the phases of the cell cycle. You will also determine the time an onion cell spends in each
part of the cell cycle.
Webpage:
http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/01.html
Procedure:
Gathering Data:
1. Open the webpage.
2. Examine the picture of the cell in mitosis and identify the phase it belongs in by clicking
the name of the phase.
3. Continue to do this until you have categorized 36 cells. Row “A” of your data table
should be complete.
4. Calculate the fraction of cells in each phase by dividing the number of cells in that phase
by the total number of cells you categorized (36 cells). Record your fractions in Row B.
5. Express your fractions as a decimal in Row C by dividing the top number by the bottom
number. You may need to round to the nearest hundredth. For example, 0.576 rounds to
0.58.
Creating a Graph:
6. Calculate the number of degrees in a circle graph for each phase by multiplying the time,
expressed as a decimal (Row C) by 360° (the number of degrees in a complete circle).
Record your degree value in Row D. You may need to round to the nearest degree. For
example, 87.65 degrees will round to 88 degrees.
7. Make a circle graph showing the amount of time, in degrees, a cell spends in each phase.
Color each portion of the circle a different color. Label each section with the phase,
percent value, and the degrees.
8. Make a key/legend that indicates which phase each color represents.
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Timing the Cell Cycle Activity
Discussion:
1. In which phase of the cell cycle does a cell spend most of its time?
2. In which phase of the cell cycle does a cell spend the least time?
3. Compare your pie graph to the cell cycle graph from your notes. Discuss similarities,
differences, and possible explanations:
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Onion Root Tip Lab
Background:
Rapid cell division occurs in rapidly growing regions of organisms, like plant roots. In this lab, you
will observe and record cells at various stages of mitosis within preserved onion root tips.
Procedure:
Use the images to help you and your lab partner find the stages of mitosis on a slide with onion root
tip cells. In the column labeled “Observation,” draw and label a representation of each stage of the
cell cycle. Use color and leader lines to label your pictures. In the space provided, use your notes to
fill in the details of what is happening during each stage of mitosis.
Conclusion Questions:
1. In which stage of the cell cycle are most of the cells you examined? Does this support what
you know about the cell cycle? Why or why not?
2. The cells in the root of an onion are actively dividing. How might the numbers you count
here be different than if you had examined cells from a different part of the plant?
3. A chemical company is testing a new product that it believes will increase the growth rate of
food plants. Suppose you are able to view the slides of a plant’s root tips that have been
treated with the product. If the product is successful, how might the slides look different
from the slides you viewed in this lab?
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Onion Root Tip Lab
Image
Observation
What’s Happening during this phase?
Interphase
Prophase
Metaphase
Anaphase
Telophase
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Your Body is Younger than You Think
by Nicholas Wade
New York Times, August 2, 2005
Whatever your age, your body is many years younger. In fact, even if you're middle aged,
most of you may be just 10 years old or less.
This heartening truth, which arises from the fact that most of the body's tissues are under
constant renewal, has been underlined by a novel method of estimating the age of human cells. Its
inventor, Jonas Frisen, believes the average age of all the cells in an adult's body may turn out to be
as young as 7 to 10 years.
But Dr. Frisen, a stem cell biologist at the Karolinska Institute in Stockholm, has also
discovered a fact that explains why people behave their birth age, not the physical age of their cells:
a few of the body's cell types endure from birth to death without renewal, and this special minority
includes some or all of the cells of the cerebral cortex.
It was a dispute over whether the cortex ever makes any new cells that got Dr. Frisen
looking for a new way of figuring out how old human cells really are. Existing techniques depend on
tagging DNA with chemicals but are far from perfect. Wondering if some natural tag might already
be in place, Dr. Frisen recalled that the nuclear weapons tested above ground until 1963 had
injected a pulse of radioactive carbon 14 into the atmosphere.
Breathed in by plants worldwide and eaten by animals and people, the carbon 14 gets
incorporated into the DNA of cells each time the cell divides and the DNA is duplicated.
