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97 Cards in this Set
- Front
- Back
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True or False. 1. Assuming independent assortment, the expected two-locus genotypic and phenotypic ratios for doubled haploids are 1:1:1:1.
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True
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2. If a plant is 2n = 42, how many pairs of homologous chromosomes would you expect to see at Zygonema?
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21
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3. If the recombination percentage between two loci is 25%, the cM value is going to be
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larger than the recombination value
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4. Homoeology refers to
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b. chromosomes in different species that have genes of similar function in the same linkage relationship
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True or false. 5. The ratio of physical distance (based on number of nucleotides) to genetic distance (based on number of crossovers) is the same at all positions on autosomal chromosomes
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False
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a. the presence of both alleles in a heterozygote can be visualized via electrophoresis.
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Codominance
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2. You have two different varieties of peas in your germplasm collection. Both are resistant to a bacterial wilt disease. In order to determine if the two varieties have the same or different resistance genes, you cross them and test for the disease resistance gene phenotype in the F1 and F2 generations. You observe that all F1 plants are resistant and in the F2 there is a ratio of 15 resistant: 1susceptible. The most likely explanation for these observations is that
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b. there are two loci involved in disease resistance and the varieties have different alleles at these loci.
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3. Where do you expect Okazaki fragments to occur?
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on lagging strands
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4. DNA polymerase synthesizes new deoxyribonucleotide chains in which direction?
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d) 5’ to 3’ in both the leading strand and the lagging strand
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5. In the following sketch of a deoxyribonucleotide, label the position of (i) each of the five carbon atoms (“1”, “2”, “3”, “4”, and “5”), (ii) the phosphate group (“P”), (iii) the hydroxyl group (“OH”), and (iv) the N-containing base (“N”). On board… DRAW IT OUT
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draw it
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A comparative analysis of the DNA sequence of the BAD2 genes of rice and maize reveals that the two genes are so similar that they are hypothesized to have evolved from a common ancestral gene. This is best described as an example of
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Orthology
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Molecular markers are more useful than morphological markers (naked eye polymorphisms) for construction of high density linkage maps because
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Molecular markers are more abundant
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In the case of partial dominance, heterozygotes can be distinguished from the dominant and recessive homozygotes based on phenotype.
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True
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In a deoxyribonucleotide, 5’ and 3’ refer to the
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carbons where (respectively) the phosphate and hydroxyl groups are attached.
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In the S phase of meiosis, DNA replication is
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semi conservative
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DNA polymerase synthesizes new deoxyribonucleotide chains in which direction?
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5’ to 3’ in both the leading strand and the lagging strand
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In higher plants, each chromosome has a single bidirectional origin of DNA replication located at the centromere.
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False
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The RNA primers that initiate DNA replication in the S phase of mitosis
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are eventually removed and replaced with the corresponding DNA nucleotides.
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Telomerase is an enzyme responsible for
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ensuring that chromosomes in some types of cells do not shorten at every mitotic division.
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What process gives rise to new alleles?
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Mutation
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The RNA primers that initiate DNA replication are the same as those that initiate transcription
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False
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Two principal methods for designing molecular markers are
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Amplification and hybridization
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For DNA marker analysis, electrophoresis is used to
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separate DNA fragments by size.
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The primers that are used for a PCR reaction to amplify genomic DNA consist of
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deoxyribonucelotides.
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The temperature cycling used in PCR reactions is needed to
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alternately allow for double strand DNA denaturation, primer binding, and primer extension.
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You would expect a restriction enzyme with four-base recognition site to generate a larger number of fragments from a sample of genomic DNA than an enzyme with an eight-base recognition site.
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True
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identified by using the same restriction enzyme and clone to visualize fragments of different lengths in two or more genotypes.
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RFLP's
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AFLPs involve Southern blotting and generate one data point per reaction.
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false
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ESTs are an excellent source of markers because they include promoter sequences.
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false
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A molecular marker based on PCR primers for conserved regions flanking a region of variable length tandem repeats is a
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STD
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DNA: DNA hybridization
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Southern Hybridization
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You get a job with a seed company and are assigned responsibility for ensuring purity of the company's F1 hybrid seed. Your boss is concerned that the F1 seed may not be 100% heterozygous: she thinks that there may some selfed seed contaminants in the F1 seed. The ideal molecular marker for testing the F1 will be
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Codominant
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Only one of the two DNA strands in the double helix serves as template for transcription throughout the entire length of the chromosome and throughout the life of the organism.
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false
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Transcription of genes located on the 20 chromosomes of maize occurs where?
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In the cytoplasm
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RNA is different from DNA in that
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RNA has the base uracil whereas DNA has the base thymine
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In eukaryotes, informational and functional RNAs are
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Coded for by genes in the nucleus
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Small nuclear RNA (snRNA) would be found in a
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spliceosome
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a binding site for RNA polymerase.
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A promoter
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What segment of a gene would be most likely to have the sequence TATA ~ 30 bp upstream (5’) from the transcription start site?
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promoter
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The sequence of the promoter can be found in a mRNA sequence.
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false
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The synthesis of the mRNA stops when
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a specific sequence in the DNA template is reached that serves as a signal for termination.
