MMSC491 Exam 1 Updated Actual Exam
Question and Answer (2026/2027) |
Grade A+
• Coding DNA is only ___% of our DNA, remainder is non-coding: -✓✓ 1.5%
• Length of protein coding genes in bacteria: -✓✓ ~1000 bp
• Starting intron consists of ______ (splice donor site) and ending intro consists of
____ (splice acceptor site) -✓✓ 1. GU
2.AG
• What does the untranslated region of mRNA do? -✓✓ Regulate Gene Expression
mRNA stability
• Start codon:
Stop Codons: -✓✓ Start: AUG
Stop: UAA, UAG, UGA
• How do tRNA carry amino acids? -✓✓ Amino acids are covalently bonded to the
3' end of tRNA
• Untranslated regions have what on the 5' end? And how it is advantageous? -✓✓
1. 7-methylguanosine linked to first nucleotide by a 5' -5' phosphodiester bond
2.Protects transcript against 5' and 3' exonuclease attack and facilitates transport to
cytoplasm and ribosomal attachment
• For untranslated region, what is on the 3' end, what is the length of it, and what
does it do? -✓✓ 1. Poly A Tail
2. ~150-200 nucleotides long
3. Transport mRNA to cytoplasm, facilitates binding to ribosomes and stabilizing
mRNA
• How is folding stabilized? -✓✓ Hydrophobic and hydrophilic interactions,
covalent cross-linking at cysteine residues (disulfide bonds)
,• Explain how protein leaves the cell -✓✓ Polypeptide carries N-terminus ladder
sequence (signal peptide) required to cross membrane -> signal peptide cleaved at
membrane, releasing mature protein
*signal peptide contain hydrophobic amino acids (100-300 bp)
• Constitute Polypeptides -✓✓ individual amino acid chains, linked by peptide
bond, that combine to form functional proteins
• Small nuclear RNA (snRNA): -✓✓ -Chemically modify specific bases in rRNA
-Spliceosome: Degrading introns in the pre-mature RNA to make a mature RNA
• small Cajal-body RNA (scaRNA) -✓✓ Chemically modify spliceosomal snRNA
• Ribozymes -✓✓ Cleave tRNA and rRNA precursors
• "RNA World Hypothesis" -✓✓ RNA is the original genetic material before DNA
and protein
-This is possible because ss-RNA has a flexible structure and can form complex
shapes w/ intramolecular H-bonds
• RNA Base Pairing: -✓✓ G-U , A-U, G-C
• In RNA, what does a stem loop in the structure help with: -✓✓ stem loop act as
recognition elements for binding regulatory proteins- critical for determining
overall RNA structure
• in rRNA, where does catalytic activity occur? -✓✓ 28s rRNA
• Two Broad Classes of long non-coding RNA:
Intergenic + intragenic
What are these and what are they involved with? -✓✓ Intergenic- between genes
(ex: regulate neighboring genes, control expression of genes on other
chromosomes)
Intragenic - reside within protein-coding genes (ex: sense and antisense. antisense:
bind to complementary sequence to downregulate gene expression)
• Tiny Non-coding RNA:
, Micro RNA (miRNA)-
Piwi Protein-Interacting RNAs (piRNA)- -✓✓ Micro RNA (miRNA)- recognize
and bind to defend target regulatory sequences present in specific mRNA to
downregulate their expression
Piwi Protein-Interacting RNAs (piRNA)- in germ cells to decrease excess activity
of transposons (mobile DNA elements)
• What's seen when a chromosome is stained? -✓✓ Alternating Bands and low
resolution
• What percent of genome is euchromatin? -✓✓ 93%
• What percent of genome is heterochromatin? -✓✓ 7% (mainly constituitive
heterochormatin)
• Psuedogenes -✓✓ Inactive copies of functional genes
• What does the BLAST Program aid in?
