The document discusses the structural components of DNA and RNA, including pyrimidines, purines, nucleosides, nucleotides, and phosphodiester linkages. It describes the discovery of DNA's role in heredity and the importance of Chargaff's rules regarding equal ratios of pyrimidine and purine bases in DNA. The structure of DNA proposed by Watson and Crick in 1953 featured complementary base pairing between adenine and thymine and between guanine and cytosine.
De novo and salvage pathway of nucleotides synthesis.pptx✨M.A kawish Ⓜ️
This slides explains Metabolism topic "De novo and salvage pathway of nucleotides synthesis. In which synthesis of Purines and pyrimidines synthesis has been occurred. In last there is a difference between these two pathways.
Pentose phosphate pathway is an alternative pathway to glycolysis and TCA cycle for oxidation of glucose. It is a shunt of glycolysis. It is also known as hexose monophosphate (HMP) shunt or phosphogluconate pathway. It occurs in cytoplasm of both prokaryotes and eukaryotes. While it involves oxidation of glucose, its primary role is anabolic rather than catabolic. It is an important pathway that generates precursors for nucleotide synthesis and is especially important in red blood cells (erythrocytes).
Conformational study of polynucleotideKAUSHAL SAHU
Introduction
History
The conformation of nucleic acid
Types of polynucleotide
DNA- types and conformation of DNA
B- DNA
A-DNA Z-DNA
RNA – types and conformation of RNA
Coding DNA
Non coding DNA
structure of RNA
Primary structure of RNA
Secondary structure of RNA
Tertiary structure of RNA
Analyzing techniques
Conclusion
References
De novo and salvage pathway of nucleotides synthesis.pptx✨M.A kawish Ⓜ️
This slides explains Metabolism topic "De novo and salvage pathway of nucleotides synthesis. In which synthesis of Purines and pyrimidines synthesis has been occurred. In last there is a difference between these two pathways.
Pentose phosphate pathway is an alternative pathway to glycolysis and TCA cycle for oxidation of glucose. It is a shunt of glycolysis. It is also known as hexose monophosphate (HMP) shunt or phosphogluconate pathway. It occurs in cytoplasm of both prokaryotes and eukaryotes. While it involves oxidation of glucose, its primary role is anabolic rather than catabolic. It is an important pathway that generates precursors for nucleotide synthesis and is especially important in red blood cells (erythrocytes).
Conformational study of polynucleotideKAUSHAL SAHU
Introduction
History
The conformation of nucleic acid
Types of polynucleotide
DNA- types and conformation of DNA
B- DNA
A-DNA Z-DNA
RNA – types and conformation of RNA
Coding DNA
Non coding DNA
structure of RNA
Primary structure of RNA
Secondary structure of RNA
Tertiary structure of RNA
Analyzing techniques
Conclusion
References
Glycoprotein, lipoprotein, structure and functionKAUSHAL SAHU
INTRODUCTION
DEFINITION
STRUCTURE
TYPES OF BONDS
N-LINKED GLYCOSYLATION
O-LINKED GLYCOSYLATION
AMOUNT OF CARBOHYDRATES PRESENT IN GLYCOPROTEIN
BIOLOGICAL SIGNIFICANCE AND
FUNCTION
BIOLOGICAL ADVANTAGE OF ADDING OLIGOSACCHARIDES TO PROTEIN
Genetic information, stored in the chromosomes and transmitted to daughter cells through DNA replication, is expressed through transcription to RNA and translation into proteins (polypeptide chains). The pathway of protein synthesis is called translation because the “language” of the nucleotide sequence on the mRNA is translated into the “language” of an amino acid sequence. The process of translation requires a genetic code, through which the information contained in the nucleic acid sequence is expressed to produce a specific sequence of amino acids. Any alteration in the nucleic acid sequence may result in an incorrect amino acid being inserted into the polypeptide chain, potentially causing disease or even death of the organism.
Glycoprotein, lipoprotein, structure and functionKAUSHAL SAHU
INTRODUCTION
DEFINITION
STRUCTURE
TYPES OF BONDS
N-LINKED GLYCOSYLATION
O-LINKED GLYCOSYLATION
AMOUNT OF CARBOHYDRATES PRESENT IN GLYCOPROTEIN
BIOLOGICAL SIGNIFICANCE AND
FUNCTION
BIOLOGICAL ADVANTAGE OF ADDING OLIGOSACCHARIDES TO PROTEIN
Genetic information, stored in the chromosomes and transmitted to daughter cells through DNA replication, is expressed through transcription to RNA and translation into proteins (polypeptide chains). The pathway of protein synthesis is called translation because the “language” of the nucleotide sequence on the mRNA is translated into the “language” of an amino acid sequence. The process of translation requires a genetic code, through which the information contained in the nucleic acid sequence is expressed to produce a specific sequence of amino acids. Any alteration in the nucleic acid sequence may result in an incorrect amino acid being inserted into the polypeptide chain, potentially causing disease or even death of the organism.
Mining is the extraction of valuable minerals or other geological materials from the earth from an orebody, lode, vein, seam, reef or placer deposits which forms the mineralized package of economic interest to the miner.
Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, or created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
A natural disaster is the effect of earths natural hazards, for example flood, tornado, hurricane, volcanic eruption, earthquake, heatwave, or landslide. They can lead to financial, environmental or human losses. The resulting loss depends on the vulnerability of the affected population to resist the hazard, also called their resilience. If these disasters continue it would be a great danger for the earth
Laboratory method for measuring enzyme activity.
