Test Review

Reviewing Key Terms

In your Science Log, match the description in A with the correct term in B

A

- a deadly chemical
- the molecule that controls life
- three DNA bases
- not a sex cell
- the sequence of bases on a set of chromosomes
- a section of DNA that makes a protein
- a genetic duplicate

B

- codon
- amino acid
- herbicide
- clone
- DNA
- somatic
- gene
- bioremediation
- hormone
- genome

Short Answer Questions

What are the different types of mutations and how can they affect an organism?

Explain the relationship between DNA, genes, and chromosomes.

How can a karyotype be used to determine the gender of a person?

What are the advantages of using biotechnology to alter crop plants?

What are the advantages of bioremediation over other forms of cleaning up toxic waste?

Essay Questions

The gene for Human Growth Hormone has been added to bacteria, which produces the hormone in quantitiy relatively cheaply. What problems might this create?

Where would you look for an "anti-freeze" gene for fish?

Biotechnology in the Environment

In the 1980's, scientists began to look for ways to use micro-organisms to break down the complex compounds in toxic waste. This process is called bioremediation. Different species of bacteria and fungi can decompose or break down almost anything -- including chemicals that are toxic to humans. In many cases, the breakdown of complex compounds requires a group of different organisms called a consortia.

Oil Spill Bioremediation

Scientists are increasingly using bacteria to break down spilled oil. Few bacteria are capable of using oil as a nutrient. Bacteria are found in almost all soils, but the types of bacteria vary with the soil conditions.

Science Inquiry

Predict, in your Science Log, where you would find soil that contains bacteria capable of breaking down oil. Why do you think the bacteria are found there? Scientists, using bacteria to break down oil, often spray fertilizer on the mixture of bacteria and oil. Why do you think they do this?

The New Animals

Bovine Growth Hormone (BGH) is a hormone produced naturally in the bodies of cows and controls calf growth and milk production. Cows injected with this hormone can produce more milk than cows that do not receive hormone injections. In the 1980's, the gene for BGH was inserted into E. coli bacteria. These genetically engineered bacteria then produce the hormone like small factories so BGH can be injected into cows regularly.

Pause & Reflect

Do you think you have the right to know what substances are in the food you eat, or how your food is produced? Would you buy milk produced by genetic engineering? Why or why not? Would you pay more for milk that was not produced in this way? Write your responses in your Science Log and we will discuss it in class next week.

Genetics and Agriculture: What's For Breakfast?

http://www.scientificamerican.com/article.cfm?id=poison-plants

Visit the above link and read the article Poison Plants?

After reading the article, write one paragraph explaining whether you think genetic engineering of crops is a good idea or a bad idea? This site contains both sides of the debate on this controversy. Come to class prepared to debate your own idea.

Biotechnology in Agriculture

Today in class we learned about how cropbreeders, using biotechnology, can select a specific genetic trait (gene) from one species and move it into the genetc code of a crop plant to create a hybrid. Biotechnology allows breeders the opportunity to use genes from not only plants, but animals and micro-organisms. Go to the link below and read the short article "New Gene Fights Potato Blight"

blight: any plant disease resulting in the browning, then death of plant tissues

http://www.sciencenewsforkids.org/articles/20030723/Note2.asp

After reading the article, imagine that you are a transgenic scientist writing a letter to a potato breeder. Write a letter explaining the advantages of using genetic engineering techniques to fight blight. Remember that farmers normally use toxic chemicals to fight blight.

Biotechnology and the Human Body

Mutations may result in genetic disorders. Scientists have identified about 3000 diseases linked to genes. Genetic disorders may produce physiological and/or physical abnormalities or malfunctions. They may be diagnosed by looking at magnified images of a person's chromosomes which is called a karyotype. Click HERE to make a karyotype.

Click HERE for a website which will review how the processes by which mutations occur, examine some common mutations and their corresponding syndromes. The activity at the end will help you review the genetic defects associated with each syndrome.

In some cases, defective genes may be replaced by normal ones in a process called gene therapy. One method uses an altered virus as a vector for healthy DNA which it inserts into the patients bone marrow cells. The figure below illustrates this process. Click HERE to view a video which illustrates the process using the example of the first person - a 4 year old girl- to receive gene therapy.
The gene therapy examined here uses somatic cells to treat a patient with an inherited disease. The person's reproductive cells will, however, remain unchanged and the disease will be passed onto their offspring. Much ethical controversy exists over treating these cells.

The genome is the complete set of genes found on all the chromosomes of an organism. Knowing the location of genes on each chromosome will be an ideal tool for diagnosing genetic disorders. The Human Genome Project began in 1990 and is devoted to mapping the entire human genome. Click HERE to watch a video on the human genome.

Not all faulty or missing genes can be replaced easily. Bacteria or animals can be used to produce the missing gene products. For example, diabetics cannot produce their own insulin ( a hormone that regulates sugar levels within a person's blood). The gene for insulin production was transferred into a bacteria, which now produce insulin at low cost. Human growth hormone (to treat growth abnormalities) and interferon (a protein for the immune system) have been produced in this way as well.

In animals, human genes are added to the fertilized egg of parents. Usually the gene codes for the production of a protein that can be collected in the animal's milk. An example is Willow, a goat and Canada's first transgenic organism. Willow excretes a human protein in her milk. Click HERE to watch a video on transgenic animals.

Cloning

Cloning is the process of making identical copies of either molecules, genes, cells, or an entire organism. Clones of certain plants can be made by taking cuttings and putting them in water to grow roots. Cloning mammals is a little more labor intensive. The following diagram describes how mammals are cloned. Click HERE to see a real-life video of the first couple of steps of the mammal cloning process: the removal of a nucleus from a cell and the insertion of a new nucleus into the cell.