BIO2581B_S24_Mon_July_15th_Session_1

Which of the following statements best describes the differences in approaches of forward and reverse genetics?

• i. Reverse genetics involves mutating a specific gene to observe the resulting phenotypes, whereas forward genetics involves screening for natural variations in a population to identify genes associated with a phenotype.
• ii. Forward genetics utilizes CRISPR-Cas9 technology to knock out genes of interest, while reverse genetics starts with a phenotype and works backwards to identify the responsible gene.
• iii. Reverse genetics involves studying inheritance pattens of traits within a population, while forward genetics focuses on creating transgenic organisms to study gene function.
• iv. Forward genetics and reverse genetics are two complementary approaches, in which forward genetics involves identifying the genetic basis of a phenotype, whereas reverse genetics involves genetic manipulation and works backwards to identify the responsible gene.
• v. Forward genetics involves analyzing the expression patterns of genes using microarrays, while reverse genetics involves sequencing the entire genome to identify mutations associated with a phenotype.

What is BCD also referred to?

• a) a form of complementation analysis
• b) maternal effect mutations
• c) mutant alleles
• d) cell and developmental biology
• e) gene expression

In a yeast cell, a deamination event occurs in a non-coding intronic region of a gene during DNA replication. If this mutation is not repaired, which of the following scenarios may occur:

• a. The gene will not be transcribed
• b. The gene will not be translated
• c. The mature mRNA will contain the mutation
• d. The protein product will be unaffected (assume normal splicing)
• e. The protein product will be inactive (assume normal splicing)

Both restriction enzymes and CRISPR Cas9 make a (1) exogenous DNA to degrade it. (2) can not recognize the stored copy of an exogenous sequence in the endogenous chromosome because the copy only encodes (3) and not (4).

• double-stranded break, restriction enzymes, restriction enzyme site, the PAM sequence
• single-stranded nick, restriction enzymes, guide RNA, methylation
• double-stranded break, CRISPR Cas 9, guide RNA, the PAM sequence
• single-stranded nick, CRISPR Cas 9, restriction enzyme site, the PAM sequence
• double-stranded break, CRISPR Cas 9, guide RNA, methylation

The following is a genotype of a bacterial strain: I+ Oc Z- / I- Ox Z+ The plus (+) sign indicates wild type allele, the negative (-) sign indicates loss of function allele, and c indicates constitutively on mutant allele. I is a lac repressor gene, O is the beta-galactosidase operator, and Z is the beta-galactosidase coding sequence. When this bacterial strain is grown in media with glucose but no lactose, there is no expression of beta-galactosidase. When it is grown in media containing lactose but no glucose, there is expression of beta-galactosidase. What is the classification of allele x?

• Wild Type
• Hypomorphic
• Gain of Function
• Dominant Negative
• Null

Which one of the RNAi results in a protein not being the end product?

• mRNA
• rRNA
• miRNA
• siRNA
• tRNA

The following figure shows the reference sequence of the human genome and a mutated genome: Reference sequence: T T C A G C C A A A G C G C G A G T A A G C T G G C T T T A C A C C T A What mutations are present in the changed genomic sequence?

• Insertions
• Deletions
• Inversions
• Transversions
• Transitions

Why do restriction enzymes only break down the invasive phage DNA, but not the genomic DNA of bacteria?

• The genomic DNA is protected by methyl groups from the restriction enzymes
• The genomic DNA lacks the PAM sequence needed for the restriction enzyme to recognize
• Restriction enzymes are only signaled to activate upon entry of phage DNA
• Restriction enzymes inevitably break down the genomic DNA, which is then repaired via homologous combination
• x