Genetics Unit
Name _________________________________________
HR ________
In the 1860s, an Austrian monk and biologist named _____________________________,
Worked with ___________ plants.
He studied characteristics or _______________________ of the pea plant:
1. ___________________________________
2. ___________________________________
3. ___________________________________
He is called the _______________________________________________
_____________________: the study of ______________________ or passing on of traits from one organism to
its offspring
Why did he use pea plants?
1. ___________________________________
2. ___________________________________
3. ___________________________________
4. ___________________________________
·
Pollen from the male part of a plant could be transferred to the female part of another plant
What did he find out?
1. Pollen from short-stemmed males transferred to short-stemmed females:
·
Offspring was _________________________, Mendel called these plants ____________________ or
true breeders
2. Pollen from tall-stemmed males transferred to tall-stemmed females:
·
Offspring was ________________________and __________________________
3. He concluded that ___________________ plants are true-breeders
Mendel knew that he had to complete more experiments to show how pea plants pass on traits to their offspring.
He wondered what would happen if he crossed true-breeding tall plants with true-breeding short plants. He
called these parent plants ______________(P1)
When he crossed the P1 plants, they produced ______________________ plants
·
The offspring were called ______________ (F1)
·
When he crossed F1 plants, their offspring were ______________ and _______________
Mendel learned that each pea plant had two types of traits:
1. _____________________________: strong ___________________ (ex) TT
2. _____________________________: weak ____________________ (ex) tt
If the genes (letters) are alike (TT or tt) the organism is called ______________________
If the genes (letters) are different (Tt) the organism is called ______________________
Mendel’s idea that genes are either dominant or recessive do not always hold true.
In 1900, ____________________________________, a German botanist, discovered that some genes blend
with others. He called this process __________________________________________________________·
He used four-o-clock flowers to show that if you crossed a red flower (RR) with a white flower (WW), you will
produce a pink flower (RW)
Through the work of scientists like Mendel and Correns, certain principles of genetics have been established:
1. ______________________ are passed on from one generation to the next
2. Traits of an organism are controlled by ____________________.
3. Organisms inherit genes in pairs, one from each ________________________.
4. Some genes are _____________________, while others are ____________________.
5. __________________________ genes hide _____________________ genes when
both are inherited by an organism
6. Some genes are neither dominant nor recessive, they show ________________________________________
How do we show the cross of organisms?
Punnett Squares
A Punnett Square is a chart used to show the possible gene combinations in a cross between two organisms. It
was developed by Reginald Punnett, an English geneticist.
Parents (P1) TT x tt
TT (Tall)
tt (short)
______________________________: physical traits of the organism
·
_________________________________________
______________________________: genetic make-up of an organism
·
_________________________________________
Second generation (F1) Tt x Tt
As long as there’s a capital letter in the genotype, the offspring will show the dominant trait. SO….. there’s a ¾
chance that the offspring will be tall and a ¼ chance that it would be short..
5. What is the probability of producing black offspring from this cross? _____________________________
6. What is the probability of producing white offspring from this cross? _____________________________
Why? ________________________________________________________________________________
7. What is the probability of inheriting two dominant traits from this cross? ___________________________
8. Are any of the offspring purebred dominant? __________________________________________________
Pedigree Charts trace inherited traits from one generation to the next.
Males
Females
Have trait
Carrier for trait
Parents
Children
How many generations are shown in this pedigree? ____________
How many children in generation 2? ________ generation 3? _________ generation 4? _________
How many children in 3rd generation are carriers? ____________ have the trait? __________
Which parent in the first generation has Sickle Cell
Anemia? __________
How many generations are shown in this pedigree?
____________
How many children in generation 2? ________
How many children in 3rd generation are carriers?
____________
How many children in the 4th generation have the Sickle Cell Anemia? __________
Is Sickle Cell Anemia a sex-linked trait? ______________ Explain your answer _________________________
__________________________________________________________________________________________
NOT all traits are dominant traits. Whit forelock trait is a recessive trait. In order to show the white forelock
trait a person would have had to have inherited two recessive genes from their parents. The only genotype to
show white forelock trait is purebred recessive (ww).
Draw your child’s face in the space below. Then answer the questions that follow.
How can you get desired traits?
Cloning
Base your answers to questions 57 and 58 on the laboratory procedure described below and on your knowledge
of science.
57. Explain why the baby rat was identical to its mother. [1] ________________________________________
58. A different female laboratory rat gave birth to several babies after being fertilized with sperm. Explain why
these babies will not be genetically identical to the mother. [1] _______________________________________
Selective Breeding
Selective breeding is a process used
by some farmers. Complete the chart
below by reading the description and
then circling either yes, if it is an
example of selective breeding, or no,
if it is not an example of selective
breeding. [1]
Genetic Engineering and Genetically Modified foods
DNA from one organism is replaced by another organism. Think Jurassic Park! But how does it work!?!?!
