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Introduction to Wikis
1 The Science of Biology
2 Organic Chemistry and Water
7 Cell Structure and Function
10 Cell Growth and Division
11 Introduction to Genetics
12 DNA and RNA
13 Genetic Engineering
13 Genetic Engineering Part 2
14 The Human Genome
12 DNA and RNA
DNA and RNA are two different nucleic acids found in everything living. They have similar structures made of long chains of nucleic units.
RNA is single stranded with an uracal at its base. DNA is a double helix with a thymine at its base.Their structures are different but they have cooperiting roles in the cell.
DNA contains genitic information of an orginism, which dictates how the body makes new protiens according to the genitic code of that partictular orginism. DNA is orginised into chromosomes which duplicate during cell dvision. The chromosomes than relece the genitic codes which are than carried by RNA to the ribosomes which willcreate new protens to help the body grow.
Oswald Avery, an Canadian biologist, discovered that DNA is the nucleic acid that stores and transmits the genetic information from one generation of an organism to the next.
The structure of DNA was discovered by Francis Crick, a British physicist, and James Watson, an American biologist. Their models were maade of cardboard and wire. They twisted and turned the models but their best results did not explain DNA's property. Watson and Crick had the break through after they saw a copy of Franklin's X-ray pattern. Within weeks they figured the structure out, a double helix with two strands wounded around each other.
DNA is a long molecule mad up of units called nucleotides, made up of three basic parts: 1) a 5 carbon sugar called deoxyribose
2) a phosphate group
3) a nitrogenous base -> 4 bases: 1) Adenine (not finished)
3 Main Differences between DNA and RNA:
1) The sugar in RNA is ribose instead of deoxyribose.
2) RNA is single-stranded and DNA is double-stranded.
3) RNA contains uracil in place of thymine.
Types of RNA:
1) Messenger RNA: carry copies of instructions for assembling amino acids into proteins (called mRNA)
2) Ribosomal RNA: Protens are assembled on ribosomes. Ribosomes are made up of several dozen proteins, as well as a form of RNA known as ribosomal RNA (called rRNA)
3) Transfer RNA: transfers each amino acid to the ribosome as it is specified by coded messages in mRNA (called tRNA)
During DNA replication, the DNA molecule produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template for new strand.
This process ensures that each resulting cell will have a complete set of DNA molecules.
RNA molecules are produced by copying part of the nucleotide sequence of DNA into a complementary sequence in RNA, a process called
Transcription requires an enzyme known as RNA polymerase that is simular to DNA polymerase. During transcription, RNA polymerase binds to DNA and seperates the DNA strands. RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled in to a strand of RNA.
Transformation is the process of passing a characteristic from one bacteria to another. Example: The scientist Griffith isolated two slightly different strains of pneumonia disease and
injected mice with both of the bacterias and the first strain (the disease-causing) killed the mice but the harmless one did not. The next thing Griffith did was heating the disease-
causing up to kill the bacteria. He injected mice and they survived. After that he injected both (the heat killed disease-causing and the harmless bacteria) in mice and expected them
to survive but most of the mice died. So he examined the mice's lungs and found them full with disease-causing bacteria. Somehow the heat-killed bacteria had passed their disease
-causing ability to the harmless strain. Griffith called this process
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