Untitled Flashcard Set

1. Which type of gene is always active and essential for basic cell functions?
A. Conditionally expressed genes
B. Housekeeping genes
C. Repressible genes
D. Signal-response genes

2. Euchromatin is typically associated with:
A. Silenced genes
B. Tightly packed DNA
C. Highly expressed genes
D. Nuclear periphery localization

3. Activators increase transcription by:
A. Binding silencer sequences
B. Blocking RNA polymerase
C. Binding enhancer sequences and recruiting chromatin remodelers
D. Recruiting histone deacetylases

4. Which of the following is a mechanism of post-transcriptional regulation?
A. DNA methylation
B. Alternative splicing
C. Chromatin remodeling
D. Core promoter binding

5. RNA interference (RNAi) primarily targets:
A. DNA
B. mRNA
C. Proteins
D. Ribosomes

6. In epigenetics, DNA methylation generally:
A. Activates transcription
B. Blocks transcription
C. Enhances mRNA translation
D. Causes tRNA mutations

7. Which post-translational modification can target a protein for degradation?
A. Phosphorylation
B. Ubiquitination
C. Acetylation
D. Methylation

8. Somatic mutations differ from germline mutations because:
A. Somatic mutations can be inherited
B. Germline mutations affect only body cells
C. Somatic mutations cannot be passed to offspring
D. Germline mutations do not alter DNA sequence

9. A transition mutation is defined as:
A. Purine ↔ pyrimidine
B. Purine ↔ purine or pyrimidine ↔ pyrimidine
C. Stop codon creation
D. Frameshift mutation

10. Which process generates genetic diversity during meiosis?
A. DNA replication
B. Crossing-over and independent assortment
C. Translation
D. Mitosis

11. Mendel’s Law of Segregation explains:
A. Traits are blended in offspring
B. Alleles separate during gamete formation
C. Genes on different chromosomes are linked
D. Only dominant alleles are expressed

12. In a dihybrid cross AaBb × AaBb, the expected F2 phenotypic ratio is:
A. 3:1
B. 9:3:3:1
C. 1:2:1
D. 1:1:1:1

13. Which of the following describes conservative transposition?
A. Copy-and-paste of a transposon
B. Cut-and-paste of a transposon
C. DNA replication
D. Frameshift mutation

14. Which type of histone modification generally opens chromatin and activates transcription?
A. Deacetylation
B. Methylation
C. Acetylation
D. Ubiquitination

15. In pedigree analysis, an autosomal recessive trait:
A. Appears only in heterozygotes
B. Appears only in homozygotes
C. Appears in every generation
D. Is always linked to sex chromosomes

16. Which type of genes are turned on or off depending on internal and external signals?
A. Housekeeping genes
B. Conditionally expressed genes
C. rRNA genes
D. Structural genes

17. Gene location in the nucleus affects expression because:
A. DNA sequence changes in the periphery
B. Heterochromatin is loosely packed
C. Euchromatin is clustered in transcription hubs
D. Chromosomes are identical

18. Silencers decrease transcription by:
A. Recruiting chromatin remodeling complexes
B. Blocking activators or compacting chromatin
C. Recruiting RNA polymerase
D. Enhancing mRNA translation

19. Signal response elements (like ARE or ERE) are:
A. Types of silencers
B. Enhancers responding to specific signals
C. Housekeeping gene promoters
D. Sites for tRNA binding

20. Mutations in cis-regulatory sequences typically:
A. Change the DNA coding sequence
B. Disrupt transcription control
C. Always create a dominant phenotype
D. Affect tRNA anticodon loops

21. Reporter assays test:
A. Protein degradation
B. Promoter and enhancer activity
C. DNA replication fidelity
D. Ribosome binding efficiency

22. PolyA tail length affects:
A. DNA replication
B. Chromatin condensation
C. mRNA translation efficiency
D. RNAi targeting

23. Methylated adenine in C. elegans may:
A. Activate gene expression
B. Silence gene expression like 5-methylcytosine
C. Create frameshift mutations
D. Enhance translation

24. In RNAi, perfect complementarity between gRNA and mRNA results in:
A. Translational enhancement
B. mRNA cleavage by Argonaute
C. Chromatin remodeling
D. Histone acetylation

