Multiple Choice Questions 10×1=10
1
At which stage of mitosis chromosomes line up in the centre?
A
Prophase
B
Metaphase 📍
C
Anaphase
D
Telophase
2
Which event is unique to meiosis but not mitosis?
A
DNA replication
B
Chromosome alignment
C
Crossing over 🔄
D
Nuclear division
3
DNA replication occurs during which phase?
4
Which is synthesized during the S phase:
A
Protein
B
RNA
C
DNA 🧬
D
Lipids
5
Reorganization of cellular contents of mitosis begin in:
6
The main purpose of G2 phase is to:
A
Replicate DNA
B
Grow and prepare for mitosis 📈
C
Perform specialized proteins
D
Degrade unnecessary
7
Malignant tumors that spread to tissues are formed:
A
Benign
B
Metastasis 🦠
C
Phragmoplast
D
Kinetochore
8
What is the process called when homologous chromosomes pair up during Prophase-1?
A
Crossing over
B
Synapsis 🤝
C
Cytokinesis
D
Disjunction
9
Which process restores the diploid number of chromosomes after meiosis?
A
Crossing over
B
Synapsis
C
Fertilization 🧬
D
Cytokinesis
10
What is formed at the end of telophase-II?
A
2 Diploid cells
B
4 haploid cells 🔄
C
1 diploid cell
D
3 haploid cells
Short Answer Questions 15×2=30
1
Enlist the events that occur during the G1 phase of interphase.
ii
What is the main purpose of S phase in the cell cycle?
Hint: Think about what happens to DNA during this phase
iii
During which phase of mitosis sister chromatids separate?
Prophase → Metaphase → Anaphase → Telophase
iv
What is the role of spindle fibers in mitosis?
v
How is cytokinesis in animal cell different from plant cell?
vi
What is the difference between prophase of mitosis and prophase-I of meiosis-I?
vii
What are the key events of anaphase in mitosis?
viii
Why do skin cells divide continuously throughout an organism’s existence, but nerve and muscle cells permanently exit the cell cycle?
ix
How does crossing over contribute to genetic variation in meiosis?
x
What happens to chromosome structure during the S phase?
xi
What is produced during the G1 phase to prepare for DNA replication?
xiii
What are two major phases of mitosis?
xiv
What is the role of spindle fibers in meiosis?
xv
What is non-disjunction and what are its consequences?