Types of Variation
Nondisjunction
Complementation Testing
Feeding Experiment/Intermediate Accumulation
Miscellaneous
100
Patau Syndrome is an aneuploidy of autosomes for chromosome 13. More specifically the syndrome is trisomic for chromosome 13. How many TOTAL chromosomes would this individual have?
What is 47 chromosomes (2n + 1)
100
At what stage of meiosis and meiosis does nondisjunction occur?
What is anaphase.
100
True or False: Determines which strains have mutations in the same gene
What is TRUE.
100
What does the feeding experiment determine?
Determines which step in pathway is blocked
100
Amino acids are linked together by...(what bond?)
What is peptide bonds
200
True or False: Translocation refers to the movement of DNA between homologous chromosomes.
What is FALSE; translocation is movement between NON-HOMOLOGOUS CHROMOSOMES.
200
Looking at the karyotype, at what chromosome is there a genetic disorder.
What is chromosome 21
200
What does it mean when strains do not complement?
What is they have mutations in the same gene
200
What does the intermediate accumulation experiment determine?
Gives order of intermediates in biochemical pathway.
200
Interactions between domains of 2° structure and is the 3-D shape of the protein...
What is Tertiary Structure (3°)
300
What is the phenomenon where due to a deletion to parts of chromosomes, a dominant allele is deleted and there is expression of the masked recessive allele?
What is pseudodominance
300
Trisomy and monosome can be a product of nondisjunction in __.
What is Meiosis I and II and Mitosis
300
True or False: Auxotrophy strains that do no complement will grow on minimal media
What is FALSE; if they complement they grow on minimal media because the genes complement each other in such way that they compensate for the defects in biosynthesis pathways.
300
True or False: when performing the feeding experiment, the compound that all mutants grown on must be final product.
What is TRUE
300
Species 1 has 2n = 20 chromosomes. How many chromosomes will be found per cell if a cell is nullisomic to the original 2n=20
What is null = none therefore 2n-2 = 18 chromosomes (missing 2 copies of 1 chromosome).
400
Suppose you have a mutation where individuals contain streaks of grey hair throughout their heads. This mutation is due to the loss of the GRY gene after translocation which inhibits transcription of the grey streaks. What type of translocation is this?
What are... unbalanced translocations. Translocations should not typically result in a loss of information but rather just a switch.
400
Why does mosaicism occur when nondisjunction occurs in somatic cells?
What is because mutations are present in a subset of individual's cells (not all cells have nondisjunction occur - random event in cells).
400
TRUE OR FALSE: All organisms in the same complementation group have identical DNA sequence.
What is FALSE; Organisms in the same complementation group are mutant in the same gene. However, the mutations do not have to be identical. There are many ways to cause a loss of function mutation in a gene. These different mutants would still display the same phenotype.
400
Mutant Neurospora strains 1 and 2 cannot catalyze the steps in the biochemical pathway as shown below. Which strain(s) would you expect to grown on minimal media that is supplemented with compound A?
2. 1.
pre --> A --> B --> C
What is Compound B
400
True or False: In organisms that exhibit allopolyploidy, the chromosomes may not pair during meiosis.
What is true... Example: copy from chromosome 1 of one species will not pair during prophase 1 with another copy of chromosome one from another species; they are both copies of chromosome q but there is enough difference between them that the 2 will not synapse.
500
Describe what happens in Robertsonian translocations
Fusion of 2 acrocentric chromosomes; Result: end up with a larger metacentric chromosome and a little metacentric chromosome (p arms come together)
500
How might a sperm containing two identical X chromosomes arise?
What is... Meiosis II (Hint: Just remember identical = Meiosis II, non-identical = Meiosis I)
500
You are trying to study heart development and you using a fish as a model organism. You identify three homozygous mutant lines that have embryos with slow-beating hearts. You name the genes slowheart1, slowheart2, and slowheart3. You perform complementation tests of the the lines and the results are shown:
Cross 1: slowheart1 X slowheart2 results in embryos with slow-beating hearts.
Cross 2: slowheart1 X slowheart3 results in embryos with wild-type heartbeat rate.
Cross 3: slowheart2 X slowheart3 results in embryos with wild-type heartbeat rate.
Which mutant lines are likely to have mutations in the same gene?
What is Cross 1; because the offspring display a phenotype that is similar to parents, which is not the case of complementation is present (you would see the wild-type phenotype)
500
Mutant Neurospora strains 1 and 2 cannot catalyze the steps in the biochemical pathway as shown below. Which strain(s) would you expect to grown on minimal media that is supplemented with compound A?
2. 1.
pre --> A --> B --> C
What is Strain 2
500
Why is the "One Gene - One Enzyme" Model inaccurate?
What is... 1 enzyme may be composed of multiple polypeptides, each of which is encoded by a distinct gene. Therefore many genes encode polypeptides that do not function as enzymes.