25. Partial complementarity in RNAi results in:
A. Immediate mRNA degradation
B. mRNA sequestration in P-bodies
C. DNA methylation
D. Frameshift mutations

26. Histone deacetylation generally:
A. Activates transcription
B. Condenses chromatin → transcription OFF
C. Changes DNA sequence
D. Enhances RNA splicing

27. DNA methylation recruits:
A. Histone acetyltransferases
B. Histone deacetylases (HDACs)
C. RNA polymerase I
D. Ribosomes

28. Imprinting leads to:
A. Both alleles expressed equally
B. Only one allele expressed based on parental origin
C. Random mutation in offspring
D. Complete silencing of all genes

29. Which disorder results from paternal deletion in imprinted chromosome 15?
A. Angelman Syndrome
B. Prader-Willi Syndrome
C. Cystic fibrosis
D. Albinism

30. Which disorder results from maternal deletion in imprinted chromosome 15?
A. Angelman Syndrome
B. Prader-Willi Syndrome
C. Hemochromatosis
D. PKU

31. Active genes typically have:
A. High DNA methylation, low histone acetylation
B. Low DNA methylation, high histone acetylation
C. DNA hypermethylation only
D. Condensed heterochromatin

32. What is a major effect of alternative splicing?
A. Chromatin condensation
B. Different mRNA isoforms
C. DNA methylation
D. Frameshift mutations

33. Which post-transcriptional mechanism can store or localize mRNA before translation?
A. Alternative splicing
B. Localized translation
C. DNA replication
D. Transposon insertion

34. Ubiquitination:
A. Turns proteins on
B. Targets proteins for degradation
C. Acetylates histones
D. Creates stop codons

35. Mutations are generally:
A. Directed by cellular need
B. Random events
C. Controlled by enhancers
D. Caused only by radiation

36. Mutation hot spots include:
A. Heterochromatin
B. Tandem repeats and euchromatin
C. Only coding sequences
D. All tRNA genes

37. Which of the following is a frameshift-inducing mutagen?
A. Intercalating agent
B. Alkylating agent
C. Base analog
D. Tautomeric shift

38. CFTR ΔF508 is an example of:
A. Single codon deletion
B. Frameshift mutation
C. Nonsense mutation
D. Transition mutation

39. In meiosis, homologous chromosomes separate during:
A. Meiosis I
B. Meiosis II
C. Mitosis
D. S phase

40. Sister chromatids separate during:
A. Meiosis I
B. Meiosis II and mitosis
C. Only mitosis
D. Fertilization

41. Crossing-over occurs during:
A. Mitosis
B. Meiosis I
C. Meiosis II
D. DNA replication

42. After S phase, each gene in a diploid organism has:
A. 1 copy per chromosome
B. 2 copies per chromosome
C. 3 copies per chromosome
D. Variable copies

43. Independent assortment explains:
A. Alleles on the same chromosome are linked
B. Different gene pairs segregate independently in gametes
C. Only dominant alleles are transmitted
D. Crossing-over never occurs

44. Number of different gametes for AaBbCc:
A. 4
B. 8
C. 6
D. 12

45. Complete dominance occurs when:
A. Both alleles contribute equally
B. One functional allele masks a nonfunctional allele
C. Only recessive alleles are expressed
D. Genes are imprinted

46. In autosomal recessive disorders like PKU, affected individuals are:
A. Heterozygotes
B. Homozygous recessive
C. Homozygous dominant
D. Always carriers

47. In autosomal dominant disorders like polydactyly:
A. Only homozygotes show the trait
B. Heterozygotes show the trait
C. Trait is only in males
D. Trait is never inherited

48. Branch diagrams in genetics are used to:
A. Show chromatin remodeling
B. Predict multi-gene cross outcomes
C. Measure transcription factor activity
D. Track tRNA mutations

49. Product rule in genetics:
A. Sums probabilities of events
B. Multiplies probabilities of independent events
C. Determines mRNA stability
D. Controls epigenetic inheritance

50. Polar bodies are:
A. Male gametes
B. Small byproducts of female meiosis
C. Crossing-over sites
D. Housekeeping genes