Most molecules in a cell are constantly being replaced but the DNA is not. All the carbon 14
in a cell's DNA is acquired on the cell's birth date, the day its parent cell divided. Hence the extent of
carbon 14 enrichment could be used to figure out the cell's age, Dr. Frisen surmised. In practice, the
method has to be performed on tissues, not individual cells, because not enough carbon 14 gets into
any single cell to signal its age. Dr. Frisen then worked out a scale for converting carbon 14
enrichment into calendar dates by measuring the carbon 14 incorporated into individual tree rings
in Swedish pine trees.
Having validated the method with various tests, he and his colleagues have reported in the
July 15 issue of Cell the results of their first tests with a few body tissues. Cells from the muscles of
the ribs, taken from people in their late 30's, have an average age of 15.1 years, they say.
The epithelial cells that line the surface of the gut have a rough life and are known by other
methods to last only five days. Ignoring these surface cells, the average age of those in the main
body of the gut is 15.9 years, Dr. Frisen found.
The Karolinska team then turned to the brain, the renewal of whose cells has been a matter
of much contention. Prevailing belief, by and large, is that the brain does not generate new neurons
after its structure is complete, except in two specific regions, the olfactory bulb that mediates the
sense of smell, and the hippocampus, where initial memories of faces and places are laid down.
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Your Body is Younger than You Think
This consensus view was challenged a few years ago by Elizabeth Gould of Princeton, who
reported finding new neurons in the cerebral cortex, along with the elegant idea that each day's
memories might be recorded in the neurons generated that day.
Dr. Frisen's method will enable all regions of the brain to be dated to see if any new neurons
are generated. So far he has tested only cells from the visual cortex. He finds these are exactly the
same age as the individual, showing that new neurons are not generated after birth in this region of
the cerebral cortex, or at least not in significant numbers. Cells of the cerebellum are slightly
younger than those of the cortex, which fits with the idea that the cerebellum continues developing
after birth.
Another contentious issue is whether the heart generates new muscle cells after birth. The
conventional view that it does not has recently been challenged by Dr. Piero Anversa of the New
York Medical College in Valhalla. Dr. Frisen has found the heart as a whole is generating new cells,
but he has not yet measured the turnover rate of the heart's muscle cells.
Although people may think of their body as a fairly permanent structure, most of it is in a
state of constant flux as old cells are discarded and new ones generated in their place. Each kind of
tissue has its own turnover time, depending in part on the workload endured by its cells. The cells
lining the stomach, as mentioned, last only five days. The red blood cells, bruised and battered after
traveling nearly 1,000 miles through the maze of the body's circulatory system, last only 120 days
or so on average before being dispatched to their graveyard in the spleen.
The epidermis, or surface layer of the skin, is recycled every two weeks or so. The reason
for the quick replacement is that "this is the body's saran wrap, and it can be easily damaged by
scratching, solvents, wear and tear," said Elaine Fuchs, an expert on the skin's stem cells at the
Rockefeller University.
As for the liver, the detoxifier of all the natural plant poisons and drugs that pass a person's
lips, its life on the chemical-warfare front is quite short. An adult human liver probably has a
turnover time of 300 to 500 days, said Markus Grompe, an expert on the liver's stem cells at the
Oregon Health & Science University.
Other tissues have lifetimes measured in years, not days, but are still far from permanent.
Even the bones endure nonstop makeover. The entire human skeleton is thought to be replaced
every 10 years or so in adults, as twin construction crews of bone-dissolving and bone-rebuilding
cells combine to remodel it.
About the only pieces of the body that last a lifetime, on present evidence, seem to be the
neurons of the cerebral cortex, the inner lens cells of the eye and perhaps the muscle cells of the
heart. The inner lens cells form in the embryo and then lapse into such inertness for the rest of their
owner's lifetime that they dispense altogether with their nucleus and other cellular organelles.
But if the body remains so perpetually youthful and vigorous, and so eminently capable of
renewing its tissues, why doesn't the regeneration continue forever?
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Your Body is Younger than You Think
Some experts believe the root cause is that the DNA accumulates mutations and its
information is gradually degraded. Others blame the DNA of the mitochondria, which lack the
repair mechanisms available for the chromosomes. A third theory is that the stem cells that are the
source of new cells in each tissue eventually grow feeble with age.
"The notion that stem cells themselves age and become less capable of generating progeny
is gaining increasing support," Dr. Frisen said. He hopes to see if the rate of a tissue's regeneration
slows as a person ages, which might point to the stem cells as being what one unwetted heel was to
Achilles, the single impediment to immortality.