Vital for study of enzyme kinetics and enzyme inhibition.
Measurement of enzyme activity – follow the change in concentration of substrate or product – measure reaction rate.
Deciphering reaction mechanism with intermediate trappingDaniel Morton
This module provides an overview of a tool used to gain information on a reaction mechanism; reactive intermediate trapping.
A reactive intermediate is a short-lived, high-energy, highly reactive molecule. When generated in a chemical reaction, it will quickly convert into a more stable molecule. When their existence is indicated, reactive intermediates can help explain how a chemical reaction takes place.
Contributed by:
Shuangyu Ma & Yiling Bi (Undergraduate Students)
University of Utah
2014
Hemoglobin estimation and Blood typing experiment and Vijay Hemmadi
A hemoglobin test measures the amount of hemoglobin in your blood. Hemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your
The ABO group consists of four possibilities: A, B, AB, and O. The Rh type is either positive or negative. Individuals with AB Positive blood are known as universal recipients because they can receive any one of the blood groups or Rh types in a blood transfusion
Determination of protein concentration by Bradford method.pptxVijay Hemmadi
Bradford uses Coomasie Blue which is a dye that binds specifically to proteins. It is very accurate and sensitive, compatible with most buffers, sugars, and chaotropic agents but high concentrations of detergent interfere in the assay
Liposomes-Classification, methods of preparation and application Vijay Hemmadi
liposome preparation and application
A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Liposomes can be filled with drugs, and used to deliver drugs for cancer and other diseases. Membranes are usually made of phospholipids, which are molecules that have a head group and a tail group
Automated sequencing of genomes require automated gene assignment
Includes detection of open reading frames (ORFs)
Identification of the introns and exons
Gene prediction a very difficult problem in pattern recognition
Coding regions generally do not have conserved sequences
Much progress made with prokaryotic gene prediction
Eukaryotic genes more difficult to predict correctly
if your doing fish dissection and need some anatomical information then go through my slides.
in this i have written fish anatomy with its physiological implications
Are you looking for some good journals to publish your data? Then this is the correct time to read my article. I am writing this with the hope of inhibiting you from publishing your data in predatory and fake journals.
These are the following criteria you should know before submitting your manuscript to a journal:
Secondary Structure Prediction of proteins Vijay Hemmadi
Secondary structure prediction has been around for almost a quarter of a century. The early methods suffered from a lack of data. Predictions were performed on single sequences rather than families of homologous sequences, and there were relatively few known 3D structures from which to derive parameters. Probably the most famous early methods are those of Chou & Fasman, Garnier, Osguthorbe & Robson (GOR) and Lim. Although the authors originally claimed quite high accuracies (70-80 %), under careful examination, the methods were shown to be only between 56 and 60% accurate (see Kabsch & Sander, 1984 given below). An early problem in secondary structure prediction had been the inclusion of structures used to derive parameters in the set of structures used to assess the accuracy of the method.
Some good references on the subject:
Introduction to Environment
Global environmental issues
National environmental issues
Food Scarcity in India
water Scarcity in India
Sustained development
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
Follow us on: Pinterest
Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
263778731218 Abortion Clinic /Pills In Harare ,sisternakatoto
263778731218 Abortion Clinic /Pills In Harare ,ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group of receptionists, nurses, and physicians have worked together as a teamof receptionists, nurses, and physicians have worked together as a team wwww.lisywomensclinic.co.za/
CDSCO and Phamacovigilance {Regulatory body in India}NEHA GUPTA
The Central Drugs Standard Control Organization (CDSCO) is India's national regulatory body for pharmaceuticals and medical devices. Operating under the Directorate General of Health Services, Ministry of Health & Family Welfare, Government of India, the CDSCO is responsible for approving new drugs, conducting clinical trials, setting standards for drugs, controlling the quality of imported drugs, and coordinating the activities of State Drug Control Organizations by providing expert advice.
Pharmacovigilance, on the other hand, is the science and activities related to the detection, assessment, understanding, and prevention of adverse effects or any other drug-related problems. The primary aim of pharmacovigilance is to ensure the safety and efficacy of medicines, thereby protecting public health.
In India, pharmacovigilance activities are monitored by the Pharmacovigilance Programme of India (PvPI), which works closely with CDSCO to collect, analyze, and act upon data regarding adverse drug reactions (ADRs). Together, they play a critical role in ensuring that the benefits of drugs outweigh their risks, maintaining high standards of patient safety, and promoting the rational use of medicines.
Adv. biopharm. APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMSAkankshaAshtankar
MIP 201T & MPH 202T
ADVANCED BIOPHARMACEUTICS & PHARMACOKINETICS : UNIT 5
APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMS By - AKANKSHA ASHTANKAR
2. Pyrimidines and Purines
• In order to understand the structure and properties
of DNA and RNA, we need to look at their structural
components.
• We begin with certain heterocyclic aromatic
compounds called pyrimidines and purines.
Dr. Wolf's CHM 424 28- 2
3. Pyrimidines and Purines
• Pyrimidine and purine are the names of the
parent compounds of two types of nitrogen-
containing heterocyclic aromatic compounds.
Dr. Wolf's CHM 424 28- 3
PyrimidinePyrimidine PurinePurine
NN
NN NN
HH
NN
NNNN 11
22
33
44
5577
88
99
11
22
33
44
55
66
66
4. Pyrimidines and Purines
• Amino-substituted derivatives of pyrimidine and
purine have the structures expected from their
names.
