Texas A&M University (TAMU) BIMS 320 Biomedical Genetics Exam 1 Practice

These questions are part of the practice quiz. Start practicing

• Genetics is defined as the study of ____.
• DNA methylation typically represses transcription when methyl groups are added to cytosines in CpG dinucleotides. How does imprinting relate to this mechanism?
• Linked genes tend to be inherited together unless crossing over occurs. True or False?
• The threshold model posits that susceptibility to a multifactorial trait is distributed, and disease manifests when liability crosses a threshold. Which statement best describes this?
• Which statement correctly defines codominance and provides a typical example?
• Which statement best defines the phenotype?
• Inheritance of mitochondrially encoded traits is typically maternal: They are transmitted to all offspring.
• Independent assortment refers to the random alignment of homologous chromosomes during which principle?
• Total human chromosome count and organization?
• Which of the following best defines autosomes in humans?
• In the cell cycle, the S phase represents which process?
• Name the major enzymes involved in DNA replication initiation and elongation in bacteria and eukaryotes.
• Which statement best distinguishes an autosomal dominant trait in a pedigree from autosomal recessive inheritance?
• Normal human haploid gametes contain how many chromosomes?
• There are four common alleles of the gene that controls human blood type.
• Define a silent (synonymous) mutation and indicate a scenario where it might affect phenotype.
• A dihybrid cross AaBb x AaBb is expected to yield which phenotypic ratio under independent assortment?
• What is the central dogma of molecular biology?
• In eukaryotes, RNA polymerase II synthesizes which molecules and requires which elements?
• How many different types of chromosomes do humans possess?
• Which chromosomal alteration is described by moving a segment of DNA from one chromosome to a nonhomologous chromosome?
• Under Hardy-Weinberg assumptions, which statement is true about allele frequencies over generations?
• Which enzyme primarily synthesizes new DNA strands during replication?
• Two unaffected individuals who are carriers for an autosomal recessive allele have a child. What is the probability that the next child will be affected?
• In a cross involving mitochondrial inheritance, Mendelian rules do not apply. Which statement is true?
• How is recombination frequency used to map genes, and what is the maximum observable recombination fraction for linked genes?
• The tall and short phenotypes in Mendel's pea plants are examples of
• Define autosomal dominant inheritance and describe typical pedigree features.
• Pedigree analysis can identify the mode of inheritance but cannot determine which of the following?
• State the central dogma of molecular biology and name a well-known exception.
• What features characterize a eukaryotic promoter and what is the role of transcription factors?
• List two major ethical considerations in clinical biomedical genetics.
• More than one mode of inheritance can be seen for a single trait.
• What is a restriction enzyme and how is it used in cloning?
• How does Sanger sequencing work, and what is a common limitation?
• What is the basic unit of DNA, and how are the two strands oriented relative to each other?
• What is a genome-wide association study (GWAS) and what kind of variants does it typically implicate?
• Which mapping approach would provide the exact DNA distance between two genes?
• Mendel's principle of independent assortment is directly related to an event that occurs in which phase of meiosis?
• Replication slippage commonly involves which genomic feature and can lead to length changes?
• In Mendel's terminology, what did we call 'factors' that we now call?
• Which statement about penetrance is correct?
• How does a nonsense mutation differ from a missense mutation in terms of protein product?
• A large pedigree across five generations shows affected males in every generation and no affected females. What is the most likely mode of inheritance?
• MicroRNAs primarily regulate gene expression at which level?
• In a monohybrid cross with complete dominance, the phenotypic ratio is 3:1.
• Which statement about PKU treatment is true?
• Two phenotypically normal parents who are each heterozygous for recessive albinism and recessive deafness have a child; what is the probability that the child will be both albino and deaf?
• In the genetic code, what does degeneracy mean?
• Which statement best describes the Hardy-Weinberg principle and its key assumptions?
• Replication slippage is a replication error that can lead to insertions or deletions, and may cause duplications if repeats misalign and expand. Which statement best reflects this?
• What post-transcriptional modifications occur on eukaryotic mRNA before export?
• Chromosomal translocations involve exchange of segments between nonhomologous chromosomes. Which genetic consequence can result from this event?
• What does a recombination frequency of 50% indicate about two genes?
• Crossing over is partially responsible for our genetic diversity.
• For an autosomal recessive disorder, two carrier parents have a child. Probability of affected child?
