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Molecular Basis of Inheritance Part 3 | NEET 2024 | Seep Pahuja

Unacademy NEET・116 minutes read

Genetic code translation, the Human Genome Project, and DNA fingerprinting are crucial topics covered, with a focus on interdisciplinary collaborations and the significance of genetic information in healthcare and ethical considerations. Repetitive DNA sequences and DNA fingerprinting techniques, including PCR for enhanced sensitivity, are highlighted for identification and paternity testing applications.

Insights

  • The genetic code, composed of A, T, C, and G letters, contains 64 words, with 61 meaningful and 3 meaningless words, each triplet corresponding to an amino acid, crucial for protein synthesis.
  • The Human Genome Project (HGP) aimed to identify 3*10 base pairs, equivalent to storing vast information, leading to advancements in DNA understanding, disease diagnosis, and ethical considerations.
  • DNA fingerprinting, introduced by Alec Jeffreys, utilizes unique non-coding sequences, like VNTRs, for identification and paternity testing, involving cutting DNA, agarose gel electrophoresis, and Southern Blot transfer.
  • Translation process involves ribosomes, TRNA, and mRNA with start and stop codons, forming peptide bonds, essential for protein synthesis and regulated by factors like inducers and lac operon activation.

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Recent questions

  • What is the genetic code?

    The genetic code is a language written on DNA and RNA, consisting of letters like A, T, C, and G. It comprises 64 words, with 61 meaningful and 3 meaningless words. Each three-letter code (triplet) in the genetic code corresponds to an amino acid. The genetic code is crucial for protein synthesis, with each codon representing an amino acid. Scientists like Nirenberg and Khorana made significant contributions to cracking the genetic code.

  • How does translation occur?

    Translation involves converting genetic information from nucleic acids to proteins. Scientists from various disciplines collaborated to develop the genetic code, including George Gamow and Hargobind Khorana. TRNA, also known as adapter RNA, plays a vital role in linking amino acids to the mRNA for protein synthesis. Ribosomes play a crucial role in protein synthesis, consisting of structural RNA and about 80 different proteins. The process of translation involves the ribosome moving from one codon to the next, adding amino acids sequentially until a peptide bond is formed.

  • What is the Human Genome Project?

    The Human Genome Project (HGP) was a mega project that aimed to identify 3*10 base pairs, store vast amounts of genetic information, and utilize bioinformatics extensively. It took 13 years from 1990 to 2003, involving scientific institutes, staff, scientists, and contributions from various countries. The completion of the project led to significant advancements in understanding DNA variations, disease diagnosis, prevention, and ethical, legal, and social concerns. The data from the project could revolutionize healthcare, agriculture, energy production, and environmental protection.

  • What is DNA fingerprinting?

    DNA fingerprinting involves identifying unique sequences in an individual's DNA, such as variable number tandem repeats (VNTRs). VNTRs are sequences that repeat alternately in individuals, with different numbers of repetitions distinguishing one person from another. The technique was introduced by Alec Jeffreys in the UK and is crucial for identification, paternity testing, and forensic studies. Sensitivity in DNA fingerprinting is enhanced through PCR, allowing for a wide range of applications in genetic diversity studies.

  • How does the lac operon function?

    The lac operon is activated in the presence of an inducer like lactose, while glucose can act as an inducer to turn it off. Understanding the lac operon's functioning is essential for grasping gene expression in prokaryotes. Enzymes like beta galactosidase are crucial for breaking down lactose, and the lac operon remains inactive in the absence of an inducer. Inducers play a vital role in gene expression regulation, highlighting the intricate mechanisms involved in genetic regulation.

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Summary

00:00

Genetics: Unraveling the Molecular Language of Life

  • The chapter being discussed is Molecular Basis of Inheritance, focusing on genetics.
  • The topics covered include DNA structure, genetic material search, DNA vs. RNA, replication, and transcription.
  • The chapter will delve into genetic code translation, OPER, HGP, and DNA Finger Printing.
  • The aim is to complete the chapter in the current session and revise NCR line by line.
  • A free test series on Genetics is scheduled for the day after tomorrow.
  • The genetic code is a language written on DNA and RNA, consisting of letters like A, T, C, and G.
  • The genetic code comprises 64 words, with 61 meaningful and 3 meaningless words.
  • Each three-letter code (triplet) in the genetic code corresponds to an amino acid.
  • The genetic code is crucial for protein synthesis, with each codon representing an amino acid.
  • Scientists like Nirenberg and Khorana made significant contributions to cracking the genetic code.

