Lab Exam Flashcards
How many functional centromeres are in each cell? How many chromosomes are in each cell? How many DNA molecules are in each cell?
Is this cell diploid or haploid?
Four
Four
Four
Diploid Cell
Has the number of functional centromeres changed? Has the number of chromosomes changed? Has the number of DNA molecules changed? Do sister chromatids have the same alleles or can they be different?
No
No
Yes
Same Alleles- they can’t be different
What are the stages of life for the fly at 25 C
How do you distinguish a male fly from a female fly
Males have a wide dark band with a rounded abdomen shape
Female flies have a striped pigmented patter with a pointed abdomen shape
Male flies have sex combs on the front legs of the fly
Females have no external genitalia
What features are unclear in newly emerged flies?
Abdomen shape and abdomen pattern, must use sex comb and genitalia to distinguish
What is the mutant or wild type body color for flies
- x-linked
- Wild type body color is light brown
- Mutant body color is pale or slightly yellow (recessive)
What is the the mutant or wild type for bristles?
X-linked gene
Wild type flies have long bristles all extending in one direction toward the posterior of the fly
Mutant flies have shortened, disorganized bristles with a split end appearance (recessive)
What is the mutant or wild type for crossveins in flies
X-linked
Crossveins are present in wild type flies
Crossveins are absent in mutant flies (recessive)
What is incomplete dominance?
Is intermediate to phenotype of both homozygotes
What is co-dominance
Shows characteristic of both homozygotes, like blood types
What is over-dominance
Is more extreme than either homozygote or heterozygote and has selective advantage
exp: carrier for sickle cell has no anemia but more resistant to malaria than either homozygote
What should the gene abbreviation be named after?
Gene symbol should be between 1-5 characters long, named after the mutant phenotype and provide a mnemonic clue to it’s name.
Does allele frequency depend on dominance?
For one gene, dominant allele may be more frequent than a recessive allele. For another gene, dominant allele may be less frequent than recessive allele.
What is the wild type and mutant type for eye color?
- Autosomal
- Plum mutant (dominant)
- Red, wild type - X linked
- White, recessive, mutant
- Red, dominant, wild type
What type of ratio does Rr Ww x rr ww produce
1:1:1:1
What is independent assortment
Alignment and separation of each pair of homologous chromosomes is independent of other pairs.
What does a Rr Ww x Rr Ww produce
9:3:3:1
What is a priori chi-square test
Used to determine if observed values differ significantly from an expected standard
observed numbers of offspring conform to mendelian expectations
What is a contingency chi square test?
Used to determine if two or more variables are behaving independently
Inheritance of two different genetic characteristics is independent
How do you determine the degree of freedom?
Priori test: n-1 where n = expected number of classes
Contingency test: (rows-1)(columns -1)
What does a p-value less than .05 mean?
Significant difference between observed and expected, reject the null hypothesis
What does a P-value greater than .05 mean?
Chance is likely responsible for the difference between observed and expected. Fail to reject the null hypothesis.
How do you get the expected for a contingency chi square test
(CT1 x RT1) / GT
A cell in G1 of interphase of mitosis has 12 chromosomes (2n = 12).
In G1 of interphase, this cell would have [A] chromosomes and [B] DNA molecules.
In G2 of interphase, it would have [C] chromosomes and [D] DNA molecules.
In anaphase of mitosis, it would have [E] chromosomes and [F] DNA molecules.
At the end of mitosis (after telophase), each daughter cell would have [G] chromosomes and [H] DNA molecules.
Specified Answer for: A Correct12 Specified Answer for: B Correct12 Specified Answer for: C Correct12 Specified Answer for: D Correct24 Specified Answer for: E Correct24 Specified Answer for: F Correct24 Specified Answer for: G Correct12 Specified Answer for: H Correct12
The specific portion of a molecule of DNA that contains the information to produce one protein is defined as a [1].
A [2] is the specific position of a gene on a chromosome.
[3] organisms possess two sets of chromosomes (genetic information), one inherited from each parent.
Chromosomes that are similar in length, gene content and loci, and centromere position are said to be [4].
While a single gene encodes for a characteristic, such as hair color, alternative forms of that gene can determine brown, black, or blonde hair. These alternative gene forms are called [5].
The genetic makeup of an organism, as determined by alleles at a specific gene loci, is called a [6].
The physical expression of alleles at a specific gene loci is called a [7].
