The document discusses the properties of Group 1 elements (alkali metals) on the periodic table. Some key points:
1) The alkali metals have a general electronic configuration of ns1 and include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).
2) Their physical properties, such as atomic radius and ionization energy, decrease down the group as nuclear charge decreases due to the lanthanide contraction.
3) Their chemical properties include reacting vigorously with water to form alkaline hydroxides and oxygen to form oxides/peroxides/superoxides. They are highly reactive metals.
Revision Slides for AQA A-Level Chemistry on the Group Two Elements. Designed for the new Exam Series of June 2017, but relevant for all series and exam boards.
Revision Slides for AQA A-Level Chemistry on the Group Two Elements. Designed for the new Exam Series of June 2017, but relevant for all series and exam boards.
Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, loss and gain of electrons, Balancing redox reactions, Half reaction method, Types of redox reaction- direct and indirect method, Electrochemical cell, Classification of redox reactions.
A quick overview regarding redox reactions for grade 10's. There are no ionic equations here, and no oxidation numbers yet. This will be re-uploaded as soon as the chapter is completed.
Class 10 chemical reactions and equationssarunkumar31
Types of reactions, Redox reactions, Reaction between acid and metal, Types of decomposition reaction, corrosion and rancidity.Acidic and basic nature of oxide, prevention method of corrosion.
Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, loss and gain of electrons, Balancing redox reactions, Half reaction method, Types of redox reaction- direct and indirect method, Electrochemical cell, Classification of redox reactions.
A quick overview regarding redox reactions for grade 10's. There are no ionic equations here, and no oxidation numbers yet. This will be re-uploaded as soon as the chapter is completed.
Class 10 chemical reactions and equationssarunkumar31
Types of reactions, Redox reactions, Reaction between acid and metal, Types of decomposition reaction, corrosion and rancidity.Acidic and basic nature of oxide, prevention method of corrosion.
S-Block Elements - Group I Metals (Alkali metals) and Group II Metals (Alkaline Earth Metals)
Physical and Chemical Properties # General characteristics # Distiguih between both groups of metals # Some Examples of both groups metals
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
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 .
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
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.
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.
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.
2. 1. Group 1 elements called alkali
metals as their hydroxides are
strongly alkaline.
2. General electronic
configuration-ns1
3. Francium is highly radioactive.
4. Na,K abundant.Li,Rb,Cs less
abundant
3. Physical Properties
Periodic trends
depend on-
1.nuclear charge
2. Screening effect
Why does reactivity
increase down the
group?
1. Atomic radii- largest in respective period.
Increases down the group i.e Li<Na<K<Rb<Cs
2. Ionization Enthalpy- M(g) M+(g) + e- HIE
lowest in respective period
Decreases down the group.
3. Hydration Enthalpy- M+(S) M+(AQ)
Proportional to charge/radius ratio.
The magnitude of hydration enthalpy decreases down a group. Li salts are always
hydrated as it has maximum degree of hydration enthalpy.
4. Reason behind
flame tests-
Heat excites electron
to higher energy
level,electron emits
radiation while
returning to ground
state.
How would E
value change
across a period?
4. Melting and boiling points- decrease down the group.
5. Density- Li<Na>K<Rb<Cs
6.Appearance- the alkali metals are silvery white,soft and light metals.
7.Flame test- Alkali metals and their salts impart characteristic colour to an oxidizing flame
and can be detected by their respective flame tests.
8. Standard Electrode Potential- measure of reducing power of element.
Magnitude decreases down the group .
5. Chemical Properties
1. Reaction with air-
Metal + dioxygen(from air) Metal Oxide [ Li reacts with N2 to form Li3N as well. Alkali metals are
Stored in kerosene because of their high reactivity towards
air and water.]
