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10.1 Cell Cycle Phases & Overview — Test 1
Q1. During cell division:✓ The total volume of the cell stays the same while the surface area increases
Q2. The order of stages in the cell cycle is:✓ G1, S, G2, M
Q3. DNA synthesis in eukaryotes occurs during:✓ S
Q4. The shortest phase during the cell cycle is:✓ M
Q5. Integrity of DNA is assessed at this checkpoint:✓ G1
Q6. The non-proliferative phase of the cell cycle is:✓ G1 → G0
Q7. The phase between two successive M-phases is called:✓ Interphase
Q8. The G1 phase in a eukaryotic cell cycle essentially is:✓ Gap phase that is essential to prepare for the subsequent steps of replication and division
Q9. Which of the following cells is arrested at G0 phase in humans?✓ Mature nerve cell
Q10. The 'mid-blastula transition' is the point in development when:✓ Transcription of zygotic genes begins
Q11. Which one of the following statements about stem cells is correct?✓ During asymmetric stem-cell division, only one daughter is retained as a stem cell
Q12. In typical mitotic cell division, M phase occurs immediately after:✓ G2
Q13. Which statement about eukaryotic asymmetric cell division is NOT correct?✓ Chromosomes are unequally distributed
Q14. In eukaryotic cells, DNA replication is restricted to the S phase because:✓ MCM helicases get activated (origins fire) in S phase
Q15. A synchronous culture is one in which the majority of cells proceed through:✓ Each cell cycle phase (G1, S, G2 and M) together
Q16. Which one of the following cells has the shortest S phase of the cell cycle?✓ Embryonic stem cell
Q17. The period between two nuclear divisions during mitosis is characterized by:✓ DNA replication
Q18. The phase of the cell cycle that shows the greatest variation in duration is:✓ G1 phase
Q19. Individual chromosomes are clearly seen during which phase of the cell cycle?✓ M phase
Q20. Which of the following is the characteristic of a normal (non-transformed) cell?✓ Dependent on external growth factor
Q21. During flow-cytometric analysis, cells are stained with propidium iodide to identify:✓ Stage of the cell cycle
Q22. With regard to DNA quantity, the correct order for different phases of the cell cycle is:✓ G2 > S > G1
Q23. To study cell-cycle progression in cultured mammalian cells, one would typically NOT utilize:✓ The kinase inhibitor LY294002
Q24. The amount of DNA present in a mature spermatozoan and in a skin cell that is in G2 phase, respectively, are:✓ 1X and 4X
Q25. Which statement holds true for the G0/G1-phase organization of chromosomal DNA in a mature eukaryotic nucleus?✓ Organized in constrained locations and interacts with other chromosomal DNA non-randomly
Q26. If a mature neuron at the G0 stage contains X amount of DNA, then a mature spermatozoon will contain _____ DNA.✓ 0.5X
Q27. Which one of the following therapies will, in principle, target only the cancerous cells but not the normal cells?✓ Immunotherapy
Q28. A culture started with 4 cells and ended with 256 cells. How many generations (divisions) did the cells go through?✓ 6
Q29. Which one of the following techniques can be used to determine the stage of the cell cycle in a given cell population?✓ Fluorescence-activated cell sorting (FACS)
Q30. A mature rat sperm contains 2.5 µg of (haploid) genomic DNA. The amount of DNA in a somatic cell of the same rat in G2 phase is:✓ 10 µg
Q31. The number of times a normal somatic, differentiated human cell population will divide before cell division stops is known as the:✓ Hayflick limit
Q32. If a secondary spermatocyte has 12 chromosomes, how many chromosomes were present in the primary spermatocyte that gave rise to it?✓ 24
Q33. Many cells in the body divide only rarely, such as neurons. In which portion of the cell cycle would such cells be considered to be?✓ G0 phase
Q34. Bacterial reproduction by binary fission involves the formation of a ring-like structure at the centre of the cell which is known as:✓ FtsZ-ring
Q35. A culture started with 100 cells, generation time 2 h, in ideal synchrony for 24 h. The cell number at 2 h and at 9 h respectively will be:✓ 2.0×10², 1.6×10³
Q36. Hydroxyurea blocks DNA synthesis. If it is applied to a mammalian cell culture with properly functioning checkpoints, what is expected to happen?✓ Cell division will halt in S phase
Q37. Cells in S-phase were fused with cells in G1, G2 and M phase and grown in tritiated thymidine. Maximal freshly labelled DNA is likely to be obtained in S-phase cells fused with:✓ G1 phase cells
