BIOL 3001 MIDTERM QUESTIONS WITH
CORRECT ANSWERS
What are the learning objectives for Lab 1? - ANS- Understand the basic attributes of
Drosophila melanogaster
- Conduct crosses and collect progeny data using the fly portal
- Design and diagram monohybrid crosses
- Complete chi-squared analyses to compare observed versus expected traits
- Better understand the effects of different progeny number (sample size) on expected
ratios
modes of inheritance - ANSmanner in which a genetic trait or disorder is passed from
one generation to the next
What family, order, and class is Drosophila melanogaster classified in? - ANSFamily:
Drosophilidae
Order: Diptera (which also includes flies, mosquitoes and midges)
Class: Insecta (insects)
What does Drosophila (genus name) mean? - ANSdew-lover
What does melanogaster mean? - ANSblack abdomen
What other names do fruit flies have? - ANSred-eyed pomace fly, vinegar fly and wine
fly, all relating to this species' attraction to fermenting fruits
How did fruit flies get their name? - ANSbecause they are collected by placing a bottle
containing over-ripe fruit (often bananas) outside
wild-type - ANSphenotype most commonly captured in the wild
How many chromosomes do fruit flies have? - ANS4 pairs (2n=8)
What chromosome in fruit flies determines sex? - ANSchromosome I
lygaues mode - ANSpresence of different sex chromosomes
T or F: Sex-determination in fruit flies follows the lygaeus mode. - ANStrue
T or F: In fruit flies, females are XX and males are XY. - ANStrue
, T or F: Sex is dependent on the actual number of X chromosomes in fruit flies. -
ANStrue
How can the genders be distinguished in fruit flies? - ANS- Females are larger than
males.
- Females have a "knob" (ovipositor) on the tip of the abdomen.
- Males have a solid abdomen while females have stripes.
standard F1 cross - ANScrosses offspring from the F1 Generation to each other
backcross - ANSperformed by crossing one of the F1 progeny back to one of the
original parents to produce the F2 generation
Why are backcrosses useful? - ANSfor isolating (separating out) a specific trait in a
related population of organisms
phenotype - ANSthe set of observable characteristics of an individual resulting from the
interaction of its genotype with the environment
genotype - ANSthe part of the genetic makeup of a cell, and therefore of an individual,
which determines one of its characteristics
homolog - ANSa gene inherited in two species from a common ancestor
How many alleles do diploid organisms have at each locus? - ANS2
Mendel's Big Six - ANS- AA x AA --> Pure A
- aa x aa --> Pure a
- AA x aa --> Parental (P1)
- Aa x Aa --> F Cross
- Aa x aa --> Recessive Backcross
- Aa x AA --> Dominant Backcross
What is the difference between testcross and backcross? - ANSA test cross is an
experimental cross when an organism that has the dominant phenotype with an
unknown genotype is crossed with a homozygous recessive genotype (and phenotype).
A backcross is when an organism is crossed with one of its parents or another organism
genetically similar to one of its parents. A recessive backcross can also be a test cross.
What is the goal of a chi-squared test? - ANSto estimate how much the results that we
obtain deviate from what we predicted based on a specific hypothesis
What is the chi-squared formula? - ANSχ2 = Σ (o-e)2/e
T or F: A perfect fit of the Observed (o) to the Expected (e) produces a Chi-squared
statistic of zero (0 = no deviation). - ANStrue
CORRECT ANSWERS
What are the learning objectives for Lab 1? - ANS- Understand the basic attributes of
Drosophila melanogaster
- Conduct crosses and collect progeny data using the fly portal
- Design and diagram monohybrid crosses
- Complete chi-squared analyses to compare observed versus expected traits
- Better understand the effects of different progeny number (sample size) on expected
ratios
modes of inheritance - ANSmanner in which a genetic trait or disorder is passed from
one generation to the next
What family, order, and class is Drosophila melanogaster classified in? - ANSFamily:
Drosophilidae
Order: Diptera (which also includes flies, mosquitoes and midges)
Class: Insecta (insects)
What does Drosophila (genus name) mean? - ANSdew-lover
What does melanogaster mean? - ANSblack abdomen
What other names do fruit flies have? - ANSred-eyed pomace fly, vinegar fly and wine
fly, all relating to this species' attraction to fermenting fruits
How did fruit flies get their name? - ANSbecause they are collected by placing a bottle
containing over-ripe fruit (often bananas) outside
wild-type - ANSphenotype most commonly captured in the wild
How many chromosomes do fruit flies have? - ANS4 pairs (2n=8)
What chromosome in fruit flies determines sex? - ANSchromosome I
lygaues mode - ANSpresence of different sex chromosomes
T or F: Sex-determination in fruit flies follows the lygaeus mode. - ANStrue
T or F: In fruit flies, females are XX and males are XY. - ANStrue
, T or F: Sex is dependent on the actual number of X chromosomes in fruit flies. -
ANStrue
How can the genders be distinguished in fruit flies? - ANS- Females are larger than
males.
- Females have a "knob" (ovipositor) on the tip of the abdomen.
- Males have a solid abdomen while females have stripes.
standard F1 cross - ANScrosses offspring from the F1 Generation to each other
backcross - ANSperformed by crossing one of the F1 progeny back to one of the
original parents to produce the F2 generation
Why are backcrosses useful? - ANSfor isolating (separating out) a specific trait in a
related population of organisms
phenotype - ANSthe set of observable characteristics of an individual resulting from the
interaction of its genotype with the environment
genotype - ANSthe part of the genetic makeup of a cell, and therefore of an individual,
which determines one of its characteristics
homolog - ANSa gene inherited in two species from a common ancestor
How many alleles do diploid organisms have at each locus? - ANS2
Mendel's Big Six - ANS- AA x AA --> Pure A
- aa x aa --> Pure a
- AA x aa --> Parental (P1)
- Aa x Aa --> F Cross
- Aa x aa --> Recessive Backcross
- Aa x AA --> Dominant Backcross
What is the difference between testcross and backcross? - ANSA test cross is an
experimental cross when an organism that has the dominant phenotype with an
unknown genotype is crossed with a homozygous recessive genotype (and phenotype).
A backcross is when an organism is crossed with one of its parents or another organism
genetically similar to one of its parents. A recessive backcross can also be a test cross.
What is the goal of a chi-squared test? - ANSto estimate how much the results that we
obtain deviate from what we predicted based on a specific hypothesis
What is the chi-squared formula? - ANSχ2 = Σ (o-e)2/e
T or F: A perfect fit of the Observed (o) to the Expected (e) produces a Chi-squared
statistic of zero (0 = no deviation). - ANStrue
