The document discusses orbitals and quantum numbers. It introduces the four quantum numbers - principal (n), azimuthal (l), magnetic (ml), and spin (ms) - that describe an electron's location and properties. The classical view of electrons orbiting the nucleus like planets gave way to the modern atomic model where electrons exist as probabilistic wave functions within orbitals. Orbitals are regions of high probability of finding an electron and come in s, p, d, and f shapes depending on the quantum numbers. Electron configurations use these orbitals to describe the arrangement of electrons in atoms and predict properties.
This lesson will help you know how atoms of each element are arranged in an orbital and where atoms are exactly located that give distinct characteristics to the element.
This lesson will help you know how atoms of each element are arranged in an orbital and where atoms are exactly located that give distinct characteristics to the element.
This presentation is about the ionisation of energy of hydrogen, way to compute the value of ionisation energy of hydrogen, quantum numbers and a brief description of Schrodinger Equation.
This presentation is about the ionisation of energy of hydrogen, way to compute the value of ionisation energy of hydrogen, quantum numbers and a brief description of Schrodinger Equation.
The Fundamentals of Chemistry is an introduction to the Periodic Table, stoichiometry, chemical states, chemical equilibria, acid & base, oxidation & reduction reactions, chemical kinetics, inorganic nomenclature, and chemical bonding.
Quantum mechanical model of atom belongs to XI standard Chemistry which describes the quantum mechanics concept of atom, quantum numbers, shape and energies of atomic orbitals.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Mammalian Pineal Body Structure and Also Functions
Orbitals hl
1. Orbitals
Because of observations made regarding ionization energy, the fine structure of element spectra, and new
discoveries made regarding the wave nature of matter (specifically, electrons), scientists came up with a
new model of the atom. In order to write a mathematical expression that would allow them to predict
ionization energies and calculate the wavelengths that show up in an element’s spectrum (which is precisely
what Niels Bohr was trying to do, but only managed to do it for Hydrogen), it was necessary to take into
consideration more than just what energy level a particular electron is in. Scientists deduced that there
must be 4 “properties” of electrons and these 4 properties are called quantum numbers. Every electron can
be completely described with its 4 quantum numbers and no two electrons within the same atom have the
same 4 quantum numbers. Given the four quantum numbers, the mathematical equations can be solved for
each electron to give ionization energies or other spectroscopic data.
The 4 quantum numbers are:
o n or principle quantum number
o l or orbital quantum number
o ml or magnetic quantum number
o ms or spin quantum number
Symbol Name Spectroscopy Possible
Values
Classical
Meaning
Actual
Meaning
n principle the sharpest line 1, 2, 3, … Orbit Energy
level
l orbital The more detailed structure of the
spectrum that kind of blur t give n.
Not observed until tools got better
0, 1, 2, …(n-1) Shape of
orbit
Sublevel,
(s,p,d,f)
ml magnetic Observed when the element spectrum
is observed in a magnetic field
-(l-1)…(l+1) 3-d shape
of orbit
Orbital (on
s orbital, 3
p orbitals)
ms spin Needed to make the equations work out +1/2 or – 1/2 Direction
of electron
movement
Magnetic
moment of
electron
Exercise 1
(a) Give all the possible orbital quantum numbers for energy level 1, 2, 3
(b) Give all the possible magnetic quantum numbers for energy level 2
2. The difference between the classical meaning and the actual meaning of the quantum numbers is that in the
classical meaning, scientists still thought of electrons as particles orbiting a nucleus in a defined path. Once
Schroedinger showed that treating an electron as a wave resulted in calculations that accurately predicted
properties of the elements, we couldn’t really think of electrons as travelling in defined paths. In addition,
Heisenberg stated that there is a limitation to what we are actually able to measure. There is a theoretical
limit to how small the uncertainty in our measurements can be. Therefore, we can never know both the
position and the speed of an electron. If we have measured it’s position very precisely than by doing that
we must have affected its speed and, therefore, don’t have any idea how fast it’s travelling. So…we can’t
know where its going to be at any time in the future. If we measure it’s speed than we must have affected
its position and if we don’t know where it was to begin with, than knowing its speed doesn’t help us predict
where it is at a later time. So…we can only say where an electron is LIKELY to be and that is what an
orbital is: a 3-Dimensional space predicting, with a 98% probability of where an electron could be.
As a help in picturing the orbitals imagine you were able to take a large number of photographs of a
hydrogen atom, containing one electron. By superimposing these photographs, you would get an impression of
where the electron spends most of its time. The picture you would get would be something like the one
below.