DNA Reading Comprehension
1
An embryonic cell divides again and again. Where there was one cell there are two, then four, then eight,
and so on. Each holds all the genetic information needed to create a new human being. Your fingernails grow
nonstop, day in and day out. The cells of your fingernails somehow generate all of the protein that makes up
your nails. How is this protein created? How, exactly, do these cells make copies of themselves? The answers to
these questions are DNA replication and protein synthesis.
2
When organisms reproduce, traits are passed from parent to offspring. These traits are carried in DNA, the
genetic material found in a cell's nucleus. DNA acts like a blueprint for the cells of an organism, instructing the
cells how to put together materials to produce certain traits.
3
DNA stands for deoxyribonucleic acid (pronounced de-ox-ee-ribe-o-new-clee-ick as-id). It's made of just a
few kinds of atoms: carbon, hydrogen, oxygen, nitrogen, and phosphorus. The traits that make organisms
different from one another are coded for in their DNA. Chromosomes are made of DNA. Chromosomes are
genetic structures that contain the information used to direct a cell's activities and make new cells. They are
found in the nucleus of a cell.
4
A person has 46, or 23 pairs, of chromosomes. Our cells have two copies of each chromosome. One came
from the mother, and one from the father. The chromosome starts as half of the familiar X. As the cell grows, it
replicates the DNA to make the other half of the X, which is identical. When the cell divides, each daughter cell
receives half of each chromosome (called a chromatid). The two copies of the gene are alike on one
chromosome but the "matching" pair of chromosomes may have slightly different genes (dominant or recessive
alleles) as one came from the mother and one from the father. The dominant gene of the two is the one that is
expressed. For example, if one parent gives a gene that carries the trait for blue eye color and the other parent
gives a gene that carries the trait for brown eye color, the child would have brown eyes. The trait for brown eye
color is dominant, and that is the color that would be expressed in the child.
5
DNA is a very large molecule with a shape like a twisted ladder. You have probably heard of the DNA
molecule referred to as a double-helix. The rungs of the ladder are made up of molecules called bases. These
nucleotide bases are adenine, thymine, guanine, and cytosine. The bases always pair up so that adenine is joined
with thymine (A-T) and cytosine is joined with guanine (C-G). Each rung of the ladder is made of two bases one for each side of the ladder.
6
The nucleotides join by hydrogen bonds. Because they bond at an angle between the two base pairs, the
whole structure twists into a helix. These base pairs carry the code for the cell. How the pairs are arranged in the
DNA make up the genetic code. The sides of the ladder are made up of phosphate and sugar molecules. They do
not carry any information. They hold the bases in their proper order.
7
A DNA molecule may contain millions of base pairs. It is the arrangement of these base pairs that
determines whether the organism is a fern, a ferret, a fish, or a fruit fly. In a human, this ladder is about three
million base pairs long. The two ends link together to form a ring, and then the ring gets wadded up so it can fit
inside the cell.
8
In human cells, DNA is tightly wrapped into 23 pairs of chromosomes. One member of each chromosomal
pair comes from your mother, and the other comes from your father. In other words, your DNA is a
combination of your mother's and your father's. Unless you have an identical twin, your DNA is unique to you.
This is what makes DNA evidence so valuable in criminal investigations. It's impossible for someone else to
have DNA that is identical to yours.
9
Cells live for only a short time, and so they must replace themselves. As a child grows, his body adds new
cells. When fingernails grow, they add new cells also. They do this by a process called cell division. Before a
cell divides, it copies its own DNA. The two strands of DNA separate. The hydrogen bonds break between the
nucleotides, and the strands come apart like the two halves of a zipper. Each strand's complement is recreated.
An enzyme makes the complementary strand by finding the correct base in the mixture and bonding it with the
original strand. In this way, the base on the old strand dictates which base appears on the new strand, and the
cell ends up with an extra copy of its DNA. Then the cell divides, and each new cell receives one copy of the
DNA.
10
The process of copying DNA is called DNA replication or DNA synthesis. The two resulting double
strands are generally almost perfectly identical, but sometimes errors in replication or exposure to chemicals or
radiation can result in a less than perfect copy. This is called mutation. Each copy has one original and one
newly synthesized strand.
11
This is DNA's main purpose: to make proteins within the cell. These proteins, which include enzymes that
do specialized jobs, control the activities of the cell. Different cells have different activities. By controlling
protein synthesis within each cell, the genes that make up DNA control the life of the entire organism.