Dr. Wolf's CHM 424 28- 4
4-Aminopyrimidine4-Aminopyrimidine 6-Aminopurine6-Aminopurine
HH
NN NN
NNNN
HH
HH
NNHH22
NN
NN
HH
HH
HHHH22NN
5. Pyrimidines and Purines
• But hydroxy-substituted pyrimidines and purines
exist in keto, rather than enol, forms.
Dr. Wolf's CHM 424 28- 5
enolenol
NN
NN
HH
HH
HHHHOO
NN
NN
HH
HH
HHOO
HH
ketoketo
6. Pyrimidines and Purines
• But hydroxy-substituted pyrimidines and purines
exist in keto, rather than enol, forms.
Dr. Wolf's CHM 424 28- 6
HH
NN NN
NNNN
HH
HH
OOHH
enolenol ketoketo
HH
NN NN
NN
HH
HH
OO
HHNN
7. Important Pyrimidines
• Pyrimidines that occur in DNA are cytosine and
thymine. Cytosine and uracil are the pyrimidines
in RNA.
Dr. Wolf's CHM 424 28- 7
HHNN
NN
HH
OO
OO
UracilUracil
HHNN
NN
HH
OO
OO
CHCH33
ThymineThymine
HHNN
NN
HH
NNHH22
OO
CytosineCytosine
8. Important Purines
• Adenine and guanine are the principal purines of
both DNA and RNA.
Dr. Wolf's CHM 424 28- 8
AdenineAdenine
NN
NN
NNHH22
NN
NN
HH
GuanineGuanine
OO
HHNN
NN
HH
NN
NN
HH22NN
9. Caffeine and Theobromine
• Caffeine (coffee) and theobromine (coffee and
tea) are naturally occurring purines.
Dr. Wolf's CHM 424 28- 9
CaffeineCaffeine
NN
NN
OO
NN
NN
HH33CC
OO
CHCH33
CHCH33
TheobromineTheobromine
OO
HHNN
NNNN
NN
CHCH33
CHCH33
OO
10. Nucleosides
• The classical structural definition is that a nucleoside
is a pyrimidine or purine N-glycoside of D-
ribofuranose or 2-deoxy-D-ribofuranose.
• Informal use has extended this definition to apply to
purine or pyrimidine N-glycosides of almost any
carbohydrate.
• The purine or pyrimidine part of a nucleoside is
referred to as a purine or pyrimidine base.
Dr. Wolf's CHM 424 28- 10
11. Table 28.2
• Pyrimidine nucleosides
Dr. Wolf's CHM 424 28- 11
NNHH22
HOHO OHOH
OOHOCHHOCH22
OO
NN
NN
Cytidine occurs in RNA;Cytidine occurs in RNA;
its 2-deoxy analog occurs in DNAits 2-deoxy analog occurs in DNA
CytidineCytidine
12. Table 28.2
• Pyrimidine nucleosides
Dr. Wolf's CHM 424 28- 12
OO
NN
NNHH
OO
HOHO
OO
HH33CC
HOCHHOCH22
Thymidine occurs in DNAThymidine occurs in DNA
ThymidineThymidine
13. Table 28.2
• Pyrimidine nucleosides
Dr. Wolf's CHM 424 28- 13
HOCHHOCH22
OO
NN
NNHH
OO
OHOHHOHO
OO
Uridine occurs in RNAUridine occurs in RNA
UridineUridine
14. Table 28.2
• Purine nucleosides
Dr. Wolf's CHM 424 28- 14
AdenosineAdenosine
Adenosine occurs in RNA;Adenosine occurs in RNA;
its 2-deoxy analog occurs in DNAits 2-deoxy analog occurs in DNA
HOCHHOCH22 OO
OHOHHOHO
NN
NN
NN
NHNH22
NN
15. Table 28.2
• Purine nucleosides
Dr. Wolf's CHM 424 28- 15
GuanosineGuanosine
Guanosine occurs in RNA;Guanosine occurs in RNA;
its 2-deoxy analog occurs in DNAits 2-deoxy analog occurs in DNA
HOCHHOCH22
NN
NHNH
OO
OO
HOHO
NN NHNH22
NN
OHOH
16. Adenosine 5'-Monophosphate (AMP)
• Adenosine 5'-monophosphate (AMP) is also called
5'-adenylic acid.
Dr. Wolf's CHM 424 28- 16
OCHOCH22PPHOHO
OO
HOHO
OO
OHOHHOHO
NN
NN
NN
NHNH22
NN
5'5'
1'1'
2'2'3'3'
4'4'
18. Adenosine Triphosphate (ATP)
• ATP is an important molecule in several
biochemical processes including:
energy storage (Sections 28.4-28.5)
phosphorylation
Dr. Wolf's CHM 424 28- 18
OOPP
OO
HOHO
OO OCHOCH22PP
OO
HOHO
OO
OHOHHOHO
NN
NN
NN
NHNH22
NN
PP
OO
HOHO
HOHO
19. ATP and Phosphorylation
Dr. Wolf's CHM 424 28- 19
ATPATP ++
hexokinasehexokinaseThis is the first step in theThis is the first step in the
metabolism of glucose.metabolism of glucose.
