Cell Cycle And Cell Division NEET Questions recognition on understanding the degrees of cell boom and replica. Key topics encompass the levels of the cell cycle (G1, S, G2, and M), mitosis, meiosis, and their regulatory mechanisms. Questions regularly take a look at expertise of the variations among mitotic and meiotic processes, checkpoints, and the effect of mobile cycle dysregulation on fitness. Mastery of those ideas is important for NEET, as they form the premise of cell biology and genetics.”
- Introduction to Cell Cycle and Cell Division
- Download: Cell Cycle And Cell Division NEET Questions
- Phases of the Cell Cycle
- Mitosis and Its Stages
- Meiosis and Its Significance
- Regulation of the Cell Cycle
- Cell Cycle in Unicellular and Multicellular Organisms
- NEET Practice NEET Questions
- Topics and Question Patterns
- FAQs about Cell Cycle And Cell Division NEET Questions
Introduction to Cell Cycle and Cell Division
The cell cycle is a series of events in a cell that causes its DNA (DNA replication) to cleave and duplicate to form two daughter cells.
Cell division is the process by which a single cell divides into two or more daughter cells. It is essential for the growth, development, maintenance and reproduction of organisms.
Cell cycle is important in NEET
Understanding the cell cycle is important for NEET preparation because:
- Cellular Basis of Life: It is the foundation of cell biology, which is a core subject in NEET.
- Meiosis and Mitosis: The cell cycle is the basis for both mitosis (somatic cell division) and meiosis (germ cell division).
- Genetics: This involves the replication and distribution of the genetic material (DNA).
- Cell structure: Understanding cell structure, cell growth and development is essential.
- Disease: Abnormal cell cycle regulation leads to cancer and other diseases.
Download: Cell Cycle And Cell Division NEET Questions
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Phases of the Cell Cycle
The cell cycle is split into two principal phases: Interphase and Mitotic (M) Phase. Interphase is in addition subdivided into three stages: G1, S, and G2.
G1 Phase (First Gap Phase)
Purpose: Cell growth, protein synthesis, and preparation for DNA replication.
Key Events:
- The cell increases in size.
- Organelles are duplicated.
- Proteins important for DNA replication are synthesized.
- The cell passes a checkpoint to ensure it’s ready to proceed to DNA replication.
S Phase (Synthesis Phase)
Purpose: DNA replication.
Key Events:
- Each chromosome is duplicated to form two sister chromatids, which are joined together at the centromere.
- The cell’s DNA content doubles.
G2 Phase (Second Gap Phase)
Purpose: Final preparations for cell division.
Key Events:
- The cell continues to grow.
- Proteins necessary for mitosis are synthesized.
- The cell passes a checkpoint to ensure that DNA replication has been completed successfully.
M Phase (Mitosis)
Purpose: Division of the cell’s nuclear material and cytoplasm.
Key Events:
Karyokinesis (nuclear division):
- Prophase: Chromosomes condense, nuclear envelope breaks down, and spindle fibers form.
- Metaphase: Chromosomes align at the equator of the cell.
- Anaphase: Sister chromatids separate and move to opposite poles.
- Telophase: Nuclear envelopes re-form, chromosomes decondense, and cytokinesis begins.
Cytokinesis (division of cytoplasm):
- In animal cells, a cleavage furrow forms, dividing the cell into two daughter cells.
- In plant cells, a cell plate forms, dividing the cell into two daughter cells.
Mitosis and Its Stages
Mitosis is a kind of cell division that produces daughter cells, each identical to the parent cell. It’s important for growth, repair, and asexual reproduction.
Prophase
- Chromatin condensation: Chromatin condenses to form visible chromosomes.
- Nuclear envelope breakdown: The nuclear envelope disintegrates, releasing the chromosomes into the cytoplasm.
- Centrosome separation: The centrosome divides and migrates to opposite poles of the cell.
- Spindle fiber formation: Microtubules polymerize and form spindle fibers to connect to the chromosomes and help move them during mitosis.
Metaphase
- Chromosome alignment: Chromosomes align at the metaphase plate, an imaginary plane equidistant from the two poles of the cell.
- Spindle fiber attachment: Spindle fibers attach to the centromere of each chromosome, which holds the sister chromatids together.
Anaphase
- Sister chromatid separation: Sister chromatids are pulled apart and move toward opposite poles of the cell by the spindle fibers.
- Chromosome segregation: Chromosomes are segregated into two equal sets, each destined for a daughter cell.
Telophase
- Nuclear envelope reformation: Nuclear envelopes re-form around the two sets of chromosomes at the cell poles.
