BIO2581 Section 4

Question: You are a scientist investigating the early evolution of photosynthetic eukaryotes, particularly the ancestors of modern plants. Using a time machine, you travel back 1.7 billion years, a period believed to be about 100 million years after the first eukaryotes emerged. You collect thousands of microbial species and analyze their genomes to determine gene origins. You are specifically looking for a potential ancestor of modern plants—an organism that has already established a chloroplast through endosymbiosis. Given the gene origin patterns shown below, which pie chart best represents such an ancestor?

• A
• B
• C
• D
• E

In the context of genome assembly, why are paired-end reads particularly useful for constructing contigs?

• They increase the overall length of individual sequencing reads, reducing the need for overlap.
• They provide information about the approximate distance and orientation between two reads, helping to bridge gaps and resolve repeats.
• They eliminate the occurrence of sequencing errors by providing two identical copies of the same fragment.
• They allow sequencing of only the ends of contigs, reducing the total amount of data required for assembly.
• . They ensure that all contigs are automatically connected into a single continuous sequence without gaps.

Which DNA sequencing method uses chain termination with labeled dideoxynucleotides to determine the DNA sequence?

• A) Illumina (Next Gen Sequencing)
• B) PacBio
• C) Sanger sequencing
• D) Nanopore
• F) None of the above

If you had a sequence of DNA 20,000 bases in length and with very long repeating sequences with some non repeating sequences, what sequencing method(s) would you use?

• Sanger
• Nanopore and Sanger
• Pacbio and Illumina
• Nanopore
• Myosin

see image

• 2,4,1,3
• 4,2,1,3
• 2,3,1,4
• 1,3,2,4
• 4,3,2,1

Which of the following correctly describes how genetic screens are performed in haploid and diploid organisms?

• In haploid organisms, mutants are directly screened for phenotypic changes, while in diploid organisms, additional generations or techniques like self-crossing or backcrossing are required to isolate homozygous mutants.
• Both haploid and diploid organisms require multiple generations of crossing to isolate recessive mutations before phenotypic screening.
• In diploid organisms, genetic screens involve directly observing mutations in the F1 generation, while in haploid organisms, additional crosses are needed to reveal phenotypic effects.
• In diploid organisms, genetic screens involve directly observing mutations in the F3 generation, while in haploid organisms, genetic screens involve directly observing mutations also in the F3 generation.
• Genetic screens are only effective in haploid organisms, as mutations cannot be identified in diploids due to dominant alleles.

Below are given genotypes for 2 bacterial strains. The + sign indicates a WT allele a - sign indicates loss of function. Z=beta-galactosidase,I=repressor,O= operator s=super repress or allele c= constitutive expression allele and f is an unknown allele. Indicate what allele f represents based off data below Genotype. No glucose. Glucose I+O+Z+/I+O+Z+. No. Yes Is Of Z+/ I+O-Z- Yes Yes

• f is a loss of function allele
• f is a gain of function allele
• F is a dominant negative allele
• f is a wild type allele
• F is a halpoinsufficent allele