BIO NMDCAT BIOLOGICAL MOLECULES

nmdcat.online June 27, 2026

The instability of RNA compared to DNA is primarily due to the

A. Presence of uracil instead of thymine

B. Presence of a 2'-hydroxyl group on its ribose sugar

✓

C. Single-stranded nature of all RNA molecules

D. Inability of RNA to form hydrogen bonds

📝 Explanation

The 2'-OH group in the ribose sugar of RNA is reactive. It can act as a nucleophile and attack the adjacent phosphodiester bond under alkaline conditions, leading to the self-hydrolysis (cleavage) of the RNA strand. DNA, lacking this 2'-OH, is far more chemically stable.

📖 Additional Information

Presence of uracil instead of thymine
Presence of a 2'-hydroxyl group on its ribose sugar
Single-stranded nature of all RNA molecules
Inability of RNA to form hydrogen bonds

The 2'-OH group in the ribose sugar of RNA is reactive. It can act as a nucleophile and attack the adjacent phosphodiester bond under alkaline conditions, leading to the self-hydrolysis (cleavage) of the RNA strand. DNA, lacking this 2'-OH, is far more chemically stable.

🔗 Share This Question

Facebook Twitter LinkedIn WhatsApp

🧭 Navigate Questions

Previous Question

The term "metabolism" encompasses all chemical reactions occurring in a cell, and the two fundamental, opposing processes of metabolism are

Next Question

The function of a chelating agent, such as EDTA, in an enzyme reaction is to

Back to All Questions

🔗 Related MCQs

An increase in the incidence of ectopic pregnancies within a population can often be epidemiologically correlated with a prior increase in the prevalence of which sexually transmitted disease?

In the life cycle of Herpes Simplex Virus 2 (HSV-2), the virus travels along nerve fibers to reach the sensory ganglia. The cellular mechanism responsible for this retrograde transport utilizes:

A defining characteristic of the lesions associated with the secondary stage of syphilis is that they:

The causative agent of genital herpes, HSV-2, is enveloped. The biological significance of this viral envelope in the context of transmission is that it makes the virus:

The structural basis for the severe cardiovascular complications seen in tertiary syphilis, such as aortic aneurysms, is the chronic inflammation and destruction of:

Categories

BIO by M Tahir ( Lecturer Al Azhar )
50
- virus chapter
  50
BIO NMDCAT
1785
- ACELLULAR LIFR
  20
- AIDS and HIV Infection
  50
- Biological Importance of Water
  95
- BIOLOGICAL MOLECULES
  126
- Brain
  25
- Carbohydrates
  100
- cell membrane
  70
- CELL STRUCTURE & FUNCTION
  100
- Chromosomes
  76
- Concept of Evolution
  50
- Conjugated molecules
  100
- Cytoplasmic Organelles
  75
- Darwinism
  50
- ENZYMES
  108
- Factors that Affect the Rate of Enzyme Reactions
  60
- Inhibitors
  40
- Lamarckism
  50
- Lipids
  45
- Mode of Enzyme Action
  60
- Neurons
  41
- Proteins
  95
- Receptors
  40
- Respiration
  15
- Ribonucleic acid (RNA)
  100
- Sexually transmitted diseases
  50
- Structure of DNA
  98
- Viruses
  46
BS Nursing
5385
- Adult health nursing -II
  149
- Anatomy & Physiology -II
  150
- Anatomy & Physiology 1
  78
- Applied Nutrition
  25
- Behavioral Psychology
  48
- Bio chemistry for nurses
  164
- Clinical Practicum
  200
- Community Health Nursing -I
  200
- Community Health Nursing-I
  200
- Community Health-II
  200
- Computer skills
  200
- Critical Care Nursing
  194
- Cultural Health & Society
  200
- Developmental Psychology
  200
- English -VI ( Academic Writing )
  210
- English 1 Fundamental
  228
- Epidemiology
  200
- fundamentals of nursing
  51
- Health Assessment 1
  141
- Introduction To Biostatistics
  195
- Introduction to Nursing
  174
- Islamiat
  324
- Leadership and management in Nursing
  142
- MCQSt of Patho 1 First three unites
  35
- Microbiology
  120
- Nursing Ethics
  199
- Nursing Research
  48
- Pak Study
  19
- Pathophysiology
  141
- Pathophysiology-II
  197
- Pediatric Health Nursing-II
  200
- Pharmacology-I
  251
- Teaching Learning Principles & Practice
  580
Chemistry NMDCAT MCQs
305
- Limiting and Excess Reactants
  74
- Moles and Avogadro's Numbers
  150
- Moles and Avogadro’s Numbers
  120
- Yield
  80
Computer
217
- Power Point
  217
direct and indirect narrations
1
English NMDCAT
3146
- ADJECTIVES
  51
- ADVERB AND ITS TYPES
  51
- Adverb placement and sentence structure
  80
- Antonyms
  51
- Articles
  61
- CAPATILIZATION
  31
- CLAUSES
  61
- CLUASES AND PHRASES POSTIONING
  111
- colon
  61
- Common Article Errors
  51
- Common Grammatical Errors
  51
- CONJUNCTION
  71
- Contextual Vocabulary
  1
- COORDINATING CONJUCTION
  51
- CORELATIVE CONJUNCTION
  61
- Correcting Tense Errors
  31
- Dash & Hyphen
  51
- direct and indirect narrations
  80
- Figurative Language & Literary Devices
  31
- Gerunds and Gerund Phrases
  60
- Gerunds and Gerund Phrases mdcat
  59
- Homonyms
  101
- Homophones
  31
- Identifying Sentence Errors
  30
- Inference-based MCQs from the passages
  20
- MCQs – Infinitives and Infinitive Phrases mdcat
  121
- MCQs – Synonyms & Semantic Nuance mdcat
  97
- Misused Words and Phrases
  20
- NOUN
  80
- ORDER OF ADJECTIVES
  99
- Phrasal verbs
  208
- Prefixes and Suffixes
  39
- Prepositions
  30
- PRHASES
  107
- Pronoun Antecedent Agreement
  140
- Punctuation
  169
- Reading Comprehension
  59
- Scanning and Locating Information
  80
- Semi-colon
  39
- Sentence Structure
  30
- Sentence Structure & Inversion NMDCAT
  30
- Subject Verb Agreement
  20
- Synonyms
  40
- Tenses
  37
- Transitional Devices
  99
- Types of Sentences
  46
- Use of Tenses
  29
- Verb & Verb Phrases
  95
- Word Choice and Style
  39
- Word Formation
  37
- Word Relationships
  38
- Writing Skill and Proofreading
  60
Physics
91
- Acceleration FORCE AND MOTION
  1
- Addition of Vectors
  1
- CURRENT ELECTRICITY
  1
- DAWN OF MODERN PHYSICS
  1
- Displacement-time Graph-FORCE AND MOTION
  1
- ELECTROMAGNETIC INDUCTION
  1
- ELECTROMAGNETISM
  1
- ELECTRONICS
  1
- THERMODYNAMICS
  91