Q38. Match List I (cell-cycle phases) with List II:✓ A-iv, B-iii, C-ii, D-i
Q39. In a Hoechst-stained flow-cytometry DNA profile, three populations X, Y and Z show increasing fluorescence intensity (X < Y < Z, i.e. increasing DNA content). The correct assignment is:✓ X is G1, Y is S and Z is G2+M
Q40. The overall length of the cell cycle equals the doubling time of an exponentially proliferating population. If a population of mouse L cells doubles in 20 h, the overall length of the cell cycle is:✓ 20 h
Q41. Mammalian cells in one phase were fused with cells in another phase. Which combination of observations is correct?✓ A, B and D
10.2 Cell Cycle Regulation — Test 2
Q42. Wee1 kinase:✓ Phosphorylates the inhibitory site of Cdks
Q43. Cdk2/cyclin E functions in:✓ G1/S transition
Q44. In vertebrates, Cyclin D binds with:✓ Cdk4 and Cdk6
Q45. Cyclin-dependent kinases (CDKs) are:✓ Ser/Thr protein kinases controlling cell-cycle progression
Q46. M-Cdk functions in association with:✓ Polo-like kinases and Aurora kinases
Q47. Which of the following regulate the cell cycle?✓ Cyclins
Q48. Maturation promoting factor (MPF) is represented by:✓ Cyclin B – Cdk1
Q49. The key mode of regulation during the cell cycle is:✓ Activation of protein function via protein–protein interaction
Q50. The activation of Cdk2 in vertebrates is dependent on:✓ Association with cyclin A
Q51. Which of the following represents mammalian mitotic cyclins?✓ Cyclins A and B
Q52. Mitotic cyclin–CDK activity peaks in M phase. This is because:✓ The kinase subunit is activated by dephosphorylation only in M phase
Q53. The active cyclin–CDK complex regulates the cell cycle through:✓ Phosphorylation of specific proteins
Q54. Which of the following statements regarding cyclins is NOT correct?✓ They catalyze the phosphorylation of proteins
Q55. The Anaphase Promoting Complex (APC/C) has which enzymatic activity?✓ Ubiquitin ligase
Q56. Which cyclin has essential functions in the S-phase of the cell cycle?✓ A-type
Q57. Cells with high levels of Maturation Promoting Factor (MPF) are present in:✓ M phase
Q58. The phase of the cell cycle in which the titre of Cdk2/cyclin E is high is:✓ G1/S transition
Q59. Which one of the following conditions will hamper proper completion of mitosis?✓ Inactivation of Cdc20 prior to metaphase
Q60. Which complex initiates phosphorylation of the Rb protein during cell-cycle regulation?✓ Cdk4/6–cyclin D complex
Q61. Which of the following statements regarding cyclin-dependent protein kinases is NOT correct?✓ Each type of cell contains one specific form
Q62. In the metazoan cell cycle, the metaphase-to-anaphase transition is regulated by the activity of:✓ APC/C
Q63. Which protein inhibits the kinase activity of yeast CDK by phosphorylation during the G2 checkpoint?✓ Wee1
Q64. Transition from Metaphase to Anaphase involves activation of the Anaphase Promoting Complex (APC/C) by:✓ CDC20
Q65. Which of the following proteins are involved in binary fission as well as in eukaryotic mitotic division?✓ Actin and tubulin
Q66. During eukaryotic cell division, the metaphase-to-anaphase transition is regulated by the degradation of:✓ Cyclin B1
Q67. Cyclin-dependent kinases that control progression through cell-cycle checkpoints are totally activated by:✓ Binding to cyclin, plus phosphorylation by a Cdk-activating protein kinase
Q68. At the onset of Anaphase II, APC/C activation triggers cleavage of __________ and sister-chromatid separation.✓ Cohesin
Q69. At the end of each phase of the cell cycle, the cyclins activating Cdks in that phase are inactivated irreversibly by:✓ Destabilization by proteolysis in a proteasome
Q70. Progression across the G1/S boundary, followed by entry into S-phase, is promoted by activation of which protein complex?✓ Cdk2/Cyclin E
Q71. In Anaphase I of meiosis, centromeric cohesin remains intact and prevents the separation of sister chromatids by the protective action of:✓ Shugoshin
Q72. A temperature-sensitive S. pombe mutant shows cell-cycle arrest at BOTH the G1→S and the G2→M transitions. This is most likely a mutant of:✓ Cdc2 only
Q73. A family of proteins that rise and fall in concentration, thereby regulating progression of the cell through eukaryotic cell-cycle checkpoints, is known as:✓ Cyclin proteins
Q74. The E3 ubiquitin ligase that promotes destruction of a specific set of proteins, thereby promoting separation of sister chromatids and completion of M phase, is:✓ APC/C
