Human biology
Difference between
Cell
Energy, Enzymes and membrane
Plant
Botanical Name
Biodiversity
Symptoms, diseases
Causes
Other Topics
Bio Articles (Alphabetic order)
- Blood Circulatory System
- Blood
- Bones of The Legs
- Bones of The Foot
- Bones of The Ankle
- Bones of Pelvis
- Blood Groups
- Scientific Name of Human Being
- Largest Organ In Human Body
- Largest Internal Organ in The Human Body
- Human Respiratory System
- Human Population
- Human Physiology
- Human Life Cycle
- Human Insulin
- Human Impact on the Environment
- Human Heart
- Human Health and Diseases
- Human Genome Project Goals Significance
- Human Excretory System
- Human Evolution Progress
- Human Ear
- Human Diseases
- Human Digestive System
- Human Circulatory System Transportation
- Anatomy and Physiology of the Human Body
- Effects of Air Pollution on Human Health
Difference between
- Difference between Turner Syndrome and Klinefelter Syndrome
- Difference Between Transpiration and Guttation
- Difference Between Transpiration and Evaporation
- Difference Between Tracheids and Vessels
- Difference Between Thorns and Spines
- Difference Between T Cells and B Cells
- Difference Between Sympathetic and Parasympathetic
- Difference Between Sporophyte and Gametophyte
- Difference Between Spermatogenesis and Oogenesis
- Difference Between Sperm and Ovum
- Difference between Species, Population, and Community
- Difference Between Sleep and Hibernation
- Difference Between Saturated and Unsaturated Fats
- Difference Between Rust and Smut
- Difference Between Right and Left Lung
- Difference Between Replication and Transcription
- Difference Between Renewable and Non Renewable Resources
- Difference Between Red and White Muscle
- Difference Between Radicle and Plumule
- Difference Between Prokaryotic and Eukaryotic Transcription
- Difference Between Plasma and Serum
- Difference Between Pharynx and Larynx
- Difference Between Organs and Organelles
- Difference Between Open and Closed Circulatory Systems
- Difference Between Ocean and Sea
- Difference Between Monocytes and Lymphocytes
- Difference Between Mitochondria and Chloroplast
- Difference Between Lytic and Lysogenic Cycle
- Arteries and Veins Difference
Cell
- Growth and Development of an organism
- Meiosis Cell Division
- Cellular Respiration Concept Map
- Cell Signalling
- Cell Organelles
- Cell Cycle and Cell Division
- Cell Biology
Energy, Enzymes and membrane
Plant
- Scientific Names of Animals and Plants
- Plant Respiration
- Plant Physiology
- Plant Life Cycle and Alternation of Generations
- Plant Kingdom Plantae
- Plant Growth Regulators
- Plant Fibres
- Mendelian Inheritance Using Seeds of Different Colours Sizes of Any Plant
- Grassland Dominant Plants
- Effects of Air Pollution on Plants
- Biodiversity In Plants and Animals
Botanical Name
- Mustard Botanical Name
- Marigold Botanical Name
- Chilli Botanical Name
- Botanical Name of Tea
- Botanical Name of Sugarcane
- Botanical Name of Soybean
- Botanical Name of Rose
- Botanical Name of Rice
- Botanical Name of Pea
- Botanical Name of Lady Finger
- Botanical Name of Groundnut
- Botanical Name of Grapes
- Botanical Name of Coffee
- Botanical Name of Cabbage
- Botanical Name of Banyan Tree
- Botanical Name of Bajra
Biodiversity
- Biodiversity Pattern Species
- Biodiversity Conservation
- Biodiversity and Conservation Concept Map
- Biodiversity
Symptoms, diseases
- Hormones Heart Kidney GI
- Blood Cancer
- Arthritis
- Aids and Hiv
- Nervous System Diseases
- Modes of Transmission of Diseases
- Migraine Symptoms
- Menopause Symptoms
- Lysosomal Storage Disease
- Lung Diseases
- Lung Cancer Symptoms
- Hyperthyroidism Symptoms
- Hypertension Symptoms
- Chicken Pox Symptoms
- Blood Pressure Symptoms