• Mendel's laws are applicable to which of the following?
• Describe the three main steps of PCR.
• Hayflick limit describes ____.
• Distinguish transitions from transversions in DNA mutations.
• Which term describes the maximum number of times a normal somatic cell can divide in culture?
• Karyotyping can detect which chromosomal abnormalities, and how do they arise?
• Which statement best defines promoter?
• What is a primary purpose of human pedigree analysis?
• Which statement best classifies Werner syndrome in the context of genetic disorders?
• In X-linked recessive inheritance, a carrier mother x normal father have a son. What is the probability the son is affected?
• Which statement about imprinting is true?
• What is the role of the ribosome in translation?
• Which statement about color vision defects in humans is correct?
• What does the term aneuploidy describe in chromosomal abnormalities?
• Which chromatids exchange during crossing-over?
• Which statement correctly identifies the appropriate statistical test for Hardy-Weinberg equilibrium by comparing observed and expected genotype counts?
• How do transcription factors influence gene expression?
• Which enzyme synthesizes DNA during replication?
• In cloning experiments, what is the purpose of using a circular plasmid?
• In human oogenesis, how many mature eggs result from meiosis?
• Which enzyme lays down the RNA primer to start DNA synthesis in replication?
• Which enzyme removes RNA primers and fills the resulting gaps with DNA?
• Alkaptonuria most commonly arises when both parents are unaffected due to which inheritance pattern?
• Explain how the lac operon illustrates negative regulation and inducible expression.
• Which chromosomal alteration reverses the orientation of a segment within the same chromosome?
• If two genes are linked, the observed offspring ratios deviate from the 9:3:3:1 expectation due to recombination.
• During mitosis, the chromosome number in the daughter cells is...
• In CRISPR editing, which repair mechanism enables precise edits using a donor template?
• Describe the inheritance pattern and molecular basis of sickle cell disease.
• Nucleotide excision repair (NER) removes bulky helix-distorting lesions by excising a short DNA segment around the damage. Which disease is associated with defects in NER?
• In heterozygous crosses, the phenotypic and genotypic ratios differ for complete dominance but are the same for incomplete dominance.
• In CRISPR-Cas9 genome editing, what guides Cas9 to the target site, and what are the two common DNA repair outcomes?
• In a cross between a true-breeding plant bearing smooth, yellow seeds and a true-breeding plant with wrinkled, green seeds, the genotype of the F1 plants is which of the following?
• Which statement best describes differences between Huntington disease and sickle cell disease?
• Defects in mismatch repair (for example MLH1 and MSH2) predispose to which cancer syndrome?
• Somatic mutations differ from germline mutations in that:
• What property of VNTR markers makes them useful in population genetics?
• During DNA replication, which strand is synthesized continuously and which in fragments, and what are those fragments called?
• Which components are required for a typical PCR reaction?
• What is alternative splicing and its significance?
• What is a plasmid and why is it used in recombinant DNA technology?
• Which mutation type is most likely to completely disrupt protein function?
• Distinguish codominance from incomplete dominance with examples.
• A child is born with a lethal dominant allele. Which explanation could account for this?
• Outline the essential steps of a standard PCR cycle.
• Explain the concept of linkage equilibrium.
• Which enzyme seals nicks in the sugar-phosphate backbone after Okazaki fragment synthesis?
• Explain how gel electrophoresis separates DNA fragments.
• In humans, autosomes represent ____.
• How does alternative splicing contribute to proteome diversity?
• Explain X-linked recessive inheritance and why affected males are more common.
• Missegregation during cell division can lead to which genomic abnormality?
• What is Huntington disease, and what are key genetic features of its inheritance?
• In humans with incomplete dominance for hair texture, where curly is the dominant genotype and wavy is heterozygous, what is the probable phenotypic outcome of crossing a man with wavy hair with a woman who has curly hair?
• Describe microRNA function in post-transcriptional gene regulation.
• Which statement about eugenics is UNTRUE?
• What is the catabolite repression mechanism in the lac operon?
• What is the main difference between linkage mapping and physical mapping?
• Which genotype yields the AB phenotype in the ABO blood group system?
• Which of the following is NOT a typical symptom of Marfan syndrome?
• In incomplete dominance, the phenotype of the heterozygote is:
• For an X-linked recessive trait, if a carrier mother has a son, what is the probability that another son will be affected?