ADPADP ++
OO
OHOH
HOHO
HOHO
HOHO
(HO)(HO)22POCHPOCH22
OO
HOCHHOCH22
OO
OHOH
HOHO
HOHO
HOHO
20. cAMP and cGMP
• Cyclic AMP and cyclic GMP are
"second messengers" in many
biological processes. Hormones
(the "first messengers")
stimulate the formation of
cAMP and cGMP.
Dr. Wolf's CHM 424 28- 20
Cyclic adenosine monophosphate (cAMP)Cyclic adenosine monophosphate (cAMP)
CHCH22 OO
OHOH
NN
NN
NN
NHNH22
NN
OO
OO
PP
OO
HOHO
21. cAMP and cGMP
• Cyclic AMP and cyclic GMP are
"second messengers" in many
biological processes. Hormones
(the "first messengers")
stimulate the formation of
cAMP and cGMP.
Dr. Wolf's CHM 424 28- 21
OO
OO
PP
OO
HOHO
Cyclic guanosine monophosphate (cGMP)Cyclic guanosine monophosphate (cGMP)
CHCH22
NN
NHNH
OO
OO
NN NHNH22
NN
OHOH
22. Bioenergetics
• Bioenergetics is the thermodynamics of biological
processes.
• Emphasis is on free energy changes (∆G)
• when ∆G is negative, reaction is
spontaneous in the direction written
• when ∆G is 0, reaction is at equilibrium
• when ∆G is positive, reaction is not
spontaneous in direction written
Dr. Wolf's CHM 424 28- 22
23. Standard Free Energy (∆G°)
• Sign and magnitude of ∆G depends on what the
reactants and products are and their
concentrations.
• In order to focus on reactants and products,
define a standard state.
• The standard concentration is 1 M (for a reaction
in homogeneous solution).
• ∆G in the standard state is called the standard
free-energy change and given the symbol ∆G°.
Dr. Wolf's CHM 424 28- 23
mmA(A(aqaq)) nnB(B(aqaq))
24. Standard Free Energy (∆G°)
• Exergonic: An exergonic reaction is one for which
the sign of ∆G° is negative.
• Endergonic: An exergonic reaction is one for
which the sign of ∆G° is positive.
Dr. Wolf's CHM 424 28- 24
mmA(A(aqaq)) nnB(B(aqaq))
25. Standard Free Energy (∆G°)
• It is useful to define a special standard state for
biological reactions.
• This special standard state is one for which the
pH = 7.
• The free-energy change for a process under
these conditions is symbolized as ∆G°'.
Dr. Wolf's CHM 424 28- 25
mmA(A(aqaq)) nnB(B(aqaq))
26. Hydrolysis of ATP
• ∆G°' for hydrolysis of ATP to ADP is –31 kJ/mol
• Relative to ADP + HPO4
2–
, ATP is a "high-energy"
compound.
• When coupled to some other process, the
conversion of ATP to ADP can provide the free
energy to transform an endergonic process to an
exergonic one.
Dr. Wolf's CHM 424 28- 26
ATP + HATP + H22OO ADP + HPOADP + HPO44
2–2–
27. Glutamic Acid to Glutamine
Dr. Wolf's CHM 424 28- 27
++ NNHH44
++––
OCCHOCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
+ H+ H22OOHH22NNCCHCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
∆∆GG°' = +14 kJ°' = +14 kJ Reaction is endergonicReaction is endergonic
28. Glutamic Acid to Glutamine
Dr. Wolf's CHM 424 28- 28
++ NNHH44
++––
OCCHOCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
Reaction becomes exergonicReaction becomes exergonic
when coupled to the hydrolysiswhen coupled to the hydrolysis
of ATPof ATP
+ ATP+ ATP
+ HPO+ HPO44
2–2–
HH22NNCCHCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
∆∆GG°' = –17 kJ°' = –17 kJ
+ ADP+ ADP
29. Glutamic Acid to Glutamine
Dr. Wolf's CHM 424 28- 29
––
OCCHOCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
Mechanism involvesMechanism involves
phosphorylation of glutamicphosphorylation of glutamic
acidacid
+ ATP+ ATP
OOCCHCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
+ ADP+ ADPPP
OO
––
OO
––
OO
30. Glutamic Acid to Glutamine
Dr. Wolf's CHM 424 28- 30
followed by reaction offollowed by reaction of
phosphorylated glutamic acidphosphorylated glutamic acid
with ammoniawith ammonia
HH22NNCCHCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
+ HPO+ HPO44
2–2–
OOCCHCCH22CHCH22CHCOCHCO––
++
NHNH33
OO OO
++ NNHH33
PP
OO
––
OO
––
OO
31. Phosphodiesters
• A phosphodiester linkage between two
nucleotides is analogous to a peptide bond
between two amino acids.
• Two nucleotides joined by a phosphodiester
linkage gives a dinucleotide.
Three nucleotides joined by two
phosphodiester linkages gives a trinucleotide, etc.
(See next slide)
• A polynucleotide of about 50 or fewer
nucleotides is called an oligonucleotide.
Dr. Wolf's CHM 424 28- 31
32. Fig. 28.1
The
trinucleotide
ATG
• phosphodiest
er linkages
between 3' of
one
nucleotide
and 5' of the
next
Dr. Wolf's CHM 424 28- 32
3'
5'
HOCH2
O
O
N
N
N
N
P OCH2O
HO
NH2
OCH2
O
NH
N
N
N
HO
O
NH2
HO
O P
H3C
O
O
O
O
NH
N
AA
TT
GG
free 5' endfree 5' end
free 3' endfree 3' end
33. Nucleic Acids
• Nucleic acids first isolated in 1869 (Johann
Miescher)
• Oswald Avery discovered (1945) that a substance
which caused a change in the genetically
transmitted characteristics of a bacterium was
DNA.
