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29 Cards in this Set
- Front
- Back
Where does replication begin? |
replication origin. |
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Each replication origin consists of _____ . |
two replication forksmoving in opposite directions. |
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What is DNA polymerase and what does it do? What does it require? |
The enzyme that directs new synthesis of DNA is calledDNA polymerase. DNA polymerase provides anenvironment in which the correctnitrogenous base can be aired with the next base in the template. |
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WHat does a primer do and how is it synthesized? |
afree 3’OH is provided by a primer that is actually made ofRNA. This primer is synthesized by a specialized RNApolymerase called a primase, which can incorporate newribonucleotides without a pre-existing 3’OH. |
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What drives the reaction between the 3’OH on the ribose sugar and thephosphate group joined to the 5’carbon on the incoming nucleotide? |
The energy of hydrolysis of thepyrophosphate (PPi) drives thereaction. |
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memorize this (flip) |
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Which is the leading strand? which is the lagging? Where is synthesis continuous? |
leading is on the 5'-3' end of the DNA. The leading strand is thus created from the DNAs 3' end to the 5'. The lagging is the exact opposite. |
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Why is synthesis not continuous in the lagging strand? |
not continuous becauseof the need to polymerize in the 5’ to 3’ direction so a new single strandeed DNA is exposed and new primers must be made. |
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What are okazaki fragments? |
The regions representingRNA primers and new DNA, with gaps. |
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What is the final step? This final step is catalyzed by______ and requires energy from ______. |
The final step is replacing the RNA primers with DNA. |
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What is PCR? What is the goal? |
Polymerase Chain Reaction. goal: generate large amounts of a particular double-strandedregion of DNA, starting with very little initial material, or from a complex mixture of material that includesthe DNA of interest plus a large amount of undesired DNA. |
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What are the three steps of PCR? Briefly describe. |
Denature: heat to 95 C |
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Applications of PCR? |
amplification of gene wo cloning. |
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Immediately following DNA replication, each _______ will consist of two ________ joined at a ________. |
chromosome, sister chromatids, centromere |
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What is a ploidy? If you carry two complete copies of your genome you are considered a ______, abbreviated _____. |
The number of copies of the complete genome in a cell. |
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What is the total # of chromosomes in most of our body cells? Where do we get our chromosome pairs from ? |
2n= 46. 1 from mom, 1 from dad. |
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What are homologous chromosomes? Homologous chromosomes have the same _____ in the same locations, but might differ in the ______. |
The two members of a chromosome pair. |
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What is a zygote? what does it do and how does it do this? |
a single cell 2n=46 created by the fusion of sperm and egg (fertilization), will replicate manytimes over to generate the ~10^14 cells in the human body. The process that accomplishes this is mitosis |
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True or false? all cells in our bodies carrythe complete genome |
True |
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Mitosis creates two types of cells, what are they? What is the starting cell and end product of meiosis? |
Soma and germ. |
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Differences and similarities between meiosis and mitosis? |
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Describe Meiosis. |
One parent cell (a "meiocyte") duplicates its DNA and undergoes through two sequential divisions("Meiosis I" and "Meiosis II"), resulting in four meiotic products that have half as many chromosomes as thestarting meiocyte. Meiosis has to occur in diploid (2n) cells -- the meiotic products will always be haploid(n). |
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What does the cell cycle look like? what are its components (5 or 2) ? |
during interphase, cells carryout metabolism and growth. |
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What happens during each phase of mitosis? |
interphase: DNAis replicated, chromosomes begin to condense(become more tightly wound), and structures calledcentrosomes divide telophase:, the DNA becomes decondensed,the nuclear envelope reforms, and cytokinesis follows soon after |
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what does it look like? |
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Meiosis produces.... |
four haploid (n)meiotic products |
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What happens in each step of meiosis? |
prophase I: closeassociation of homologous chromosomesthrough a pairing process called synapsis.During this close association of chromosomes, a reciprocal exchange event called crossing over occurs |
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True or false? There is DNA synthesis in mitosis and meiosis. |
False. not in meiosis. |
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reductional division vs equational division |
Because meiosis I results in a halving of chromosome number (2n -> n), it is called the reductional division,while meiosis II is called equational (n -> n). |