1. DNA is ______.
Atoms of carbon, hydrogen, oxygen,
nitrogen, and phosphorus
A double helix
Nucleotide bases and sugar-phosphate
molecules
All of the above
2. Chromosomes are ______.
Found in the nucleus of a cell
Made of DNA
Both A and B
None of the above
3. Humans have ______.
4 chromosomes
3 million chromosomes
46 chromosomes in 23 pairs
4. In DNA, adenine always pairs with ______.
Cytosine
Guanine
Thymine
5. In DNA, guanine always pairs with ______.
Thymine
Cytosine
Adenine
6. In DNA replication _______.
The two strands of DNA come apart.
A copy is made.
Each copy has one strand of "old" DNA and
one strand of "new" DNA.
All of the above
7. What can cause a mutation when the cell copies its 8. With over 6 billion people living on Earth, it is
DNA?
common for two people to have the same DNA.
Errors
False
Exposure to chemicals
True
Exposure to radiation
All of the above
ATC GCC TCC AGG TGT TTA CGA ACG
________
_________
_________ __________ _________ __________ __________ __________
You should know how to match the base pairs!
Genetic Engineering of Plants
By Mary Lynn Bushong
1
It seems like something out of a science fiction novel: scientists changing the DNA of plants grown for
food so that more could be grown with less. It sounds wonderful, but what are the long-term effects?
2
What is involved in making plants more efficient? There are two ways of doing this. The first is through
traditional plant breeding practices of selecting and cross-breeding plants of the same kind for certain traits. If
you were growing corn in Kansas, you might want to grow shorter corn plants that would be able to withstand
strong gusts of wind. You would select corn plants that were shorter for cross breeding and cross those until you
came up with a plant that was the height you wanted. This is an example of intentional plant breeding, assisted
by humans. This type of plant breeding can also occur naturally, without human intervention.
3
The second way of making plants more efficient is through genetic engineering. It is also called genetic
modification, gene splicing, or recombinant DNA technology. In plants, it involves the selection of desirable
genes and adding the gene or genes into the genetic code of a plant that you want to modify. Selected genes may
come from a closely related plant or a completely different plant. They may even come from a completely
different organism like a bacterium, a virus, or even an animal. It is not something that could naturally occur in
a plant.
4
Scientists can use several methods to join the new genetic material with the DNA of the plant they are
changing. Some types of bacteria can be used to insert the new genetic material into the plant's DNA through a
process called genetic recombination. Some plant viruses can be used to incorporate the new genetic
information into the plant's DNA. However, this method has several limitations. Also, there are several types of
new technology that allow the genetic material to be injected into the plant's DNA without the use of other
organisms. The gene gun is one of these. Microinjection is another.
5
Genetic engineering promises to do many great things to improve crop yields, boost farm profits, improve
plant hardiness, and even increase the nutritional value of crops. Still, many people are wary of this technology.
Critics argue that more research must be done before we allow genetically modified crops to flood our markets.
While there has been little evidence presented that these crops are harmful, there are a lot of questions that no
one knows how to answer about what effects genetic engineering may have on our environment, our food, and
our bodies years into the future.
6
How could genetic engineering cause problems in the environment? There are several ways. One concern is
that these genetically engineered crops have already contributed and will continue to contribute to a lack of
biodiversity. Long ago, there were many different varieties of crops grown all around the world. As large
commercial farms replaced backyard gardens, many of those crops began to vanish. In the United States it is
believed that 90% of the varieties of fruits and vegetables grown here in the past have become extinct. It is the
same throughout much of the rest of the world. Today, just twelve plant species provide about 75% of the
world's food.
7
Remember when we talked about traditional plant breeding? It mimics what can happen on its own in
nature. Well, this natural cross-breeding of plants is another way that genetic engineering could be a very bad
thing for the environment. One of the most popular methods of genetically engineering plants has been to insert
DNA that allows a plant to become resistant to the effects of weed killers. This allows farmers to plant their
crops and then spray their fields with weed killer to get rid of the weeds without harming their crops.
Unfortunately, this has created herbicide-resistant super-weeds. A worldwide report in 1978 counted only one
variety of herbicide-resistant weed. Today that number is closer to 200.
8
Yet another concern is how genetically modified crops will affect animals. Some evidence has already
shown us that they may be unintended victims. In Britain, the planting of a genetically modified sugar beet crop
that was resistant to herbicides led to a significant decrease in weeds. While farmers were pleased with this
result, the local skylark population was not. The seeds of those weeds were an important part of the diet of
skylarks. Scientists estimate that 80% of the skylark population had to find a different food source.