• Scientists revised their opinion of the function of
DNA and began to suspect it was the major
functional component of genes.
Dr. Wolf's CHM 424 28- 33
34. Composition of DNA
• Erwin Chargaff (Columbia Univ.) studied DNAs
from various sources and analyzed the
distribution of purines and pyrimidines in them.
• The distribution of the bases adenine (A), guanine
(G), thymine (T), and cytosine (C) varied among
species.
• But the total purines (A and G) and the total
pyrimidines (T and C) were always equal.
• Moreover: %A = %T, and %G = %C
Dr. Wolf's CHM 424 28- 34
35. Composition of Human DNA
• Adenine (A) 30.3% Thymine (T) 30.3%
• Guanine (G) 19.5% Cytosine (C) 19.9%
• Total purines: 49.8% Total pyrimidines: 50.1%
Dr. Wolf's CHM 424 28- 35
For example:For example:
PurinePurine PyrimidinePyrimidine
36. Structure of DNA
• James D. Watson and Francis H. C. Crick proposed
a structure for DNA in 1953.
• Watson and Crick's structure was based on:
•Chargaff's observations
•X-ray crystallographic data of Maurice
Wilkins and Rosalind Franklin
•Model building
Dr. Wolf's CHM 424 28- 36
37. Base Pairing
• Watson and Crick proposed that A and T were
present in equal amounts in DNA because of
complementary hydrogen bonding.
Dr. Wolf's CHM 424 28- 37
2-deoxyribose2-deoxyribose N
NN
N N
H
H
N
N
O CH3
O
H
2-deoxyribose2-deoxyribose
AA TT
38. Base Pairing
• Watson and Crick proposed that A and T were
present in equal amounts in DNA because of
complementary hydrogen bonding.
Dr. Wolf's CHM 424 28- 38
39. Base Pairing
• Likewise, the amounts of G and C in DNA were
equal because of complementary hydrogen
bonding.
Dr. Wolf's CHM 424 28- 39
N
NN
N O
N
H
H
H
N
N
N
O
H
H
2-deoxyribose2-deoxyribose
2-deoxyribose2-deoxyribose
GG CC
40. Base Pairing
• Likewise, the amounts of G and C in DNA were
equal because of complementary hydrogen
bonding.
Dr. Wolf's CHM 424 28- 40
41. The DNA Duplex
• Watson and Crick proposed a double-stranded
structure for DNA in which a purine or pyrimidine
base in one chain is hydrogen bonded to its
complement in the other.
• •Gives proper Chargaff ratios (A=T and G=C)
• •Because each pair contains one purine and
one pyrimidine, the A---T and G---C distances
between strands are approximately equal.
• •Complementarity between strands suggests
a mechanism for copying genetic information.
Dr. Wolf's CHM 424 28- 41
42. Fig. 28.4
• Two antiparallel
strands of DNA
are paired by
hydrogen bonds
between purine
and pyrimidine
bases.
Dr. Wolf's CHM 424 28- 42
O
O
Ğ
O
Ğ
O
Ğ
O
O
O
O
O
OP
O
O
P O
O
O
P O
O
O
O
O
O
Ğ
O
Ğ
O
Ğ
O
O
O
O
O P
O
O
PO
O
O
PO
O
O
C G
AT
AT
CG
3'
5'
5'
5'
5' 5'
5'
5'
5'
3'
3'
3'
3'
3'
3'
3'
43. Fig. 28.5
• Helical structure
of DNA. The
purine and
pyrimidine bases
are on the inside,
sugars and
phosphates on
the outside.
Dr. Wolf's CHM 424 28- 43
44. DNA is coiled
• A strand of DNA is too long (about 3 cm in length)
to fit inside a cell unless it is coiled.
• Random coiling would reduce accessibility to
critical regions.
• Efficient coiling of DNA is accomplished with the
aid of proteins called histones.
Dr. Wolf's CHM 424 28- 44
45. Histones
• Histones are proteins rich in basic amino acids
such as lysine and arginine.
• Histones are positively charged at biological pH.
DNA is negatively charged.
• DNA winds around histone proteins to form
nucleosomes.
Dr. Wolf's CHM 424 28- 45
46. Histones
Dr. Wolf's CHM 424 28- 46
Each nucleosome contains one and three-quartersEach nucleosome contains one and three-quarters
turns of coil = 146 base pairs.turns of coil = 146 base pairs.
Linker contains about 50 base pairs.Linker contains about 50 base pairs.
47. Histones
Dr. Wolf's CHM 424 28- 47
NucleosomeNucleosome == Histone proteinsHistone proteins + Supercoiled DNA+ Supercoiled DNA
48. Fig. 28.8 DNA Replication
• The DNA to be copied is a double helix, shown here as flat
for clarity.
Dr. Wolf's CHM 424 28- 48
A T C C G T A G G A T T A GC
5'3'
AT G CG A T C C T G A A T C
3'5'
The two strands begin to unwind. (next slide)
49. Fig. 28.8 DNA Replication
• Each strand will become a template for construction of its
complement.
