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By the end of this section, you will be able to:
  • Explain the basic techniques used to manipulate genetic material
  • Explain molecular and reproductive cloning

Biotechnology is the use of artificial methods to modify the genetic material of living organisms or cells to produce novel compounds or to perform new functions. Biotechnology has been used for improving livestock and crops since the beginning of agriculture through selective breeding. Since the discovery of the structure of DNA in 1953, and particularly since the development of tools and methods to manipulate DNA in the 1970s, biotechnology has become synonymous with the manipulation of organisms’ DNA at the molecular level. The primary applications of this technology are in medicine (for the production of vaccines and antibiotics) and in agriculture (for the genetic modification of crops). Biotechnology also has many industrial applications, such as fermentation, the treatment of oil spills, and the production of biofuels, as well as many household applications such as the use of enzymes in laundry detergent.

Manipulating genetic material

To accomplish the applications described above, biotechnologists must be able to extract, manipulate, and analyze nucleic acids.

Review of nucleic acid structure

To understand the basic techniques used to work with nucleic acids, remember that nucleic acids are macromolecules made of nucleotides (a sugar, a phosphate, and a nitrogenous base). The phosphate groups on these molecules each have a net negative charge. An entire set of DNA molecules in the nucleus of eukaryotic organisms is called the genome. DNA has two complementary strands linked by hydrogen bonds between the paired bases.

Unlike DNA in eukaryotic cells, RNA molecules leave the nucleus. Messenger RNA (mRNA) is analyzed most frequently because it represents the protein-coding genes that are being expressed in the cell.

Isolation of nucleic acids

To study or manipulate nucleic acids, the DNA must first be extracted from cells. Various techniques are used to extract different types of DNA ( [link] ). Most nucleic acid extraction techniques involve steps to break open the cell, and then the use of enzymatic reactions to destroy all undesired macromolecules. Cells are broken open using a detergent solution containing buffering compounds. To prevent degradation and contamination, macromolecules such as proteins and RNA are inactivated using enzymes. The DNA is then brought out of solution using alcohol. The resulting DNA, because it is made up of long polymers, forms a gelatinous mass.

Four test tubes are illustrated, showing four steps in extracting DNA. In the first, cells are lysed using a detergent that disrupts the plasma membrane. In the second, cell contents are treated with protease to destroy protein, and RNase to destroy RNA. In the third, cell debris is pelleted in a centrifuge. The supernatant (liquid) containing the DNA is transferred to a clean tube. In the fourth test tube, the DNA is precipitated with ethanol. It forms viscous strands that can be spooled on a glass rod.
This diagram shows the basic method used for the extraction of DNA.

RNA is studied to understand gene expression patterns in cells. RNA is naturally very unstable because enzymes that break down RNA are commonly present in nature. Some are even secreted by our own skin and are very difficult to inactivate. Similar to DNA extraction, RNA extraction involves the use of various buffers and enzymes to inactivate other macromolecules and preserve only the RNA.

Questions & Answers

How many bones are in the human skeleton
Treasure Reply
203
Oyeleke
procce of digestion of proteins a long human alimentarycanal
Carson Reply
what are the properties of lipids?
Isiah Reply
They are: Fatty acids, fats, oils, waxes, phospholipid, glycolipids, steroids and some vitamins
Rachel
explain why a fresh water fish excrete ammonia
Leonard Reply
plz answer my question
Leonard
sorry i meant it has a nucleous unlike plant cells lol
Lailah
Ammonia is the end product of protein catabolism and is stored in the body of the fish in high concentrations relative to basal excretion rates. Ammonia, if allowed to accumulate, is toxic and is converted to less toxic compounds or excreted
Rachel
What are eukaryotic cells?
Nwosueke Reply
cell with no nucleous so not a plant cell
Lailah
eukaryotic cells are membrane bound organelles that have a membrane bound nucleus
ojeen
where does the cell get energy for active transport processes?
A'Kaysion Reply
IDK maybe glucose
Lailah
what is synapsis
Adepoju Reply
how many turns are required to make a molecule of sucrose in Calvin cycle
Amina Reply
why Calvin cycle occurs in stroma
Amina
why do humans enhale oxygen and exhale carbondioxide?
Maryam Reply
why do humans enhale oxygen and exhale carbondioxide? For the purpose of breaking down the food
dil
what is allele
uzoka Reply
process of protein synthesis
SANTOSH Reply
what is cell
Zulf Reply
a cell is a smallest basic, structural and functional unit of life that is capable of self replication
Lucas
why does a fresh water fish excrete ammonia
Leonard
plz answer my question
Leonard
Ammonia is a toxic colorless gas and when its inside the fish biological system is converted to a less toxic compound then excreted in the form of urea. However too much ammonia will kill the fish " Ammonia Poisoning " which is a very common disease among fish.
This
what is cytoplasm
uzoka Reply
cytoplasm is fluid of cell.
Deepak
how many major types of Cloning
Saeed Reply
two
amir
two
Zulf
comparative anatomy of gymnosperms?
Meenakshi Reply
anatomy of gymnosperms
Meenakshi

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Source:  OpenStax, Concepts of biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11487/1.9
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