BIO302 Exam 2 (Application)

A

Assume that an organism exists in which crossing over does not occur, but that all other processes associated with meiosis occur normally. Consider how the absence of crossing over would affect the outcome of a single meiotic event. Which of the following statements would be true if crossing over did not occur? a.) There would be less genetic variation among gametes. b.) The two sister chromatids of each replicated chromosome would no longer be identical. c.) The daughter cells of meiosis I would be diploid, but the daughter cells of meiosis II would be haploid. d.) Independent assortment of chromosomes would not occur. e.) The four daughter cells produced in meiosis II would all be different. f.) The two daughter cells produced in meiosis I would be identical.

A; _A__________B____________ (chromosome one) _a___________b____________ (chromosome two)

Choose the diagram illustrating the alleles on homologous chromosomes for the genotype AB/ab, assuming that the genes reside on the same chromosome in the order written. a.) AB / ab b.) aB / Ab c.) Bb / Aa d.) Ab / aB

C; _a__B__c_________ (chromosome one) _a__b__C________ (chromosome two)

Choose the diagram illustrating the alleles on homologous chromosomes for the genotype aBc/abC, assuming that the genes reside on the same chromosome in the order written. a.) aBc / acB b.) aBc / cba c.) aBc / abC d.) aBC / abc

nonsister chromatids.

Crossing over during meiosis occurs between alleles on ____________.

meiosis I, anaphase

During which part of meiosis (meiosis I or meiosis II) do the two alleles of a gene separate? During which phase does the separation occur? (Assume no recombination.) State your answer as meiosis I or meiosis II followed by a comma and the name of the phase (for example, if your answer is meiosis II and metaphase, enter meiosis II, metaphase).

C A cross between a plant of unknown genotype and one that is known to be homozygous recessive is called a test cross because the recessive homozygote tests whether there are any recessive alleles in the unknown. Because the recessive homozygote will contribute an allele for the recessive characteristic to each offspring, the second allele (from the unknown genotype) will determine the offspring's phenotype.

How could the botanist best determine whether the genotype of the green-pod plant is homozygous or heterozygous? a.) Cross the green-pod plant with another green- pod plant. b.) Self-pollinate the green-pod plant. c.) Cross the green-pod plant with a yellow-pod plant.

By integration of the F plasmid into the bacterial chromosome

How is an Hfr chromosome formed?

3

How many different RNA polymerase enzymes are required to transcribe the various classes of RNA in eukaryotic cells?

half of the gametes formed are parental and the other half are recombinant

If crossing over occurs, ______________________________________.

30%

If two genes are 30 map units apart, what proportion of the gametes produced by a dihybrid individual (AB/ab) would be recombinant?

B Thirty map units is defined as 30% recombinant products of meiosis. Provide Feedback

If two genes are 30 map units apart, what proportion of the gametes produced by a dihybrid individual (AB/ab) would be recombinant? a.) 15% b.) 30% c.) 35% d.) 70%

B ; By performing a punnett square you will obtain a 1:2:1 genotypic ratio and a 3:1 phenotypic ration.

If two genes on the same chromosome exhibit complete linkage, what is the expected F2 phenotypic ratio from a selfed heterozygote with the genotype a + b + ⁄⁄ ab? a.) 9:3:3:1 b.) 3:1 c.) 1:1 d.) 1:1:1:1

DNase

In 1944, Avery, MacLeod, and McCarty provided direct evidence that DNA was the hereditary molecule. They treated heat-killed extracts from lethal SIII (smooth) bacteria with various enzymes and found that transformation was prevented only upon treatment with __________.

1'

In a DNA nucleotide, to which carbon on deoxyribose is the nitrogenous base attached?

1.67

In a hypothetical strand f DNA, the [A + G] / [C + T] or purine / pyrimidine ratio for one strand of a double-stranded DNA molecule is 0.6 What is the purine / pyrimidine ratio in the complementary strand?

Transformation

In which process of genetic exchange in bacteria is one strand of DNA degraded as it enters the recipient cell?

B

Independent assortment explains _______. a.) why meiosis in a cell of genotype Aa yields A gametes and a gametes in roughly equal numbers b.) why a collection of meiotic products that includes gametes of genotype Ab will also include gametes of genotype AB in roughly the same proportion c.) why meiosis in a cell of genotype Aa yields A gametes and a gametes, but no Aa gametes d.) why meiosis in a cell of genotype AaBb cannot yield Ab gametes

All in "Both" box In organisms that reproduce sexually, the processes of DNA replication, the precise pairing of homologs during crossing over, chromosome alignment and separation in meiosis I and II, and fertilization ensure that traits pass from one generation to the next. Unlike with asexual reproduction, offspring of sexual reproduction are genetically different from each other and from both of their parents. Mechanisms that contribute to genetic variation include errors (mutations) that occur during DNA replication the production of recombinant chromosomes due to crossing over the independent assortment of homologous chromosomes in meiosis I the separation of sister chromatids (which are no longer identical due to crossing over) in meiosis II the random fusion of male and female gametes during fertilization

Meiosis guarantees that in a sexual life cycle, offspring will inherit one complete set of chromosomes (and their associated genes and traits) from each parent. The transmission of traits from parents to offspring is called heredity. Another important aspect of meiosis and the sexual life cycle is the role these processes play in contributing to genetic variation. Although offspring always resemble their parents, they are genetically different from both of their parents and from one another. The degree of variation may be tremendous. The following processes are associated with meiosis and the sexual life cycle: -DNA replication before meiosis -crossing over -chromosome alignment in metaphase I and separation in anaphase I -chromosome alignment in metaphase II and separation in anaphase II -fertilization Sort each process into the appropriate bin according to whether it contributes to heredity only, genetic variation only, or both. (Note that a bin may be left empty.)