Conclusion Questions:
1. Which parts of your body are the “youngest” (they are replaced more than the other
parts)?
2. Which parts of your body are the “oldest” (they are not replaced often or at all)?
3. What do you think we would be like if the brain divided as frequently as the liver?
4. This article addresses normal cell division in a human body. How would you refer to
abnormal cell division in an organism?
5. Chemotherapy is treatment that cancer patients undergo. It kills cells, and prevents
cells from dividing, hopefully killing the cancerous cells in the patient’s body. Why do
you think a person’s hair falls out when they are undergoing chemotherapy to treat
cancer?
Why do you think nausea is another common side effect?
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20 Things You Didn’t Know About DNA
By Kirsten Weir | Discover Magazine, June 13, 2011
1. Sorry, Jimmy: James
Watson and Francis Crick did not
discover DNA. That honor goes to Swiss
biochemist Friedrich Miescher, who in
1869 found the molecule in the nuclei of
white blood cells and called it nuclein.
2. Nor did they figure out that DNA is
our genetic blueprint;
bacteriologist Oswald Avery and his
colleagues did that in the early 1940s.
3. What Watson and Crick did do, in 1953, was decipher the double-helix structure of DNA. Their
discovery ran as a single-page paper in Nature.
4. Phosphorus is a key component of DNA, but late last year a team of NASA scientists published
a controversial study reporting that they had found a bacterium that could use arsenic instead.
“What else can life do that we haven’t seen yet?” wondered lead researcher Felisa Wolfe-Simon.
5. Don’t try this at home: If uncoiled, the DNA in all the cells in your body would stretch 10 billion
miles—from here to Pluto and back.
6. Most of that DNA resides not in the cell nuclei, which control heredity, but in our mitochondria,
the organelles (units within cells) that generate metabolic energy.
7. Puny humans: Paris japonica, a flowering plant native to Japan, has the longest known genome,
nearly 150 billion base pairs. That’s 50 times as long as the human genome.
8. Aside from bacteria, the smallest genome belongs to the intestinal parasite Encephalitozoon
intestinalis, with a trifling 2.3 billion base pairs.
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9. Scientists are working to create vaccines against HIV, flu, and hepatitis C from snippets of
synthetic DNA; the DNA tricks the body into producing harmless viral proteins that train the
immune system to attack real viruses.
10. DNA vaccines for West Nile virus, melanoma, and hemorrhagic disease are already available for
horses, dogs, and salmon, respectively.
11. At the Chinese University of Hong Kong, fetal DNA was extracted from a pregnant woman’s
blood plasma and tested for Down syndrome. Prenatal DNA screening could someday replace
amniocentesis.
12. Telomeres, sequences of DNA at the tips of chromosomes, get shorter every time a cell divides;
when they get too short, the cell dies. Some scientists are trying to extend life by extending the
telomere.
13. Good news if you’re a mouse: Researchers at Dana Farber Cancer Institute in Boston
engineered mice with telomerase (an enzyme that adds DNA to telomeres) that could be switched
on and off. With the enzyme activated, the mice grew new brain cells and lived longer.
14. Bad news if you’re a mouse: Scientists at Osaka University recently developed mice that are
especially susceptible to DNA copying errors, seeking to increase the rate of mutations and see what
new traits appear.
15. The results so far include short-legged mice, mice with fewer toes than normal, and mice that
chirp like songbirds.
16. Guess who’s in your DNA? At least 8 percent of the human genome originated in viruses,
whose genetic code was integrated with ours over roughly 40 million years of primate evolution.
17. Over the next five years, the International Barcode of Life Project aims to establish genetic
identifiers for 500,000 species—short sections of unique DNA in the same location on the genome,
a bit like the UPC on your box of Froot Loops.
18. Already, forensic specialists can identify criminals from traces of “touch DNA” left in fingerprints at a crime scene.
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19. Next up: food forensics. British microbiologists sequenced DNA to identify the bacteria in a
round of Stilton blue. They found that at least six microbial groups influence the flavor of the
cheese’s “dairy matrix.”
