biology homework?

Question

i need help studying for a biology test tomorrow on gene technology. can anyone help me??? if so, could you possible tell me asap???? thank you.

Answer 1

Gene technology is a term that refers to a whole range of techniques for genetic analysis that depend on the direct manipulation of DNA, the material substance of heredity.

The use of gene technology in biomedicine, agriculture, food production and processing is an issue that has evoked strong public interest and concern. The debate has focused on the use of genetically modified organisms (GMOs) in food, their safety and potential impact on the environment. The public better accepts medical and industrial uses of gene technology.

The majority of Australians are eager for more quality information about the technology and its applications.

Most people think of gene technology as adding genes from other life forms to plants and animals. While this is certainly part of it, the technology is broader than that, and has many more uses.

Gene technology is developing at a rapid rate and it will continue to revolutionise basic biological research and development. It provides the potential to improve our health, create a safer and more secure food supply, generate greater prosperity and attain a more sustainable environment.

Gene technology is already providing new ways of preventing, treating and curing human and animal diseases; it is helping farmers improve agricultural production with less impact on the environment; and in the near future, it will allow better food products to be available to consumers at reduced cost.

The technology has given us vital new products like human insulin for diabetes, interferon and other drugs for treating certain cancers, and vaccines against diseases like hepatitis B. Millions of human lives are protected by gene technology every day.



What are genes?

Genes are made from a chemical called DNA (deoxyribonucleic acid) that is common to all forms of life on Earth. Genes carry information for making all the proteins required by all organisms. These proteins determine, among other things, how the organism looks, how well its body uses food or fights infection, and sometimes even how it behaves.

DNA is made up of four similar chemicals (called bases and abbreviated A,T, C, and G) that are repeated millions or billions of times throughout a genome. A genome is the entire DNA in an organism, including its genes. The human genome, for example, has 3 billion pairs of bases.

The particular order of As, Ts, Cs, and Gs is extremely important. The order is called DNA sequence and variations in sequence underlie all of life’s genetic diversity. DNA sequence is the database determining how the cell is to make proteins and what functions the proteins can perform.

Because all organisms are related through similarities in DNA sequences, insights gained from non-human genomes often lead to new knowledge about human biology, and insights from the genes of a bacterium, worm or bee might contribute to new solutions for the wheat farmer.



What is gene technology?

Gene technology consists of tools and techniques that scientists can use to study, identify or modify the genes of living organisms.



Techniques and tools

Genetic modification

Over 20 years ago it was discovered that genes, and parts of genes, could be extracted from DNA using protein "scissors" then copied, or cloned.

The gene could then be equipped with genetic "switches" to turn it up or down and inserted back into a living organism. This is the basis of genetic modification. It allows the sequences of genes to be determined.

Transferring single genes between different plants and animals, turning existing genes up or down, or removing a gene from its original position and placing it in a new position in the same organism are all referred to as genetic modification (GM). The terms genetic engineering (GE) or genetic manipulation also mean the same thing.

Plants, animals or microbes which have a new gene inserted into them are called genetically modified organisms (GMOs) or transgenics. The modified gene belongs to the new host but its sequence is altered for example, on the basis of specific information gleaned from studies of other organisms.

DNA sequencing

DNA sequencing is the process of determining the exact order of the chemical building blocks (bases) that make up DNA. It is a laboratory procedure that involves first breaking down the DNA into short pieces, followed by separating the individual fragments using a technique called gel electrophoresis. A bar code pattern of the DNA pieces is produced which can then be read by computer.

An enormous volume of information on the genetics of organisms is being generated using this technique and is providing computer experts with a great challenge in handling the data.

Human Genome Project

The Human Genome Project (HGP), which began in 1990, was a 13-year international project involving Australia. Its goal was to discover the approximate 50,000 genes that make up the human genome, make them accessible for further biological study and to determine the complete sequence of the 3 billion DNA subunits.

