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26 Cards in this Set
- Front
- Back
How do you define genetics?
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Field of biology that studies the transfer of traits from one generation to another.
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In genetics, what is the flow of information in the cell, from DNA to RNA and eventually to proteins called?
How do viruses contradict this? |
Central dogma
Contradict it by going from RNA to DNA to protein, etc. |
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What is the the information containing region of the chromosome? How many of these regions are in E. coli?
What is it transcribed into? |
Gene; E.coli contains 3,000 to 4,000 different genes.
Into an RNA message |
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What is the the total complement of genes found in a cell?
What is the genetic composition of an organism? What is called when an organism expresses observable characteristics? |
Genome
Genotype Phenotype |
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How is phenotype observed in microbes?
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By looking at factors such as utilization of carbs or virulence
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T or F: A microbe can be virulent even though it has a simplistic metabolic pathway
If true, name an example |
TRUE FOOL
Ex: mycoplasma genitalium is deadly to infants but has small kbp |
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The genetic information contained in the DNA is first copied into mRNA a process called...
The mRNA relays information to synthesize protein molecules. This synthesis is called... |
transcription
translation |
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Prokaryotic mRNA is often BLANK (more than one cistron or gene).
This type of mRNA encodes for? |
polycistronic
Encodes for several proteins |
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What are the four bases of the genetic code? How many codons? How many code for AAs?
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A,G,U,C; 64 codons; 61 codons
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What are the three nonsense or termination codons?
What is their purpose? |
UAA, UAG, and UGA
They signal the termination of protein synthesis |
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Many amino acids are represented by more than one codon, thus...
The third position of the codon is... |
the code is degenerate.
the most degenerate. |
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Describe the degenerate codons for alanine
Which AAs are specified by one codon? |
They all start with GC (GCU, GCC, GCA and GCG); only the 3rd position matters
Tryptophan and methionine |
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Describe the two experiments that proved DNA was the genetic material.
What does this lead to? OTOH, very few strains... |
In 1928, Giffith found that nonvirulent R strains of S. pnuemoniae could be made virulent when mixed with heat killed S virulent strains.
In 1944, Avery, MacLeod, and McCarty found that this occured because DNA was taken up by R strains from S strains. This led to transformed recipients but very few strains of bacteria in nature are transformable |
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What did Watson and Crick find?
DNA details: The helix has a diameter of BLANK, and makes a complete turn every BLANK. There are BLANK per turn of the helix. BLANK bonding link the bases between the strands. The nucleotides are joined to each other in a chain by covalent BLANK bond between the BLANK carbon of one to a BLANK carbon of the adjoining deoxyribose. |
In 1953, DNA molecule consists of 2 polynucleotide chains arranged in a slender double helix.
20 A; 34 A; 10 bp Hydrogen; phosphodiester; # 3 (3’); # 5 (5’) |
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Species of bacteria vary as to their proportion of G+C to A+T. This ratio is as expressed as...
It ranges from BLANK to BLANK in bacteria. DNA with a high percentage of BLANK bonding tends to be more stable to unwinding or denaturation |
the mole % of G+C in the DNA (thermal mel curve)
22% to 74% G+C |
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As DNA denatures there is a sharp increase...
The temperature that corresponds to the midpoint of their increase in absorption is their BLANK. Differences in mole % between bacteria mean they are... |
in their UV abs, @ 260 nm.
Tm probably different species. |
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DNA structure details:
1. A binds to....and G binds to... 2. 2 polynucleotide chains in DNA helix are complementary and are... 3. So one strand is BLANK to BLANK, the other BLANK to BLANK. 4. What is the overall net charge? |
A=T and G=C
antiparallel 5’-PO4 to 3’-OH, the other strand is 3’-OH to 5’-PO4 negative |
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The chromosome in E. coli is BLANK bps and has a MW of BLANK.
Thus the DNA molecule is BLANK times longer than the E.coli cell length. |
4.7 x 10^6 bps; MW of 2.5 x 10^9
550 |
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Who came up with the semiconservative replication of DNA in 1958?
Describe their experiment. |
Meselson and Stahl
Grew isotope labeled nitrogen; after several generations, found that strands served as template for daughter strands as hybrid labeled DNA was seen. |
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DNA replication is both BLANK and BLANK. DNA was seen as a circular molecule with 2 replication forks, called BLANK replication.
Who discovered this replication pattern and how? |
Sequential and bidirectional; theta (Ө)
Cairns used autoradiographs by exposing 3H-thymidine treated lysed cells to photographic film, revealing the shape and replication pattern of the replicating DNA molecule. |
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In DNA replication, BLANK proteins recognize/bind to specific DNA sequence of BLANK bases at the...
This protein complex then binds to a DNA helicase which... DNA topoisomerases assist in... What are the two types of topoisomerases? |
Initiator; 300, origin of replication (ori C)
unwinds short sections of the helix in advance of the replication fork the DNA unwinding and rejoining of the DNA molecule type 1: works on 1 strand; type 2: works on both strands |
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Describe the sequences/steps of enzymes involved in DNA replication
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Dna A (9-mer/9bp from origin)
Dna C Dna B Dna polyemerase III loads the sliding clamp Dna polymerase binds to clamp and leading strand synthesis at the beginning of each template |
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In the process of DNA replication, Okazaki fragments in 1964 demonstrated that one of the DNA daughter strands was ...
These strands are called... |
synthesized discontinuously in short segments of 1,000 to 2,000 nucleotides in a 5’ to 3’ direction
The lagging strand |
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E. coli, has 3 different polymerases, I,II, and III. They all add mononucleotides to...
DNA polymerase III, will polymerize... DNA polymerase I, the Kornberg enzyme, is involved in... |
3’-OH end of a preexisting growing polynucleotide.
up to 30,000 nucleotides per minute DNA repair of UV damage, the excision-repair mechanism of DNA. |
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DNA polymerases, as studied in E. coli, are similar in size but...
DNA poly III is unique in that it is... DNA poly I primarily works on BLANK damage while DNA poly III is primarily for... |
but they polymerize different numbers of nucleotides.
the biggest and polymerizes the most nucleotides UV damage; synthesis |
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What is another mechanism of DNA replication? What things use this mechanism?
Describe this mechanism |
The rolling circle mechanism; seen in bacterial viruses/bacteriophages and during DNA replication in conjugation.
One of the strands is nicked at a specific site and the subsequent free 3’-OH end is extended by a DNA polymerase. |