Identical copies of chromosomal DNA held together by a common functional centromere are called [8]
Specified Answer for: 1 Correct gene Specified Answer for: 2 Correct locus Specified Answer for: 3 Correct diploid Specified Answer for: 4 Correct homologous Specified Answer for: 5 Correct alleles Specified Answer for: 6 Correct genotype Specified Answer for: 7 Correct phenotype Specified Answer for: 8 Correct sister chromatids
What is drosophila cross
Mating male and female flies with different genotypes in order to generate new flies that also have different genotypes
Drosophila subculture
Mating male and female flies of the same genotype in order to generate new flies that also have the same genotype
Scoring
The process of comparing traits in wild-type and mutant flies. This process involves examining specific traits, such as body color or eye color, for comparison.
Mating ratio
When setting up a cross or a subculture, approximately 10-12 females and 4-6 males should be combined in a fresh food vial.
In this lab you will working with Drosophila as part of a semester-long project. In particular, you will examine three specific genes that reside on the x-linked chromosome. What are these three genes of interest?
bristle shape (unforked versus forked bristles)
body color (brown versus yellow body)
wing type (crossveined versus crossveinless wings)
Please choose the dominant allele in the following genotypes
Full Genotype Allele A Allele B [1] Cw Cw+ Cw+ Cw+ [2] ub+ ub ub+ ub+ [3] G G+ G+ G+ [4] md md+ md+ md+ [5] qu qu+ qu+ qu+
Specified Answer for: 1 Correct Cw Specified Answer for: 2 Correct ub+ Specified Answer for: 3 Correct G Specified Answer for: 4 Correct md+ Specified Answer for: 5 Correct qu+
Let’s say we crossed a bear heterozygous for brown fur and green eyes (BbEe) with a bear homozygous for tan fur and blue eyes (bbee), and found that they produced.
34 bears with tan fur and green eyes
29 bears with brown fur and blue eyes
9 bears with tan fur and blue eyes
101 bears with brown fur and green eyes
If you performed an A prior chi-square test….
What would your null hypothesis (expected ratio) be? (write 1:1:1:1 or 9:3:3:1) [1]
What would your degress of freedom be? (write a single number, like ‘1’ or ‘5’) [2]
With a Chi-square value of 5.41 and your calculated degrees of freedom, is your p-value significant? (write ‘yes’ or ‘no’) [3]
Would you reject or fail to reject the null hypothesis? (write ‘reject’ or ‘FTR’) [4]
Do your observations match your expectations? (write ‘yes’ or ‘no’)
Specified Answer for: 1 1:1:1:1 Specified Answer for: 2 3 Specified Answer for: 3 No Specified Answer for: 4 FTR Specified Answer for: 5 Yes
Let’s say a flower heterozygous for red and pointy leaves (AaPp) is crossed with another flower heterozygous for red and pointy leaves (AaPp).
From Mendelian genetics, we know that a punnett square of these two genotypes would produce a 9:3:3:1 ratio of genotypes among the offspring.
If we want to determine whether the genotypes of the offspring conform to this expected ratio (9:3:3:1), what sort of Chi-Square test should we use?
A priori Chi-Square test to determine if the observed data match expectations
Let’s say a pea plant heterozygous for green and round peas (GgRr) is crossed with another flower heterozygous for green and round peas (GgRr).
From Mendelian genetics, we know that a punnett square of these two genotypes would produce a 9:3:3:1 ratio of genotypes among the offspring.
If we want to determine whether the genes for pea color and pea shape sort independently, what sort of Chi-Square test should we use?
Contingency Chi-Square test to determine if the genes for pea color and pea shape are inherited independently
When the p-value = 0.50, there is a 50% probability that both the observed data and the null hypothesis are true.
For an A priori test, rejecting the null hypothesis means the observed data match expectations.
Using Table 4-7 in your lab manual, you should reject the null hypothesis for a Chi-square value = 3.05 with D.F. = 1
Failing to reject the null hypothesis means that both the null hypothesis and the observed data could be true at the same time.
When the p-value = 0.03, you should reject the null hypothesis.
Specified Answer for: 1 True Specified Answer for: 2 False Specified Answer for: 3 False Specified Answer for: 4 True Specified Answer for: 5 True
The probability value, or p-value, is an important value generated by a variety of statistical analyses. Select all of the following that are true when considering a p-value:
a.
