lab test 4

Term
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You will cross a true-breeding fly with red eyes & dumpy wings to a true-breeding fly with brown eyes & long wings.
a. genotypes of parental generation?
b. genotype and phenotype of F1 generation?
c. F2 generation Punnett square and phenotypic ratios?
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Terms in this set (20)
You will cross a true-breeding fly with red eyes & dumpy wings to a true-breeding fly with brown eyes & long wings.
a. genotypes of parental generation?
b. genotype and phenotype of F1 generation?
c. F2 generation Punnett square and phenotypic ratios?
a. RRWW x rrww
b. RrWw, heterozygous red eyes & long wings
c. 9 red eyes, long wings : 3 red eyes, short wings : 3 brown eyes, long wings : 1 brown eyes, short wings
what is a cistron
a section of a DNA or RNA molecule that codes for a specific polypeptide in protein synthesis.
a. If 2 different mutant rII phages are able to lyse E. coli K (our lab manual's shorthand for K12(λ)) when they co-infect it, while neither mutant can lyse it separately, what can you say about the 2 mutations?
b. What is the name for this kind of test?
a) The two mutations are recombinant and reversed back to wildtype
b) complementation test
he 2 phage mutants we are using in lab, rII 29 & rII 31, are NOT able to lyse E. coli K when they co-infect it. What does this tell you about the 2 mutations?
They do not recominate and revert to the wildtype
If E. coli B is co-infected with rII 29 & rII 31, a small percentage of the progeny phage are able to lyse E. coli K. Draw a picture that shows what happened.
----x----x----
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What does chloroform do?
Liberates any mature phage particles inside the bacteria and prevents any phage DNA and immature phage particles from developing into complete phage particles
What does KCN do?
Dissipates the potential across the bacterial plasma membrane, permitting adsorption of the phage particles to the bacterial wall but preventing the injection of the phage DNA into the cell.
How many different genes are we following in the phage recombination experiment? How many alleles are there of each?
1 gene, two alleles
There are 4 quantities that you must measure in order to work out the recombination frequency between the two mutations. What are they?
1) Total concentration of Unabsorbed phage from U series
2) Total concentration from the b plates
3) The concentration of the wild type from the K series
4) The concentration of the double mutants from the K series
a. What is multiplicity of infection (MOI)?
b. What is the ratio of phage to bacteria that you are combining in step 1 page 74? SHOW YOUR WORK!
c. Why is this ratio desirable for our purposes?
a) Ratio of agents
b) phage conc/e.coli conc= (2x10^9/10^8) = 20:1
c) Because multiple phage can infect one bacteria
Why must you multiply the "titer on K" by 2 to get the recombination frequency?To account for double cross overBy what 2 different mechanisms could mutant phages change to become capable of lysing E. coli K?Recombination and reversionPiebald spotting is a condition found in humans in which there are patches of skin that lack pigmentation. The condition results from the inability of pigment-producing cells to migrate properly during development. Two adults with piebald spotting have one child who has this trait and a second child with normal skin pigmentation. a. Is the piebald spotting trait dominant or recessive? What information led you to this answer? (3 points)b. What are the genotypes of the parents?Two affected individuals have an affected child and a normal child. This outcome is not possible if the affected individuals were homozygous for a recessive allele conferring piebald spotting, and if the trait is controlled by a single gene. Therefore, the piebald trait must be the dominant phenotype.A mutant cucumber plant has flowers that fail to open when mature. Crosses can be done with this plant by manually opening and pollinating the flowers with pollen from another plant. When closed x open crosses were done, all the F1 progeny were open. The F2 plants were 145 open and 59 closed. A cross of closed x F1 gave 81 open and 77 closed. How is the closed trait inherited? What evidence led you to your conclusion?Closed trait is inherited as recessive trait.In humans, a dimple in the chin is a dominant characteristic.a. A man who does not have a chin dimple has children with a woman with a chin dimple whose mother lacked a dimple. What proportion of their children would be expected to have a chin dimple? Show the parents' genotypes. (2 points) b. A man with a chin dimple and a woman who lacks the dimple produce a child who lacks a dimple. What is the man's genotype? (1 point) c. A man with a chin dimple and a nondimpled woman produce eight children, all having chin dimples. Can you be certain of the man's genotype? Why or why not? (2 points)a) half the children are expected to have the dimple b) Aa c) AAa. How is earwax type inherited? b. Why are no 3:1 or 1:1 ratios present in the data shown?a) Earwax is inherited as a simple dominant or recessive Mendelian trait. Sticky is to be dominant and Dry is recessive. b) the Sticky individuals were unknown combinations of homozygous DD and heterozygous Dd individuals. Only the "Dry" d/d individuals can be expected to be true breeding.You have just purchased a black stallion. You mate him to a red mare, and she delivers twin foals, one red and one black. Can you tell from these results how color is inherited, assuming that alternative alleles of a single gene are involved? What crosses could you do to work this out?The Black Stallion was heterozygous, and the red are was recessive. Bb x bbIf you roll a die (singular of "dice"), what is the probability that you will roll: a. a "6"? b. an even number? c. a number divisible by 3? If you roll a pair of dice, what is the probability that you will roll: d. two "6"s? e. an even number on one and an odd number on the other? f. matching numbers?a) 1/6 b) 1/2 c) 1/3 d) 1/36 e) 1/2 f) 1/36How many genetically different eggs could be formed by women with the following genotypes? a. Aa bb CC DD b. AA Bb Cc dd c. Aa Bb cc Dd d. Aa Bb Cc Dd2, 4, 8, 16What is the probability of producing a child that will phenotypically resemble either one of the two parents in the following four crosses? How many phenotypically different kinds of progeny could potentially result from each of the following four crosses?