15:42

"Genetic Code: Protein Synthesis and Translation"

  • mRNA is used to create protein, specifically phenyl alanine and phenyl allene.
  • The poly peptide chain is made of phenyl alanine.
  • Scientists like Hargobind Khorana used homo polymers and co-polymers in protein synthesis.
  • The genetic code is universal, except for mitochondrial DNA in mammals and yeast.
  • Mitochondrial DNA has four stop codons, including AG and AA.
  • The genetic code is highly specific, with one codon coding for one amino acid.
  • The genetic code is continuous, without gaps or overlapping.
  • The code is degenerate, with multiple codons coding for the same amino acid.
  • Translation involves converting genetic information from nucleic acids to proteins.
  • Scientists from various disciplines collaborated to develop the genetic code, including George Gamow and Hargobind Khorana.

32:16

"Decoding Sirin: Crucial Codons and Degeneracy"

  • Remember the codes Y Y U Y U C U U A and U AG for Sirin
  • These codes are for Sirin and are crucial to pay attention to
  • There are four codons to remember for Sirin
  • Multiple codes exist for coding amino acids, leading to degeneracy
  • An example of degeneracy is seen in Amigas donating amino acids to multiple codes
  • Stop codons like UAA, UAG, and UGA are crucial to note
  • Mitochondrial DNA contains four stop codons, including AG and AA
  • Degeneracy is evident in coding Sirin, understanding the concept is essential
  • Mutations can occur due to insertions and deletions of bases, leading to frame shift mutations
  • TRNA, also known as adapter RNA, plays a vital role in linking amino acids to the mRNA for protein synthesis

48:26

"Translation Process: TRNA, Ribosomes, Amino Acids"

  • The structure discussed is an inverted L shape, with a reverse L being described as an upside-down L.
  • The structure is where the five primes end, and the prime comes after roaming around.
  • A code will be added at the end, along with an anti-codon loop.
  • Amino acid is linked somewhere in this structure.
  • TRNA's task is to adopt molecules, with a mechanism to read the genetic code.
  • TRNA has an anti-codon loop and binds to amino acids.
  • TRNA is specific for each amino acid, with different codes for initiation and stop codons.
  • Ribosomes are made up of rRNA and proteins, with 70s ribosomes in prokaryotic mitochondria and cytoplasm.
  • The 30s subunit contains 16s rRNA and 21 proteins, the 50s subunit has 23s rRNA and 34 proteins, and the 60s subunit contains 28s rRNA and 40 proteins.
  • Translation involves the polymerization of amino acids to form a polypeptide, with the order and sequence defined by bases in mRNA.

01:03:30

Protein Synthesis: From mRNA to Peptide Bond

  • mRNA has a 5 prime to 3 prime order, matching the amino acid sequence.
  • Peptide bonds join amino acids together.
  • Energy is required for peptide bond formation, with the first amino acid being activated in the presence of ATP and linking to Cognate T RNA.
  • Translation occurs inside DNA, with the charging of T RNA and activation of amino acids being the initial step, utilizing ATP and an enzyme called acyl synthetase.
  • A charged TR NA is formed, resembling an inverted L, with amino acids added sequentially to form a peptide bond.
  • Ribosomes play a crucial role in protein synthesis, consisting of structural RNA and about 80 different proteins.
  • The translation unit in mRNA initiates the conversion into protein, starting with a start codon and ending with a stop codon.
  • Untranslated regions in mRNA are essential for efficient translation, with Shine Dal Garno sequence aiding in recognition.
  • The process of translation involves the ribosome moving from one codon to the next, adding amino acids sequentially until a peptide bond is formed.
  • Release factors bind to the stop codon, terminating translation and releasing the complete poly peptide from the ribosome.

01:18:21

Regulation of gene expression in prokaryotes

  • RNA transcription can be stopped at a crucial point to prevent further growth.
  • NCERT outlines four steps in the UK transcriptional process.
  • E. coli has a single step in controlling the rate of transcriptional initiation.
  • The Open Model method is applicable only in prokaryotes.
  • Inducers like lactose play a vital role in gene expression regulation.
  • Enzymes like beta galactosidase are crucial for breaking down lactose.
  • The lac operon is activated in the presence of an inducer like lactose.
  • Glucose can act as an inducer, turning off the lac operon.
  • In the absence of an inducer, the lac operon remains inactive.
  • Understanding the lac operon's functioning is essential for grasping gene expression in prokaryotes.

