Nucleotides are the building blocks of nucleic acids and consist of a nitrogenous base, a pentose sugar, and a phosphate group. Nucleotides play key roles as the monomers of nucleic acids DNA and RNA, as well as functioning as energy carriers like ATP and cofactors like NAD. Nucleic acids such as DNA contain the genetic information through base pairing and various structures enable different functions like protein synthesis and catalysis.
chemistry of nucleic acids,
history --> Discovered by JOHANN FRIEDRICH MIESCHER
central dogma of life
components of nucleic acids-->Nitrogenous base +pentose sugar +phosphate group.
structure of nucleotides --> purines and pyrimidens
minor bases in nucleic acids are 5-methylcytosine,N4-acetylcytosine, N6-methylsdenine, N6,N6-dimethyladenine, pseudouracil.
Biologically importanat Bases-->Hypoxanthine, Xanthine, uric acid.
Purines bases of plant --> caffeine,theophylline, theobromine
Nucleic acids are biopolymers, or small biomolecules, essential to all known forms of life. They are composed of nucleotides, which are monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. If the sugar is a compound ribose, the polymer is RNA (ribonucleic acid); if the sugar is derived from ribose as deoxyribose, the polymer is DNA(deoxyribonucleic acid).
chemistry of nucleic acids,
history --> Discovered by JOHANN FRIEDRICH MIESCHER
central dogma of life
components of nucleic acids-->Nitrogenous base +pentose sugar +phosphate group.
structure of nucleotides --> purines and pyrimidens
minor bases in nucleic acids are 5-methylcytosine,N4-acetylcytosine, N6-methylsdenine, N6,N6-dimethyladenine, pseudouracil.
Biologically importanat Bases-->Hypoxanthine, Xanthine, uric acid.
Purines bases of plant --> caffeine,theophylline, theobromine
Nucleic acids are biopolymers, or small biomolecules, essential to all known forms of life. They are composed of nucleotides, which are monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. If the sugar is a compound ribose, the polymer is RNA (ribonucleic acid); if the sugar is derived from ribose as deoxyribose, the polymer is DNA(deoxyribonucleic acid).
The slide has some brief introduction to nucleotide chemistry, History, General features of nucleotides, Nomenclature, Individual properties of bases, Classification
and Synthetic analogues of biomedical importance.
RNA- A polymer of ribonucleotides, is a single stranded structure. There are three major types of RNA- m RNA,t RNA and r RNA. Besides that there are small nuclear,micro RNAs, small interfering and heterogeneous RNAs. Each of them has a specific structure and performs a specific function.
The slide has some brief introduction to nucleotide chemistry, History, General features of nucleotides, Nomenclature, Individual properties of bases, Classification
and Synthetic analogues of biomedical importance.
RNA- A polymer of ribonucleotides, is a single stranded structure. There are three major types of RNA- m RNA,t RNA and r RNA. Besides that there are small nuclear,micro RNAs, small interfering and heterogeneous RNAs. Each of them has a specific structure and performs a specific function.
This is a lecture slide for MBBS, BDS, paramedical as well as for those who are interested in molecular biology, molecular life sciences, biochemistry, medical biochemistry, general biochemistry etc.
For the more elucidated and connected information, try to refer to the nucleic acids slides.
Each month, join us as we highlight and discuss hot topics ranging from the future of higher education to wearable technology, best productivity hacks and secrets to hiring top talent. Upload your SlideShares, and share your expertise with the world!
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Nucleic acid-DNA and RNA
Gene-part of DNA
Functions of DNA
RNA-Functions, different types of RNA-Ribosomal RNAs (rRNAs), Messenger RNAs (mRNAs), Transfer RNAs (tRNAs)-Other RNA-Small nuclear RNA (snRNA), Micro RNA (miRNA), Small interfering RNA (siRNA), Heterogenous RNA (hnRNA).
Nucleic acid-nucleotides-nucleoside
Components of nucleotide-a nitrogenous (nitrogen-containing) base (pyrimidine and purine), (2) a pentose, and (3) a phosphate
Structure of pentose sugar, and 5 major bases (cytosine, thymine, uracil-pyrimidine bases and adenine, guanine-purine bases).