D (Update with how)

Part A Part complete Two genes, A and X, exhibit incomplete linkage. The frequency of each parental gamete (AX and ax) is 45%. What is the approximate frequency of the Ax gamete? a.) 5% b.) 55% c.) 10% d.) 45%

g g g g G Gg Gg G Gg Gg G Gg Gg g gg gg The genotypes in a Punnett square show all the possible combinations of alleles in offspring that could result from the particular cross. A Punnett square reveals the expected probabilities of each genotype among the offspring. For example, the Punnett square on the right reveals that there is a 50% chance that each offspring will have green pods and a 50% chance that each offspring will have yellow pods.

Punnett squares can be used to predict the two possible outcomes of the botanist's test cross. The Punnett square on the left shows the predicted result if the unknown plant is homozygous (GG); the Punnett square on the right shows the predicted result if the unknown plant is heterozygous (Gg). Test cross Homozygous g ? g ? G ?? ?? G ?? ?? ? ?? ?? ? ?? ??

A, B, C, and D; Assuming that crossing can occur. Each of the following gametes can be produce following mitoses.

Select the gametes produced by an organism with the genotype Rt/rT. a.) r / t b.) R / T c.) R / t d.) r / T

D

Suppose that the botanist carried out the test cross described in Parts A and B and determined that the original green-pod plant was heterozygous (Gg). Which of Mendel's findings does her test cross illustrate? a.) law of independent assortment b.) chromosome theory of inheritance c.) linkage d.) law of segregation

False

True/False Crossing over during prophase I of meiosis occurs between alleles on sister chromatids

False

True/False Independent assortment occurs only in cells that are heterozygous for two genes (AaBb) and not in cells that are completely homozygous (AABB or aabb).

B

What is the definition of a map unit? a.) 1 kb (1000 base pairs) of DNA b.) 1% recombinant products of meiosis c.) One crossover event in meiosis d.) The frequency of recombination between two or more gene

A

What is the highest possible frequency of recombination between linked genes that can be generated by any type of the crossover event? a.) 50% b.) 33% c.) 100% d.) It depends on the distance between genes.

Relaxosome

What is the name of the complex that binds to the origin of transfer (oriT) in the process of conjugation?

Conjugation

What is the name of the process in bacteria that involves DNA transfer through a cytoplasmic connection known as a pilus?

3.0 or greater

What lod score is associated with a significant likelihood of linkage?

D

What lod score is associated with a significant likelihood of linkage? a.) -2.0 to 0 b.) 0 to 2.0 c.) -2.0 or less d.) 3.0 or greater

RNA pol II promoters for mRNA

Which eukaryotic promoters display a high degree of variability in the type, number, and location of consensus sequence elements?

tRNAs, rRNAs, and snRNAs

Which of the following are classified as functional or structural RNAs?

The presence of a recombination cold spot between the two genes

Which of the following factors is likely to result in mapping data that place genes closer to one another than they appear on a physical map?

B

Which of the following factors is likely to result in mapping data that place genes closer to one another than they appear on a physical map? Which of the following factors is likely to result in mapping data that place genes closer to one another than they appear on a physical map? a.) Having fewer base pairs per map unit than is typical between the two genes b.) The presence of a recombination cold spot between the two genes c.) A double crossover between the two genes d.) The presence of a recombination hot spot between the two genes

A

Which of the following genotypes represents a gamete produced by a failure to segregate during meiosis in a cell of genotype AaBbCC? a.) AaBC b.) aBC c.) abC d.) ABC

C

Which of the following statements about gamete formation during meiosis is false? a.) Parental gametes contain the same combinations of linked genes as found in the parent cell. b.) Recombinant gametes contain combinations of alleles not found in the parent cell. c.) Parental gametes can be formed only if there is no crossing over during meiosis. d.) Complete linkage results in the formation of only parental gametes.

Specialized transduction

Which process of genetic exchange in bacteria is capable of transferring only a small, specific region of the bacterial chromosome?

D Correct. In 1911, while he was an undergraduate in Thomas Hunt Morgan's lab, Alfred Sturtevant created the first genetic map of the X chromosome in Drosophila.

Who is generally credited with creating the first genetic linkage map? a.) Alfred Sturtevant b.) Bateson and Punnett c.) Gregor Mendel d.) Thomas Hunt Morgan

Because alignment of the chromosomes is random, the alignment that produces Ab is just as likely as the alignment that produces AB. Therefore, the two genotypes should both occur with equal frequency.

Why a collection of meiotic products that includes gametes of genotype Ab will also include gametes of genotype AB in roughly the same proportion