01:33:25

"Human Genome Project: Genetic Advancements and Implications"

  • HGP stands for Human Genome Project, a mega project that took 13 years from 1990 to 2003, costing billions of US dollars.
  • The project involved scientific institutes, staff, scientists, technicians, and contributions from various countries like the US, UK, Japan, France, Germany, and China.
  • The Human Genome Project aimed to identify 3*10 base pairs, store vast amounts of information equivalent to 3300 books with 1000 pages each, and utilize bioinformatics extensively.
  • The project's completion in 2003 led to significant advancements in understanding DNA variations, disease diagnosis, prevention, and potential ethical, legal, and social concerns.
  • The project's data could lead to personalized genetic information, disease susceptibility predictions, and ethical dilemmas regarding genetic manipulation and privacy.
  • Genetic information could revolutionize healthcare, agriculture, energy production, and environmental protection, with potential applications in non-human models like bacteria, yeast, and nematodes.
  • Sequencing methods like Sanger sequencing and expressed sequence tags were used to extract coding and non-coding DNA sequences, with vectors like bacterial artificial chromosomes and yeast artificial chromosomes employed.
  • Automated DNA sequencers and computer-based programs were crucial in aligning and annotating DNA sequences, assigning them to specific chromosomes, with chromosome 1's sequence completed in 2006.
  • The Human Genome Project's completion marked a significant milestone in genetic research, paving the way for personalized medicine, disease prevention, and ethical considerations surrounding genetic information.
  • The project's impact extended beyond human health to various fields, emphasizing the importance of genetic information in shaping future advancements and ethical guidelines.

01:49:48

"Genetic Discoveries: Chromosomes, SNPs, and DNA Fingerprinting"

  • Chromosome number one was sequenced in 2006, revealing it has the highest number of genes at 2968.
  • Single nucleotide polymorphisms (SNPs) are variations at a single nucleotide level, impacting diseases like sickle cell anemia.
  • SNPs can make populations more vulnerable to certain diseases, such as cancer, and can affect resistance to HIV.
  • The human genome has 316 million base pairs, with an average gene size of 3000 bases, contrary to the previous estimate of 80,000 genes.
  • The number of genes discovered now stands at 30,000, with only 2 proteins remaining out of thousands.
  • Repetitive sequences in the human genome, like microsatellites, are used for DNA fingerprinting and are non-coding.
  • DNA fingerprinting involves identifying unique sequences in an individual's DNA, such as variable number tandem repeats (VNTRs).
  • VNTRs are sequences that repeat alternately in individuals, with different numbers of repetitions distinguishing one person from another.
  • DNA fingerprinting involves cutting DNA with restriction enzymes, separating VNTRs from non-VNTRs, and using agarose gel electrophoresis for separation.
  • The technique of DNA fingerprinting was introduced by Alec Jeffreys in the UK, while Lalji Singh is considered the Indian father of DNA fingerprinting.

02:04:50

DNA Transfer and Fingerprinting Techniques Explained

  • DNA is transferred from a gel to nylon or nitrocellulose paper due to the gel's instability.
  • This process is known as Southern Blot, named after scientist Sadran Blut.
  • RNA transfer is called Northern, while protein transfer is referred to as Western.
  • Probes are used to complement DNA and RNA, aiding in reading and tagging.
  • DNA fingerprinting reveals unique non-coding sequences in individuals.
  • Genetic differences are identified through DNA sequencing, which can be costly.
  • Repetitive DNA sequences, like satellite DNA, are separated during centrifugation.
  • Polymorphism in satellite DNA forms the basis of DNA fingerprinting.
  • DNA fingerprinting is crucial for identification and paternity testing.
  • Sensitivity in DNA fingerprinting is enhanced through PCR, allowing for forensic and genetic diversity studies.

02:19:36

"Hard work key to success in studying"

  • The speaker emphasizes the importance of hard work and dedication in studying, suggesting completing chapters in a single day and focusing on serious students who show sincerity in their efforts.
  • An invitation is extended for a demo class on 22nd January for a new batch on YouTube, emphasizing the high enrollment rate and success of previous students, encouraging interested individuals to participate in a test on Sunday at 12 noon.
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