20. And scientists at the University of Guelph in Ontario showed that DNA from the worm
(actually an agave butterfly caterpillar) traditionally placed in bottles of mescal leaches into the
liquor. So now we know: You don’t actually have to “swallow the worm” to swallow the worm.
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DNA: Coloring & Reading
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DNA: Coloring & Reading
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Organic Compounds
What is the function of Nucleic Acids?
____________________________________________________________________________
____________________________________________________________________________
Lipids
Nucleic Acids
What elements make up Nucleic Acids? _______, _______, _______,
_______, and _______.
Proteins
Carbohydrates Nucleic Acids
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Building a DNA Model
Materials:
Models are built using a basic repetitive structure.
Three different pieces are required:
 The 135° connectors
 Short rods
 Long rods
Background:
The connectors serve as the deoxyribose sugar units of the helix backbone. Phosphodiester bonds
linking the sugar units are represented by the short rods. Hydrogen bonded base pairs are
represented by the long rods.
Procedure:
The connections for the simplest model are illustrated below. The double helix is composed of two
backbones held together by hydrogen bonded bases. Each backbone is formed by joining
connectors in a chain using the short rods attached to the outer slots. The backbones are cross
linked with the long rods. Long rod attachment should be at the third slot of the connectors on each
chain. Because the chains are anti-parallel, on one chain attachment should be at the third slot from
the left and on the other chain, third slot from the right.
Follow the arrows above to produce the segment pictured below. When the second long rod is
attached, the two backbones will start to twist around each other. Once your double helix is
complete, connect it to another strand of DNA!
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The Race to Discover DNA Review Sheet – Part 1
1. Explain the “Central Dogma of Molecular Biology”, using the image below.
2. For each of the images (I – IV) describe what this study proved to Frederick Griffith.
I.
II.
III.
IV.
3. Briefly summarize how Avery, McCarty and McLeod further developed Griffiths
experiment in the space below:
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Nucleic Acid & DNA Notes
Nucleic acids are “____________________________________________________”: They
code for all of the proteins in an organism
What are nucleic acids?
Polymer: Nucleic Acid
Monomer: _______________________________________
Each Nucleotide is made up of:
1) _______________________________________________________
2) _______________________________________________________
– Ribose or deoxyribose
3) _______________________________________________________
– Adenine (A), Cytosine(C), Thymine (T),
Guanine(G), and Uracil (U)
There are two main nucleic acid polymers:
– ___________________________________________
– ___________________________________________
What are the two main
types of nucleic acids
and how are they
related?
The _____________________________________________ (A, C, G, T) are what makes up
the DNA “code”
RNA codes are ___________________________________ or made from DNA codes
Proteins are then ___________________________________ or made from RNA codes
What is the central
dogma of molecular
biology?
____________________________________________________________________
_____________________________________ was a bacteriologist studying pneumonia
He discovered two types of bacteria:
– ___________________________ colonies
– ___________________________ colonies
How was
transformation
accidentally discovered
during Griffith’s
experiment?
CONCLUSION: The _______________________ colonies must carry the disease!
When _____________________ was applied to the deadly smooth type and
injected into a mouse, the mouse ______________________________!
Griffith injected the ______________________________ type and the non-deadly
rough type of bacteria.
The bacteria “_______________________________” itself from the heated nondeadly type to the deadly type.
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The Race to Discover DNA Review Sheet – Part 2
1. Explain the experiment and the results of the Hershey-Chase experiment, which is visualized
below.
2. According to Chargaff’s rule, how do the bases of DNA pair with one another?
3. Why do they pair in this way?
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Nucleic Acid & DNA Notes
To the heat-killed smooth type, they added enzymes that
destroyed…
Avery, McCarty, and
MacLeod repeated
Griffith’s experiment
with what variation?





________________________________
________________________________
________________________________
________________________________
________________________________
CONCLUSION: _____________________ was the transforming factor!
Alfred Hershey & Martha Chase worked with a bacteriophage
(a virus that invades __________________. ) It consists of a
____________________________ and a ____________________________.
Hershey and Chase mixed the _____________________ - __________________
viruses with the bacteria.
How was the HersheyChase experiment
conducted, and what
did it confirm about
DNA?