Knowledge gained through this research will allow scientists and doctors of the future to prevent or treat most diseases at the level of genes.

While it is now common to screen infants for inherited genetic diseases, further understanding of the human genome will allow doctors to determine a person’s chances of developing particular diseases later in life. They will then be able to give advice or treatment to prevent, slow or cure those diseases.



Cloning technology

A "clone" is a copy of a plant, animal, microorganism or gene derived from a single common ancestor gene, cell or organism. Identical twins are natural clones from the one fertilised egg. A plant cutting is a clone of the original plant.

Some confusion arises because the word clone is also applied to genes. A gene is said to be cloned when its sequence is multiplied many times in a common laboratory procedure. The cloning of a gene is a step in determining its sequence and initiating many types of experiments to understand its function and biology.

The possibility of human cloning, raised when Scottish scientists at the Roslin Institute created the much-celebrated sheep "Dolly" in 1996, aroused worldwide interest and concern because of its scientific and ethical implications.

Dolly was produced by injecting a nucleus from a mammary cell into an egg cell without a nucleus and raising an animal from that egg by treating it as a fertilised egg. Dolly was therefore a genetic clone of the animal from which the nucleus was taken. The important difference from identical twins is that the donor was a mature sheep and could even be made the mother of the clone.

Cloning of animals and plants can be used to develop more efficient ways to produce superior breeds of animals. Cloning also enables genes to be added (such as those for human proteins) to produce animals that can generate hormones and other pharmaceuticals in milk, eggs or other products.

The governments of many nations involved in gene technology have banned the cloning and genetic modification of human individuals. However, cloning technology may soon be available for human benefit to produce whole organs or special tissues from single cells for transplant to humans. It should be possible to use cells from the patient’s own body and correct genetic defects before growing the tissue for transplant back into the donor. This is called therapeutic cloning.



Gene marker technology

DNA probes in diagnosis

Scientists can use gene technology to locate and analyse single genes in a chain of many thousands. They can make gene probes that recognise DNA sequences associated with genetic diseases. The diagnostic tests involve analysing minute tissue samples collected from adults, or taken from embryos.

This information can assist parents and doctors to reduce the incidence of crippling genetic defects, and treat other disorders much better.

Forensic DNA fingerprinting

No two individuals have the same genetic makeup, a fact that is now being used by forensic scientists to identify individuals from cell samples left at a crime site.

"Forensic DNA fingerprinting" involves taking a blood or tissue sample from a person and using one of a number of gene technologies to generate patterns of DNA fragments separated by size. Those patterns look something like a long bar code and are dependent on the exact sequences in the sample. A match between the genetic fingerprint from the crime sample and the suspect has been admissible evidence for a number of years.

DNA markers in breeding

For centuries plants and animals have been selectively cross-bred for desirable traits such as size, enhanced quality and pest resistance.

Scientists can now use DNA information to identify desirable traits in organisms. These DNA markers are helping breeders to select superior strains of plants or types of animals for commercial production.

The technique is similar to the forensic DNA fingerprint but where a particular DNA bar is known to be associated with a specific superior trait. By using these markers superior animals or plants can be identified easily and early and these individuals selected for further breeding to improve the herd or crop.

CSIRO research on gene markers includes:

markers in cattle for carcass weight, fat content, colour, meat tenderness and leanness. This information assists breeders to select superior types of animals.
in fish farming, markers are helping breeders of super prawns select for desirable traits like size and colour, disease resistance and environmental suitability.
in crop breeding, markers are being used to combine genes for disease resistance and quality characteristics, such as higher yield and bread making properties in wheat.
Most animals, plants and fish are still bred in the same way they have been for over 2000 years — but gene technology means that breeders can now pick the best parents with greater precision.



Transgenics

Because DNA is the same in all living things, researchers have found it possible to use genetic information derived from one organism in the modification of the genes of another. It is possible to modify the physical characteristics in precise ways.