Deoxyribonucleotides and Ribo nucleotides-Molecular structure of deoxyadenosine monophosphate (dAMP), deoxyguanosine monophosphate (dGMP), deoxythymidine monophosphate (dTMP), deoxycytidine monophosphate (dCMP) and Adenosine monophosphate (AMP), Guanosine monophosphate (GMP), Cytosine monophosphate (CMP) and Uridine monophosphate (UMP), Watson crick base pairing, Hoogsteen base pairing,
Helical structure-Heterocylic N -Glycosides, Syn and Anti Conformers, detailed structure of single strand and double stranded DNA.
DNA Nucleotides and Tautomeric Form-Tautomers of Adenine, Cytosine, Guanine, and Thymine
Template strand, non coding strand and coding strand
Hydrogen bonds, phosphodiester linkage, hydrolysis of DNA and RNA.
Different forms of DNA-A, B, and Z forms.
Palindrome sequence, Linear DNA, Cruciform DNA, H DNA (Triplex DNA), Denaturation of DNA, Hyperchromicity, Tm, Renaturation of DNA, Tertiary structure of DNA, Difference of DNA and RNA, RNA structural elements, primary. secondary and tertiary structure of RNA. Detailed structure and functions of tRNA, mRNA, rRNA, miRNA, siRNA, hn RNA, snRNA.
Nucleic acid hybridization, C0t analysis, Buoyant density of DNA, Isopycnic centrifugation.
The skin is divided into two parts: the superficial part, the
epidermis; and the deep part, the dermis (Fig. 1.4). The
epidermis is a stratified epithelium whose cells become flat
tened as they mature and rise to the surface. On the palms of
the hands and the soles of the feet, the epidermis is extremely
thick, to withstand the wear and tear that occurs in these
regions. In other areas of the body, for example, on the ante
rior surface of the arm and forearm, it is thin. The dermis is
composed of dense connective tissue containing many blood
vessels, lymphatic vessels, and nerves. It shows considerable
variation in thickness in different parts of the body, tending
to be thinner on the anterior than on the posterior surface.
It is thinner in women than in men. The dermis of the skin
is connected to the underlying deep fascia or bones by the
superficial fascia, otherwise known as subcutaneous tissue.
The skin over joints always folds in the same place, the
SKIN CREASES (Fig. 1.5). At these sites, the skin is thinner
than elsewhere and is firmly tethered to underlying struc
tures by strong bands of fibrous tissue.
The appendages of the skin are the nails, hair follicles,
sebaceous glands, and sweat glands.
The nails are keratinized plates on the dorsal surfaces of
the tips of the fingers and toes. The proximal edge of the
plate is the root of the nail (see Fig. 1.5). With the exception
of the distal edge of the plate, the nail is surrounded and
overlapped by folds of skin known as nail folds. The sur
face of skin covered by the nail is the nail bed (see Fig. 1.5).
Hairs grow out of follicles, which are invaginations
of the epidermis into the dermis (see Fig. 1.4). The folli
cles lie obliquely to the skin surface, and their expanded
extremities, called hair bulbs, penetrate to the deeper part
of the dermis. Each hair bulb is concave at its end, and
DNA and RNA molecules are linear polymers built from individual units called nucleotides connected by bonds called phosphodiester linkages. DNA and RNA are used to store and pass genetic information from one generation to the next.
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
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
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.
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.