____________________ the viruses from the bacteria by agitating the
virus-bacteria mixture in a blender
Centrifuged the mixture so that the bacteria would form a
________________ at the bottom of the test tube
Measured the ___________________ in the ______________and in the
__________________
The Hershey-Chase results reinforced the Avery, McCarty, and
MacLeod CONCLUSION: DNA carries the ______________ code!
In the 1940’s, Linus Pauling discovered the __________________________
_________________ structure of ______________________________.
What other
investigations led to
the discovery of DNA’s
structure?
____________________ + ____________________ = perfect fit from x-ray data
or ____________________ + ____________________
This is known as _______________________________________ Rule.
An x-ray diffraction image of DNA taken in 1951 by ________________
____________________________________ also helped towards discovering
the shape of DNA.
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The Race to Discover DNA Review Sheet – Part 3
1. What about DNA did this image reveal?
2. Who won the race to discover DNA’s structure?
3. What is the backbone of DNA made of?
4. What does this do to the overall charge of DNA?
5. Label the DNA structure below and fill in the missing nucleotides.
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Nucleic Acid & DNA Notes
Who is credited with
discovering the
structure of DNA?
In 1953, ____________________________________________ and
______________________________________________________ compiled data from
previous scientists to build a double-helical model of DNA
1. DNA is made up of :
•
Four nitrogenous bases:
____denine, ____hymine, ____uanine and ____ytosine
•
These follow the rules of base-pairing:
–
What was known about
DNA after the “race to
discover DNA’s
structure” was over?
•
____________________________ bond with _________________________:
•
_____________________bonds with Thymine
•
Guanine bonds with ___________________________
A __________________ - ____________________ backbone
2. A sugar-phosphate backbone plus one nitrogenous base is called a
______________________________________.
3. DNA is arranged in a _____________________ - helix, made up of
_____________________ ____________________________.
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DNA Replication Checking for Understanding
1. For each image below explain what is happening during DNA replication. Be sure to include all
of the enzymes involved with replication.
2. Knowing what you know about base-pairing rules, label the following nitrogenous bases.
3. Why do you think that DNA replication is called semi-conservative? Explain your answer.
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DNA Replication Notes
What is DNA
replication?
How are the two
strands of DNA in a
double helix related?
What is the first step in
replication?
After the DNA has
separated into two
strands, what happens
next?
DNA replication is the process by which _____________________________________
The _______________________________ shape of DNA helped explain replication.
The ____________________________________________________ has two complementary
strands of DNA.
We say that they are “complementary” because each is base paired by
____________________________________ with its specific partner:
________ with ________ &
________ with ________
The first step in replication is the ________________________________ of the two
complementary strands.
An enzyme called ___________________________________ binds to a specific site on
the DNA and __________________________________________________________________
Each ____________________________________________________now serves as a
__________________________ that determines the order of the ___________________
along a new complementary strand.
__________________________________________________ moves down the strands, and
inserts ____________________________________________________________________________
____________________________________________________________________________________
Another enzyme called _____________________________ forms bonds between
the _______________________ and _______________________ in the DNA backbone
What are the last steps
of DNA replication?
What is the “result” of
DNA replication?
_____________________________________________________________________double check
the new strands, then the strands “zip up” and two new “daughter” DNA
molecules are present.
Each “daughter” DNA molecule consists of __________________________________
___________________________________________________________________________________
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DNA Replication: Coloring & Reading
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DNA Replication: Coloring & Reading
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Semi-Conservative Replication
1. Color the DNA molecule red. What does the diagram to the
right show happening to the DNA molecule? (Be complete).
2. Color the new DNA nucleotides in the diagram to the right
blue. Color the original DNA strands red. What does the
diagram to the right show happening to the DNA molecule?
3. In the diagram to the right, color the new DNA strands blue
and color the other DNA strands red. According to the
diagram to the right, what has been produced from the
original DNA molecule in question 1?
Which color, red or blue, represents the original template?
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DNA Extraction Lab
Flowchart (see directions on page 16)
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DNA Extraction Lab
Pre-Activity Questions:
1. In what organelle is DNA located in the cell? Explain the structural components of this organelle.
2 Three meters of DNA must fit inside this organelle. What structure allows for the condensation of
the DNA? Is this structure a protein, lipid, or carbohydrate?
