Gentics exam 3

1. What is the correct order of gene expression events?
   A. Translation → Transcription → Protein Folding
   B. Transcription → Translation → Protein Folding
   C. Protein Folding → Translation → Transcription
   D. Translation → Protein Folding → Transcription

2. Which molecule carries the genetic code from DNA to the ribosome?
   A. Ribosomal RNA (rRNA)
   B. Transfer RNA (tRNA)
   C. Messenger RNA (mRNA)
   D. Pre-messenger RNA (pre-mRNA)

3. What is the function of the promoter in gene expression?
   A. Terminates transcription
   B. Signals the start of DNA replication
   C. Binds RNA polymerase to start transcription
   D. Splices introns from RNA

4. Which of the following is added to the 3′ end of mRNA during processing?
   A. Cap
   B. Stop codon
   C. Poly-A tail
   D. Anticodon

5. What is the start codon sequence, and what amino acid does it code for?
   A. UGA – Tryptophan
   B. AUG – Methionine
   C. UAA – Stop
   D. GGG – Glycine

6. What structure forms the core of ribosomes?
   A. mRNA
   B. tRNA
   C. DNA
   D. rRNA

7. Which part of tRNA recognizes and binds to the codon on mRNA?
   A. Start codon
   B. Anticodon
   C. Ribosome binding site
   D. Poly-A tail

8. Which of the following is removed from pre-mRNA during RNA processing?
   A. Exons
   B. Start codon
   C. Introns
   D. Cap

🧫 Section II: Proteins and Phenotypes

9. What type of bond links two amino acids together?
   A. Hydrogen bond
   B. Disulfide bond
   C. Peptide bond
   D. Ionic bond

10. Which structure refers to the sequence of amino acids in a protein?
    A. Primary structure
    B. Secondary structure
    C. Tertiary structure
    D. Quaternary structure

11. What helps fold a polypeptide into a functional shape?
    A. Ribosome
    B. tRNA
    C. Chaperone
    D. Peptide bond

12. What is the N-terminus of a polypeptide?
    A. The end with a free carboxyl group
    B. The middle of the chain
    C. The end with a free amino group
    D. The folded protein's outer edge

13. Which of the following describes a proteome?
    A. All DNA in a cell
    B. All RNA in a cell
    C. All proteins present in a cell at a given time
    D. All enzymes active during transcription

14. What type of molecule results from the translation process?
    A. Ribosome
    B. mRNA
    C. Protein
    D. DNA

15. Which of the following is a functional consequence of a change in protein structure?
    A. Ribosomal assembly
    B. Change in phenotype
    C. Base pairing mismatch
    D. DNA methylation

16. Which disorder results from the inability to break down homogentisic acid?
    A. Galactosemia
    B. PKU
    C. Thalassemia
    D. Alkaptonuria

⚠ Section III: Mutations and Epigenetics

17. Which mutation results in a premature stop codon?
    A. Missense mutation
    B. Sense mutation
    C. Nonsense mutation
    D. Silent mutation

18. What mutation causes a shift in the codon reading frame?
    A. Missense mutation
    B. Frameshift mutation
    C. Sense mutation
    D. Nucleotide substitution

19. A mutation that changes one amino acid to another is called:
    A. Missense mutation
    B. Nonsense mutation
    C. Sense mutation
    D. Frameshift mutation

20. What does epigenetics study?
    A. Changes to DNA sequence
    B. DNA replication
    C. Chemical modifications that affect gene expression
    D. Transcriptional errors

21. What is methylation in genetics?
    A. Deletion of a base
    B. Substitution of amino acids
    C. Addition of a methyl group to DNA
    D. Expansion of a trinucleotide repeat

22. What term refers to the chemical state of a cell's DNA and histones?
    A. Epigenome
    B. Proteome
    C. Genome
    D. Transcriptome

23. Which molecule can silence gene expression by binding mRNA?
    A. DNA polymerase
    B. Ribosome
    C. RNA interference (RNAi)
    D. Start codon

24. Which term describes the expansion of repeated sequences like CAG in a gene?
    A. Base analog
    B. Trinucleotide repeat
    C. Missense mutation
    D. Frameshift mutation

25. What is a mutagen?
    A. Enzyme that fixes mutations
    B. Sequence that causes gene activation
    C. Agent that causes mutations
    D. Protective protein in transcription

26. What is the unit of radiation exposure used to measure damage in humans?
    A. Millivolt
    B. Rem
    C. Watt
    D. Megabase

27. Which of the following is an inborn error of metabolism?
    A. Influenza
    B. Galactosemia
    C. Sickle cell trait
    D. COVID-19

28. Which of the following is true about essential amino acids?
    A. They are made by ribosomes
    B. They can be substituted freely in proteins
    C. They must be obtained from the diet
    D. They are synthesized in the mitochondria