PS3 Genetics Flashcards
In drosophila Virilis, nuclei of somatic cells contain 12 CHROMOSOMES while nuclei of sperm cells contain only 6 CHROMOSOMES. What does “n” equal for this species?
“n”= 6
Drosophila melanogaster has four pairs of chromosomes. Sperm from this species are formed by a meiotic process in which homologous chromosomes pair and segregate but do not undergo crossing over. How many genetically different kinds of sperm could be produced by a drosophila melanogaster male?
16
Which of the following statements applies to homologous chromosomes?
They contain the same genes in the same order but may have different alleles of some genes.
Non-disjunction can occur at either the first or second division of Meiosis. XYY individuals would most likely arise from nondisjunction at the —— meiotic division in the —–.
Second, father
The cells below are from an organism of the genotype A/a;B/b. To the right of each cell, indicate wether that cell is in mitosis, meiosis1, Meiosis 2, or None. (I.e: The diagram does not correctly represent a stage of normal mitosis or Meiosis).
<a>
B||b. B||b</a>
None
The cells below are from an organism of the genotype A/a;B/b. To the right of each cell, indicate wether that cell is in mitosis, meiosis1, Meiosis 2, or None. (I.e: The diagram does not correctly represent a stage of normal mitosis or Meiosis).
<a>
b||b</a>
Meiosis 2
The cells below are from an organism of the genotype A/a;B/b. To the right of each cell, indicate wether that cell is in mitosis, meiosis1, Meiosis 2, or None. (I.e: The diagram does not correctly represent a stage of normal mitosis or Meiosis).
<a>
b||b
B||B
a||a</a>
Mitosis
The cells below are from an organism of the genotype A/a;B/b. To the right of each cell, indicate wether that cell is in mitosis, meiosis1, Meiosis 2, or None. (I.e: The diagram does not correctly represent a stage of normal mitosis or Meiosis).
<a>
a||a </a>
None
The cells below are from an organism of the genotype A/a;B/b. To the right of each cell, indicate wether that cell is in mitosis, meiosis1, Meiosis 2, or None. (I.e: The diagram does not correctly represent a stage of normal mitosis or Meiosis).
<a>
B||b
A||a
B||b</a>
</a>
None
The cells below are from an organism of the genotype A/a;B/b. To the right of each cell, indicate wether that cell is in mitosis, meiosis1, Meiosis 2, or None. (I.e: The diagram does not correctly represent a stage of normal mitosis or Meiosis).
<a>
B||B b||b</a>
Meiosis 1
Aspergillus is a fungus that can exist in either HAPLOID or DIPLOID state. A geneticist is interested in the genes required to synthesize leucine in aspergillus. She treats the HAPLOID cells with ultraviolet light to increase the mutation rate and obtains 5 HAPLOID leucine requiring mutants (named a,b,c,d,and e) all of which need leucine to be added to the medium in order for them to multiply (undergo meiotic divisions) without leucine none of them will multiply. Note that wild type aspergillus can make their own leucine and don’t require it in the medium.
How would our geneticist friend determine wether each mutation is RECESSIVE or dominant?
Mate a mutant HAPLOID cell to a wild type HAPLOID cell
Aspergillus is a fungus that can exist in either HAPLOID or DIPLOID state. A geneticist is interested in the genes required to synthesize leucine in aspergillus. She treats the HAPLOID cells with ultraviolet light to increase the mutation rate and obtains 5 HAPLOID leucine requiring mutants (named a,b,c,d,and e) all of which need leucine to be added to the medium in order for them to multiply (undergo meiotic divisions) without leucine none of them will multiply. Note that wild type aspergillus can make their own leucine and don’t require it in the medium.
What result would tell her that mutation “a” is RECESSIVE?
The resulting DIPLOID (A/a) will be able to proliferate on medium lacking leucine
Aspergillus is a fungus that can exist in either HAPLOID or DIPLOID state. A geneticist is interested in the genes required to synthesize leucine in aspergillus. She treats the HAPLOID cells with ultraviolet light to increase the mutation rate and obtains 5 HAPLOID leucine requiring mutants (named a,b,c,d,and e) all of which need leucine to be added to the medium in order for them to multiply (undergo meiotic divisions) without leucine none of them will multiply. Note that wild type aspergillus can make their own leucine and don’t require it in the medium.
She now mates the mutant HAPLOID cells with each other to make DIPLOID cells, and obtains the results shown below, where (+) indicates that the DIPLOID cells multiplied in medium lacking leucine, and (-) indicates that the DIPLOID cells were not able to multiply on medium lacking leucine.
a. b. c. d. e a. - +. +. +. -
b. - +. +. +
c. - +. +
d. - +
e. -
What is this test called?
Complementation test
Aspergillus is a fungus that can exist in either HAPLOID or DIPLOID state. A geneticist is interested in the genes required to synthesize leucine in aspergillus. She treats the HAPLOID cells with ultraviolet light to increase the mutation rate and obtains 5 HAPLOID leucine requiring mutants (named a,b,c,d,and e) all of which need leucine to be added to the medium in order for them to multiply (undergo meiotic divisions) without leucine none of them will multiply. Note that wild type aspergillus can make their own leucine and don’t require it in the medium.
She now mates the mutant HAPLOID cells with each other to make DIPLOID cells, and obtains the results shown below, where (+) indicates that the DIPLOID cells multiplied in medium lacking leucine, and (-) indicates that the DIPLOID cells were not able to multiply on medium lacking leucine.
a. b. c. d. e a. - +. +. +. -
b. - +. +. +
c. - +. +
d. - +
e. -
How many genes are defined by the five mutations?
4 genes
Aspergillus is a fungus that can exist in either HAPLOID or DIPLOID state. A geneticist is interested in the genes required to synthesize leucine in aspergillus. She treats the HAPLOID cells with ultraviolet light to increase the mutation rate and obtains 5 HAPLOID leucine requiring mutants (named a,b,c,d,and e) all of which need leucine to be added to the medium in order for them to multiply (undergo meiotic divisions) without leucine none of them will multiply. Note that wild type aspergillus can make their own leucine and don’t require it in the medium.
She now mates the mutant HAPLOID cells with each other to make DIPLOID cells, and obtains the results shown below, where (+) indicates that the DIPLOID cells multiplied in medium lacking leucine, and (-) indicates that the DIPLOID cells were not able to multiply on medium lacking leucine.
a. b. c. d. e a. - +. +. +. -
b. - +. +. +
c. - +. +
d. - +
e. -
Which if any mutations are in the same genes?
a and e are in the same gene
they fail to compliment