Q75. Passage of a cell through the stages of the cell cycle is controlled by a protein kinase that phosphorylates many different proteins at appropriate times. This is the:✓ Cyclin-dependent kinase
Q76. Cell cycle is controlled by:✓ b and d
Q77. Normal stem cells have a doubling time of ~24 h and tumour-derived stem cells ~12 h. If both are grown continuously with radioactive thymidine for a week, the amount of radioactivity per cell after a week will be:✓ Same in both
Q78. Cyclin D binds CDK4 to form a complex that phosphorylates Rb, activating E2F to transcribe downstream cyclins. In a cell where Rb is mutated so that it CANNOT be phosphorylated, the expression pattern of Cyclin E after mitotic stimulation will be:✓ Cyclin E expression will fail or remain severely suppressed
Q79. Match the enzymes (List I) with their cell cycle functions (List II):✓ A-iii, B-iv, C-ii, D-i
Q80. Match the cell cycle proteins (List I) with their functions (List II):✓ i-II, ii-IV, iii-III, iv-I
Q81. During G2 phase, cyclin B forms a complex with CDK (MPF). For conversion of an inactive MPF to an active MPF that initiates mitosis, which of the following events are correct?✓ 2 and 3
Q82. In yeast, the anaphase-promoting complex triggers the separation of sister chromatids. Which of the following mechanisms are correct?✓ iii and iv
Q83. During the cell cycle, entry into S-phase is tightly regulated. Which statements are correct?✓ i and iii
Q84. Which combination represents ALL correct statements about cell-cycle regulation in fission yeast (S. pombe)?✓ A, C and E
Q85. In S. pombe, cdc2− (recessive) produces abnormally long cells while cdc2ᴰ (dominant) produces abnormally small cells. Possible explanations:✓ A and B only
Q86. The following statements were made about cell cycle regulation in eukaryotes:✓ A, B and D
Q87. Match the cell-cycle regulatory proteins (List I) with their functions (List II):✓ A-iv, B-iii, C-i, D-ii
Q88. The following statements were made about cell cycle regulation:✓ A, C, E
Q89. The following statements were made about characteristics of cyclin proteins:✓ A, C, D
10.3 Cell Cycle Checkpoints — Test 3
Q90. The p53 protein is associated with which of the following?✓ Transcription and tumour suppression
Q91. Which of the following is NOT an actual cell cycle checkpoint?✓ S checkpoint
Q92. During cell-cycle regulation, the p53 gene product acts at the:✓ G1/S checkpoint
Q93. In mammalian cells that have just crossed the restriction point, you are likely to find:✓ Highly phosphorylated retinoblastoma protein
Q94. The tumour suppressor protein Rb normally influences the cell cycle at G1 phase by inhibiting:✓ E2F transcription factor
Q95. Which tumour suppressor gene is popularly known as the 'guardian' of the mammalian cell/genome?✓ p53
Q96. To selectively kill the newly dividing mammalian cells in a culture assay, which method would you use?✓ Treatment with 5-bromo-2'-deoxyuridine (BrdU) followed by UV-A exposure
Q97. The tumour suppressor p53 ('guardian of the genome') arrests the cell cycle in response to DNA damage by:✓ Leading G2/M arrest through inhibition of the Cyclin B–Cdc2 complex
Q98. RhoA localization/activity during cytokinesis is modulated by:✓ A, B, C and D
Q99. Overexpression of protein 'A' arrests cells in G1 (where cyclin D-CDK4 normally phosphorylates Rb to release E2F). Which statement is TRUE?✓ 'A' inhibits CDK4 activity
Q100. Eukaryotic cells with DNA damage often cease progression through the cell cycle until the damage is repaired. This type of control over the cell cycle is referred to as:✓ Checkpoint control
Q101. Budding yeast cells deficient for Mad2 (a spindle-attachment checkpoint component) are killed by benomyl (which depolymerizes microtubules), yet in the absence of benomyl the cells are perfectly viable. Which explanation justifies this?✓ Without benomyl, most spindles form normally and the Mad2 checkpoint plays no essential role
Q102. Arrange the following cell-cycle events in the correct chronological order:✓ B → A → C → D
10.4 Mitosis & Cytokinesis — Test 4
Q103. White blood cells divide by:✓ Mitosis
Q104. Kinetochore assembly is regulated by:✓ All of these
Q105. Colchicine-treated cells are arrested in:✓ Metaphase
Q106. In mitosis, the centromere divides during:✓ Anaphase
Q107. The term 'Open mitosis' is used in which context?✓ Nuclear envelope breaks down before the chromosomes separate
Q108. Which cells do not divide under normal conditions?✓ Neurons
Q109. Chromosome measurements are generally taken during:✓ Metaphase
Q110. What is the role of Aurora B kinase during mitosis?✓ Correction of kinetochore attachments
