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27 Cards in this Set
- Front
- Back
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What is the ‘central dogma’ of molecular biology?
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The central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. It states that information cannot be transferred back from protein to either protein or nucleic acid.
*Once information is sent to protein, it can’t go back to the nuclei acid |
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What is replication?
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The process by which double-stranded DNA makes copies of itself, each strand, as it separates, synthesizing a complementary strand.
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What is transcription?
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The process by which genetic information on a strand of DNA is used to synthesize a strand of complementary RNA.
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What is translation
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The process by which a messenger RNA molecule specifies the linear sequence of amino acids on a ribosome for protein synthesis.
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What is a nucleotide?
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A compound consisting of a nucleoside linked to phosphoric acid.
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What is the leading strand?
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Newly synthesized DNA
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What is the lagging strand?
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Because of DNA’s Antiparallel nature and the directionality of DNA polymerase, the other DNA strand is synthesized, again in the 5’ to 3’ direction, as a series of fragments.
A series of fragments Each individually synthesized in a direction opposite to the overall direction of replication |
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What is the Okazaki fragment?
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A re joined together by DNA ligase
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what does DNA polymerase do?
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bond new strands of DNA, after copying
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What does the replication fork do?
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At either end of the bubble, where the existing strands are being separated and the new, complementary strands are being synthesized, the molecule appears to form a Y-shaped structure
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What is an exon?
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A segment of DNA that is both transcribed into RNA and translated into protein
Exons are characteristic of eukaryotes. |
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What are Introns?
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A portion of mRNA as transcribed from eukaryotic DNA that is removed by enzymes before the mRNA is translated into protein
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Describe Genetic Code.
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Universal, almost identical in all organisms
The genetic code consists of 64 condons (triplet combinations of mRNA bases) and their corresponding amino acid. Of the 64 condons, 61 specify particular amino acids. The other three condons are stop signals, which cause the polypeptide chain to terminate. |
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What's an amino acid?
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Nitrogen containing organic acids, the units, or “building blocks” from which protein molecules are built
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What does Transfer RNA do?
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Translate the coded nucleotide sequence of mRNA into the amino acid sequence of protein.
Carries the amino acids to the ribosome’s, where they are attached to a growing polypeptide |
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What does messenger RNA do?
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DNA serves as a template for the synthesis of mRNA molecules, a process called transcription
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What is RNA and how does it differ from DNA?
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•Sister molecule to DNA
•Cells that are synthesizing large amounts of protein invariably contain large amounts of RNA •Found mostly in the cytoplasm where protein synthesis takes place •Long-chain macromolecule of nucleic acid •Different from DNA: oIn the nucleotides of RNA, the sugar component is ribose rather than deoxyribose oThe nitrogenous base thymine is found in DNA but does not occur in RNA. Instead, RNA contains a closely related pyrimidines, uracil. Uracil, like thymine, pairs with only adenine. oRNA is usually single-stranded and does not from a regular helical structure |
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Describe the process of transcription DNA to RNA
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The genetic information encoded in the DNA is transcribed into an RNA copy. This copy is then modified with the addition of a cap at the 5’ and a poly-A tail at the 3’ end. The introns are snipped out, and the exons are spliced together. The mature mRNA then passes to the cytoplasm where it is translated into protein.
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Describe the process of translation RNA to proteins
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A ribosome is formed from two subunits, one large and one small, each consisting of characteristic ribosomal RNAs (rRNA) complexed with specific proteins. Also required for protein synthesis is another group of RNA, tRNA. These small molecules can carry an amino acid on one end, and they have a triplet of bases, the anticodon, on a central loop at the opposite end of the three-dimensional structure. The tRNA molecule is the adapter that pairs the correct amino acid with each mRNA codon during protein synthesis. There is at least one kind of tRNA molecule for each kind of amino acid found in protein.
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What does a restriction enzyme do?
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Detects specific sequences of DNA
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What does Single strand binding (SSB) do?
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prevents reannealing (keeps the strands separated)
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What does the sliding clamp do?
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helps hold polymerase on DNA
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what does DNAse H do?
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Removes RNA primers
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What does Polymerase do?
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Extends DNA Chain
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what does primase do?
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create RNA primers
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What does helicase do?
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seperates DNA strands
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What does ligase do?
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Links short DNA chains
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