Metal Oxide + vapour(from air) Metal Hydroxide
Li-oxide Characteristics of alkali metal oxides-
Na-peroxide 1.superoxide(O2-) and peroxide are larger anions than oxide ion.Hence larger
Cations form peroxides and superoxides as they are more stable.[ fajans law]
K,Rb,Cs-superoxides 2.oxide,peroxide=colourless.superoxide=yellow/orange.
6. 2. Reaction with water-
2M +2 H2O 2 M+ + 2 OH- + H2
Aqueous metal hydroxide [here M is reducing H2O]
Despite having the highest E value, Li reacts less vigorously with water due to-
1. Its small size high ionization enthalpy
2. High hydration energy.
Characteristics of alkali metal hydroxides-
1.They are strongest of all bases.
2.They are white crystalline solids.
7. 3. Reaction with Dihydrogen
2M + H2 2(M+)(H-)
METAL HYDRIDE
T=673K except for Li which reacts at 1073K
Reason: Lithium’s small size makes it less reactive than the other alkali metals.
8. 4. Reaction with Halogens
2M + X2 2(M+)(X-)
METAL HALIDE
1.Li halides are somewhat covalent due to Li’s polarising power.
[ polarisation=Distortion of electron cloud of anion by the cation]
2. As Iodine is the largest halogen, LiI is the most covalent metal halide
Characteristics of metal halides-
1.Enthalpy of formation decreases down the group for chlorides,bromides and iodides but increases down the group for
fluorides.
2.Enthalpy of formation for fluorides>chlorides>bromides>iodides due to increase in size down the group.
3.Solubility of (M+)(X-) decreases down a group as hydration energy decreases and lattice energy increases(except
flourides)..
4.LiF has low solubility due to high lattice energy and CsI has low solubility due to low hydration enthalpy.
9. 5. Reducing Nature
M(s) M(g) sublimation energy H1
M(g) M+(g) ionization enthalpy H2
M +(g) M+(aq) hydration enthalpy H3
Lesser the value of [ H1+H2+H3] better the reducing agent.
High degree of hydration enthalpy makes lithium a strong reducing agent.
10. 6.Solutions in Liquid Ammonia
1. M + NH3 (M(NH3))+ + (e(NH3))-
Ammoniated ion - imparts blue colour to solution
2. M + NH3 MNH2 + ½ H2 [M is reducing NH3]
3. In concentrated solution ( excess of M) , the blue colour changes to bronze colour.
11. 7. Alkali metal salts of oxoacids
Oxoacids - acidic proton is on a hydroxyl group with an oxo group attached to the same atom i.e the (OH) and (O) is attached
to the same atom. Eg:H2SO4,H2CO3,HNO3,H3PO4 etc.
1. M + H2CO3 M2CO3 + 2 H+ [ M REDUCES H2C03]
2. M + H2CO3 MHCO3 + H+
1.These salts are soluble in water and are thermally stable.
2. Stability of the metal carbonates and bicarbonates increase down a the group .
Reason: increase in electropositivity down the group.
3. Boiling point and melting point is directly proportional to the ionic character of the salt.
Hence, LiHCO3 does not exist as solid under normal conditions. Li2CO3 is not stable to heat, it polarises (CO3)2-
ion as follows-
Li2CO3 Li2O + CO2
12. Anomalous properties of Lithium
Difference between Li and alkali metals-
1. It’s high B.P and M.P makes it harder than other metals.
2. It’s least reactive, strongest reducing agent and its forms monoxide and reacts with atmospheric nitrogen.
3. It’s deliquescent [ all these properties are due to its small size and high polarising
4. LiHCO3 isn't formed in solid state. ability]
5. Does not form ethynide when reacted with ethyne.
Similarity between Li and Mg-
1. Equal charge/radius ratio and ionic size. [ Li has a charge of 1 and Mg of 2 and their radii are similar,
2. They react slowly with water and react with nitrogen. Then how is charge/ radius ratio same?]
3. Their chlorides are soluble in organic solvents.
4. Both are deliquescent.