- Arthritis Symptoms
- Appendicitis - Formation, Symptoms, Treatment
- Anemia Symptoms
- Acidity Symptoms Causes and Risk Factors involved
Causes
Other Topics
Bio Articles (Alphabetic order)
- Antigens and Immunology
- Scientific Name of Vitamins
- Scientific Name of Neem
- Schistosomiasis Life Cycle
- Scabies Life Cycle
- Salient Features of The Kingdom Monera
- Saddle Joints
- Root Modifications
- Role of Microbes In Food Processing
- RNA: World Genetic Material
- Rna Interference
- Ringworm
- Rigor Mortis
- Retrovirus
- Respiratory Quotient
- Respiratory and Lung Volumes
- Adolescence Secondary sexual characteristics
- Prolactin Hormone
- Productivity In Ecosystem
- Prions
- Principles of Treatment
- Principles of Prevention
- Principles of Inheritance and Variation
- Principles of Genetics
- Primary Ciliary Dyskinesia
- Prepare Pedigree Charts of Any One of the Genetic Traits Such as Rolling Of Tongue, Blood Groups, Ear Lobes, Widow’s Peak and Colour Blindness
- Prepare A Temporary Mount of The onion Root Tip To Study Mitosis
- Preparation and Study of Transverse Section of Dicot and Monocot Roots and Stems
- Pregnancy Parturition Lactation
- Neural Control and Coordination
- Nervous Tissue
- Nervous System Definition
- Nervous System Coordination
- Nervous System
- Nerves
- Nephron Function Renal Tubules
- Nephritis
- Nematoda
- Need For Hygiene and Sanitation
- Natural Selection Biological Evolution
- Natural Disasters
- National Parks and Sanctuaries
- Mycology
- Myasthenia Gravis
- Mutualism
- Mutation Genetic Change
- Mutagens
- Muscular Dystrophy
- Muscle Contraction Proteins
- Mountains and Mountain Animals
- Morphology and Anatomy of Cockroach
- Monohybrid Cross - Inheritance of One Gene
- Molecular Basis of Inheritance
- MOET Technology - Multiple Ovulation Embryo Transfer Technology
- Modern Synthetic Theory of Evolution
- Miller Urey Experiment
- Micturition - Urination Process
- Microfilaments
- Microbodies
- Metabolism Metabolic Pathways
- Metabolism Living State Basis
- Mendelian Disorders
- Melatonin Hormone
- Meiosis Phases
- Meiosis I - Stages and Process
- Megafauna
- Measles
- Mayfly Life Cycle
- Mass Flow Hypothesis
- Mass Extinctions
- Marine Biology
- Mammalia Diversity In Living Organisms
- Malthusian Theory of Population
- Male Sex Hormone
- Macromolecule
- Luteinizing Hormone
- Lung Cancer
- Love Hormone
- Locust Life Cycle
- Lizard Life Cycle
- Living Fossil
- Lipoproteins
- Lipids
- Lipid Peroxidation
- Linkage Recombination
- Life Cycle of Living Organism
- Lice Life Cycle
- Leprosy
- Length of Epididymis
- Leishmania Life Cycle
- Leg Muscles
- Law of Segregation and Law of Dominance
- Law of Independent Assortment
- Hypothyroidism
- Hypothalamus
- Hypogeal Germination
- Hypocalcaemia
- Hypertension
- Hyperparathyroidism
- Hydroponics
- Hydrarch Succession
- Horses and Donkeys Same Species
- Hormonal Disorders
- Hormones Secreted by Non-Endocrine
- Hookworm Life Cycle
- Honey Bee Life Cycle
- Homo erectus
- Homeostasis
- History of Clothing Material
- Characteristics and classification of Gymnosperms
- Guttation
- Griffith Experiment: The Genetic Material
- Grazing Food Chain
- Grasshopper Life Cycle
- Gram Positive Bacteria
- Gout
- Gonorrhea
- Gonads
- Goiter
- Embryology
- Embryo Development
- Elisa Technique
- Electron Transport Chain
- Electrocardiograph
- Effects of Water Pollution
- Effects of Waste Disposal
- Effects of Wastage of Water
- Effects of Plastics
- Life Cycle of Chicken
- Chemotrophs
- Chemiosmotic Hypothesis
- Centromere
- Central Dogma Inheritance Mechanism
- Cartilaginous Joints
- Carnivores and Herbivores
- Cardiac Output
- Carbon Cycle
- Carbohydrate Metabolism
- Can a Community Contain Two Populations of the Same Species?
