ch 12-4: mutations indicator 3.3.4 students will learn the effects of dna alteration in order to...
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CH 12-4:
Mutations
Indicator 3.3.4Students will learn the effects of DNA alteration in order to understand how they can be beneficial
or harmful to the individual, society, and/or environment
Mutation – any change in a gene or chromosome
Gene Mutation
May happen when: DNA is copied (during
DNA Replication) RNA is made (during
Transcription)
Chromosome MutationMay happen when: Chromosomes tangle and fail
to separate during meiosis causing egg or sperm cells to have too many or too few chromosomes
Gene Mutations
Substitution Insertion Deletion
The wrong base might be added, and extra base might be added, a base may be removed
These mutations can cause the cell to make the wrong protein or a defective protein
The wrong protein can change the organism’s physical appearance or traits
Variation Within a Species Mutations are a source of variation within a species
Some mutations may be beneficial. A new protein may be produced that helps an
organism survive in a different environment or a changing environment
Some mutations may be harmful. Sickle Cell Anemia Alzheimer’s Disease
Sickle Cell Anemia
Disorder that affects the shape of red blood cells
A protein called hemoglobin does not form properlycausing red blood cells to be rigid and concave
Cells get stuck in the blood vessels & are unable to transport oxygen effectively, causing pain and damage to the organs
Normal red blood cells are round and flexible & transport oxygen freely through narrow blood vessels
A Benefit: Persons afflicted with sickle cell anemia are immune to malaria. A benefit in areas where malaria is prevalent.
Cystic Fibrosis
Disorder that affects the respiratory & digestive systems
Protein produced by this gene normally helps salt (NaCl) move in and out of cells
Defective protein blocks the movement of salt & an abnormally thick sticky mucous is produced on the outside of the cell
Lung cells are seriously affected by this due to mucous clogging the airways in the lungs, thus increasing the risk of infection by bacteria
Phenylketonuria (PKU)
PKU is caused by a mutation in a genethat codes for aprotein found in theliver that breaks down the amino acid phenylalanine into other products the body needs
Mutated gene causes a phenylalanine build up in the blood and poisons nerve cells (neurons) in the brain
Alzheimer’sDisease
Causes dementia (loss of brain function, dealing w/memory, thought, & language)
Caused by a malfunctioning protein that causes tangling of microtubules which ultimately damage healthy cells around them
CH 13-2, 13-3: Genetic Engineering
Students will learn how scientists manipulate DNA in order to understand how organisms with
more desirable traits may be produced
Genetic Engineering New technology used to alter
genetic instructions of organismsto have more desirable traits
In recent years, DNA of plants & animals have been manipulated to produce organisms with beneficial traits i.e. plants manipulated
to make chemicals that kill the insects that feed on them; bacteria engineered to be used to clean up oil spills or produce human growthhormone
CH 13: Genetic Engineering (pp.318-
333)
Gene Splicing
Genes from one organism are put into the DNA of another organism. Technique used to create bacteria that can
make human proteins
i.e. – The human insulin gene is put into bacterial cells. The cells make insulin. The insulin is collected to treat diabetes.
The bacterial DNA that contains the human insulin gene is an example of Recombinant DNA – DNA produced by combining DNA from two different sources
Click to View Another Animation of Gene Transfer using Recombinant DNA Select Animations & Images, then
Creation of a Recombinant DNA
Human Cell
Gene for human growth hormone
Recombinant DNA
Gene for human growth hormone
Sticky ends
DNA recombination
DNA insertion
Bacterial Cell
Plasmid
Bacterial chromosome
Bacterial cell for containing gene for human growth hormone
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Reco
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Restriction Enzymes – work like scissors by cutting long DNA molecules at different locations from a human cell and a circular piece of DNA (a plasmid) from a bacterial cell
The cut segment is transferred to the new organism The new organism’s cell makes the same protein product
Cloning
Method of developing organisms with more desirable traits
Clone – an organism that has exactly the same genes as the organism from which it was produced
Vegetative Reproduction is an example of cloning plants
Scientists have cloned 11 different animals, including sheep, cows, pigs, mice, and horses. Cloning animals is more difficult than cloning plants
How Is Cloning Done?
Involves removing chromosomes from an animal’s egg cell and replacing them with chromosomes taken from a body cell belonging to a different adult animal
When the egg cells startsdividing into an embryo, it is put into a surrogate mother (doesn’t have to be the same animal that provided the chromosomes)
The surrogate just provides the womb for the clone to develop
Problems Associated with Cloning
Resemble animals born prematurely Lungs aren’t fully developed Hearts don’t quite work right Livers full of fat Grow hugely overweight
and bloated Die at an earlier age than
normal
Dolly, 1st cloned sheep
Dewey, 1st
deer clone
Applications of Biotechnology
New technology and methods enable us to locate and determine base sequences of genes that cause disease to possibly alter the affected cells
New technology may lead to genetically engineered organisms with more favorable traits (i.e. genetically modified foods)
DNA Fingerprinting
Can be used for: Determining paternity Identifying suspects of a
crime To clear someone of a crime A DNA fingerprint is
constructed by: Extracting a DNA Sample
from body tissue or fluid such as hair, blood, or saliva
The sample is segmented using restriction enzymes
The segments are arranged by size using a process called electrophoresis
Gel Electrophoresis Procedure used to
separate and analyze DNA fragments
Helps scientists determine the gene composition of different organisms
Helps identify particular genes out of thousands in an indiv. genome
Helps establish paternity
Helps determine a suspect in a crime
How Does it Work?Go to www.phschool.com
to find out.
Active Art webcode cbp-4132
Running a Gel Electrophoresis
1. DNA is cut into smaller fragments using restriction enzymes.2. DNA fragments are placed in wells found on the gel.3. A ladder marker may be added to a well to approximate the size of DNA
fragments.4. The DNA fragments will run in lanes when an electric voltage is
applied.5. DNA molecules have a negative (-) charge and will move toward the
positive (+) end of the gel when the power is turned on.6. The smaller the DNA fragment, the faster and farther it moves.
DNA analysis from twins (A and B)
Examples of DNA profile after running thru gel electrophoresis
Gel Electrophoresis Set-up
Who Did It????
The ScenarioSomeone broke into the guidance office and attempted to tamper with students’ grades before the issuance of progress reports. Apparently, the culprit cut themself on glass from the broken door. Five students were caught on camera after school hours near the office. Your task is to analyze the DNA fingerprint to the left to determine which student should be expelled.
Closure
1. What may happen when chromosomes do not separate correctly during meiosis. (p.C-45, #72)
a. An extra base is added to DNA.
b. The wrong base is added to DNA.
c. A cell might have too many chromosomes
2. Which is an example of a clone? (p.C-47, #75)a. Corn grown from seeds
b. A plant grown from the stem of a cut plant
c. Kittens that look different from the mother
3. Scientists transfer genes from one organism into the DNA of another organism in ________________.
The Use of Restriction Enzymes
Half the class will: Cut the sentence using a restriction enzyme that cuts between “rr.”
The other half of the class will: Cut the sentence using a restriction enzyme that cuts between “he.”
My twin sister Sherry, older brother Larry, and I all went to the shopping mall to purchase a gift for our mother and new baby brother Harry.