- Chromatin decondensation: Chromosomes begin to decondense, becoming less visible.
- Spindle fiber disassembly: Spindle fibers disassemble.
- Nucleolus reappearance: Nucleoli reappear in the newly formed nuclei.
Cytokinesis
- Division of cytoplasm: The cytoplasm divides into two daughter cells.
- Cleavage furrow formation (animal cells): A cleavage furrow forms at the equator of the cell, pinching it in two.
- Cell plate formation (plant cells): A cell plate forms at the equator of the cell, dividing it into two daughter cells.
Meiosis and Its Significance
Meiosis is a type of cell division that produces gametes (sperm and egg cells) for sexual reproduction. Unlike mitosis, which produces identical daughter cells, meiotic division produces genetically distinct daughter cells. These changes are important for genetic variation in species.
Analysis of the First and Second Meiotic Divisions
Meiosis is divided into two stages: primary meiosis and secondary meiosis.
Meiosis I
- Stage 1: The chromosomes unite, the nuclear envelope disassembles, and parallel chromosomes duplicate (synapsis).
- Crossing Over: The exchange of genes between homologous chromosomes, resulting in genetic mutations.
- Step 1: Two parallel sets of chromosomes are arranged on the equator.
- Anaphase I: Parallel chromosomes separate and move to opposite poles.
- Telophase I and Cytokinesis: The nuclear envelope remodels, the chromosomes separate, and the cytoplasm divides to form two daughter cells.
Meiosis II
- Similar to mitosis, but with half the number of chromosomes.
- The result is four haploid daughter cells (gametes).
Crossing Over and Genetic Diversity
- Crossing Over: The exchange of genes between homologous chromosomes during the first phase of meiotic division.
- Recombination: New combinations of genes lead to genetic diversity.
- Genetic Variation: Essential for evolution, adaptation, and natural selection.
Difference Between Mitosis and Meiosis
- Mitosis:
- Produces two identical daughter cells.
- Occurs in somatic cells (body cells).
- Used for growth, maintenance, and asexual reproduction.
- Meiosis:
- Produces four genetically distinct daughter cells (gametes).
- Occurs in germ cells (sex cells).
- Used for sexual reproduction.
- Involves two cell divisions.
Significance of Meiosis
- Genetic Diversity: Essential for evolution and adaptation.
- Sexual Reproduction: Allows for the combination of genetic material from parents, creating new and diverse offspring.
- Reduction of Chromosome Number: Ensures that when sperm and egg cells combine during fertilization, the resulting zygote has the correct number of chromosomes.
Regulation of the Cell Cycle
The Cell Cycle and Its Regulation
The cell cycle is a tightly regulated technique that ensures proper mobile division and stops out of control growth. Several key elements play a function in this regulation, inclusive of cyclins and cyclin-structured kinases (CDKs), and checkpoints.
Role of Cyclins and CDKs
- Cyclins: Proteins that adjust in awareness during the mobile cycle.
- CDKs: Enzymes that require cyclins to be energetic.
- Cyclin-CDK Complexes: Together, cyclins and CDKs form complexes that manipulate the progression of the cell cycle.
- Phosphorylation: CDKs phosphorylate goal proteins, which triggers particular cell occasions.
Key Cyclin-CDK Complexes:
- G1-S cyclin-CDK complex: Promotes the transition from the G1 segment to the S phase.
- S-phase cyclin-CDK complex: Initiates DNA replication.
- M-phase cyclin-CDK complex: Drives the entry into mitosis and promotes chromosome segregation.
Checkpoints within the Cell Cycle
- G1 checkpoint: Ensures that the cellular is prepared to divide and has no DNA harm.
- G2 checkpoint: Verifies that DNA replication has been completed correctly and that the mobile is prepared to go into mitosis.
- M checkpoint: Checks that each one chromosomes are nicely connected to spindle fibers earlier than anaphase.
If a checkpoint detects a hassle, the cell cycle may be paused to allow for repairs or cellular dying.
Apoptosis and Cancer
- Apoptosis: Programmed mobile dying. It is a everyday manner that eliminates broken or pointless cells.
- Cancer: Uncontrolled cellular growth and division. It takes place whilst cells lose their ability to respond to regulatory alerts and divide excessively.
- Mutations: Mutations in genes that modify the cell cycle can contribute to most cancers.
- Deregulation of Cyclins and CDKs: Abnormal activity of cyclins and CDKs can cause out of control cellular proliferation.
- Checkpoint Failure: Defects in checkpoints can allow damaged cells to divide, increasing the threat of most cancers.