3. Based on your responses above, infer what must be done to the cell in order to obtain or get to
the the DNA?
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DNA Extraction Lab
Abstract:
Materials: Gatorade, 15-mL plastic test tube, pipettes, lysis buffer solution, cold alcohol, small
plastic test tube with cap
Procedure:
1. Swish your mouth with Gatorade for one minute. Chew lightly on your cheeks. Be careful not
to swallow the solution.
2. Spit the solution back into the cup.
3. Carefully pour the spit solution into the 15-mL plastic test-tube provided and screw on the cap.
4. With a centrifuge, ask your teacher to spin the down your cheek cells for 30 seconds until it
forms into a nice pellet at the bottom of the tube.
5. Use your pipette to carefully draw off most of the liquid on top, without disturbing the cell
pellet in the bottom. Leave about 2 mL of liquid.
6. Using a different pipette, add 2 mL of lysis buffer solution to your test-tube. The total amount
of liquid in your tube should be 4 mL.
7. Screw the cap back on and gently tilt the test-tube back and forth to mix the solution.
8. Using a different pipette, hold your 15mL test tube at a 45⁰ angle, and drip 4 mL of cold
alcohol down the side of the test tube, so that it forms a layer on top of your solution without
splashing. Do NOT mix.
9. Let the tube stand upright and undisturbed. You should begin to see clear strands of DNA
clumping together in the alcohol layer.
10. With your pipette, carefully transfer the precipitated DNA along with about 1 ml of the
alcohol solution into the small test tube.
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DNA Extraction Lab
Conclusion Questions:
1. Where is DNA found within the cell?
2. One of the ingredients in the DNA Extraction Buffer is soap. Thinking back to our discussion of
lipids, why do you think soap is used in this lab?
3. One of the ingredients in the “lysis buffer solution” is meat tenderizer. What’s the purpose of the
meat tenderizer in this lab?
4. Explain what happened in the final step when you added alcohol. (Hint: DNA is soluble in water,
but not in ethanol)
5. A person cannot see a single cotton thread 100 feet away, but if you wound thousands of
threads together into a rope, it would be visible much further away. Explain how this extraction
is analogous to our DNA extraction.
6. Why is it important for scientists to be able to remove DNA from an organism? Describe two
reasons.
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DNA & Mitosis Unit Concept Cards
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DNA & Mitosis Unit Concept Map
(see directions on page 21)
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Parent/ Significant Adult Review Page
Student Portion
Name _________________________________________________
Unit Summary (write a summary of the past unit using 5-7 sentences):
Explain your favorite assignment in this unit:
Adult Portion
Dear Parent/ Significant Adult:
This Interactive Notebook represents your student’s learning to date and should contain
the work your student has completed. Please take some time to look at the unit your
student just completed, read his/ her reflection and respond to the following
Ask your child to explain one “fact” about DNA or mitosis that they did not know before this
unit. Jot down the fact below:
One area my child needs to improve is:
Parent/ Significant Adult Signature:
Comments? Questions? Concerns? Feel free to email their teachers.
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DNA & Mitosis Unit Study Guide
1. In the space below, create a flow chart or pie chart that represents the cell cycle. Include the
following terms or labels:
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
S
Mitosis
G1
G2
Anaphase
Interphase
Metaphase
Telophase
Prophase
Cytokinesis
2. What is the correct order of images for mitosis?
3. For each image above, describe what is happening and label important structures.
A.
B.
C.
D.
E.
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DNA & Mitosis Unit Study Guide
4. At actual size, all of the DNA in one human cell would reach almost 3 meters in length if
stretched out in a straight line. Write a paragraph explaining how so much DNA can fit into the
nucleus of a cell. Be specific, and include the terms: histone, nucleosome, DNA, chromosome
5. Mark each statement as true or false.
a.
In Griffith’s experiments, the strain of live coated bacteria caused mice to die.
b.
The uncoated bacteria strain did not harm the mice.
c.
The dead coated strain caused mice to die.
6. What happened when Griffith mixed the dead smooth bacteria with the live rough bacteria and
injected this mixture into the mice? What did he find when he examined the blood of the mice?
7. What term did Griffith use to describe this process? __________________________________________________
8. Place the following steps in Avery’s experiments in the correct order by numbering the steps.
____
a. Some bacteria grew coats.