What other programs are involved? -✓✓ Compare human coding DNA to other
related sequences in the genomes of other mammals
Works: translating putative coding DNA in all 6 reading frames (3 per strand) then
compare
BLASTN- nucleotide query / BLASTP- protein sequence / TBLASTN - protein
sequence to nucleotide sequence / BLAT- rapid sequence search across whole
genome
• Why do RNA genes lack open-reading frames? -✓✓ Poorly conserved through
evolution
• What does ENCODE (Encyclopedia of DNA Elements) aid in? -✓✓ Compare
RNA sequence to genome wide transcription analysis, evolutionary sequence
comparisons, and functional assays (bioinformatics)
• What occurred millions of years ago that started the evolution of the human
genome? How did the genome become bigger? -✓✓ 1.Aerobic prokaryote was
endocystosed by an anaerobic precursor cell
Mitochondrial genome originated from a from a prokaryote genome excise,
causing large decrease in size
Question and Answer (2026/2027) |
Grade A+
• Coding DNA is only ___% of our DNA, remainder is non-coding: -✓✓ 1.5%
• Length of protein coding genes in bacteria: -✓✓ ~1000 bp
• Starting intron consists of ______ (splice donor site) and ending intro consists of
____ (splice acceptor site) -✓✓ 1. GU
2.AG
• What does the untranslated region of mRNA do? -✓✓ Regulate Gene Expression
mRNA stability
• Start codon:
Stop Codons: -✓✓ Start: AUG
Stop: UAA, UAG, UGA
• How do tRNA carry amino acids? -✓✓ Amino acids are covalently bonded to the
3' end of tRNA
• Untranslated regions have what on the 5' end? And how it is advantageous? -✓✓
1. 7-methylguanosine linked to first nucleotide by a 5' -5' phosphodiester bond
2.Protects transcript against 5' and 3' exonuclease attack and facilitates transport to
cytoplasm and ribosomal attachment
• For untranslated region, what is on the 3' end, what is the length of it, and what
does it do? -✓✓ 1. Poly A Tail
2. ~150-200 nucleotides long
3. Transport mRNA to cytoplasm, facilitates binding to ribosomes and stabilizing
mRNA
• How is folding stabilized? -✓✓ Hydrophobic and hydrophilic interactions,
covalent cross-linking at cysteine residues (disulfide bonds)
,• Explain how protein leaves the cell -✓✓ Polypeptide carries N-terminus ladder
sequence (signal peptide) required to cross membrane -> signal peptide cleaved at
membrane, releasing mature protein
*signal peptide contain hydrophobic amino acids (100-300 bp)
• Constitute Polypeptides -✓✓ individual amino acid chains, linked by peptide
bond, that combine to form functional proteins
• Small nuclear RNA (snRNA): -✓✓ -Chemically modify specific bases in rRNA
-Spliceosome: Degrading introns in the pre-mature RNA to make a mature RNA
• small Cajal-body RNA (scaRNA) -✓✓ Chemically modify spliceosomal snRNA
• Ribozymes -✓✓ Cleave tRNA and rRNA precursors
• "RNA World Hypothesis" -✓✓ RNA is the original genetic material before DNA
and protein
-This is possible because ss-RNA has a flexible structure and can form complex
shapes w/ intramolecular H-bonds
• RNA Base Pairing: -✓✓ G-U , A-U, G-C
• In RNA, what does a stem loop in the structure help with: -✓✓ stem loop act as
recognition elements for binding regulatory proteins- critical for determining
overall RNA structure
• in rRNA, where does catalytic activity occur? -✓✓ 28s rRNA
• Two Broad Classes of long non-coding RNA:
Intergenic + intragenic
What are these and what are they involved with? -✓✓ Intergenic- between genes
(ex: regulate neighboring genes, control expression of genes on other
chromosomes)
Intragenic - reside within protein-coding genes (ex: sense and antisense. antisense:
bind to complementary sequence to downregulate gene expression)
• Tiny Non-coding RNA:
, Micro RNA (miRNA)-
Piwi Protein-Interacting RNAs (piRNA)- -✓✓ Micro RNA (miRNA)- recognize
and bind to defend target regulatory sequences present in specific mRNA to
downregulate their expression
Piwi Protein-Interacting RNAs (piRNA)- in germ cells to decrease excess activity
of transposons (mobile DNA elements)
• What's seen when a chromosome is stained? -✓✓ Alternating Bands and low
resolution
• What percent of genome is euchromatin? -✓✓ 93%
• What percent of genome is heterochromatin? -✓✓ 7% (mainly constituitive
heterochormatin)
• Psuedogenes -✓✓ Inactive copies of functional genes
• What does the BLAST Program aid in?
What other programs are involved? -✓✓ Compare human coding DNA to other
related sequences in the genomes of other mammals
Works: translating putative coding DNA in all 6 reading frames (3 per strand) then
compare
BLASTN- nucleotide query / BLASTP- protein sequence / TBLASTN - protein
sequence to nucleotide sequence / BLAT- rapid sequence search across whole
genome
• Why do RNA genes lack open-reading frames? -✓✓ Poorly conserved through
evolution
• What does ENCODE (Encyclopedia of DNA Elements) aid in? -✓✓ Compare
RNA sequence to genome wide transcription analysis, evolutionary sequence
comparisons, and functional assays (bioinformatics)
• What occurred millions of years ago that started the evolution of the human
genome? How did the genome become bigger? -✓✓ 1.Aerobic prokaryote was
endocystosed by an anaerobic precursor cell
Mitochondrial genome originated from a from a prokaryote genome excise,
causing large decrease in size