9
A study in the United States found that the caterpillars of Monarch butterflies also may be harmed by
genetically modified crops. In the study, caterpillars were fed "large amounts" of pollen from a genetically
modified variety of corn. The corn was modified to produce a toxin that served as a pesticide. In the study, 44%
of the caterpillars died after consuming the pollen. What effect will genetically modified crops have on bees?
They are the main pollinators for the majority of our crops. Are genetically modified crops responsible for the
declines that we are seeing in the bee population?
10
People also worry about what effects genetically modified crops will have on humans. Again, there are
many different ideas on how humans might be affected. Some genetically modified plants are created with
genes for antibiotic resistance. Some people are concerned that these genes may be passed along to other
species and that this type of genetic engineering will make worse the already growing problem of antibiotic
resistant disease causing bacteria. People also wonder if using bacteria and viruses to introduce new genetic
material into plants could lead to the creation of new types of bacteria or viruses that could cause disease.
11
Another concern that people have about genetically modified crops is how the food from these crops will
be different from traditional crops. Will a corn plant that has been engineered to produce a pesticide produce
that same toxin in the corn that is grown from it? If it does, what long term effects will the pesticide have on
people who eat it?
12
Allergens are another concern in genetically modified crops. Will inserting a single gene from a highly
allergenic food into other crops cause allergic reactions to the food grown by the genetically modified plant?
Experiments have already shown that this is certainly a possibility. How will consumers with allergies know
what foods they should avoid?
13
Genetically modified foods began to enter the food supply in 1994. Since then, the number of genetically
modified foods, or products containing genetically modified ingredients, available to consumers has increased
dramatically. Governments had to decide how to handle these new products. The United States decided to allow
these genetically modified foods to be sold without requiring a label to inform consumers that they were buying
a product that had been altered by genetic engineering. Many other countries in the world felt differently. As of
2013, 64 countries require genetically modified foods to be labeled as such.
14
Many consumers are now demanding that the United States should require the labeling of genetically
modified foods as well. Those who are concerned about the genetically modified foods want to know what they
are eating and want people to be able to avoid genetically modified foods as they see fit. Those who are
adamantly opposed to genetically modified foods sometimes refer to them by another name -- "Frankenfoods."
15
There is much that is still unknown about genetically engineered plants. It is possible that some of them
might hold the key to feeding a hungry world as the Earth's population grows larger. Even if that is the case,
many people believe that governments need to test for long-term safety before these engineered plants are
allowed out of the laboratory. It can sometimes take years of exposure for problems to turn up. Those cautious
of genetic engineering in plants believe these studies should test long-term effects before the genetically
engineered genie is all the way out of the bottle.
1. How can people make plants more efficient?
Selective breeding
Genetic engineering
Both a and b
There is no way people can affect plants.
2. Scientists use _______ to carry new genetic
material to an existing DNA strand.
Microinjection
A gene gun
Bacteria or viruses
All of the above
3. What negative effect(s) are some people worried
4. How does conventional plant breeding differ from
might come from using bacteria or viruses to carry
genetic engineering?
genes for genetic recombination?
5. What is the purpose or goal for genetically
engineering plants?
Making plants more efficient so that more
food could be grown with less
Seeing how people can affect the ways that
food is grown
Using bacteria and viruses in a helpful way
Seeing how far people can push the
boundaries of nature
6. What is one of the possible dangers of having
unlabeled genetically engineered food?
Some people call genetically modified foods “Frankenfoods.” Is this a good nickname?
_________________________________________________________________________________________
Transformed Taters
Researchers managed to genetically engineer a gene from a fluorescent jellyfish into a potato. Why? The gene
that makes something glow (fluoresce) is tied to the potato plant's need for water. When the plant is low on
water, the gene turns on and the plant glows green, signaling the farmer to water it. These transformed taters
would be sprinkled throughout the regular crop, serving as low-water or drought signals. The glowing plants
would be removed before harvest so they wouldn't be consumed.
Why would this be a good idea? _______________________________________________________________
What's in the Beef?
Genetically engineered growth hormones are commonly used in beef production. The hormones have been
Food and Drug Administration (FDA) approved since the 1950s, but are now produced using genetic
engineering techniques. The United States Department of Agriculture (USDA) says the use of the hormones
creates a more flavorful and more tender product at lower costs to cattle producers, the environment, and
consumers.
There are six approved growth hormones that are produced using genetic engineering: estradiol, progesterone,
testosterone, zeranol, melengestrol acetate, and trenbolone acetate. The first three hormones occur in both
humans and animals. The other three substances are artificial hormones designed to act like the natural
hormones.