- Bt Crops
- Bryophyta
- Blastocyst
- Bird Life Cycle
- Biotechnology Jobs
- Biotechnology Agriculture
- Biosafety Issues
- Bioreactor Obtaining Foreign Gene
- Biopiracy
- Biomolecules In Living Organisms
- Biomes of The World
- Biomass Definition Ecology
- Biofortification
- Asteraceae Brassicaceae Poaceae
- Ascaris Life Cycle
- Artificial Pollination
- Archaebacteria
- Apoptosis Definition, Pathway, Significance, and Role
- Apoplast and symplast pathway
- AntiMullerian Hormone (AMH)
- Antimicrobial Resistance
- Antibiotics
- Ant Life Cycle
- Annelida Meaning, Classification, Types, and FAQs
- Animal Nervous System
- Animal Kingdom Concept Map
- Animal Kingdom : Animalia Subphylum
- Animal Kingdom
- Animal Husbandry: Types and Advantages
- Animal Husbandry and Poultry Farming & Management
- Angina Pectoris
- Anatomy and Morphology of Animal Tissues
- Anagenesis
- An overview of Anatomy, its types and their applications
- Amphibolic Pathway
- Amphibia
- Amoebiasis
- Ammonotelism
- Ammonification
- Amino acids Properties, Functions, Sources
- Amensalism
- Alternatives To Dams
- Allergies Autoimmunity
- Allee Effect
- Alimentary Canal Anatomy
- Algae Definition, Characteristics, Types, and Examples
- Alcohol and Drug Abuse Measures for Prevention and Control
- Air Pollution Definition, Causes, Effect and Control
- Agriculture Seeds Selection Sowing
- Agriculture Practices - Organic Farming & Irrigation
- Agriculture Fertilizers
- Agricultural Implements and Tools
- Aerobic and Anaerobic Respiration Major Differences
- Advantages of Dams
- Adolescence and Drug Abuse
- Adh Hormone
- Adaptive Radiation Evolution
- Acth Hormone
- Acromegaly Causes, Symptoms, Treatment
- Acquired and Inherited Traits
- Acoustic Neuroma Symptoms, Causes, Diagnosis
Griffith Experiment: The Genetic Material
Introduction to Genetic Material
Mendel’s experiments with garden peas were a setting stone in genetics. He knew that some “factor” was responsible for the characteristics observed in organisms, which were passed down from each parent to the offspring. At that time, he wasn’t aware of what this factor was.
However, one thing was certain; the genetic material was expressible and inheritable. After continued speculation regarding the molecular nature of the genetic material, certain groundbreaking experiments, including those by Fredrick Griffith (1928), Averty, MacLeod, and McCarty (1944), and Hershey and Chase (1952) laid conclusive evidence that helped estabpsh that it is certainly the DNA, and not the RNA or proteins, which is the molecular basis of inheritance.
Characteristics of Genetic Material
Genetic material should not only be inheritable, but it must also be able to express all the information that’s coded in it. This is the defining characteristic of genetic material.
The genetic material must be reppcable so that it can be transferred to the progeny
The genetic material must be ubiquitous across all pfe forms
The genetic material must be chemically and physically stable
The expression of the genetic material controls all the activities of the cell and also the duppcation of the cells.
Genetic material is prone to mutation and hence, accounts for the variations among organisms
The Griffith Experiment
In 1928, Fredrick Griffith performed some transformation experiments in an attempt to determine the nature of genetic material in organisms.
The experiment involved two strains of the bacterium Streptococcus pneumoniae, one being the virulent strain (serotype IIIS), which produced smooth colonies in an agar plate, and the other, the avirulent one (serotype IIR), which produced rough colonies on an agar plate. The virulent strain has a polysaccharide capsule that acts as the virulence factor. The avirulent strains lack this capsule and are easily phagocytosed.
Griffith injected these two different strains of bacteria into mice. The virulent strain, as expected, killed the mice, while the avirulent strain didn’t.
In another experiment, he subjected the virulent strain to heat, kilpng the bacterial cells. This heat-killed strain was injected into a mouse. Griffith observed that the mouse survived and didn t develop pneumonia.
