front 1 Transcriptional regulation requires DNA-protein interactions that determines | back 1 (1) will transcription happen at all, (2) in what amount? |
front 2 Regulatory proteins often work as | back 2 dimers, trimers, or tetramers for interacting with DNA |
front 3 “helix-turn-helix” | back 3 the most common structure in bacterial regulatory proteins |
front 4 What does The Homodimer allow | back 4 It allows contact at inverted repeats, a common regulatory sequence |
front 5 Bacterial Genomes | back 5
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front 6 Operon | back 6 A group of genes that are controlled by the same regulatory machinery |
front 7 β-galactosidase | back 7 Cleaves lactose; converts some to allolactose |
front 8 Permease | back 8 Facilitates passage of lactose into the cell |
front 9 Transacetylase | back 9 Protects against damagin byproducts of lactose metabolism |
front 10 What type of aneuploidy is responsible for Turner syndrome in humans? A) trisomy 13 B) trisomy 18 C) trisomy 21 D) monosomy XO E) monosomy YO | back 10 D) monosomy XO |
front 11 When nondisjunction occurs early in embryogenesis rather than gametogenesis, what would you expect in the resulting karyotype? A) monosomy B) trisomy C) mosaicism D) uniparental disomy E) random X-inactivation | back 11 C) mosaicism |
front 12 Prader-Willi and Angelman syndromes are caused by which type of chromosomal mutations, both in connection with chromosome 15? A) monosomy B) trisomy C) mosaicism D) uniparental disomy E) random X-inactivation | back 12 D) uniparental disomy |
front 13 In an allopolyploid organism, what is true regarding the fertility of interspecies hybrids? A) Interspecies hybrids are fertile due to nonhomology of chromosomes. B) Chromosome doubling and nondisjunction in gametocytes can lead to homologous chromosome pairing, disjunction, and fertile hybrids. C) Interspecies hybrids will be fertile so long as there is an even number of chromosomes in the offspring. D) Mitotic nondisjunction results in haploid cells. E) Meiotic nondisjunction produces three haploid gametes and one diploid gamete. | back 13 B) Chromosome doubling and nondisjunction in gametocytes can lead to homologous chromosome pairing, disjunction, and fertile hybrids. |
front 14 If a plant is an autotetraploid with the genotype A1A1A2A2, what is the frequency of offspring with the genotype A1A1A1A1 following self-fertilization of the plant? A) 1/2 B) 1/4 C) 9/16 D) 8/36 E) 1/36 | back 14 E) 1/36 |
front 15 Which type of chromosome breakage results in very small deletions that are too small to identify on a karyotype? A) acentric deletions B) microdeletions C) terminal deletions D) partial deletions E) interstitial deletions | back 15 B) microdeletions |
front 16 Which type of chromosome deletions is caused by two concurrent chromosome breaks (rather than a single break)? A) acentric deletions B) microdeletions C) terminal deletions D) partial deletions E) interstitial deletions | back 16 E) interstitial deletions |
front 17 Heterozygous carriers of chromosome inversions or translocations A) will be viable and completely fertile because no genes were deleted. B) may or may not exhibit phenotypic abnormalities. C) may be infertile due to complications during meiosis. D) Both A and B are correct. E) Both B and C are correct. | back 17 E) Both B and C are correct. |
front 18 A region of a chromosome on spanning the centromere is broken and reattached in the reverse direction. This is an example of which type of chromosomal defect? A) paracentric inversion B) pericentric inversion C) pericentric translocation D) dicentric inversion E) dicentric translocation | back 18 B) pericentric inversion |
front 19 A chromosome has broken, and a piece of one chromosome is translocated to a nonhomologous chromosome. This is an example of what type of chromosomal alteration? A) paracentric inversion B) dicentric bridge C) unbalanced translocation D) Robertsonian translocation E) inversion loop | back 19 B) dicentric bridge |
front 20 Crossover suppression implies that A) there are no crossovers between homologous chromosomes. B) recombinant chromosomes are absent in the progeny. C) small inversions have a high frequency of crossover. D) nonreciprocal translocations prevent equal exchange of chromosomes, resulting in loss of chromosome fragments. E) Both A and C are correct. | back 20 B) recombinant chromosomes are absent in the progeny. |
front 21 A chromosome contains the following gene order: A B C D • E F G H Which of the following rearrangements represents a pericentric inversion? A) A B C • D E F G H B) A F G H • B C D E C) A C B D • E F G H D) A F D E • C B G H E) A B C D • H G F E | back 21 D) A F D E • C B G H |
front 22 A chromosome contains the following gene order: A B C D • E F G H Which of the following rearrangements represents a paracentric inversion? A) A B C • D E F G H B) A F G H • B C D E C) A C B D • E F G H D) A F D E • C B G H E) A B C D • H G F E | back 22 C) A C B D • E F G H |
front 23 If an organism is an inversion heterozygote, A) homologous chromosomes align during meiosis through formation of an inversion loop at synapsis. B) homologous chromosomes align during meiosis through formation of a Holliday junction at synapsis. C) nonhomologous chromosomes pair during meiosis due to the translocation of genes between two different chromosomes. D) it will experience normal chromosome synapsis during meiosis. E) it will be unable to complete replication due to DNA damage, and the cell cycle will be arrested. | back 23 A) homologous chromosomes align during meiosis through formation of an inversion loop at synapsis. |