There is concern by some researchers and consumers that these hormones may cause cancer, hormonal
imbalance, developmental and immune risks in humans who eat these growth hormones.
List 2 pros (Advantages) of using hormones:
1. ______________________________________________
2. _______________________________________________
List 2 cons (Disadvantages) of using hormones:
1. _______________________________________________
2. _______________________________________________
Enough about food....what about Jurassic Park?
Imagine a dodo bird waddling on a pond near your house. Or a woolly mammoth
lumbering along. How about a pterodactyl soaring overhead? Sound far out? Genetic engineering (GE) makes it
possible to "resurrect" extinct species, just like in the movie Jurassic Park. As an animated tour guide in the
movie explains, it all comes down to DNA. If you can recover a useable sample of an organism's DNA (easier
said than done), then biotechnology gives you the tools to clone (copy) that DNA, insert it into an egg, and
develop it into a dinosaur or any extinct animal. This process is not just movie make-believe though, it is really
happening! In Iowa, a cow named Bessie bore a calf that was not a cow at all but a gaur, an ox-like animal
native to the jungles of India and Burma. The gaur DNA was cloned into a cow's egg, which had its own DNA
removed. That egg was then implanted into Bessie who carried the gaur and gave birth to it. (Sadly, the gaur
died shortly after its birth due to a bacterial infection.)
The gaur is not extinct, but endangered, which brings up an important point. GE could actually help save
species teetering on the edge of extinction, an opportunity in the eyes of some scientists. They view GE as a
way to preserve biodiversity, keeping as many species in the mix as possible. They also see it as a way to
reverse the harmful effects humans have on the animal kingdom. Not everyone shares that sunny outlook
though. Critics say the technology will produce herds of animals that are genetically identical. These identical
herds would share not only the same strengths, but the same weaknesses. This would leave them vulnerable to
diseases that could wipe out the entire herd, actually reducing biodiversity. Another concern centers on habitats
for these cloned animals.
Many animals face endangerment and extinction because their natural habitat is disappearing, or because the
habitat no longer has the food, water, or shelter the animal needs to survive. Will a zoo be the only place these
clones can live?
GE gives researchers a lot of tools to tinker with, and a lot of questions to consider when it comes to
"engineering" the animal world.
Jurassic Park Movie Sheet
1. The mosquito in the amber is an organism preserved over millions of years. This is a perfect example of a
____________________. (vestigial structure or fossil).
2. According to Dr. Grant, dinosaurs are closely related to __________________.
3. DNA strands are ____________________ (blue prints or signs) for living things.
4. Fossilized tree sap is called ______________(amber or fossiliferous limestone).
5. How come all of the animals in Jurassic park can’t breed?
________________________________________________________________.
6. The scientists took DNA codes from frogs and spliced/placed them into the dinosaur DNA. Taking genes
from one organism and placing them into the DNA of another organism is an example of
_____________________ (selective breeding or genetic engineering)
7. According to Dr. Malcolm (guy in black leather jacket), “Dinosaurs had their shot and ______________
selected them for extinction.”
8. _____________ ______________ is the process where natural pressures selects favorable traits that allows
certain organisms to survive and reproduce
9. Dilophosaurus spits out it’s venom causing ______________ and _____________ in it’s victims allowing
them to eat.
10. Why does Dr. Sattler (female) examine the dinosaur’s droppings? ____________
_________________________________________________________________
11. The name of the sick dinosaur was ____________________________.
12. Dr. Grant says to stay still because Tyrannosaurus Rex’s vision is based on _________________ (body heat
or movement).
13. Why was T. Rex able to see the insurance broker in the bathroom? ___________
________________________________________________________________
14. The brachiosaurus’ are ____________________ which means they only eat plants.
15. The dinosaurs were able to begin breeding because the DNA of some frogs will allow them to do what?
_______________________________________________________________
_______________________________________________________________
16 The Tyrannosaurus Rex ate the Galamimus. What kind of ecological relationship does this demonstrate?
__________________ and _________________ .
17. When Dr. Grant, Dr Sattler and the kids climb into the ceiling, what is written on the Velociraptor’s neck ?
(*Hint: It’s outlined by light) ___________________________________________________
18. The underlying theme throughout the movie is an everlasting conflict between man vs. nature.
a. Which force won this battle in the movie? ______________________
b. Do you agree with Dr. Malcom when he says nature cannot be contained and that evolution of life will
“always find a way”. ___________
c. Why or why not? _______________________________________________________________________
________________________________________________________________________________________
_________________________________________________________________________________________