Q111. Which of the following does NOT occur during mitosis?✓ Replication of DNA
Q112. If serum is removed from a HEK cell culture, the cells will:✓ Undergo cell-cycle arrest
Q113. What structure forms during the cytokinesis of animal cells?✓ Cleavage furrow
Q114. This structure tends to vanish during both meiosis and mitosis:✓ Nucleolus and nuclear membrane
Q115. During meiosis, reduction in the chromosome number occurs during:✓ Anaphase I
Q116. The site of the division plane during cytokinesis of animal cells is determined:✓ By the central spindle
Q117. The phase of the cell cycle in which the ovum exists when a human female ovulates is:✓ Metaphase II
Q118. During which phases of cell division is the morphology of the chromosomes best studied?✓ Metaphase and anaphase
Q119. The region that facilitates the movement of chromosomes during mitosis and meiosis is the:✓ Kinetochore
Q120. Which one of the following processes is NOT necessary for chromosome separation in mitosis?✓ Degradation of mitotic cyclin B
Q121. Treatment of root-tip meristem cells with colchicine results in all of the following EXCEPT:✓ Cessation of DNA replication
Q122. For efficient attachment of sister chromatids to the spindle, which one of the following processes is required?✓ Breakdown of the nuclear membrane
Q123. A chromosome with a single kinetochore attached simultaneously to both spindle poles during cell division is known as:✓ Merotelic
Q124. To ensure proper segregation of chromosomes during mitosis, which is the correct kinetochore–microtubule attachment configuration?✓ Amphitelic
Q125. _____ class of microtubules has a role in orientation and repositioning of the mitotic spindle by interaction with the cell cortex.✓ Astral
Q126. Which one of the following terms describes a mitotic cell division giving rise to two daughter cells without increasing the size of the original parental cells?✓ Cellulation
Q127. Assertion: In a synchronous culture, the majority of cells move to the next phase simultaneously.✓ A is true but R is false
Q128. In an adult mouse liver, only 3 out of 250 cells are found undergoing mitosis (mitotic index). If M phase lasts 30 minutes, the approximate length of the cell cycle is:✓ 42 hours
Q129. Which statements are TRUE for colchicine?✓ a and d
Q130. Which of the following events happen in telophase of mitosis?✓ a and c only
Q131. Spindle assembly requires the formation of numerous new microtubules. Which option includes ALL factors that DIRECTLY impact microtubule nucleation for spindle assembly?✓ A, B and C only
Q132. Which of the following statements about mitosis and cell division is/are true?✓ All of A, B, C and D
10.5 Meiosis — Test 5
Q133. Chiasmata formation becomes clearly visible in:✓ Diplotene
Q134. Which one of the following statements is INCORRECT?✓ Pluripotent cells have the ability to regenerate an entire organism in vitro
Q135. Lampbrush chromosomes are characteristically seen at:✓ Diplotene of meiotic Prophase I
Q136. After Meiosis I, the resultant daughter cells contain:✓ Twice as much DNA as a gamete contains
Q137. Which of the following occurs in meiosis but NOT in mitosis?✓ Pairing of homologous chromosomes at the metaphase plate
Q138. Which of the following statements about meiosis is NOT true?✓ Sister kinetochores attach to microtubules from opposite poles in Meiosis I
Q139. Crossing over between maternal and paternal chromatids occurs during:✓ Pachytene
Q140. During meiosis, the zipper-like pairing of homologous chromosomes is called:✓ Synapsis
Q141. The phase of meiosis in which homologous chromosomes exchange genetic information is:✓ Prophase I
Q142. Which of the following is correctly matched for a meiotic Prophase I stage and its event?✓ Pachytene – Homologous chromosomes are fully synapsed (paired)
Q143. The maternal and paternal chromosomes pair with each other during which stage of the cell cycle?✓ Prophase I of meiosis
Q144. A cell in G1 has 12 chromosomes. How many chromatids will be present in a cell at Metaphase II of meiosis?✓ 12
Q145. During which stage of meiosis does the synaptonemal complex break down, leading to separation of homologous chromosomes?✓ Diplotene
Q146. Assertion (A): Meiosis produces haploid cells from diploid cells.✓ Both A and R are true and R is the correct explanation of A
Q147. Which of the following statements about meiosis are true?✓ a, b and c only
Q148. Which of the following features are important for the segregation of homologous chromosomes in Meiosis I?✓ A, B and D only