The p-value is the probability that both the null hypothesis and the observed data are both true at the same time
b.
A high p-value, say p = 0.40, means is it highly unlikely that the null hypothesis and the observed data are both true.
c.
A high p-value, say p = 0.40, means is it highly likely that the null hypothesis and the observed data are both true.
d.
When the p-value is greater than alpha (p > 0.05), we fail to reject the null hypothesis. The observed data do match our expectations.
e.
When the p-value is less than alpha (p < 0.05), we reject the null hypothesis. The observed data do not match our expectations.
a.
The p-value is the probability that both the null hypothesis and the observed data are both true at the same time
c.
A high p-value, say p = 0.40, means is it highly likely that the null hypothesis and the observed data are both true.
e.
When the p-value is less than alpha (p < 0.05), we reject the null hypothesis. The observed data do not match our expectations.
Do linked genes sort independently?
Linked genes reside on the same chromosome and do not assort independently
How is the annotation for linked genes written?
What is the first cross in controlled mating?
homozygous mutant females
wild type males
Why must virgin females be used?
Females store sperm, so when doing controlled mating, must use virgin females
How long after flies emerge from the pupa do they not mate
They do not mate for 8 hours
What is the genotype for the second cross?
Heterozygotes wild type female
Mutant males
What can be used to confirm a virgin female
Virgin females flies have a dark spot on the underside of the abdomen called meconium
Use time as the primary determinant of virginity; use presence of meconium as confirmation only
Give a timeline of the genetic mapping experiment
What type of organism is Sordaria?
fungus
In what stage do sordaria spend most of its life
Haploid state
describe the sordaria life cycle
Spores begin mitosis and form a mycelium with many hyphae (filaments)
Hyphae fuse and nuclei become diploid for a short time forming a perithecium containing multiple ascus
Diploid cells undergo meiosis within an ascus sack to form haploid spores again
Where are the ascospores located
ascus
What is the big A and little a
A = light spores a = dark spores
What is type I, II, II
How do you determine the map distance between the gene for a spore color and its centromere
(recombinant asci / total asci) / 2 * 100%
In a cluster of asci where is the bottom and the top?
What do you do if you find an unexpected spore pattern?
Ignore, unexpected spore patterns
ONLY score asci that have mixtures of light and dark spores
With regards to today’s lab, how will we test whether the four chromatids involved in a tetrad are equally likely to engage in crossing-over? Select all of the following that apply
a.
We will assume a 1:1 ratio, or that there should be an equal ratio of # dark-up nonrecombinant asci to # light-up nonrecombinant asci
b.
We will hypothesize (null hypothesis) that the number of Type II recombinant asci should equal the number of Type III recombinant asci if all four chromatids equally participate in crossing-over at random
c.
We will assume a 1:1 ratio, or that there should be an equal ratio of # Type II recombinant asci to # Type III recombinant asci
d.
We will perform an a priori chi-square test on the number of non-recombinant asci scored in class
e.
We will perform an a priori chi-square test on the number of recombinant asci scored in class
f.
We will hypothesize (null hypothesis) that the number of light-up nonrecombinant asci should equal the number of dark-up nonrecombinant asci if all four chromatids equally participate in crossing-over at random
B
C
E
Meiosis is the process by which haploid gametes, such as sperm and egg cells, are made. What aspect(s) of meiosis contribute to genetic recombination - and ultimately genetic variation - in the gametes produced?
a.
Crossing over between sister chromatids during Prophase I of Meiosis
b.
The random alignment of homologous chromosomes on the metaphase plate during Metaphase I of Meiosis
c.
The random alignment of homologous chromosomes on the metaphase plate during Metaphase II of Meiosis
d.
Crossing over between non-sister chromatids during Prophase I of Meiosis
e.
The separation of sister chromatids during Anaphase I of Meiosis
B
D
Using the __[1]__ of genetic recombination, distance between a gene and the __[2]__ can be calculated.
When a diploid cell in an ascomycete fungus undergoes meiosis, it produces __[3]__ ascospores held within an single __[4]__.
The orientation of ascospores within a single ascus reflects the order in which __[5]__ separate during __[6]__.
The order of light and dark __[7]__ within the ascus depends on whether or not an exchange takes place between __[8]__ non-sister chromatids.
