Toelatingsexamen Arts & Tandarts België (Medical & Dental Entrance Exam) · Biology and Life Sciences

Cellular Biology, Molecular Genetics, and General Genetics

35 practice questions, each with the answer and an explanation.

Practise Cellular Biology, Molecular Genetics, and General Genetics now

Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 35 questions

  1. What is the primary role of cholesterol in animal cell plasma membranes at low physiological temperatures?
  2. Which stoichiometry describes the transport cycle of the standard sodium-potassium pump (Na+/K+-ATPase)?
  3. By which transport mechanism does D-glucose cross the apical membrane of intestinal enterocytes against its concentration gradient?
  4. Which cellular organelle is primarily responsible for the post-translational mannose-6-phosphate tagging that targets acid hydrolases to lysosomes?
  5. In eukaryotic cellular respiration, what is the immediate source of energy that directly drives ATP synthesis by the mitochondrial ATP synthase complex?
  6. During which phase of mitotic cell division do sister chromatids synchronously separate and move toward opposite spindle poles?
  7. Which critical cytogenetic event occurs exclusively during prophase I of meiosis, distinguishing it from mitotic prophase?
  8. How does the tumor suppressor protein p53 primarily respond when extensive double-stranded DNA damage is detected during the G1 phase?
  9. During bidirectional eukaryotic DNA replication, what is the role of DNA ligase?
  10. Which enzymatic activity allows DNA polymerases to excise mispaired bases immediately after incorporation during replication?
  11. Which consensus promoter sequence, situated roughly 25 to 30 base pairs upstream of the transcription start site, binds TFIID in eukaryotic protein-coding genes?
  12. What molecular modification is added to the 5' terminus of eukaryotic pre-mRNA immediately following initiation of transcription?
  13. Why is the universal genetic code described as 'degenerate' (or redundant)?
  14. During ribosomal peptide chain elongation, which ribosomal site receives the incoming aminoacyl-tRNA specified by the next mRNA codon?
  15. Which type of mutation results from a single base substitution that converts a codon specifying an amino acid into a premature stop codon?
  16. How does histone acetylation by histone acetyltransferases (HATs) affect eukaryotic gene transcription?
  17. In a classical Mendelian cross between two individuals heterozygous for a single autosomal gene exhibiting complete dominance (Aa x Aa), what is the expected genotypic ratio among the offspring?
  18. A carrier female for an X-linked recessive disorder (such as hemophilia A) has children with an unaffected male. What is the probability that a son born to this couple will be affected?
  19. Which genetic mechanism explains why individuals with blood group AB express both A and B carbohydrate antigens simultaneously on their erythrocyte surfaces?
  20. Cystic fibrosis is an autosomal recessive disorder caused by mutations in the CFTR gene. If both parents are asymptomatic carriers (heterozygotes), what is the probability that their first child will…
  21. In agarose gel electrophoresis of DNA restriction fragments, which factor governs the relative rate of migration toward the positive anode?
  22. What occurs during the annealing step of a standard three-step Polymerase Chain Reaction (PCR) cycle?
  23. Which characteristic is shared by the cleavage sites recognized by type II restriction endonucleases (such as EcoRI)?
  24. Which developmental category describes embryonic stem cells derived from the inner cell mass of a blastocyst that can give rise to all cell types of the adult body, but not extraembryonic tissues?
  25. During the intrinsic pathway of apoptosis, which mitochondrial protein is released into the cytosol to bind Apaf-1 and form the apoptosome complex?
  26. In a population in Hardy-Weinberg equilibrium, the frequency of an autosomal recessive allele (q) is 0.2. What is the expected frequency of heterozygous carriers (2pq) in this population?
  27. Which form of natural selection favors individuals at both phenotypic extremes while selecting against intermediate phenotypes?
  28. What geographic condition defines allopatric speciation as opposed to sympatric speciation?
  29. How does a competitive enzyme inhibitor alter the kinetic parameters Km (Michaelis constant) and Vmax (maximum velocity)?
  30. How does a non-competitive (allosteric) enzyme inhibitor affect enzyme kinetics?
  31. Which thermodynamic parameter determines whether a biochemical reaction will proceed spontaneously at constant temperature and pressure?
  32. Which molecule acts as the terminal electron acceptor in the mitochondrial electron transport chain during aerobic respiration?
  33. During which phase of the eukaryotic cell cycle does semi-conservative replication of genomic nuclear DNA take place?
  34. What is the function of the telomerase enzyme in eukaryotic germline and stem cells?
  35. What term describes the phenomenon where one single gene influences multiple seemingly unrelated phenotypic traits in an organism?

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