Dr. Wolf's CHM 424 28- 49
A T C C G T A G
G
A
T
T A
G
C
AT G CG A
T
C
C T
G
A
A
T C
3'
5'
5'
3'
50. Fig. 28.8 DNA Replication
• Two new strands form as nucleotides that are
complementary to those of the original strands are joined
by phosphodiester linkages.
Dr. Wolf's CHM 424 28- 50
A'
T'
G'
C'
A T C C G T
A G
G A
T
T A G
C
5'
3'
AT G CG A
T
C
C T
G
A
A
T C
5'
5'
T' A'
3'
3'
leading strand
lagging strand
3'
5'
C'T'
A'A'
Polynucleotide chains grow in
the 5'-3' direction—continuous in
the leading strand, discontinuous
in the lagging strand.
51. Fig. 28.8 DNA Replication
• Two duplex DNAs result, each of which is identical to the
original DNA.
Dr. Wolf's CHM 424 28- 51
A' T' C' C' G' T' A' G' G' A' T' T' A' G'C'
5'3'
AT G CG A T C C T G A A T C
3'5'
A T C C G T A G G A T T A GC
5'3'
A'T' G' C'G' A' T' C' C' T' G' A' A' T' C'
3'5'
+
52. Elongation of the growing DNA chain
• The free 3'-OH group of the growing DNA chain
reacts with the 5'-triphosphate of the appropriate
nucleotide.
Dr. Wolf's CHM 424 28- 52
55. DNA and Protein Biosynthesis
• According to Crick, the "central dogma" of
molecular biology is:
"DNA makes RNA makes protein."
• Three kinds of RNA are involved.
messenger RNA (mRNA)
transfer RNA (tRNA)
ribosomal RNA (rRNA)
• There are two main stages.
transcription
translation
Dr. Wolf's CHM 424 28- 55
56. Transcription
• In transcription, a strand of DNA acts as a
template upon which a complementary RNA is
biosynthesized.
• This complementary RNA is messenger RNA
(mRNA).
• Mechanism of transcription resembles mechanism
of DNA replication.
• Transcription begins at the 5' end of DNA and is
catalyzed by the enzyme RNA polymerase.
Dr. Wolf's CHM 424 28- 56
57. Fig. 28.10 Transcription
Dr. Wolf's CHM 424 28- 57
Only a section of about 10 base pairs in the DNAOnly a section of about 10 base pairs in the DNA
is unwound at a time. Nucleotides complementaryis unwound at a time. Nucleotides complementary
to the DNA are added to form mRNA.to the DNA are added to form mRNA.
58. The Genetic Code
• The nucleotide sequence of mRNA codes for the
different amino acids found in proteins.
• There are three nucleotides per codon.
• There are 64 possible combinations of A, U, G, and
C.
• The genetic code is redundant. Some proteins are
coded for by more than one codon.
Dr. Wolf's CHM 424 28- 58
59. Table 28.3 (p 1175)
• UUU Phe UCU Ser UAU Tyr UGU Cys U
• UUC Phe UCC Ser UAC Tyr UGC Cys C
• UUA Leu UCA Ser UAA Stop UGA Stop A
• UUG Leu UCG Ser UAG Stop UCG Trp G
• U
• C
• A
• G
• U
• C
• A
• G
• U
• C
• A
• G
Dr. Wolf's CHM 424 28- 59
UU CC AA GG
UU
CC
AA
GG
First letterFirst letter
Second letterSecond letter
Third letterThird letter
60. • UUU Phe UCU Ser UAU Tyr UGU Cys U
• UUC Phe UCC Ser UAC Tyr UGC Cys C
• UUA Leu UCA Ser UAA Stop UGA Stop A
• UUG Leu UCG Ser UAG Stop UCG Trp G
• CUU Leu CCU Pro CAU His CGU Arg U
• CUC Leu CCC Pro CAC His CGC Arg C
• CUA Leu CCA Pro CAA Gln CGA Arg A
• CUG Leu CCG Pro CAG Gln CCG Arg G
• AUU Ile ACU Thr AAU Asn AGU Ser U
• AUC Ile ACC Thr AAC Asn AGC Ser C
• AUA Ile ACA Thr AAA Lys AGA Arg A
• AUG Met ACG Thr AAG Lys ACG Arg G
• GUU Val GCU Ala GAU Asp GGU Gly U
• GUC Val GCC Ala GAC Asp GGC Gly C
• GUA Val GCA Ala GAA Glu GGA Gly A
• GUG Val GCG Ala GAG Glu GCG Gly G
Dr. Wolf's CHM 424 28- 60
UU CC AA GG
UU
CC
AA
GG
61. • U
• C
• UAA Stop UGA Stop A
• UAG Stop G
• U
• C
• A
• G
• AUU Ile ACU Thr AAU Asn AGU Ser U
• AUC Ile ACC Thr AAC Asn AGC Ser C
• AUA Ile ACA Thr AAA Lys AGA Arg A
• AUG Met ACG Thr AAG Lys ACG Arg G
• U
• C
• A
• G
Dr. Wolf's CHM 424 28- 61
UU CC AA GG
UU
CC
AA
GG
AUG is the "start" codon. Biosynthesis of all
proteins begins with methionine as the first amino
acid. This methionine is eventually removed after
protein synthesis is complete.
UAA, UGA, and UAG
are "stop" codons that
signal the end of the
polypeptide chain.
62. Transfer tRNA
• There are 20 different tRNAs, one for each amino
acid.
• Each tRNA is single stranded with a CCA triplet at
its 3' end.