The picture is itself an over-simplification since it is restricted to two dimensions. The complete model is
three-dimensional and spherical. Since even the two-dimensional picture is tedious to draw, we often use
instead a boundary round the region where the probability of finding an electron is high - about 98% - as
shown below.
Each energy level has between 1 and 4 sublevels and each sublevel is associated with a particularly shaped
probability density.
Exercise 2
Associate the pictures below with the quantum numbers.
3. The shape of s, p and d orbitals
Note :
• The orbitals are 3-dimensional and not precisely defined. The charge density falls off sharply at a
certain distance from the nucleus.
• All s-orbitals are spherical 1s < 2s < 3s etc.
• All p-orbitals are dumbell shaped in 3 directions in space 2p < 3p < 4p.
Exercise 3
Observe the grand orbital table at: http://www.orbitals.com/orb/orbtable.htm
And the orbital movies (my website under atomic structure resources). Record your observations.
4. Exercise 4
Each orbital can only hold 2 electrons. Explain why this must be true given the Pauli Exclusion Principle that
no two electrons can have the same four quantum numbers.
Exercise 5
(a) Observe the patterns and make predictions for energy level 5
(b) Fill in the blanks with the appropriate quantum number
Quantum shell Sub-shells Number of
electrons
Number of orbitals
n = 1 K shell One sub-shell
1s sub-shell 2
1
n = 2 L shell Two sub-shells
2s sub-shell ___
2p sub-shell ___
2 8
6
1
3
n =3 M shell Three sub-shells
3s sub-shell ___
3p sub-shell ___
3d sub-shell ___
2
6 18
10
1
3
5
n=4 N shell Four sub-shells
4s sub-shell ___
4p sub-shell ___
4d sub-shell ___
4f sub-shell ___
2
6 32
10
14
1
3
5
7
n=5 Predict… Predict… Predict…
5. Now that you know what an orbital is, you need to know how to use the orbital to describe the electron
structure of elements. There are two ways to do this:
(1) electron configurations
a. Standard: 1s2
2s2
2p6
3s2
3p6
4s2
3d10
…
b. More detailed: 1s2
2s2
2px
2
2py
2
2pz
2
3s2
3px
2
3py
2
3pz
2
4s2
3dz2
2
3dx2-y2
2
3dxy
2
3dxz
2
3dyz
2
…
i. Since all p orbitals are degenerate (have the same energy) it doesn’t matter which
one you put electrons in first, but see below for Hund’s rule
ii. Same goes for d orbitals and f orbitals
c. Noble Gas: [Ne] 3s2
…
(2) orbital diagrams (arrows)
Aufbau described the order that electrons fill the orbitals: from lowest to highest energy. It may seem a
little odd, but the 4s orbital is actually lower in energy than the d orbitals in the 3rd
energy level. To
remember the order you can use the following :
In an atom the orbitals are filled in order of increasing energy, starting from 1s.
An aid to remembering the order in which orbitals are filled is to write them down in columns as shown.
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d
7s 7p
The order of filling is then given by drawing diagonal lines through the symbols.
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d
7s 7p
Exercise 6
Write out the complete order in which orbitals are filled:
6. One other rule you must know: Hund’s Rule
Degenerate orbitals (of the same energy) are occupied by one electron before any orbital is occupied by a
second electron and all electrons in singly occupied orbitals must have the same spin.
Exercise 7
On a separate sheet of paper write the electron configuration and orbital diagrams for elements 3 to 10.
Exercise 8
Give the quantum numbers for all 8 of oxygen’s electrons.
Exercise 9
An electron has quantum numbers( n, l, ml, ms): 3, 0, 0, +1/2
(a) In what energy level is the electron located?
(b) In what subshell is the electron located?
(c) What is the shape of this subshell?
An electron has quantum numbers: 3, 1, -1, -1/2, draw it’s orbital diagram.
Exercise 8
(a) Write the electron configuration for Na.
(b) Explain why the electron configuration for Na can be written [Ne] 3s1
7. Exercise 9
(a) Relate electron configuration and location on the periodic table.
(b) What group has electron configurations that end in s1
?
(c) What group has electron configurations that end in p2
?
(d) What group has electron configuration that end in d3
?
Exercise 10
(a) According to our IE graphs, boron and aluminium had a lower IE than expected. Why?
(b) According to our IE graphs, oxygen and sulphur had a lower IE than expected. Why?
Exercise 11
(a) Write the electron configuration for Copper and Chromium.
(b) According to that awesome fancy periodic table I gave you at the beginning of the year, what is the
electron configuration for copper and chromium?
(c) Why do you think the actual e-config is different than predicted? (Hint: everything in chemistry has
to do with energy)