Term
What are the four nitrogenous bases in DNA? Purines and Pyrimidines? |
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Definition
| Purines (adenine and guanine) Pyrimidines (cytosine and thymine) |
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Term
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Definition
| Nitrogenous base, pentose sugar (deoxyribose), and phosphate |
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Term
| How are the two polynucleotide strands held together in the DNA double helix? |
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Definition
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Term
| What is the pattern of complementary base pairing in DNA? |
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Definition
Adenine - Thymine Cytosine - Guanine |
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Term
| To which end of each growing strand are nucleotides added in DNA replication? |
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Definition
| The 3’ end which contains the hydroxyl (OH) group |
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Term
| What is the replication complex? |
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Definition
| A large protein complex that binds to the template strand of the DNA |
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Term
| What is an origin of replication? |
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Definition
| The specific site on the template DNA that the replication complex binds to, this site is specific |
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Term
| What is the replication fork? |
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Definition
| From each origin of replication the DNA is replicated in both direction called the replication fork |
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Term
| 1. What is the function of DNA polymerase? |
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Definition
| Unzips the DNA (along with other enzymes) and synthesizes new DNA (5’ to 3’) in both directions, corrects mistakes |
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Term
| 1. What are the leading and lagging strands? |
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Definition
| The leading strand it where replication takes place continuously. The lagging strand makes many small fragments that have to be connected later on by the enzymes from the replication complex. |
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Term
| 1. How does replication differ on the leading and lagging strands? |
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Definition
| Leading strand the replication is continuous whereas the lagging strand makes the new DNA in short discontinuous fragments that will be connected by the replication complex. |
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Term
| 1. What is the role of Okazaki fragments? |
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Definition
| Is to synthesize the other copy of DNA that is going in the “wrong” direction |
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Term
| 1. What does the proofreading function of DNA polymerase accomplish? |
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Definition
| If there is a wrong nucleotide then the DNA polymerase removes it and replaces it with the correct one. |
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Term
| 1. What is the function of mismatch repair proteins in DNA replication? |
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Definition
| The mismatch repair proteins search for mismatches in the newly formed DNA, if they find one they remove the mismatch and a few nucleotides around it and DNA polymerase comes through and replaces the missing nucleotides. |
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Term
| 1. How does RNA differ from DNA? |
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Definition
RNA consists of a single polynucleotide strand the sugar molecule in RNA is ribose, rather than deoxyribose the nitrogenous base uracil (U) occurs in place of thymine (T) (the other 3 bases are the same).
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Term
| 1. What is the function of RNA polymerase? |
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Definition
| It catalyzes the formation of mRNA from DNA (i.e. transcription) |
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Term
| 1. How do initiation, elongation, and termination occur during transcription? |
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Definition
| Initiation – RNA polymerase binds to the promoter of the DNA. Elongation – after binding to the promoter, the RNA polymerase begins to add nucleotides to the 3’ position on the new strand. Termination – elongation stops when it reaches a specific nucleotide sequence in the DNA |
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Term
| 1. What is a promoter in the context of transcription? |
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Definition
| It is the site were the RNA polymerase binds to begin transcription, it includes the initiation site |
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Term
| 1. What is the genetic code (in general terms)? |
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Definition
| It is the sequence of nucleotides on the mRNA that code for the amino acid to be produced. |
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Term
| 1. What do the codons AUG and UAG specify? |
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Definition
| AUG – Methionine or start codon UAG – Stop codon |
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Term
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Definition
| Sites of translation. In Eukaryotes there are 3 large subunit that contain 45 different proteins molecules and the one smaller subunit contains 33 protein molecules |
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Term
| 1. What is transfer RNA and how does it function in translation? |
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Definition
| Transfer RNA has the anticodon of the mRNA codon. The mRNA will bind to the tRNA and the other side of the tRNA has a spot for a specific amino acid that the mRNA coded for. |
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Term
| 1. How do initiation, elongation, and termination occur in translation? |
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Definition
Initiation - small ribosome binds to mRNA and a charger tRNA (methionine) binds to the mRNA and so does the large ribosome Elongation - binds one to 2 and releases one and adds another Termination - Stop condon binds a release factor which hydrolizes the polypeptide sequence |
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Term
| 1. What is an initiation complex? |
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Definition
| Translation of mRNA begins with the formation of an initiation complex. Specifically, a small ribosomal subunit binds to a recognition sequence on the mRNA molecule, and a charged tRNA molecule carrying a methionine binds to the start codon (AUG) on the mRNA. |
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Term
| 1. What amino acid is the first one in the polypeptide sequence (as specified by the start codon)? |
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Definition
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Term
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Definition
| An assemblage consisting of an mRNA molecule with a set of associated ribosomes and their growing polypeptide chains is called a polysome. |
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Term
| More that 4 codons, varies at the ___ position? |
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Definition
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Term
| Less than 4 codons, varies at the ___ position? |
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Definition
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Term
| What drives the elongation reaction? |
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Definition
| breaking of the phosphate bonds |
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