• A particular amino acid is attached to the tRNA by
an ester linkage involving the carboxyl group of
the amino acid and the 3' oxygen of the tRNA.
Dr. Wolf's CHM 424 28- 62
63. Transfer RNA
• Example—Phenylalanine transfer RNA
Dr. Wolf's CHM 424 28- 63
One of the mRNA codons for phenylalanine is:One of the mRNA codons for phenylalanine is:
UUCUUC5'5' 3'3'
AAGAAG3'3' 5'5'
The complementary sequence in tRNA is calledThe complementary sequence in tRNA is called
thethe anticodonanticodon..
65. Ribosomal RNA
• Most of the RNA in a cell is ribosomal RNA
• Ribosomes are the site of protein synthesis. They
are where translation of the mRNA sequence to
an amino acid sequence occurs.
• Ribosomes are about two-thirds RNA and one-
third protein.
• It is believed that the ribosomal RNA acts as a
catalyst—a ribozyme.
Dr. Wolf's CHM 424 28- 65
66. Protein Biosynthesis
• During translation the protein is synthesized
beginning at its N-terminus.
• mRNA is read in its 5'-3' direction
begins at the start codon AUG
ends at stop codon (UAA, UAG, or UGA)
Dr. Wolf's CHM 424 28- 66
67. Fig. 28.12 Translation
• Reaction that occurs is
nucleophilic acyl
substitution. Ester is
converted to amide.
Dr. Wolf's CHM 424 28- 67
Methionine at N-terminusMethionine at N-terminus
is present as its N-formylis present as its N-formyl
derivative.derivative.
69. Fig. 28.12 Translation
• Ester at 3' end of
alanine tRNA is Met-Ala.
• Process continues along
mRNA until stop codon
is reached.
Dr. Wolf's CHM 424 28- 69
70. AIDS
• Acquired immune deficiency syndrome
• More than 22 million people have died from AIDS
since disease discovered in 1980s
• Now fourth leading cause of death worldwide and
leading cause of death in Africa (World Health
Organization)
Dr. Wolf's CHM 424 28- 70
71. HIV
• Virus responsible for AIDS in people is HIV (human
immunodeficiency virus)
• Several strains of HIV designated HIV-1, HIV-2, etc.
• HIV is a retrovirus. Genetic material is RNA, not
DNA.
Dr. Wolf's CHM 424 28- 71
72. HIV
• HIV inserts its own RNA and an enzyme (reverse
transcriptase) in T4 lymphocyte cell of host.
• Reverse transcriptase catalyzes the formation of
DNA complementary to the HIV RNA.
• HIV reproduces and eventually infects other T4
lympocytes.
• Ability of T4 cells to reproduce decreases,
interfering with bodies ability to fight infection.
Dr. Wolf's CHM 424 28- 72
73. AIDS Drugs
• AZT and ddI are two drugs used against AIDS that
delay onset of symptoms.
Dr. Wolf's CHM 424 28- 73
O
NN OO
NN33
OO
HH33CC
HOCHHOCH22
OO
NNHH
AZTAZT
O
NN
OO
HOCHHOCH22
OO
NNHH
ddIddI
NN
NN
HH
HH HH
HH
74. AIDS Drugs
• Protease inhibitors are used in conjunction with
other AIDS drugs.
• Several HIV proteins are present in the same
polypeptide chain and must be separated from
each other in order to act.
• Protease inhibitors prevent formation of HIV
proteins by preventing hydrolysis of polypeptide
that incorporates them.
Dr. Wolf's CHM 424 28- 74
75. DNA Sequencing
• Restriction enzymes cleave the polynucleotide to
smaller fragments.
• These smaller fragments (100-200 base pairs) are
sequenced.
• The two strands are separated.
Dr. Wolf's CHM 424 28- 75
76. DNA Sequencing
• Single stranded DNA divided in four portions.
• Each tube contains adenosine, thymidine,
guanosine, and cytidine plus the triphosphates of
their 2'-deoxy analogs.
Dr. Wolf's CHM 424 28- 76
POCHPOCH22
OHOH
OOOO
OO
OHOH
PP
OO
OHOH
PP
OO
HOHO basebase
HHHHOO
OO
77. DNA Sequencing
• The first tube also contains the 2,'3'-dideoxy analog of
adenosine triphosphate (ddATP); the second tube the
2,'3'-dideoxy analog of thymidine triphosphate (ddTTP),
the third contains ddGTP, and the fourth ddCTP.
Dr. Wolf's CHM 424 28- 77
POCHPOCH22
OHOH
OOOO
OO
OHOH
PP
OO
OHOH
PP
OO
HOHO basebase
HHHH
OO
78. DNA Sequencing
• Each tube also contains a "primer," a short section
of the complementary DNA strand, labeled with
radioactive phosphorus (32
P).
• DNA synthesis takes place, producing a
complementary strand of the DNA strand used as
a template.
• DNA synthesis stops when a dideoxynucleotide is
incorporated into the growing chain.
Dr. Wolf's CHM 424 28- 78
79. DNA Sequencing
• The contents of each tube are separated by
electrophoresis and analyzed by autoradiography.
• There are four lanes on the electrophoresis gel.
• Each DNA fragment will be one nucleotide longer
than the previous one.