• Define autosomal recessive inheritance and describe typical pedigree features.
• In a family where both parents are carriers of an autosomal recessive allele, what is the probability their child will be affected?
• Which statement best describes mapping that provides actual base-pair distances?
• In autosomal recessive inheritance, what is the typical risk to offspring when two carriers mate?
• What is the basic principle of Sanger sequencing?
• Autosomal recessive inheritance— which statement is true?
• Which statement best describes a polygenic trait compared to a single-gene trait?
• Name two methods used to assess gene expression levels.
• Chi-square tests in genetics are used to determine whether observed offspring phenotypes fit what?
• If a trait shows continuous variation in a population, what genetic architecture is most likely responsible?
• Crossing over occurs during meiosis and increases genetic diversity.
• A test cross is used to determine the genotype of an individual with a dominant phenotype by crossing with:
• What is promoter-proximal pausing and its regulatory significance?
• What information does gel electrophoresis provide in a genetic assay, and how are DNA fragments separated?
• What is a frameshift mutation, and what is its typical impact on a protein?
• A dihybrid cross with independent assortment produces a phenotypic ratio of 9:3:3:1.
• How does next-generation sequencing (NGS) differ from Sanger sequencing, and what are typical applications?
• Which of the following genetic conditions involve defects in DNA repair that affect cell division?
• In which scenario would the statement 'Both alleles are expressed in the phenotype of heterozygotes' be true?
• What is a silent mutation and when is it silent?
• Independent assortment means that _____.
• How do enhancers and transcription factors regulate gene expression in eukaryotes, and how does chromatin state influence access?
• Which description defines a frameshift mutation and its typical effect on the resulting protein?
• Which term describes imprinting?
• What is the role of RNA polymerase II in eukaryotes?
• Which pair of disorders is described as involving defects in DNA repair and includes premature aging features?
• Which gene is mutated in cystic fibrosis, and what phenotype does this cause?
• Give an example of an autosomal aneuploidy and a common trisomy with characteristic features.
• For a trait displaying incomplete dominance, a heterozygous cross yields a 1:2:1 phenotypic ratio.
• The threshold model for multifactorial traits helps explain the frequency of a disorder among relatives compared with the general population. Which disorder was discussed as a threshold disorder?
• What is genomics?
• Pleiotropy occurs when a single gene influences multiple phenotypic traits.
• In base excision repair, after the damaged base is removed to create an abasic site, which enzyme cleaves the DNA backbone at that site?
• What is a chromosome with a single centromere called, and what is the significance?
• Which event is not a typical feature of prophase in mitosis?
• Twins concordant for a trait when
• Explain how imprinting affects inheritance patterns.
• In a three-point mapping experiment, what is the specific role of observing double crossovers?
• The proband in a pedigree is always heterozygous.
• In a three-point mapping experiment, what information do single crossovers provide, and how is gene order inferred?
• Which statement is true about X-linked recessive patterns?
• Define a VNTR and why it is useful in genetics.
• What are copy number variations (CNVs), and how can they influence phenotype?
• In a pedigree, a symbol with a diagonal line through it and in generation II indicates which of the following?
• Which mapping method uses recombination frequencies to estimate the relative positions of genes?
• What is mitochondrial inheritance and why is it unique?
• Which statement about linkage disequilibrium and its impact on genetic mapping is correct?
• In X-linked recessive inheritance, if a mother is a known carrier and the father is unaffected, what is the probability that a son will be affected?
• Which statement about chromosomal rearrangements is true?
• In a heterozygous cross Aa × Aa for a gene with complete dominance, what phenotype and genotype ratios are expected among the offspring?
• Which initiator tRNA is used to start translation?
• What is the purpose of the poly(A) tail on mRNA?
• In a pedigree showing X-linked inheritance, where most affected individuals are male and mothers are carriers, what pattern would you expect?
• In translation, what is the start codon, what initiator tRNA initiates translation, and where does initiation begin on the ribosome?
• What is pharmacogenomics, and why is it important for personalized medicine?
• What is the heritability classification of human fingerprints?
• Name two mechanisms of epigenetics that affect gene expression without changing DNA sequence.
• If a woman is color blind due to X-linked recessive inheritance, what is the probability that her son will be color blind?
• Which chromatin feature is commonly associated with active gene expression?