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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
How to Give Better Lectures: Some Tips for Doctors
Nucleotides- 13
1. Nucleotides and nucleic acids
10/10/05
1
Fig. 8-1, 8-19, 8-25
Nucleotides are the building blocks of nucleic acids
Nucleotides also play other important roles in the cell
Nucleotide
DNARNA
2. Roles of nucleotides
10/10/05
2
• Building blocks of nucleic acids (RNA, DNA)
•Analogous to amino acid role in proteins
• Energy currency in cellular metabolism (ATP:
adenosine triphosphate)
• Allosteric effectors
• Structural components of many enzyme
cofactors (NAD: nicotinamide adenine
dinucleotide)
3. Roles of nucleic acids
10/10/05
3
• DNA contains genes, the information needed to
synthesize functional proteins and RNAs
• DNA contains segments that play a role in regulation of
gene expression (promoters)
• Ribosomal RNAs (rRNAs) are components of ribosomes,
playing a role in protein synthesis
• Messenger RNAs (mRNAs) carry genetic information
from a gene to the ribosome
• Transfer RNAs (tRNAs) translate information in mRNA
into an amino acid sequence
• RNAs have other functions, and can in some cases
perform catalysis
4. Structure of nucleotides
10/10/05
4 Fig. 8-1
A phosphate group
Nucleotides have three characteristic components:
A nitrogenous base
(pyrimidines or purine)
A pentose sugar
10. Structure of nucleotides
10/10/05
9
Below is the general structure of a nucleotide. The
pentose sugar, the base, and the phosphate moieties
all show variations among nucleotides.
Know this!
12. Ribose
10/10/0511
Fig. 8-3
• Ribose (β-D-furanose) is
a pentose sugar (5-
membered ring).
• Note numbering of the
carbons. In a nucleotide,
"prime" is used (to
differentiate from base
numbering).
5
1
23
4
13. Ribose
10/10/0512
Fig. 8-3
• An important derivative of
ribose is 2'-deoxyribose, or
just deoxyribose, in which
the 2' OH is replaced with
H.
• Deoxyribose is in DNA
(deoxyribonucleic acid)
• Ribose is in RNA
(ribonucleic acid).
• The sugar prefers
different puckers in DNA
(C-2' endo) and RNA C-3'
endo).
17. Major bases in nucleic acids
10/10/05
16 Fig. 8-2
• Among the pyrimidines, C
occurs in both RNA and
DNA, but
• T occurs in DNA, and
• U occurs in RNA
Know these!
• The bases are
abbreviated by their first
letters (A, G, C, T, U).
• The purines (A, G) occur
in both RNA and DNA
18. Some minor bases
10/10/05
17
Fig. 8-5
• 5-Methylcytidine occurs in DNA of animals and higher plants
• N6
-methyladenosine occurs in bacterial DNA
Fig. 8-5
20. Variation in phosphate group
10/10/05x
Fig. 8-6, 8-42
• Adenosine 3', 5'-cyclic
monophosphate (cyclic AMP,
or cAMP) is an important
regulatory nucleotide.
• In hydrolysis of RNA by
some enzymes,
ribonucleoside 2',3'-cyclic
monophosphates are isolable
intermediates;
ribonucleoside 3'-
monophosphates are end
products
• Another variation - multiple
phosphates (like ATP).
cAMP
19 10/10/05
21. Nucleotides in nucleic acids
10/10/05
20
• Bases attach to the C-1' of ribose or deoxyribose
• The pyrimidines attach to the pentose via the N-1 position of
the pyrimidine ring
• The purines attach through the N-9 position
• Some minor bases may have different attachments.
22. Deoxyribonucleotides
10/10/0521
Fig. 8-4
2'-deoxyribose sugar
Deoxyribonucleotides are abbreviated (for example) A, or
dA (deoxyA), or dAMP (deoxyadenosine monophosphate)
Phosphorylate the 5' position
and you have a nucleotide(here,
deoxyadenylate or
deoxyguanylate)
with a base (here, a purine,
adenine or guanine)
attached to the C-1'
position is a
deoxyribonucleoside
(here deoxyadenosine and
deoxyguanosine).
24. Ribonucleotides
10/10/05
23 Fig. 8-4
• The ribose sugar with a
base (here, a pyrimidine,
uracil or cytosine) attached
to the ribose C-1' position
is a ribonucleoside (here,
uridine or cytidine).
• Phosphorylate the 5'
position and you have a
ribonucleotide (here,
uridylate or cytidylate)
• Ribonucleotides are abbreviated (for example) U, or UMP
(uridine monophosphate)
28. Nucleic acids
10/10/05
27 Fig. 8-7
Nucleotide monomers
can be linked together via a
phosphodiester linkage
formed between the 3' -OH
of a nucleotide
and the phosphate of the
next nucleotide.
