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12bio5785
CU intro to bio: lec 12
| Question | Answer |
|---|---|
| DNA Is composed of what? | it is composed of four kinds of nucleotides, each of which consists of a five-carbon sugar (deoxyribose), a phosphate group, and one of four nitrogenous bases |
| What are the four nitrogenous bases that could be attached to a DNA molecule? | adenine (A) guanine (G) thymine (T) cytosine(C) |
| What are the similarities between the four nitrogenous bases that could be attached to DNA? | The bases are similar, but T and C are single-ringed pyrimidines, whereas A and G are double-ringed purines... |
| In 1949, Chargaff noted two critical bits of data; which were? | The four kinds of nucleotides making up a DNA molecule differ in relative amounts from species to species. in every species the amount of A = T, and the amount of G = C. |
| Rosalind Franklin used X-ray diffraction techniques to produce images of DNA molecules.From these images, Franklin made several observations such as? | DNA exists as a long, thin molecule of uniform diameter. The structure is highly repetitive. DNA is helical... |
| what is helical? | haveing the form of a spiral |
| Anti-parallel | the two strands run in opposite directions |
| in 1953 who published the structure of DNA? | Watson and Crick |
| Concept of base pairing from Watson and Crick's models.... | Single-ringed T was hydrogen bonded with double-ringed A, and single-ringed C was hydrogen bonded with a double-ringed G, along the entire length of the molecule. |
| This concept of base pairing is constant for all species, but the sequence of base pairs in a nucleotide strand is .... (watson and crick) | different from one species to the next. The sequence, then, is the basis for life’s diversity |
| The DNA backbone is made of what? (watson and crick) | chains of surgar-phosphate linkages |
| what does a molecule of DNA look like? (watson and crick) | The molecule was double-stranded and looked like a ladder with a twist to form a double helix |
| A eukaryotic chromosome contains what? (every one) | onel ong DNA molecule |
| TorF: The DNA of humans and other eukaryotes is not highly organized and can get tangled, causing sicknesses, deformities, or pains: hedaches, stomach cramps, or muscle weakness. | False:The DNA of humans and other eukaryotes is highly organized to prevent tangling |
| Histones | are a type of protein that act as spools to wind the DNA into units called nucleosomes. (Each nucleosome consists of 1 histone and 2 loops of the DNA molecule.)...Other histones stabilize this arrangement and allow the beaded chain to form looped regions |
| DNA REPLICATION!!!! DRAW IT OUT! | |
| What are the first few steps of DNA replication? | First, the two strands of DNA unwind and expose their bases. |
| RNA primase – | lays down an RNA Primer |
| DNA polymerases – | add nucleotides onto an existing strand and proofreads new bases for mismatched pairs, which are replaced with correct bases |
| What is the difference between a "new" and old strand? | AFter the replication of DNA, the strand that was replicated is called the old strand, and the strand that replicated is called the new strand. |
| What are ssBP | (“Single Strand Binding Proteins”) – bind single-stranded regions of DNA to prevent premature re-combining |
| this splits and unwinds the double-stranded DNA | Helicase |
| DNA ligase | This attaches the nucleotide to an okazaki fragment |
| What is the difference between a "new" and old strand? | AFter the replication of DNA, the strand that was replicated is called the old strand, and the strand that replicated is called the new strand. |
| What are ssBP | (“Single Strand Binding Proteins”) – bind single-stranded regions of DNA to prevent premature re-combining |
| this splits and unwinds the double-stranded DNA | Helicase |
| DNA ligase | This attaches the nucleotide to an okazaki fragment |
| How does helicase split the two strands? | by breaking the hydrogen bonds between nucleotide bases of teh two anti-parallel strands. |
| What is teh Origin of Replication? | The initiation point where the splitting starts |
| ToF: Viral and bacterial DNA unwind in many places, in contrast to Eukaryotic DNA unwinding at "one" origin | TRUE. |
| Where does the unwinding of the two strands usually occur? (relating to the type of bonds) | The unwinding of the two strands occurs in places along the molecule that are rich in A-T bonds, since this is where two hydrogen bonds hold the strands together, as compared to the three hydrogen bonds found between C & G. |
| There are __ Hydrogen bonds between A-T | two hydrogen bonds |
| there are __ hydrogen bonds between C-G | three hydrogen bonds |
| What is the replication fork? | The structure that is created (the origin of replication along with the two unwound strands) is known as the "Replication Fork. |
| When the Dna is unwinding and the strands are assembling.... which direction does the process go from the replication fork? | Unwinding and strand assembly proceed simultaneously and in both directions at replication forks. |
| WHat do DNA polymerases requre to elongate DNA. why does it need this? | They need a RNA primer (rarely DNA).They need this because they cannot begine a new strand of DNA b/c it only binds nucleotides to a free sugar (3') end of a nucleotide chain. |
| How does the RNA primer work? | RNA primase binds to the unwound strands at the origin and attaches several RNA nucleotides that serve as primers. The primers are starting points for the binding of DNA nucleotides by DNA Polymerase. |
| How does DNA Polymerization work? | It occurs in a 5'-3' direction although (It reads 3'-5') |
| What are the two types of elongation processes for DNA replication? | Continuous strand (AKA leading Strand) Discontinuous strand (AKA lagging strand) |
| Continuous Strand (AKA Leading Strand) elongation process of DNA? | Continues without interruptions.... needs only one 1 Rna primase. |
| Discontinuous (AKA Lagging Strand)elongation process of DNA? | Completely different than the Continuous strand. In the lagging strand several RNA primases are required to first add a primer. DNA then Elongates till it hits another primer in which there is a gap left in the strand. |
| Okazaki Fragments | The fragments that are separated by these gaps are called |
| "DNA Damages" are what? and are the result of what? | Mistakes in the DNA. Caused from Mismatches during elongation that were not caught by the "DNA proofreading mechanisms" ALSO Mistakes can be the cause of, viruses, radiation, and chemicals for example.S |
| Glycosylases is a what? and does what? | Repair enzyme, works to fix damaged sites on DNA that slip by the proofreaders, or occur from radiation or chemicals by excising the damage or mismatch and replacing it with a suitable base. |
| WHat are three types of Cloning that use DNA? | Embryo Cloning, Adult Cloning, and Therapeutic Cloning. |
| Embryo Cloning? | Clone large animals, not new, Small clusters of cells are then implanted into surrogate mothers, where they grow into identical clones |
| Adult Cloning? | The nucleus from an adult animal�s already differentiated cell (for example liver cells) replaces an unfertilized egg�s nucleus by microinjection in a process known as nuclear transfer. The cell is induced to divide by chemicals or electric shock |
| Therapeutic Cloning | Using nuclear transfers, DNA of a somatic cell from the heart, liver, muscles, or nerves is transplanted into a stem cell, which is an undifferentiated cell that can still divide. These cells then go different cells types of specific tissues and organs |
| Nuclear Transfers | The nucleus from an adult animal's already differentiated cell (for example liver cells) replaces an unfertilized egg�s nucleus by microinjection in a process known as nuclear transfer.�Rh�! |
| Somatic Cell nuclear Transfer.... | SCNT... produces stem cells that are a genetic match to a patient affected by an incurable disease or spinal cord injury. It also has the potential to regenerate organs. |
Created by:
jseekins
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