BIOL 3001 MIDTERM QUESTIONS &
ANSWERS(RATED A+)
What are the learning objectives for Lab 1? - ANSWER- 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 - ANSWERmanner 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? -
ANSWERFamily: Drosophilidae
Order: Diptera (which also includes flies, mosquitoes and midges)
Class: Insecta (insects)
What does Drosophila (genus name) mean? - ANSWERdew-lover
What does melanogaster mean? - ANSWERblack abdomen
What other names do fruit flies have? - ANSWERred-eyed pomace fly, vinegar fly
and wine fly, all relating to this species' attraction to fermenting fruits
How did fruit flies get their name? - ANSWERbecause they are collected by placing
a bottle containing over-ripe fruit (often bananas) outside
wild-type - ANSWERphenotype most commonly captured in the wild
How many chromosomes do fruit flies have? - ANSWER4 pairs (2n=8)
What chromosome in fruit flies determines sex? - ANSWERchromosome I
lygaues mode - ANSWERpresence of different sex chromosomes
T or F: Sex-determination in fruit flies follows the lygaeus mode. - ANSWERtrue
T or F: In fruit flies, females are XX and males are XY. - ANSWERtrue
T or F: Sex is dependent on the actual number of X chromosomes in fruit flies. -
ANSWERtrue
What is the difference between testcross and backcross? - ANSWERA 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? - ANSWERto estimate how much the results
that we obtain deviate from what we predicted based on a specific hypothesis
What is the chi-squared formula? - ANSWERχ2 = 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). - ANSWERtrue
How can the genders be distinguished in fruit flies? - ANSWER- 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 - ANSWERcrosses offspring from the F1 Generation to each other
backcross - ANSWERperformed by crossing one of the F1 progeny back to one of
the original parents to produce the F2 generation
Why are backcrosses useful? - ANSWERfor isolating (separating out) a specific trait
in a related population of organisms
phenotype - ANSWERthe set of observable characteristics of an individual resulting
from the interaction of its genotype with the environment
genotype - ANSWERthe part of the genetic makeup of a cell, and therefore of an
individual, which determines one of its characteristics
homolog - ANSWERa gene inherited in two species from a common ancestor
How many alleles do diploid organisms have at each locus? - ANSWER2
Mendel's Big Six - ANSWER- 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
T or F: The larger the Chi-squared statistic, the worse the goodness-of-fit. -
ANSWERtrue
What p-value is used in chi-squared analysis? - ANSWERp= 0.05
What are the learning objectives for Lab 2? - ANSWER- Understand the terms
associated with multi-trait crosses.
- Design and diagram crosses involving two or more traits.
ANSWERS(RATED A+)
What are the learning objectives for Lab 1? - ANSWER- 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 - ANSWERmanner 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? -
ANSWERFamily: Drosophilidae
Order: Diptera (which also includes flies, mosquitoes and midges)
Class: Insecta (insects)
What does Drosophila (genus name) mean? - ANSWERdew-lover
What does melanogaster mean? - ANSWERblack abdomen
What other names do fruit flies have? - ANSWERred-eyed pomace fly, vinegar fly
and wine fly, all relating to this species' attraction to fermenting fruits
How did fruit flies get their name? - ANSWERbecause they are collected by placing
a bottle containing over-ripe fruit (often bananas) outside
wild-type - ANSWERphenotype most commonly captured in the wild
How many chromosomes do fruit flies have? - ANSWER4 pairs (2n=8)
What chromosome in fruit flies determines sex? - ANSWERchromosome I
lygaues mode - ANSWERpresence of different sex chromosomes
T or F: Sex-determination in fruit flies follows the lygaeus mode. - ANSWERtrue
T or F: In fruit flies, females are XX and males are XY. - ANSWERtrue
T or F: Sex is dependent on the actual number of X chromosomes in fruit flies. -
ANSWERtrue
What is the difference between testcross and backcross? - ANSWERA 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? - ANSWERto estimate how much the results
that we obtain deviate from what we predicted based on a specific hypothesis
What is the chi-squared formula? - ANSWERχ2 = 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). - ANSWERtrue
How can the genders be distinguished in fruit flies? - ANSWER- 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 - ANSWERcrosses offspring from the F1 Generation to each other
backcross - ANSWERperformed by crossing one of the F1 progeny back to one of
the original parents to produce the F2 generation
Why are backcrosses useful? - ANSWERfor isolating (separating out) a specific trait
in a related population of organisms
phenotype - ANSWERthe set of observable characteristics of an individual resulting
from the interaction of its genotype with the environment
genotype - ANSWERthe part of the genetic makeup of a cell, and therefore of an
individual, which determines one of its characteristics
homolog - ANSWERa gene inherited in two species from a common ancestor
How many alleles do diploid organisms have at each locus? - ANSWER2
Mendel's Big Six - ANSWER- 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
T or F: The larger the Chi-squared statistic, the worse the goodness-of-fit. -
ANSWERtrue
What p-value is used in chi-squared analysis? - ANSWERp= 0.05
What are the learning objectives for Lab 2? - ANSWER- Understand the terms
associated with multi-trait crosses.
- Design and diagram crosses involving two or more traits.
