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Cards In This Set
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Give an over view of the break down of the MT genome
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What proportion of the MT and nuclear genome are protein or RNA encoding?
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 MT: 2/3 is protein coding genes in MT genome. about 1/3 is for RNA genes. So it is similar to a prokaryote, know because derived from symbiotic relationship between highly aerobic ? engulfed by facultative anaerobe so t’s orangization is also similar to a prokaryote |
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What is 7S DNA?
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What is the difference between the heavy and light strand of the MT genome?
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heavy strand : strand rich in G (purine)
light strand= other stand comprised mostly of C |
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In which direction does the heavy strand replicate?
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Starts at Origin of Replication for heavy (OH) ,
when replicates startes to unwind and synthesis, it goes ANTICLOCKWISE |
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Where is the OH in the MT genome?
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• in region of genome is actually non coding (no protein or RNA) very special region,
•known as D loop, triple helix (while rest of genome is double helix) the piece of extra DNA like sandwhich, juicy material is the 7S DNA. • this region is supposed to regulate DNA synthesis and other things (eg transcription. S means Svedburg constant (indirectly reflects its size) |
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What are genetic polymorphisms
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Genetic polymorphisim: genes in my genome are slightly different than yours (eg ABO blood grou)
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What is the most highly polymorphic region of the human genome?
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7S DNA is the most highly polymorphic in human genome. often used for forensics
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When does replication of the light strand initiate?
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During MT DNA synthesis, it will open up and proceed anticlockwise,
when the H strand is about 2/3 synthesized, it reaches a point in light chain (O L) which is very different from OH. so it will open up origin for light chain such that it will begin to replicate, it goes in opposite direction (clockwise). |
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How many polypeptide encoding genes are in the MT genome?
How many RNA genes? How many tRNA? How many rRNA? |
There are 13 polypeptide encoding genes.
besides these there are 24 RNA genes (in red lines). 22/24 are tRNA genes.small molecules so represented by narrow lines. in both the heavy and light chain. there are 2 genes that encode fore ribosomal RNA |
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Where does transcription start for each chain of the MT genome and in what direction?
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 heavy chain, goes in clockwise direction, Starts at PH (near OH) light chain it goes in anticlockwise direction Starts at PL (near OH) Note opposite direction from replication! |
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How many genes in MT genome?
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37 genes:
-2 rRNA -22 tRNA -13 polypeptides |
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How many MT tRNA recognize a degenerate 3rd codon?
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8 /22 tRNA
8x 4 = 32 codons |
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How many MT tRNA recognize either a purine or pyrimidine as the last base?
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14/ 22 tRNA
• total of 14 x 2 = 28 codons • i.e. the 22 mt tRNA can rec a grand total of 32 + 28 = 60 codons • human genetic code, 43 = 64 codons |
