All Free Biology MCQs with Answers
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19844 questions · page 598 of 1985
5971. Mitotic anaphase differs from metaphase in possessing:
- A. The same number of chromosomes and the same number of chromatids
- B. Half number of chromosomes and half number of chromatids
- C. Half number of chromosomes and same number of chromatids
- D. Same number of chromosomes and half number of chromatids
Explanation: Mitotic anaphase differs from metaphase in possessing the same number of chromosomes and half the number of chromatids. During anaphase of mitosis, chromosomes divide at the point of entromere or kinetochore and thus two sister chromatids are formed, while during metaphase chromosomes become maximally distinct due to further contraction and thus the size of chromosomes is measured at mitotic metaphase.
Correct answer: Same number of chromosomes and half number of chromatids5972. In meiosis, the daughter cells differ from the parent cells as well as amongst themselves due to:
- A. Segregation, independent assortment and crossing over
- B. Segregation and crossing over
- C. Independent assortment and crossing over
- D. Segregation and independent assortment
Explanation: The daughter cells differ from parent cell as well as amongst themselves due to the segregation and crossing over taking place in them. Meiosis-I brings gene recombinations and haploidy of number of chromosomes. In meiosis, the daughter cells differ from the parent cells as well as amongst themselves due to segregation, independent assortment and crossing over.
Correct answer: Segregation, independent assortment and crossing over5973. Chromosome condensation and nuclear envelope breakdown occur during the:
- A. M phase
- B. S phase
- C. G1 Phase
- D. G2 Phase
Explanation: In interphase, the cell only prepares itself for division and increases its size, while M (Mitotic) phase is characterized by the condensation of chromatin material, breakdown of nuclear envelope and chromosomal segregation.
Correct answer: M phase5974. The cell cycle involves:
- A. The growth of a cell
- B. Cell division
- C. Replication of DNA
- D. All of the above
Explanation: The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to the duplication of its DNA (DNA replication) and division of cytoplasm and organelles to produce two daughter cells
Correct answer: All of the above5975. All of the following are related to a G1 phase of the cell cycle except:
- A. Extensive metabolic activities.
- B. Cells growing in size.
- C. Accumulation of aaDNA base units.
- D. Energy storage for chromosomal movement.
Explanation: G1 phase is characterized by the extensive metabolic activities, cell growth, synthesis of specific enzymes and accumulation of nucleotides for DNA replication while the G2 phase is characterized by the storing of energy for chromosomal movement, synthesis of mitotic specific proteins, RNA and microtubule subunits.
Correct answer: Energy storage for chromosomal movement.5976. Microtubule subunits are synthesized during:
- A. G1 phase
- B. G2 phase
- C. S phase
- D. Go phase
Explanation: G2 phase is characterized by the storage of energy for chromosomal movement, synthesis of mitotic specific proteins, RNA and microtubule subunits.
Correct answer: G2 phase5977. The longest stage of interphase in the human cell cycle is:
- A. M-phase
- B. S-phase
- C. G2-phase
- D. Gl-phase
Explanation: In case of human cells, the average cell cycle is about 24 hours and the length of each phase is variable. For example:G1-phase = 9 hoursS-phase = 10 hoursG2-phase = 4.5 hoursM-phase MMM = 30 minutes
Correct answer: S-phase5978. Which one of the following is reverse of prophase?
- A. Interphase
- B. Anaphase
- C. Metaphase
- D. Telophase
Explanation: Telophase is reverse of prophase. Prophase emphasizes that Chromosomes become more and more thick ultimately each chromosome is visible having two sister chromatids, attached at the centromere. Towards the end of prophase, the nuclear envelope disappears and nuclear material is released in the cytoplasm, and nucleoli disappear. The mitotic apparatus is organized (as described above). Cytoplasm becomes more viscous while we know that in Telophase, The chromosomes decondense due to unfolding, and ultimately disappear as chromatin. Mitotic apparatus disorganizes the nuclear membrane and nucleoli reorganize, resulting in two nuclei at two poles of the cell.
Correct answer: Telophase5979. Cytokinesis in animal cells starts at:
- A. Anaphase
- B. Late telophase
- C. Metaphase
- D. Prophase
Explanation: During late telophase the astral microtubules send signals to the equatorial region of the cell, where actin and myosin are activated which form contractile ring, followed by cleavage furrow, which deepens towards the center of the cell, dividing the parent cell into two daughter cells.
Correct answer: Late telophase5980. Mitosis is a continuous process but conventionally it may be divided into two phases, i.e. _
- A. Interphase & mitotic phase
- B. Pre-mitotic phase & post-mitotic phase
- C. Prophase & telophase
- D. Karyokinesis & cytokinesis
Explanation: The cell cycle is divided into two phases; one is interphase in which the cell increases in size and DNA replicates, while the second phase of the cell cycle is the M-phase which further divided into karyokinesis and cytokinesis in which the parental cell divides into two daughter cells
Correct answer: Karyokinesis & cytokinesis