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58 Cards in this Set
- Front
- Back
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What four properties must genetic material possess?
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Stable, informational, able to replicate, and capable of variation and mutation.
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What are the five candidates for genetic material? Which three are considered part of genetic material?
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Proteins, polysaccharides
nucleic acids, DNA, and RNA. |
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Explain what the Griffith's Transformation Experiment was.
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Used different strains of Streptococcus to find a transforming principle. IIR strain = nonvirulent, IIIS strain = virulent. R = rough, S = smooth. Smooth had a polysaccharide coat. Ran four mice tests, IIR -> mouse = survives; IIIS -> mouse = dies; IIIS heated -> mouse = survives; IIR living, IIIS dead (heated) -> mouse = dies
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What is the significance of Griffith's Transformation Experiment?
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Some IIR bacteria had been transformed into smooth, virulent IIIS by an unknown transforming principle.
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What is a eukaryote?
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Meaning 'true nucleus', are organisms with cells within which the genetic material (DNA) is located in the nucleus.
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What is a prokaryote?
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Meaning 'prenuclear' do not have a nuclear envelope surrounding their DNA.
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What does the term nuclease mean?
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Enzymes that degrade nucleic acid.
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What was Avery's Transformation Experiment and what was its significance?
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RNase and DNase were added to mixtures of DNA and RNA to determine which one was the transforming principle. When no IIIS transformation resulted when DNase was used, and the opposite for RNase, DNA had to be the transforming principle.
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What was the Hershey and Chase Bacteriophage Experiment?
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It provided more evidence that DNA was the genetic material. Question was between DNA and proteins. Created two batches of T2, one with DNA labeled radioactively with P-32, other protein with S-35. Then infected E. coli. DNA passed on genetics to host, genetic material still found in protein phage ghosts.
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What is a phage?
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Short for bacteriophage, they are viruses that attack bacteria.
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What is the lytic cycle?
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The life cycle of a phage by infecting a bacteria and producing progeny phages that are released from the broken-open bacteria.
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What dd all of the experiments prove?
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They proved that the genetic material consists of one of two types of nucleic acids: DNA or RNA. Of the two, DNA is the genetic material of all living organisms and of some viruses, and RNA is the genetic material of the remaining viruses.
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What is a nucleotide?
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A nucleotide consists of a pentose sugar, a nitrogeneous base, and a phosphate group.
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Know how to draw the pentose sugars of DNA and RNA. DNA has how many OH off what carbon prime? RNA has how many OH off what carbon prime?
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DNA has an OH off 3' and an H off 2'
RNA has an OH off 3' and 2' |
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What is a purine?
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A class of nitrogenous bases which consist of Adenine and Guanine.
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What is a pyrimidine?
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A class of nitrogenous bases which consist of Cytosine, Thymine (in DNA), and Uracil (in RNA)
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Which purines and pyrimidines bind with one another?
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G and C, T (or U) and A
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What is a nucleoside?
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The combination of a sugar and a base.
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Know how to draw the structure of DNA!!
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Will do!
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What kind of bonds do A and T make? What kind of bonds to C and G make?
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A and T make two hydrogen bonds while G and C make three hydrogen bonds.
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What are the six characteristics of DNA as described by Watson and Crick?
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1. Two polynucleotide chains wound around each other in a right handed double helix.
2. Chains are antiparallel 3. Sugar-phosphate backbones on outside of double helix, base pairs inward 4. Base pairs bonded by hydrogen bonds 5. Base pairs 0.34 nm; 10 base pairs per turn. 2 nm external diameter. 6. Major and minor grooves - not equally spaced. |
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What is a phosphodiester bond?
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These are located along the backbone of the DNA molecule. These connect the pentose sugars together. Strong bond.
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What is the term genome?
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The full amount of genetic material.
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What are plasmids?
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Small chromosomes not essential to the life of the cell.
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What is the nucleoid?
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In bacteria and archaea, the chromosomes are arranged in a dense clump this region of the cell which has no membrane.
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What is meant by supercoiling? Negative supercoiling? Positive?