Cell Cycle in Unicellular and Multicellular Organisms
Asexual duplicate: Prokaryotes, inclusive of bacteria, reproduce asexually via binary fission.
Process:
- DNA replication: The single circular chromosome replicates.
- Cell elongation: The cell elongates, separating the two copies of DNA.
- Cell department: The cell wall and plasma membrane divide, forming two identical daughter cells.
- Rapid increase: Binary fission permits for speedy population increase.
Cell Cycle in Eukaryotic Organisms
More complex: The cellular cycle in eukaryotic organisms is extra complex than in prokaryotes.
Interphase and M segment: The cell cycle includes interphase (G1, S, G2) and the mitotic (M) section.
- Mitosis: For growth, repair, and asexual reproduction.
- Meiosis: For sexual reproduction.
Differences between Unicellular and Multicellular Organisms
- Purpose: In unicellular organisms, cell division is primarily for reproduction. In multicellular organisms, it’s also for growth, development, and repair.
- Coordination: Multicellular organisms have more complex regulatory mechanisms to coordinate cell division across different tissues and organs.
- Differentiation: In multicellular organisms, cells can differentiate into various specialized cell types.
NEET Important Topics and Question Patterns
| Topic | Important Concepts | Question Patterns | Weightage |
|---|---|---|---|
| Phases of the Cell Cycle | G1, S, G2, M phases; Interphase and mitotic phase | MCQ: Identify phases based totally on mobile look or occasions. | Moderate |
| Mitosis | Prophase, metaphase, anaphase, telophase, cytokinesis; spindle fibers, chromosomes | MCQ: Describe the occasions of each phase, become aware of mobile structures, and provide an explanation for the role of spindle fibers. | High |
| Meiosis | Meiosis I and II; homologous chromosomes, crossing over, genetic version | MCQ: Compare and contrast mitosis and meiosis, provide an explanation for the significance of crossing over, and perceive the goods of meiosis. | High |
| Cell Cycle Regulation | Cyclins, CDKs, checkpoints | MCQ: Explain the function of cyclins and CDKs, discover the checkpoints, and talk the outcomes of checkpoint failure. | Moderate |
| Apoptosis | Programmed cell demise, function in improvement and sickness | MCQ: Define apoptosis, describe its position, and give an explanation for its connection to cancer. | Moderate |
| Cell Division in Unicellular Organisms | Binary fission in prokaryotes | MCQ: Describe the process of binary fission and examine it to eukaryotic cell department. | Low |
Practice NEET Questions
Multiple Choice Questions (MCQs)
Which segment of the cell cycle is characterised by means of DNA replication?
- (a) G1 segment
- (b) S phase
- (c) G2 phase
- (d) M section
The spindle fibers are shaped during which section of mitosis?
- (a) Prophase
- (b) Metaphase
- (c) Anaphase
- (d) Telophase
Crossing over happens among:
- (a) Sister chromatids
- (b) Homologous chromosomes
- (c) Centromeres
- (d) Spindle fibers
Apoptosis is:
- (a) Programmed cellular loss of life
- (b) Uncontrolled mobile increase
- (c) Cell department
- (d) DNA replication
The most important distinction among mitosis and meiosis is:
- (a) The wide variety of daughter cells produced
- (b) The genetic variant in daughter cells
- (c) The presence of crossing over
- (d) All of the above
Assertion and Reasoning Questions
Assertion: Cyclin-based kinases (CDKs) are activated through cyclins.
Reason: Cyclins are proteins that vary in awareness throughout the cell cycle.
Assertion: The G1 checkpoint guarantees that DNA replication has been completed effectively.
Reason: The G1 checkpoint is a essential point inside the cell cycle where the cell decides whether to proceed to DNA replication.
FAQs about Cell Cycle And Cell Division NEET Questions
1. What is the cellular cycle?
Ans: The cell cycle is the collection of occasions that cells go through as they develop and divide. It includes levels together with G1, S, G2, and M (mitosis).
2. What are the principle stages of the mobile cycle?
Ans: The essential phases are Interphase (G1, S, G2) and Mitosis (M segment). Interphase is when the cell grows and DNA is replicated, whilst Mitosis is when the cellular divides.
3. What happens all through the G1 phase?
Ans: During the G1 segment, the cell grows and performs its ordinary features. It additionally prepares for DNA replication.
4. What happens inside the S section?
Ans: In the S section, DNA replication takes area, resulting in same copies of every chromosome.
5. What is the function of the G2 phase?
Ans: The G2 section entails further cell growth and education for mitosis, which includes the synthesis of proteins required for mobile division.