____
b. No transformation occurred.
____
c. Extracted DNA was added to a population of bacteria without coats.
____
d. DNA-destroying enzymes were added to bacteria.
____
e. Protein-destroying enzymes were added to bacteria; transformation still occurred.
1
f.
DNA was extracted from bacteria with coats
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DNA & Mitosis Unit Study Guide
9. What substance did Dr. Avery find was responsible for causing the transformation of the
bacteria in Griffith’s experiment? _________________________
10. What did Hershey and Chase conclude when they found the viruses released from the cell
contained 32P but no 35S in their make-up? Explain how their data supports their conclusion.
11. Subunits of DNA are called ______________________________. These subunits are made of three parts
a. _______________________________ group
b. 5-_____________________________________________
c. __________________________________________________
12. What is the backbone of DNA made of? ______________ and ___________________
13. What is the name of the 5 –carbon sugar that makes up DNA?
14. Larger, double ringed nitrogen bases like adenine and guanine are called
____________________________________________, while smaller, single ringed nitrogen bases like thymine
and cytosine are called ____________________________________________.
15. How does DNA maintain the same diameter across the entire length of the molecule?
16. Chargaff’s rule of nitrogen base pairing says that the amount of ___________________________ equals
the amount of thymine and the amount of guanine equals the amount of __________________________.
17. Rosalind Franklin used the technique of _______________ _____________________________ to determine
that the shape of a DNA molecule is a _______________________ ___________________________________.
18. Why is DNA called a double helix?
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DNA & Mitosis Unit Study Guide
19. What type of bond holds the nitrogen bases of DNA together? __________________________________
20. Who wrote a scientific paper in Nature in 1953, and eventually won a Nobel Prize in 1962 for
determining the shape of the DNA molecule? _________________________ and ___________________________
21. Adenine always pairs with ________________________________. ________________________________ always
pairs with ___________________________________.
22. Identify the parts of the diagram below.
a. What is the structure labeled “X”?
b. What is the structure labeled “Y”?
c.
What is the structure labeled “Z”?
23. What would be the complementary bases to the DNA sequence
T T A A C G G A T
24. What does replication mean?
25. Place the steps of DNA replication in the correct order.
____
a. The enzyme DNA polymerase moves along the exposed strands and adds
complementary nucleotides to each nucleotide in each existing strand.
____
b. The enzyme helicase breaks the DNA double helix down the middle between the
base pairs.
____
c. An enzyme called ligase forms between the sugar phosphates in the DNA backbone.
____
d. Proofreading enzymes check the new strand.
____
e. Two new identical DNA molecules have been produced.
26. The central dogma of molecular biology illustrates that ____ ____ ____ transcribes into
____ ____ ____ which translates to _________________ .
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DNA & Mitosis Unit Study Guide
27. What is the difference between a nucleotide, nucleic acid, and a nitrogenous base?
28. In the space below, draw and label DNA replication. Include the following terms by either
labelling the structure or using the term to describe what is happening in your sketch.
 Proofreading enzyme
 Parent strand
 Helicase
 Ligase
 DNA Polymerase
 Complementary
 Daughter strand(s)
 Hydrogen bond
 Phosphate backbone
 Template
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DNA & Mitosis Unit Study Guide
29. Label the parts of the Microscope.
30. To calculate the magnification of the specimen under microscopic examination, what do you
multiply?
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DNA & Mitosis Unit Study Guide
31. What is the TOTAL magnification at each of the following powers? (Show your math!)
Low:
Medium:
High:
32. How would the letter “g” look under the microscope? Describe and draw below.
33. For each item below, write the purpose of the microscope structure:
a) Course adjustment knob -b) Diaphragm -c) Light source - d) Stage clips --
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DNA & Mitosis Unit Back Page
The California State Standards I have come to use and
understand are:
 1.h. Students know most macromolecules (polysaccharides, nucleic acids, proteins, lipids) in
cells and organisms are synthesized from a small collection of simple precursors.
 5.a. Students know the general structures and functions of DNA, RNA, and protein.
 5.b. Students know how to apply base-pairing rules to explain precise copying of DNA
during semiconservative replication and transcription of information from DNA into mRNA.
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