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When the double helix is twisted in space about its own axis. Negative is when you untwist, while positive is when you twist even further.
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What are topoisomerases?
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These are enzymes which determine how much supercoiling will be done.
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What are looped domains and what are the significance of them?
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These are loops of chains of DNA which also help the DNA become more compacted.
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What is the C-value?
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The total amount of DNA in the haploid genome of a species.
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What is the C-value paradox?
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There is no direct relationship between the C-value and the structural or organizational complexity of the organism.
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What is chromatin?
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It is the stainable material in a cell nucleus: DNA and proteins.
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What are histones?
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They are small basic proteins with a net positive charge that facilitates their binding to the negatively charged DNA.
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What are nonhistones?
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They are all the proteins associated with DNA, apart from histones.
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What is chromatin?
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Chromatin is the combination of DNA and proteins that make up chromosomes.
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What is euchromatin and what are five properties of it?
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Euchromatin is a type of chromatin which is lightly stained, uncoiled during interphase, genetically active, condensed during mitosis, and is replicated early in S phase.
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What is Heterochromatin and what are five properties of it?
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Heterochromatin is a type of chromatin which is darkly stained, tightly coiled, genetically inactive, always condensed, and replicated late in S phase.
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What is constitutive heterochromatin? Is it Heterochromatic? What region does it affect? Genetically inactive? On both homologs?
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Constitutive heterochromatin is a type of heterochromatin. It is always heteromatic, affects centromeres and telomeres regions, always genetically inactive, and is in homologous regions; yes on both homologs.
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What is facultative heterochromatin? Is it Heterochromatic? What region does it affect? Genetically inactive? On both homologs?
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Facultative heterochromatin is a type of heterochromatin. It is sometimes heteromatic, affects barr bodies, sometimes genetically active, and is not on both homologs, rather on tissue, cell, and sex specific.
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What is a telomere?
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A region of DNA at the end of a chromosome.
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What is a centromere?
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A region of DNA at the middle of a chromosome that is important for chromosome segregation.
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What is meant by the term 'nondisjunction'?
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This is the failure of chromosome pairs to separate properly during cell division.
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What is a kinetochore?
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These are proteins that bind to the centromere to separate chromosomes into daughter chromosomes.
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What is meant by the term consensus?
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This is the most commonly seen sequence.
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What are CDEs and what is their purpose?
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CDEs stands for Centromere DNA Element and are regions in the centromere which are important for the connection of centromeres to microtubules.
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How do microtubules connect to centromeres?
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By using CDEs, a protein complex connects to CDE1, CDE2 is then wrapped around a histone optomer, CDE3 connects to another protein complex, then other proteins link that to the microtubules.
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What are the two types of telomere sequences?
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(1) Simple telomeric sequences (2) Telomere-associated sequences
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How would you define simple telomere sequences?
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These are short sequences located at the very end of a chromosome which are species specific and tandemly repeat.
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How would you define telomere-associated sequences?
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These are repeated and more complex than simple telomere sequences and extend from simple repeats kilobases into chromosomes.
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What are tandemly repeated DNA sequences?
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These are sequences which are clustered together which repeat many times in a row.
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What are dispersed repeated DNA sequences?
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These are sequences of irregular intervals.
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What is unique sequence DNA?
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These types of sequences do not line up with other sequences. They are a single copy.
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What is repeated sequence DNA (as well as moderately repeated sequence DNA)?
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These types of sequences are repeated sequences throughout the genome.
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What is the purpose of a t-loop?
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A t-loop in chromosomes is where one strand crosses itself which protects the free end.
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What are the two types of dispersed repeated DNA?
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(1) Long interspersed elements (LINEs) (2) Short interspersed elements (SINEs)
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What are LINEs?
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These are long interspersed elements in which the sequences range from 1,000-7,000 bp long.
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What are SINEs?
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These are short interspersed elements in which the sequences range from 100-400 bp long.
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What are transpones?
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Transpones are DNA sequences that are able to relocate.
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What are pseudogenes?
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Pseudogenes are non-functional gene copies.
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