• Define expressivity and give an example of variable expressivity.
• What is a gene’s locus?
• In Mendel's monohybrid crosses, a recessive trait is characterized by being absent in the F1 generation and reappearing in the F2 generation.
• What is the role of tRNA and the anti-codon during translation?
• Anticipation is a genetic concept observed in Huntington disease. What best describes it?
• Two normal-pigmented parents have an albino child. What is the probability that their next child will have normal pigmentation?
• The proband is the first affected individual from whom a pedigree is traced.
• Promoter-proximal pausing for rapid regulation.
• What is a single nucleotide polymorphism (SNP), and how is it used in genetic association studies?
• Which statement correctly differentiates genetic cloning from somatic cell nuclear transfer (SCNT) cloning?
• A trait inherited only through the male line and seen in males is most likely which type of inheritance?
• What is the founder effect and how can it influence allele frequencies in a new population?
• Describe the typical inheritance pattern and management of phenylketonuria (PKU).
• Non-disjunction during meiosis can lead to which outcome?
• What does OMIM stand for?
• Define karyotyping and its clinical utility.
• Based on recent genomic evidence, how many genes are involved in human eye color?
• What is a LOD score and when is it considered strong evidence for linkage?
• During DNA replication, which enzyme lays down RNA primers?
• How does DNA methylation typically affect gene expression when methyl groups are added to CpG islands in promoters?
• How do you test whether a population is in Hardy-Weinberg equilibrium using observed versus expected genotype frequencies?
• In meiosis, what is exchanged during crossing-over?
• Which statement describes a historical outcome of the eugenics movement in the United States during the 1920s?
• Base excision repair (BER) is initiated by which enzyme that excises the damaged base, creating an abasic site?
• Which type of chromosomal alteration is a duplication of a DNA segment?
• When performing gel electrophoresis, why do smaller DNA fragments separate at higher speeds?
• Describe the two-hit hypothesis in cancer genetics.
• RNA sequencing (RNA-Seq) is used to:
• What pedigree pattern suggests X-linked recessive inheritance?
• Which pattern is typical of mitochondrial inheritance?
• The branch of genetics concerned with the mechanisms by which genes are inherited across generations is called what?
• What is an oncogene and how can it contribute to cancer when mutated or overexpressed?
• Which of the following mutations does not change the encoded amino acid?
• Which enzyme unwinds the DNA double helix during bacterial DNA replication?
• Alternate forms of a gene are best described as?
• Concordance for a trait in twins means
• What does true-breeding mean in genetics?
• If two individuals with wavy hair (heterozygous for the trait) mate, what fraction of their offspring would be expected to have straight hair (recessive phenotype)?
• How does codominance differ from incomplete dominance?
• Which term describes a chromosomal change that removes a segment of DNA?
• What does the term 'penetrance' refer to in genetics?
• A cell that could not form spindle fibers could not complete which process?
• Which of the following best describes what karyotyping detects?
• List four mutation types that can alter coding sequences.
• If both parents are carriers for an autosomal recessive trait, what fraction of their children are affected?
• If a man expresses a Y-linked trait, which conclusion is correct?
• Two autosomal genes heterozygous; how many sperm types and what proportions?
• Define penetrance and explain how incomplete penetrance can affect interpreting pedigrees.
• In Sanger sequencing, which chemical is used to terminate DNA synthesis to generate fragments?
• A fusion gene is formed when segments from two different genes are joined due to chromosomal rearrangement. Which option best describes this concept?
• Differentiate between genotype and phenotype in genetics.
• Which statement correctly describes chromosomal translocations?
• Which statement correctly defines Hardy-Weinberg equilibrium and explains what p and q represent?
• Describe the role of microRNAs in gene regulation.
• In a pedigree, what does the roman numeral II indicate?
• What is the function of DNA ligase in DNA replication and repair?
• In the ABO blood group system, which statement correctly matches genotypes to phenotypes?
• What is the function of the 5' cap in mRNA processing?
• In a monohybrid cross that yields a 3:1 phenotypic ratio, which pattern of inheritance is demonstrated?
• Which base-pairing arrangement correctly describes DNA?
• A 10-year-old with a serious disorder present in a sibling but both parents are unaffected. What is the most likely inheritance pattern?
• Which statement best describes the genetic basis of human trait expression?
• Differentiate between a chromosomal deletion and a microdeletion.