Two ends of the resulting poly-
or oligonucleotide are defined:
The 5' end lacks a nucleotide at
the 5' position,
and the 3' end lacks a nucleotide
at the 3' end position.
29. Sugar-phosphate backbone
10/10/05
28
Berg Fig. 1.1
• The polynucleotide or nucleic acid backbone thus consists of
alternating phosphate and pentose residues.
• The bases are analogous to side chains of amino acids; they vary
without changing the covalent backbone structure.
• Sequence is written from the 5' to 3' end: 5'-ATGCTAGC-3'
• Note that the backbone is polyanionic. Phosphate groups pKa ~ 0.
30. The bases can take syn or anti positions
10/10/05
29 Fig. 8-18b
31. Sugar phosphate backbone conformation
10/10/05
30 Fig. 8-18a
• Polynucleotides have
unrestricted rotation about most
backbone bones (within limits of
sterics)
• with the exception of the sugar
ring bond
• This behavior contrasts with the
peptide backbone.
• Also in contrast with proteins,
specific, predictable interactions
between bases are often formed:
A with T, and G with C.
• These interactions can be
interstrand, or intrastrand.
32. Compare polynucleotides and polypeptides
10/10/05
31
• As in proteins, the sequence of side chains
(bases in nucleic acids) plays an important
role in function.
• Nucleic acid structure depends on the
sequence of bases and on the type of ribose
sugar (ribose, or 2'-deoxyribose).
• Hydrogen bonding interactions are
especially important in nucleic acids.
34. DNA structure determination
10/10/0533
• Franklin collected x-ray
diffraction data (early 1950s)
that indicated 2 periodicities
for DNA: 3.4 Å and 34 Å.
• Watson and Crick proposed a 3-
D model accounting for the data.
35. DNA structure
10/10/05
34
Fig. 8-15
• DNA consists of two helical
chains wound around the
same axis in a right-handed
fashion aligned in an
antiparallel fashion.
• There are 10.5 base pairs, or
36 Å, per turn of the helix.
• Alternating deoxyribose and
phosphate groups on the
backbone form the outside
of the helix.
• The planar purine and
pyrimidine bases of both
strands are stacked inside
the helix.
36. DNA structure
10/10/05
35
Fig. 8-15
• The furanose ring usually is
puckered in a C-2' endo
conformation in DNA.
• The offset of the
relationship of the base pairs
to the strands gives a major
and a minor groove.
• In B-form DNA (most
common) the depths of the
major and minor grooves are
similar to each other.
37. Base stacking in DNA
10/10/05
36
Berg Fig. 1.4; 5.13
• C-G (red) and A-T (blue) base
pairs are isosteric (same shape
and size), allowing stacking along
a helical axis for any sequence.
•Base pairs stack
inside the helix.
38. DNA strands
10/10/05
37
Fig. 8-16
• The antiparallel strands of DNA are
not identical, but are complementary.
• This means that they are positioned
to align complementary base pairs: C
with G, and A with T.
• So you can predict the sequence of
one strand given the sequence of its
complement.
• Useful for information storage and
transfer!
• Note sequence conventionally is given
from the 5' to 3' end
39. B,A and Z DNA
10/10/0538
Fig. 8-19
• B form - The most common
conformation for DNA.
• A form - common for RNA
because of different sugar
pucker. Deeper minor groove,
shallow major groove
• A form is favored in conditions
of low water.
• Z form - narrow, deep minor
groove. Major groove hardly
existent. Can form for some DNA
sequences; requires alternating
syn and anti base configurations.
36 base pairs
Backbone - blue;
Bases- gray
41. RNA has a rich and varied structure
10/10/05
40 Fig. 8-26
Watson-
Crick base pairs
(helical segments;
Usually A-form).
Helix is secondary
structure.
Note A-U pairs in
RNA.
DNA can
form
structures
like this as
well.