genetics progress test 3

Which of the following statements best describes a heterochromatic region of DNA?

Which of the following statements best describes a heterochromatic region of DNA?

What term describes a fruit fly that has a total of 7 chromosomes because it is missing one copy of chromosome 3?

aneuploid

If the haploid number for a plant species is 12, how many chromosomes are found in the somatic cell of a member of the species that is diploid, monosomic, trisomic, and tetraploid, respectively?

24, 12, 36, 48

A human germ cell experiences a meiotic disjunction of chromosome 21 in meiosis I. Which of the following statements best describes the pattern you would expect to observe in the resulting gametocytes?

Two cells will have 24 chromosomes, and two cells will have 22 chromosomes.

A boy with Klinefelter syndrome (47,XXY) is born to two individuals with normal color vision. If the boy is color-blind (due to a recessive X-linked allele), did nondisjunction occur during oogenesis or spermatogenesis in this child's parents and in what stage of Meiosis?

oogenesis, Meiosis II

Which of the following outcomes is not a consequence of polyploidy?

Increased fertility

Cultivated wheat is descended from three distinct species, each with a diploid set of 14 chromosomes. Thus, it is an __________ with __________ chromosomes.

autotetraploid; 28

Donkeys have a somatic chromosome number of 62. Hybrids produced by crossing donkeys and zebras are called zonkeys, are sterile, and have many characteristics intermediate between the two parental species. If a zonkey has 52 chromosomes, what is the somatic chromosome number of zebras?

42

Which human condition is the result of a partial chromosome deletion of the terminal end of chromosome 5.

Cri-du-chat syndrome

Familial Down syndrome accounts for approximately 5% of all Down syndrome cases. Which of the following statements regarding heterozygous carriers of the 14/21 Robertsonian translocation is false?

One-half of their surviving offspring would be expected to have Down syndrome.

The figure shows the structure of a series of fruit fly deletion mutants. The gap in each line represents the segment of the chromosome that is deleted in each mutant. Stains that were heterozygous for each deletion mutation and a point mutation (A, B, C, D, E, and F) were created and analyzed for wild-type (+) or mutant (-) phenotype. The results of the analyses are shown in the table.

Partial deletion map and table of progeny phenotypes.

Which of the following is the correct order of the six point mutations on the chromosome?

C,E,A,F,B,D

A normal chromosome and its homolog carrying an inversion are given. The dot (•) represents the centromere.

Normal: A B C • D E F G H I J

Inversion: a b c • d g f e h i j

What type of inversion is present and what is the name of the structure that will form during synapsis?

paracentric, inversion loop

A normal chromosome and its homolog carrying an inversion are given. The dot (•) represents the centromere.

Normal: A B C • D E F G H I J

Inversion: a b c • d g f e h i j

If there is a crossover between E and F, which of the following are the recombinant gametes?

A B C • D E f g d • c b a; J I H G F e h i j

Which of the following sets of gametes would result from alternate segregation in reciprocal balanced translocation heterozygotes?

Gametes from balanced translocation heterozygotes.

set 2

Which of the following best describes the features of histones?

The five types of histone proteins in chromatin are basic proteins with a positive charge that allows them to bind to DNA as part of the chromatin structure.

The compaction leading to a metaphase chromosome in eukaryotes involves which of the following?

all of these statements are correct:

anchoring and further compaction of the loops onto a scaffold

a structure with 6-8 nucleosomes per turn and histone H1 stabilizing the solenoid

five major types of histones (H1, H2A, H2B, H3, and H4)

the formation of the 30 nm fiber

Which of the following is/are true regarding the variegated eye phenotype that Hermann Muller studied in Drosophila melanogaster?

Even though eye color phenotypic variegation exists within the eye, all cells have the same genotype.

Which of the following is not a property shared by DNA polymerase and RNA polymerase?

uses ribonucleotide triphosphates as substrates

Where would you expect to observe coupling of transcription and translation?

In the cytoplasm of prokaryotes

There is a substantial difference between the number of genes and the number of proteins in many eukaryotic genomes, especially those of mammals. It is common for large eukaryotic genomes to express more proteins than there are genes in the genomes. Which mechanism involves post-translational processing of identical pre-mRNAs leading to different mature mRNAs?

alternative intron splicing

In bacteria, what aligns with the Shine-Dalgarno sequence during translation initiation?

16S rRNA

A tRNA contains the anticodon 3'-GAU-5'. What codon and amino acid would you expect to be carried by this tRNA?

5'-CUA-3', which corresponds to the amino acid leucine

Which enzyme initiates the 5' capping of the mRNA?

guanylyl transferase

If a cell is showing defects in intron splicing, which type of RNA is most likely defective?

snRNA

Which of the following codons would have no third base "wobble" because it lacks synonymous codons?

UGG