The third experiment yielded a very interesting observation. He combined the heat-killed virulent strain with the pve avirulent strain and injected the mixture into a mouse. Now, the two strains, when injected inspanidually, would not kill the mouse. However, the mixture of the two strains led the mouse to develop pneumonia and die.
The tissue of the dead mouse contained pve bacteria, which on culturing, produced smooth colonies, just pke the III-S strain. This strain continued to infect and kill other mice for several generations.
From these observations, Griffith concluded that the heat-killed IIIS strain of the bacteria was somehow able to “convert” the avirulent IIR strain into virulent strains that killed the mouse. He called this the transformation and referred to the genetic information that was passed on from the dead IIIS cells to the pve IIR cells as the transforming principle.
At that time, Griffith postulated that the transforming principle was probably a polysaccharide or some compound involved in the synthesis of the capsule.
However, this transforming principle was later confirmed to be the Deoxyribonucleic Acid (DNA), as estabpshed by the Hershey-Chase experiment in 1952.
DNA as Genetic Material
Deoxyribonucleic Acid (DNA) is a self-reppcating, double-stranded, hepcal molecule that is the basis for the continuity of pfe. Each DNA molecule is a polymer of single units known as nucleotides. Each nucleotide monomer contains
A nitrogenous base, which may be a derivative of a purine (adenine or guanine) or a pyrimidine (thymine or cytosine)
A deoxyribose sugar
A phosphate group
DNA contains genetic instructions that command the biological development of all forms of pfe and even the majority of viruses.
The information is in the form of genes that are inherited by the offspring from its parents. Each gene encodes a specific character for the inspanidual.
Depending upon what variant of a particular gene (i.e., allele) is inherited, the phenotypic traits between inspaniduals vary for that character.
The nucleotide sequence of a gene encodes within it the sequence of amino acids that make up a specific protein.
While DNA is the inheritable genetic material in all pving organisms, there are few viruses which carry RNA as their genetic material.
Why isn’t Protein the Genetic Material?
Initially, proteins were considered strong candidates as genetic material, considering their heterogeneity (being made of 20 different amino acids, which form a wide variety of proteins) and functional capabipties in pving organisms. However, the one thing proteins are not is the molecular basis of heredity. This is because −
Proteins are not the carriers of genetic information. They are merely translated from nucleic acids. Even the proteins that are involved in nucleic acid reppcation, packaging, transcription, and translation are encoded in the nucleic acids!
Proteins cannot reppcate themselves
Proteins themselves don t undergo any mutation. The mutations occur in the nucleotide sequences that encode the protein.
The experiments by Averty, MacLeod, and McCarty (1944) and by Hershey and Chase (1952) ultimately confirmed that it’s the DNA and not the proteins that are the genetic material of pving organisms.
Conclusion
Griffith performed experiments which showed that bacteria could change their functions via transformation by picking up a transforming principle from dead bacterial cells.
The molecular nature of the transformation principle was later estabpshed as the DNA
The ideal genetic material should not only store and express genetic information but also be inheritable, self-reppcating, prone to mutations and variations, and stable. DNA checks all these characteristics
Proteins, though widely heterogeneous and having immense functional capabipties, do not quapfy as genetic material because its neither inheritable nor self-reppcating
FAQs
Q1. Why can’t one conclude from Griffith’s experiment that the R-strains simply picked up the virulent capsule of the killed S-strains?
Ans. This conclusion proves to be false since the pving S-cells isolated from the blood sample in the first experiment were able to reproduce and form more of the S-cells. This imppes that the polysaccharide capsule trait is heritable and permanent and not just "discarded" after infecting the host.
Q2. How is genetic information translated to proteins?
Ans. The genetic information within a gene is “read” in the form of a triplet code of nucleotides, each triplet being translated into a specific amino acid.
Q3. Does the entire DNA molecule code for proteins?
Ans. No. More than 98% of the eukaryotic genome is non-coding. Only ~1.5% of the genome encodes proteins.
Q4. What is the RNA World hypothesis?
Ans. The RNA world hypothesis proposes that RNA was the first genetic material and the first pfe form on earth, supported by its abipty to store, transmit and reppcate genetic information, along with the abipty to act as a catalyst.