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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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.