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mRNA processing in eukaryotes refers to (3 things)
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5’ caps, 3’ tails, and intron removal.
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Exons are always longer than introns.
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false
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A diagnostic sequence always found in 5’ UTRs is the ATG start codon.
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false
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Translation of the mRNAs transcribed from the genes located on the 20 chromosomes of maize occurs
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In the cytoplasm
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very specialized, with each tRNA able to carry a specified amino acid.
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tRNA's
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The point of attachment of an amino acid to a tRNA is called the anticodon
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False
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Ribosomes are coded for by
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Nuclear genes
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In the process of translation, the ribosome moves
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5' to 3' on the mRNA
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During the elongation phase of the translation process, the next incoming tRNA will
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have an anti-codon sequence complementary with the codon in the mRNA.
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The mechanism by which a stop codon stops translation is that
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the ribosomes pinch off the completed sequence of amino acids.
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Given the following DNA sense strand – 5’ ATG GCC TGG ACT TCA 3’
Which is the corresponding DNA anstisense strand? |
3' to 5' . . . .
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Which is the corresponding mRNA? 5’ ATG GCC TGG ACT TCA 3’
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5’ AUG GCC UGG ACU UCA 3’
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Which is the correct translation?5’ ATG GCC TGG ACT TCA 3’
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Met Ala Trp Thr Ser
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If you know the amino acid sequence of a polypeptide you can deduce the exact DNA code of the corresponding gene.
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false
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Which of the methods of obtaining DNA is based on isolating mRNA and using the reverse transcriptase enzyme to create double stranded DNA?
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cDNA
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The purpose for using a vector (such as a plasmid) in making a DNA library is to:
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maintain and increase copy number of specific DNA fragments
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Clones in a cDNA library will be shorter than the original genomic coding sequences because the
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introns were removed during mRNA processing
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A genomic library consists of
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DNA fragments generated by a restriction digest of total nuclear DNA.
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The key attribute of dideoxy nucleotides that makes them useful for DNA sequencing is that they have
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no 3’ OH group.
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refers to the physical exchange between homologous chromosomes, its a good source of genetic variablity
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Crossing over
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the genetic result of crossing over and is detected by new combinations of alleles at two or more loci.
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Recombination
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Gene pairs are sufficiently far apart that some recombinant types are recovered. The "distance" between genes ranges from a few percent recombination to 50% recombination.
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Partial Linkage
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Gene pairs are so close together that crossing over rarely occurs and recombinant types are generally not recovered
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Complete Linkage
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Two factors that affect meiotic crossing over?
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Sex chromosomes and Position on the chromosome
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Refers to genes in different species which are so similar in sequence that they are assumed to have originated from a single ancestral gene.
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Orthology
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Refers to genetic loci that are linked on the same chromosome
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Synteny
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Refers to chromosomes, or chromosome segments, and which are similar in terms of the order and function of the genetic loci. Homoeologous chromosomes may occur within a single allopolyploid individual (e.g. the A,B, and D, genomes in wheat), or they may be found in related species
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Homeology
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True or false?there will be fewer crossovers between loci that are quite close together and more crossovers between loci that are quite far apart.
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True
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the frequency of expression of an allele when it is present in the genotype of the organism
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Penetrance
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the degree of commonality of expression across a sample of individuals with the same genotype.
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Expressivity
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A single nucleotide polymorphism? ATG -> AGG
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Mutation
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3 way DNA is capable of changing?
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Mutation, Duplication, Deletion
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2 purines and 2 pyrimidines
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A and G, T and C
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What direction does Replication move in on the DNA synthesis
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5' to 3'
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When does DNA replaication take place, what phase?
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S phase
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a PCR is an example of
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Amplification
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4 steps to Amplification
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Denaturing, add single stranded oligonucleotides, hybridize primers, and primer extension.
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The TAQ polymerase is most likely to be found in what process
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Amplification
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Southern hybridization=
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DNA : DNA
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Northern Hybridization=
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DNA : RNA
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Western hybridization=
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Protein: antibody
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These make cuts at defined recognition sites in DNA
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Restriction enzymes
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A restriction enzyme that has a 4 base recognition site will cut more than a 8 base recognition site?
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True
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3 ways RNA is different from DNA?
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U instead of T, Ribose instead of Deoxyribose, and usually single instead of double stranded
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How many different kinds of Transfer RNA are there?
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32
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3 steps to transcription?
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Initiation, Elongation, and Termination
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What is the template strand referred to as in RNA?
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Antisense
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How many RNA Polyerases are there and what is the 2nd one responsible for?
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3, Responsible for protein
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In transcription, Initiation is started by
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a promoter
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There are more introns than exons typically?
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true
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All genes begin with ATG?
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True
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Multipe codes that all specify the same amino acids?
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Degeneracy
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3 kinds of DNA that can be obtained for recombinant DNA technology?=
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Genomic (cheek Swab), cDNA, and Synthetic DNA (the oligonucleotides)
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What is the role of a Vector?
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To propagate and maintain the DNA fragments generated by restriction
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2 kinds of libraries?
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Genomic or cDNA
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A dideoxy nucleotide lacks a
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3' OH
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