Exam 3 Flashcards
What is one of the functions of spliceosomes?
Remove introns
Which of the following features is common to both DNA replication and transcription?
A sugar phosphate bond is formed between the 3’ hydroxyl and the 5’ phosphate
Which histone protein is not part of the nucleosome structure?
H1
What would you expect to find bound to the stop codon at the ribosomal A site?
A release factor
Why are abnormalities in the number of sex-chromosomes in mammals usually less severe in their phenotypic effects than abnormalities in the number of autosomes?
There are relatively few functional genes on the Y chromosome
Random X chromosome activation
A chromosome contains the following gene-order: ABCD-EFGH, which of the following rearrangements represents a pericentric inversion?
AFE-DCBGH
What is one difference between DNA replication in bacteria versus eukaryotes?
Eukaryotic chromosomes have many origins of replication, while bacteria have only one origin of replication
If you heat a solution containing DNA molecules?
The hydrogen bonds will be disrupted and the two strands will separate
Ribozymes are enzymes that
are composed of RNA
Which of the following enzymes neither makes nor breaks phosphodiester bonds?
Helicase
Consider synapsis in prophase I of meiosis for two plant species that each carry 36 chromosomes: Species A is diploid and species B is triploid. What characteristics of homologous chromosome synapsis can be used to distinguish these two species?
The diploid will have 18 bivalents whereas the triploid will have a combination of trivalents, bivalents, and univalents.
Which of the following statements about ddNTPs is true?
They have a hydrogen at the 3’ carbon of the ribose sugar
Which of the following is most likely attributable to a base substitution at a 5’ splice junction?
A longer than usual final transcript
You wish to create a mutation in which you prevent access of RNA polymerase to the gene. Which region of a gene would you target?
Promoter sequence
Which of the following is a common consequence of unequal crossover between homologs in repetitive DNA regions of the chromosome?
Partial duplication and deletion
Which type of chromosome rearrangement results in the fusion of the long arms of two nonhomologous chromosomes to produce a larger chromosome and a net reduction in chromosome number?
Robertsonian translocation
If an organism is an inversion heterozygote
Homologous chromosomes align during meiosis through formation of an inversion loop at synapsis
An organism with the genome size of n=23 experienced a Robertsonian translocation. How many chromosomes would you expect to see in the karyotype of a somatic cell in an affected individual?
44
Which of the following features is common to both DNA replication and transcription?
A sugar-phosphate bond is formed between the 3’ hydroxyl and 5’ phosphate.
If you heat a solution containing DNA molecules
The hydrogen bonds iwll be disrupted and the two strands will separate
Ribozymes are enzymes that
are composed of RNA
Which chemical group is at the 5’ end of a single polynucleotide strand?
Phosphate group
Which one of the following enzymes neither makes nor breaks phosphodiester bonds?
helicase
Which of the following is a common consequence of unequal crossover between homologs in repetitive DNA regions of the chromosome?
Partial duplication or deletion
Which type of chromosome rearrangement results in the fusion of the long arms of two nonhoomologous chromosomes to produce a larger chromosome and a net reduction in chromosome number?
Robertsonian translocation
If an organism is an inversion heterozygote
Homologous chromosomes align during meiosis through formation of a Holliday junction at synapsis
Humans with the condition of familial Down syndrome exhibit which type of chromosomal aberration?
Chromosome 14/21 Robertsonian translocation
What is one difference between DNA replication in bacteria versus eukaryotes?
Eukaryotic chromosomes have many origins of replication, while bacteria have only one origin of replication
Which of the following statements about ddNTPs is true?
They have a hydrogen at the 3’ carbon of the ribose sugar
Which of the following is most likely attributable to a base substitution at a 5’ splice junction?
A longer than usual final transcript
You wish to create a mutation in which you prevent access of RNA polymerase to the gene. Which region of a gene would you target?
Promoter sequence
Which regions of a gene are not found within the mRNA transcript?
promoter region
Which of the following feature is common to both DNA replication and transcription?
A sugar phosphate bond is formed between the 3’ hydroxyl and the 5’ phosphate
What are syntenic genes?
Genes that are located on the same chromosome
Syntenic genes can assort independently when
They are far apart on a chromosome and crossing over occurs frequently between the genes
The two loci A/a and D/d are linked. The following test cross is made: AD/ad x ad/ad. The progeny consisted of: AD/ad (50%) and ad/ad (50%). What can you deduce about the distance between A/a and D/d?
A/a and D/d are linked so closely that no crossovers ever occur
The loci A/a and B/b are linked 22 cM apart. From an individual Ab/aB, what proportion of gametes will be AB?
11%
In drosphila, the eye-color mutation scarlet (st) and the bristle mutation spineless (ss) are located in chromosome 3 at a distance of 14 map units. What phenotypes and in what proportions would you expect in the progeny from the mating of st+ ss+/ st ss females x st ss/st ss males?
43% wild type; 43% scarlet spineless; 7% scarlet; 7% spineless
For a given cross, the expected number of double recombinants is 20 and the observed number of double recombinants is 15. What is the interference in this region?
0.25
In a temperature-sensitive mutant strain of E. Coli, Okazaki fragments accumulate, and DNA synthesis is never completed. What is the enzyme or function likely affected in this strain?
DNA ligase
What is one of the functions of spliceosomes?
Remove introns
If you heat a solution containing DNA molecules
The hydrogen bonds will be disrupted and the two strands will separate
Which one of the following enzymes neither makes nor breaks phosphodiester bonds?
Helicase