Dr. Wolf's CHM 424 28- 79
81. Figure 27.29
Dr. Wolf's CHM 424 28- 81
TT
TTGG
TTGGAA
TTGGAACC
TTGGAACCAA
TTGGAACCAATT
TTGGAACCAATTAA
TTGGAACCAATTAACC
TTGGAACCAATTAACCGG
TTGGAACCAATTAACCGGTT
ddAddA ddTddT ddGddG ddCddC
AA
AACC
AACCTT
AACCTTGG
AACCTTGGTT
AACCTTGGTTAA
AACCTTGGTTAATT
AACCTTGGTTAATTGG
AACCTTGGTTAATTGGCC
AACCTTGGTTAATTGGCCAA
Sequence ofSequence of
fragmentfragment
Sequence ofSequence of
original DNAoriginal DNA
82. Human Genome Project
• In 1988 National Research Council (NRC)
recommended that the U.S. undertake the
mapping and sequencing of the human genome.
• International Human Genome Sequencing
Consortium (led by U.S. NIH) and Celera Genomics
undertook project. Orginally competitors, they
agreed to coordinate efforts and published draft
sequences in 2001.
Dr. Wolf's CHM 424 28- 82
83. DNA Profiling
• DNA sequencing involves determining the nucleotide
sequence in DNA.
• The nucleotide sequence in regions of DNA that code
for proteins varies little from one individual to
another, because the proteins are the same.
• Most of the nucleotides in DNA are in "noncoding"
regions and vary significantly among individuals.
• Enzymatic cleavage of DNA give a mixture of
polynucleotides that can be separated by
electrophoresis to give a "profile" characteristic of a
single individual.Dr. Wolf's CHM 424 28- 83
84. PCR
• When a sample of DNA is too small to be
sequenced or profiled, the polymerase chain
reaction (PCR) is used to make copies ("amplify")
portions of it.
• PCR amplifies DNA by repetitive cycles of the
following steps.
• 1. Denaturation
2. Annealing ("priming")
3. Synthesis ("extension" or "elongation")
Dr. Wolf's CHM 424 28- 84
85. Dr. Wolf's CHM 424 28- 85
Target regionTarget region
((aa) Consider double-stranded DNA containing) Consider double-stranded DNA containing
a polynucleotide sequence (the target region)a polynucleotide sequence (the target region)
that you wish to amplify.that you wish to amplify.
((bb) Heating the DNA to about 95°C causes the) Heating the DNA to about 95°C causes the
strands to separate. This is the denaturationstrands to separate. This is the denaturation
step.step.
86. Dr. Wolf's CHM 424 28- 86
((bb) Heating the DNA to about 95°C causes the) Heating the DNA to about 95°C causes the
strands to separate. This is the denaturationstrands to separate. This is the denaturation
step.step.
((cc) Cooling the sample to ~60°C causes one) Cooling the sample to ~60°C causes one
primer oligonucleotide to bind to one strand andprimer oligonucleotide to bind to one strand and
the other primer to the other strand. This is thethe other primer to the other strand. This is the
annealing step.annealing step.
87. Dr. Wolf's CHM 424 28- 87
((cc) Cooling the sample to ~60°C causes one) Cooling the sample to ~60°C causes one
primer oligonucleotide to bind to one strand andprimer oligonucleotide to bind to one strand and
the other primer to the other strand. This is thethe other primer to the other strand. This is the
annealing step.annealing step.
((dd) In the presence of four DNA nucleotides and) In the presence of four DNA nucleotides and
the enzyme DNA polymerase, the primer isthe enzyme DNA polymerase, the primer is
extended in its 3' direction. This is the synthesisextended in its 3' direction. This is the synthesis
step and is carried out at 72°C.step and is carried out at 72°C.
88. Dr. Wolf's CHM 424 28- 88
This completes one cycle of PCR.This completes one cycle of PCR.
((dd) In the presence of four DNA nucleotides and) In the presence of four DNA nucleotides and
the enzyme DNA polymerase, the primer isthe enzyme DNA polymerase, the primer is
extended in its 3' direction. This is the synthesisextended in its 3' direction. This is the synthesis
step and is carried out at 72°C.step and is carried out at 72°C.
89. Dr. Wolf's CHM 424 28- 89
This completes one cycle of PCR.This completes one cycle of PCR.
((ee) The next cycle begins with the denaturation) The next cycle begins with the denaturation
of the two DNA molecules shown. Both areof the two DNA molecules shown. Both are
then primed as before.then primed as before.
90. Dr. Wolf's CHM 424 28- 90
((ee) The next cycle begins with the denaturation) The next cycle begins with the denaturation
of the two DNA molecules shown. Both areof the two DNA molecules shown. Both are
then primed as before.then primed as before.
((ff) Elongation of the primed fragments completes) Elongation of the primed fragments completes
the second PCR cycle.the second PCR cycle.
91. Dr. Wolf's CHM 424 28- 91
((ff) Elongation of the primed fragments completes) Elongation of the primed fragments completes
the second PCR cycle.the second PCR cycle.
((gg) Among the 8 DNAs formed in the second) Among the 8 DNAs formed in the second
cycle are two having the structure shown.cycle are two having the structure shown.
92. Dr. Wolf's CHM 424 28- 92
The two contain only the target region andThe two contain only the target region and
and are the ones that increase disproportionatelyand are the ones that increase disproportionately
in subsequent cycles.in subsequent cycles.
((gg) Among the 8 DNAs formed in the second) Among the 8 DNAs formed in the second
cycle are two having the structure shown.cycle are two having the structure shown.