The term 'transgenics' often used to describe transferring genes between species, but in reality the process is a sharing of genetic knowledge for specific outcomes. In practice, the modified gene often has some of the gene sequences and signals from the host with some sequence information provided by the donor. Gene transfers typically involve the exact modification of one gene while leaving the other 50,000 genes unaffected.

Over the last 25 years, researchers have learned how to make precise genetic changes by identifying and transferring individual genes to produce a desired characteristic.

Scientists can insert new genes into an organism to add a particular trait not found in that organism. The new organism is then tested over several generations before researchers know whether the modified organism has all the intended benefits.

Methods for inserting a gene into an animal or plant include:

microinjecting into an animal egg using a fine tube
using harmless viruses to carry genes into a host
inserting DNA into plant cells on gold or tungsten particles
using Agrobacterium, a bacterium that naturally transfers DNA into plants.
Genes are being introduced into plants to produce:

resistance to insect attack or microbial damage, so reducing pesticide sprays and natural carcinogenic aflatoxins (mould toxins)
tolerance to benign herbicides, so weeds can be controlled and erosion minimised through minimum tillage farming
higher quality protein and enhanced vitamin or iron levels
healthier vegetable oils and starches.
Genes are being inserted into animals to make them:

produce more meat and less fat
grow faster
produce more meat or milk for the same amount of feed
become more resistant to disease and parasites.
Because the techniques used to transfer genes sometimes have a low success rate, before a gene is transferred, another gene — called a "selectable marker gene" - is sometimes attached to the target gene to let researchers know whether the new gene is present or not.

Scientists often use genes for antibiotic-resistance as selectable markers to show if plants have taken up a new gene. This practice allows only the genetically modified cells to grow in a special culture that contains the specific antibiotic. The antibiotics are used only in the laboratory and are of no medical significance. The antibiotic resistance genes employed are already widely distributed through the natural environment, such that their presence in the plant is of no environmental consequence.

Nevertheless, because of public concerns about antibiotic-resistance genes, researchers have developed ways to remove these gene markers from plants before they are released commercially. New types of marker genes have also been developed, such as those permitting growth in the laboratory on unusual sugars.



Gene silencing

A gene that is producing undesirable characteristics in an organism can be turned down or switched off. One way this can be achieved is by inserting a second copy of the gene, or a fragment of the gene, back to front. Other ways include RNAi and "gene shears", which cause the gene message molecule to destroy itself. This cancels the effect of the undesirable gene.

Gene silencing is being used to:

protect plants from viruses
alter the colour of ornamental flowers
delay ripening of tomatoes and peaches so they reach the consumer in better condition
remove allergens (proteins that cause allergies) from peanuts, soybeans and wheat
stop undesirable browning in potatoes and raw sugar.


Gene therapy

Many human and animal diseases have now been traced to their host being born with faulty genes that produce defective proteins. These diseases include sickle cell anaemia, cystic fibrosis, the blood clotting disorder haemophilia and Down’s syndrome.

Modern medicine and surgery have made great strides in treating patients with genetic diseases. Scientists are now exploring the use of gene therapy to attack these diseases at their source — by correcting faulty genes.

Gene therapy holds great promise for treating disease by replacing or changing a very small part of the overall genetic program of carefully selected cells, perhaps permanently, producing a cure.

It aims to restore the healthy function of cells by replacing or correcting the defective gene. Gene therapy can be used to replace an abnormal gene with a normal one, to insert a missing gene, to switch off rogue genes that may cause cancers and to stop viruses multiplying within cells. The modified cells and genes are not passed onto children.

Certain technical obstacles are yet to be overcome if gene therapy is to deliver the expected benefits to treat human disease. Among the obstacles is the lack of a delivery system, or vector, that can safely and efficiently shuttle beneficial genes into the cells of patients — and ensure they work.

Even the most advanced cell therapy techniques are still at the experimental stage in clinical trials. Further research is needed to develop safe, reliable gene therapy techniques

Answer 2

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Answer 3

whats the question you're needing help with.