Molecular Biology and Diagnostic MLS312 Finals Mock Exam

RNA Structure and Function

• RNA is typically single-stranded, unlike DNA, which is double-stranded.
• RNA uses uracil (U) instead of thymine (T) as a base to pair with adenine (A).
• RNA is usually single-stranded and contains the base uracil.

Transcription

• RNA polymerase is crucial for initiating transcription, the process of copying DNA into RNA.
• The terminator sequence marks the end of the transcribed region.
• RNA synthesis during transcription proceeds in the 5' to 3' direction.

RNA Splicing

• The spliceosome is a large protein complex that recognizes splice sites (intronic sequences) and facilitates intron removal and exon joining during RNA splicing.
• Alternative splicing allows a single pre-mRNA to be processed into different mature mRNAs by including or excluding different exons, increasing protein diversity.

Gene Expression and Regulation

• WT1 is a well-known tumor suppressor gene frequently mutated in Wilms' tumor, a childhood kidney cancer.
• Silent mutations are mutations that don't affect the amino acid sequence.

RNA Isolation

• Cell lysis is the initial step in RNA isolation, breaking open cells to release cellular contents, including RNA.
• Guanidium thiocyanate disrupts cell membranes and helps in protein denaturation during RNA isolation, allowing for better RNA extraction.

FISH (Fluorescence In Situ Hybridization)

• FISH uses fluorescent probes to target specific DNA or RNA sequences within a cell.
• FISH probes bind to their complementary sequences on the chromosomes, allowing researchers to visualize their location in the nucleus.
• Split gene probes are designed to bind to two separate regions within the same gene, used to detect breakpoints in the gene, which might be associated with genetic disorders.
• Telomere FISH probes bind specifically to the end regions of chromosomes, allowing researchers to study telomere.
• Multiple color FISH probes can be used to determine birth defects.

FISH vs. Southern Blotting

• Both FISH and Southern blotting can utilize either fluorescent or radioactive probes depending on the researcher's preference and the specific application.
• FISH is used to study DNA or RNA within a cell, while Southern blotting is used to study DNA or RNA outside of a cell.

FISH vs. Karyotyping

• FISH is used to study individual chromosomes or specific DNA sequences, while karyotyping is used to study the entire genome.