Q1. What is the process by which a single cell divides into two identical daughter cells?
a) Meiosis
b) Mitosis
c) Fertilization
d) Budding
Show Answer
Correct Answer: b) Mitosis
Explanation: Mitosis is a type of cell division where a parent cell divides into two genetically identical daughter cells. It plays a crucial role in growth, repair, and maintenance of multicellular organisms. During mitosis, the genetic material is equally distributed between the daughter cells, ensuring genetic stability.
Q2. Which of the following stages of the cell cycle is characterized by DNA replication?
a) G1 phase
b) S phase
c) G2 phase
d) M phase
Show Answer
Correct Answer: b) S phase
Explanation: The S phase, or synthesis phase, is where DNA replication occurs. During this stage of the cell cycle, the genetic material is duplicated to ensure that each daughter cell receives an identical copy of the DNA. This is essential for maintaining genetic integrity during cell division.
Q3. In which phase of mitosis do chromosomes align along the equatorial plane of the cell?
a) Prophase
b) Metaphase
c) Anaphase
d) Telophase
Show Answer
Correct Answer: b) Metaphase
Explanation: Metaphase is the stage of mitosis where chromosomes align along the equatorial plane (metaphase plate) of the cell. This alignment ensures that the replicated chromosomes are evenly distributed between the two daughter cells during cell division.
Q4. Which of the following is NOT a phase of mitosis?
a) Interphase
b) Prophase
c) Telophase
d) Anaphase
Show Answer
Correct Answer: a) Interphase
Explanation: Interphase is not a phase of mitosis but rather the phase preceding mitosis where the cell prepares for division by undergoing growth, DNA replication, and preparation of cellular organelles. Mitosis itself consists of prophase, metaphase, anaphase, and telophase.
Q5. During which phase of meiosis do homologous chromosomes pair up and exchange genetic material?
a) Prophase I
b) Metaphase I
c) Anaphase I
d) Telophase I
Show Answer
Correct Answer: a) Prophase I
Explanation: Prophase I is the stage of meiosis where homologous chromosomes pair up in a process called synapsis and exchange segments of their DNA through crossing over. This genetic exchange contributes to genetic diversity among offspring.
Q6. Which of the following events occurs during telophase of mitosis?
a) Chromosomes condense and become visible
b) Chromatids separate and move towards opposite poles
c) Nuclear envelope reforms around the separated chromosomes
d) Spindle fibers begin to disassemble
Show Answer
Correct Answer: c) Nuclear envelope reforms around the separated chromosomes
Explanation: Telophase is the final stage of mitosis where the nuclear envelope reassembles around the separated sets of chromosomes. This marks the completion of nuclear division. Meanwhile, chromatids, which were previously separated in anaphase, begin to decondense, and spindle fibers start to disassemble.
Q7. In which phase of meiosis do sister chromatids separate and move towards opposite poles of the cell?
a) Prophase I
b) Metaphase I
c) Anaphase I
d) Telophase I
Show Answer
Correct Answer: c) Anaphase I
Explanation: Anaphase I is the stage of meiosis where homologous chromosomes separate and move towards opposite poles of the cell. Unlike mitosis, where sister chromatids separate in anaphase, in meiosis, homologous chromosomes segregate during anaphase I, leading to the reduction of chromosome number.
Q8. What is the main difference between mitosis and meiosis?
a) Mitosis produces genetically identical daughter cells, while meiosis produces genetically diverse daughter cells.
b) Mitosis occurs in somatic cells, while meiosis occurs in reproductive cells.
c) Mitosis consists of one division, while meiosis consists of two divisions.
d) All of the above
Show Answer
Correct Answer: d) All of the above
Explanation: Mitosis and meiosis differ in several aspects. Mitosis results in the production of two genetically identical daughter cells, occurs in somatic cells, and involves one division. In contrast, meiosis produces genetically diverse daughter cells, occurs in reproductive cells, and involves two divisions, resulting in the formation of four haploid cells.
Q9. During which phase of the cell cycle does the cell grow and carry out its normal functions?
a) G1 phase
b) S phase
c) G2 phase
d) M phase
Show Answer
Correct Answer: a) G1 phase
Explanation: The G1 phase, or gap 1 phase, is the first phase of the cell cycle where the cell grows and carries out its normal functions. It is characterized by an increase in cell size, protein synthesis, and organelle replication. Cells may also undergo differentiation during this phase.
Q10. Which of the following is a characteristic of meiosis but not mitosis?
a) Synapsis and crossing over
b) Production of genetically identical daughter cells
c) One division resulting in two daughter cells
d) Formation of a spindle apparatus
Show Answer
Correct Answer: a) Synapsis and crossing over
Explanation: Synapsis and crossing over occur during prophase I of meiosis, facilitating the exchange of genetic material between homologous chromosomes. This process contributes to genetic diversity among offspring. In contrast, mitosis does not involve synapsis and crossing over.