Type __[9]__ recombinant asci possess a 2-4-2 arrangement of ascospores, while Type __[10]__ recombinant asci possess a 2-2-2-2 arrangement of ascospores
Correct frequency
Correct centromere
Correct haploid
Correct ascus
Correct chromatids
Correct meiosis
Correct ascospores
Correct homologous
Correct 2
Correct 3
Ascus #1
Correct A.
Light-up Type I non-recombinant ascus
Ascus #2
Correct C.
Dark-Up Type II recombinant ascus
Ascus #3
Correct E.
Light-up Type III recombinant ascus
Ascus #4
Correct D.
Light-up Type II recombinant ascus
Ascus #5
Correct B.
Dark-Up Type III Recombinant
With regards to today’s lab, how will we test whether homologous chromosomes orient at random on the meiotic spindle? Select all of the following that apply:
a.
We will hypothesize (null hypothesis) that the number of Type II recombinant asci should equal the number of Type III recombinant asci if the orientation of homologous chromosomes is truly random
b.
We will perform an a priori chi-square test on the number of recombinant asci scored in class
c.
We will hypothesize (null hypothesis) that the number of dark-up nonrecombinant asci should equal the number of light-up nonrecombinant asci if the orientation of homologous chromosomes is truly random
d.
We will perform an a priori chi-square test on the number of non-recombinant asci scored in class
e.
We will assume a 1:1 ratio, or that there should be an equal ratio of # dark-up nonrecombinant asci to # of light-up nonrecombinant asci
f.
We will assume a 1:1 ratio, or that there should be an equal ratio of # Type II recombinant asci to # Type III recombinant asci
c
d
e
In this lab you will work with Drosophila as part of a semester-long experiment, and you will set up two consecutive crosses to examine the real-life results of genetic recombination. With respect to the second cross, select all of the following that apply
a. The second cross is a mating between the offspring of the first cross
b. The second cross is a mating between heterozygous wild-type females and mutant males
c. The female flies need to be collected every 8 hours to ensure they are virgins
d. The second cross is a mating between heterozygous wild-type males and mutant females
e. New flies will begin to emerge on Day 11. Scoring should begin on Day 11 and last until Day 18 to observe all progeny
f. New flies will begin to emerge on Day 11. Scoring should begin a few days later, on Day 14, and last until Day 18 because mutant flies emerge later than wild-type flies
a
b
f
In this lab you will work with Drosophila as part of a semester-long experiment, and you will set up two consecutive crosses to examine the real-life results of genetic recombination. With respect to the first cross, select all of the following that apply:
a. The females in the first cross must be collected every 8 hours to ensure they are virgin flies
b. The first cross is made by mating mutant females with wild-type males
c. The offspring of the first cross will emerge on Day 11 and can be scored (examined) from Day 11 through Day 18
d. The first cross is made by mating wild-type females with mutant males
e. The females in the first cross do not have to be virgins since they will be mated with males of the same stock
a b c
Genes of Interest in Drosophila Mutant Phenotype Mutant Allele
Body Color [1] [4]
Bristle Shape [2] [5]
Wing Type [3] [6]
Specified Answer for: 1
yellow
Specified Answer for: 4
y
Specified Answer for: 2
forked
Specified Answer for: 5
f
Specified Answer for: 3
crossveinless
Specified Answer for: 6
cv
Fill in the correct days for the following tasks with respect to the first cross:
Day [1]: remove the parents to avoid mixing of the P and F1 flies
Day [2]: F1 flies will begin to emerge
Day [3]: Don’t collect F1 flies for 2nd cross after this day to avoid risk of collecting F2 flies
Fill in the correct days for the following tasks with respect to the second cross:
Day [4]: remove the parents to avoid mixing of the P and F1 flies
Day [5]: F1 flies will begin to emerge
Day [6]: Begin scoring F2 flies a few days after they emerge to avoid bias in the results
Specified Answer for: 1
Correct8
Specified Answer for: 2
Correct11
Specified Answer for: 3
Correct18
Specified Answer for: 4
Correct8
Specified Answer for: 5
Correct11
Specified Answer for: 6
Correct14
Genes of Interest in Drosophila Wild-type Phenotype Wild-type Allele
Body Color [1] [4]
Bristle Shape [2] [5]
Wing Type [3] [6]
Specified Answer for: 1
light brown
Specified Answer for: 4
y+
Specified Answer for: 2
unforked
Specified Answer for: 5
f+
Specified Answer for: 3
crossvein
Specified Answer for: 6
cv+