front 24 Humans with the condition of familial Down syndrome exhibit which type of chromosomal aberration? A) chromosome 21 duplication B) chromosome 21 inversion C) chromosome 14/21 Robertsonian translocation D) chromosome 21 deletion E) trisomy of chromosome 21 | back 24 C) chromosome 14/21 Robertsonian translocation |
front 25 An organism with a genome size of n = 23 experienced a Robertsonian translocation. How many chromosomes would you expect to see in the karyotype of a somatic cell in an affected individual? A) 21 B) 25 C) 42 D) 44 E) 46 | back 25 D) 44 |
front 26 In balanced translocation heterozygotes, which pattern of chromosome segregation produces viable gamets and progeny? A) adjacent-1 segregation B) adjacent-2 segregation C) alternate segregation D) Adjacent-1 and alternate segregation are both viable. E) Adjacent-1, adjacent-2, and alternate segregation are all viable. | back 26 C) alternate segregation |
front 27 In bacteria, what is contained within the IS elements? A) transposase gene B) short tandem repeats C) inverted repeats D) Both A and B are correct. E) Both A and C are correct. | back 27 E) Both A and C are correct. |
front 28 What sequences or structures within the DNA can be used to identify sites of transposition? A) target site duplication and direct repeats B) target site duplication and short tandem repeats C) inverted loops D) target site inversion and direct repeats E) chromosome translocation and insertion of transposase gene | back 28 A) target site duplication and direct repeats |
front 29 AluI is an example of which type of transposable element commonly found in the genome of humans? A) LINE elements B) SINE elements C) P elements D) Copia elements E) Ty elements | back 29 B) SINE elements |
front 30 During gametogenesis, what percentage of gametes would be aneuploid if the nondisjunction event occurs during meiosis I? | back 30 Answer: 100% (4/4) |
front 31 During gametogenesis, what percentage of gametes would be trisomic if the nondisjunction event occurs during meiosis II? | back 31 Answer: 25% (1/4) |
front 32 What is the name of the chromosomal region, located on region 21q22.2 that was identified by studying individuals with partial trisomy of chromosome 21? | back 32 Answer: DSCR (Down syndrome critical region) |
front 33 In Drosophila and Lepidoptera, sex-chromosome mosaicism produces what type of sexually ambiguous phenotype? | back 33 Answer: gynandromorphy |
front 34 Of the three mechanisms leading to autopolyploidy, which is the most rare event? | back 34 Answer: multiple fertilizations |
front 35 "Seedless" fruits and vegetables have how many chromosomes and what type of chromosomal distribution? | back 35 Answer: odd-numbered allopolyploidy |
front 36 How many possible genotypes will there be following self-fertilization of a plant with the B1B1B2B2B3B3 genotype? | back 36 Answer: 15 |
front 37 Cri-du-chat syndrome is a human disorder caused by which type of chromosomal defect? | back 37 Answer: terminal deletion |
front 38 A partial chromosome deletion or duplication can be observed at prophase I homologous chromosome synapsis during meiosis by looking for what structure? | back 38 Answer: unpaired loop |
front 39 Pseudodominance is used to map genes by using what method? | back 39 Answer: deletion mapping |
front 40 What structure, seen during synapsis, is indicative of a chromosome inversion? | back 40 Answer: inversion loop |
front 41 Gametes produced by inversion heterozygotes can produce no viable recombinant chromosomes due to what phenomenon? | back 41 Answer: crossover suppression |
front 42 What effect does a Robertsonian translocation have on chromosome number? | back 42 Answer: reduction (2n - 2) |
front 43 What are the two common patterns of chromosome segregation seen in the tetravalent structures found in translocation heterozygotes? | back 43 Answer: alternate and adjacent-1 |
front 44 Barbara McClintock identified corn mutants with the unstable mutant phenotype with what pattern of color? | back 44 Answer: colorless with purple spots |
front 45 In McClintock's maize studies, which genetic element is found at the site of chromosome breakage? | back 45 Answer: dissociation (Ds) element |
front 46 Which enzyme(s) is/are responsible for excising and copying transposable genetic elements from chromosomes and inserting them into new locations? | back 46 Answer: transposase |
front 47 The phenomenon of ________ in allopolyploids consists of more rapid growth, increased fruit and flower production, and improved disease resistance. | back 47 Answer: hybrid vigor |
front 48 ________ is rare and occurs most commonly when repetitive regions of homologous chromosomes misalign, resulting in partial deletions and partial duplications. | back 48 Answer: Unequal crossover |
front 49 ________ is a genetic phenomenon that occurs when a normally recessive allele is "unmasked" and expressed in the phenotype because the dominant allele on the homologous chromosome has been deleted. | back 49 Answer: Pseudodominance |
front 50 Chromosomal translocation involves chromosome breakage and reattachment of the broken segment to a ________. | back 50 Answer: nonhomologous chromosome |