With reference to 'stem cells', frequently in the news, which of the following statements is/are correct? 1. Stem cells can be derived from mammals only 2. Stem cells can be used for screening new drugs 3. Stem cells can be used for medical therapies Select the correct answer using the codes given below:
Contents16
- A1 and 2 only
- B2 and 3 only
- C3 only
- D1, 2 and 3
Show answer
Answer: (B) 2 and 3 only
Statement 1 is wrong — stem cells are NOT limited to mammals.
They are found in all multicellular organisms, including plants, insects, and other animals.
Statement 2 is correct — stem cells can be grown in labs to test new drugs for safety and efficacy before human trials.
Statement 3 is correct — stem cells are used in therapies like bone marrow transplants and are being researched for treating Parkinson's disease, spinal cord injuries, and diabetes.
Answer: 2 and 3 only.
Stem cells exist in all multicellular organisms including plants and insects, not just mammals, making them a widespread biological phenomenon across species.
By 2012, stem cell research had gained significant momentum with clinical trials for treating diseases like Parkinson's and diabetes, making it a prominent news topic.
The question tests whether students understand both the biological scope of stem cells and their practical applications in drug testing and medical therapy.
Stem Cells: Types & Sources
Science And Technology stem cells
Stem Cells: Definition, Types & Universal Nature
Stem cells are undifferentiated cells that can develop into specialized cell types
Found in all multicellular organisms — not just mammals
Embryonic stem cells are pluripotent; adult stem cells are multipotent
iPSCs (induced pluripotent stem cells) are adult cells reprogrammed to act like embryonic stem cells
What Are Stem Cells
Stem cells are unique because they remain undifferentiated — they haven't specialized into specific cell types yet. They have two key properties: self-renewal (ability to divide and create more stem cells) and differentiation (ability to become specialized cells like neurons, blood cells, or muscle cells).
Types of Stem Cells
Type | Source | Potency | Can Become | Key Use |
|---|---|---|---|---|
Totipotent | Fertilized egg, early embryo | Highest | Any cell type + placenta | Natural development only |
Pluripotent | Embryonic stem cells, iPSCs | High | Any body cell type | Research, therapy potential |
Multipotent | Adult tissues (bone marrow, fat) | Limited | Few related cell types | Current medical use |
Unipotent | Specific adult tissues | Lowest | One cell type only | Tissue repair |
Universal Distribution
Plants: Meristematic cells in shoot and root tips function as stem cells
Invertebrates: Found in cnidarians (like Hydra), planarians, and insects
All vertebrates: Fish, amphibians, reptiles, birds, and mammals have stem cells
Regenerative capacity: Some organisms like salamanders use stem cells to regrow entire limbs
Trap: Statement 1 claims stem cells exist only in mammals — FALSE. They're in all multicellular life.
Confusion: Don't mix up totipotent vs pluripotent — totipotent can form entire organisms, pluripotent cannot.
iPSC confusion: These are adult cells reprogrammed to act pluripotent, not natural embryonic cells.
Stem Cells in Drug Testing
Science And Technology screening new drugs
Stem Cells for Drug Screening & Development
Stem cells can be differentiated into specific cell types for drug testing
Used in preclinical screening before human trials to test safety and efficacy
Reduces need for animal testing and provides human-relevant data
How Drug Screening Works
Scientists differentiate stem cells into specific cell types (like heart cells, liver cells, or neurons) and then expose them to potential drugs. This allows testing for both therapeutic effects and toxic side effects in a controlled lab environment before moving to animal or human trials.
Drug Development Process
%%{init: {"flowchart": {"wrappingWidth": 460}}}%%
flowchart TD
s1["`**Drug Discovery**
Identify potential therapeutic compounds`"]
s2["`**Stem Cell Testing**
Test on lab-grown human cells from stem cells`"]
s3["`**Animal Testing**
If stem cell tests pass, move to animal models`"]
s4["`**Human Trials**
Clinical trials in phases I, II, III`"]
s5["`**FDA Approval**
Drug approved for medical use`"]
s1 --> s2
s2 --> s3
s3 --> s4
s4 --> s5Advantages Over Traditional Methods
Human relevance: Uses actual human cell types, not just animal models
Cost efficiency: Cheaper than maintaining animal colonies for testing
High throughput: Can test thousands of compounds simultaneously
Disease modeling: Can create diseased cell types to test targeted therapies
Remember: Statement 2 is CORRECT — stem cells ARE used for drug screening.
Don't confuse: This is about testing drugs on stem cells, not using stem cells as drugs.
Stem Cell Medical Therapies
Science And Technology medical therapies
Stem Cell Therapies: Current Uses & Future Potential
Bone marrow transplants for blood cancers are the most established stem cell therapy
Used to treat blood disorders, immune deficiencies, and some cancers
Research ongoing for Parkinson's, diabetes, spinal cord injuries
Corneal and skin stem cell treatments already in clinical use
Current vs Future Therapies
Status | Condition | Stem Cell Type | How It Works |
|---|---|---|---|
In Use | Blood cancers (leukemia) | Hematopoietic stem cells | Replace diseased bone marrow |
In Use | Severe burns | Skin stem cells | Grow new skin tissue |
In Use | Corneal blindness | Limbal stem cells | Restore clear vision |
Research | Parkinson's disease | Neural stem cells | Replace lost dopamine neurons |
Research | Type 1 diabetes | Pancreatic stem cells | Restore insulin production |
Research | Spinal cord injury | Neural stem cells | Regenerate damaged nerve tissue |
How Stem Cell Therapy Works
The basic principle is cell replacement — damaged or diseased cells are replaced with healthy ones grown from stem cells. In bone marrow transplants, patients receive stem cells that develop into new blood cells. For future therapies, scientists hope to grow specific cell types (like insulin-producing cells for diabetes) and transplant them into patients.
Challenges & Limitations
Immune rejection: Patient's body may attack transplanted cells as foreign
Cancer risk: Stem cells could grow uncontrollably into tumors
Ethical concerns: Use of embryonic stem cells raises moral questions
Technical hurdles: Difficult to control exactly what cell types develop
Remember: Statement 3 is CORRECT — stem cells ARE used in medical therapies.
Key distinction: Bone marrow transplants are proven therapy; most others are still experimental.
Stem Cell Research in India
Science And Technology
India's Stem Cell Research & Regulatory Framework
ICMR (Indian Council of Medical Research) regulates stem cell research in India
Guidelines restrict embryonic stem cell research to specific conditions
India has emerging stem cell therapy centers but many are unregulated
Regulatory Framework
The ICMR has established guidelines for stem cell research and therapy. Only hematopoietic stem cell transplantation (bone marrow transplants) is considered standard treatment. All other stem cell therapies are classified as experimental and require proper clinical trials.
Key Regulations
Embryonic research: Allowed only with strict ethical oversight and consent
Clinical trials: Must follow ICMR protocols before offering treatments
Unproven therapies: Many clinics offer unregulated treatments — patients should be cautious
International collaboration: India participates in global stem cell research networks
Indian Stem Cell Ecosystem
# Stem Cell Research India
## Regulators
- ICMR
- DBT (Dept of Biotechnology)
- CDSCO
## Research Centers
- AIIMS
- PGIMER Chandigarh
- CMC Vellore
- NCCS Pune
## Applications
- Blood disorders
- Corneal repair
- Research trials