The document discusses the rate of reaction and factors that affect it. It defines rate of reaction as the change in amount of reactants or products per unit time. The rate depends on several factors:
1) The surface area of solid reactants - Increasing the surface area by reducing particle size increases the rate, as there are more contact points for collisions.
2) Concentration of reactants - Higher concentrations increase the chance of collisions between reactant particles, speeding up the rate.
3) Temperature - Raising the temperature increases the kinetic energy of particles, making successful collisions that overcome the activation energy barrier for reaction more likely.
4) Pressure for gas reactions - Higher pressures increase the rate by squeezing
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 .
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.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
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.
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.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Richard's entangled aventures in wonderlandRichard 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.
2. Contents
1. Understanding of Rate of Reaction
2. Factors Affecting Rate of Reaction
3. Collision Theory
4. Scientific Knowledge to Enhance Quality
of Life
3. 1.1 Understanding of Rate of
Reaction
Rate of reaction is defined as the change in the amount
of reactants or products per unit time.
We usually use water displacement method to collect
gas
5. •
•
•
•
•
The reaction is fastest at the start when the reactants are
at a maximum (steepest gradient)
The gradient becomes progressively less as reactants
are used up and the reaction slows down.
Finally the graph levels out when one of the reactants is
used up and the reaction stops.
The amount of product depends on the amount of
reactants used.
The initial rate of reaction is obtained by measuring the
gradient at the start of the reaction. A tangent line is
drawn to measure rate of reaction at instantaneous time.
6. Different chemical reactions occur at different rates.
• Fast Reaction
• Slow Reaction
Fast Reaction Slow Reaction
The time taken for a fast reaction is
short.
The time taken for a slow reaction is
long.
The rate of reaction is said to be
high.
The rate of reaction for a slow
reaction is low.
Example:
•Fading of dyes on a shirt under hot
sun
•Burning of petrol in a car engine
•Striking a match
•Ripening of tomatoes
Example:
•A piece of newspaper turning yellow
•The weathering of limestone by acid
rain
•Rusting of a water pipe
12. Example:
In a chemical reaction, 2.5g of calcium carbonate react
completely with excess hydrochloric acid to produce
600cm³ of carbon dioxide gas in 1.5 minutes. Find the rate
of reaction in term of
a. decreasing mass of calcium carbonate
b. increasing volume of carbon dioxide gas produced
13. Finding Average Rate Of Reaction
From Measurable
Quantities
During a chemical reaction, two things happen
1. The quantities of reactants reduce.
2. The quantities of products increase.
Therefore, the rate of the reaction can be determined by
• measuring the decrease of the amount of the reactants over
time.
measuring the increase of the amount of the products over time.
•
However, the quantity (or change) of the
reactants/product may be measurable or immeasurable.
The easily measured quantity changes include
•
•
•
Mass
Concentration (Conductivity)
Volume of gas
14.
15. Example:
In a reaction, 5 g of calcium carbonate
takes 250 seconds to completely react
with solution of hydrochloric acid.
Calculate the average rate for this
reaction in units
a)g s-1 and
b)mol s-1
[ Relative atomic mass: C 12; O, 16; Ca,
40]
17. Example:
When the aqueous of ethanadioic is
mixed with acided potassium
manganate(VII) , the reaction happen
slowly at room temperature. The
purple colour of the solution is
bleached after 20 seconds. Calculate
the average rate of reaction.
18. Analysing Rate of Reaction from
Graph
Graph Of Product/Reactant Change Against Time
Ina chemical reaction,
•
•
the reactants will decrease over time
the product will increase over time
the rate of reaction will decrease over time because of
the decrease in concentration and total surface area of
reactants.
Ina graph of quantity of product/reactant over time, the
rate of reaction is equal to the gradient of the graph.
19. Example:
The reaction between dilute hydrochloric acid and excess
marble will produce calcium chloride and gas of carbon
dioxide. Sketch the graph of
1. the mass of the marble against time.
2. the volume of carbon dioxide against time.
3. the concentration of hydrochloric acid against time.
4. the concentration of calcium chloride against time.
20.
21. Finding The Average Rate Of Reaction From A Graph
Example:
Inareactionbetweencalciumcarbonateandliquidhydrochloricacid,
carbondioxidegasthatisreleasediscollectedinaburette.The graph
showsthevolumeof carbondioxidecollectedovertime.Find the
averagerateof reactioninthefirst 60s.
22. Finding Instantaneous Rate Of Reaction From A Graph
The rate of reaction changes from time to time as the
reaction happens.
The rate of reaction at a particular time is called the
instantaneous rate.
The instantaneous rate of a reaction is equal to the
gradient of tangent at a particular time.
23. Example:
The graph shows the volume of carbon dioxide gas
released over time in a chemical reaction. Find the
rateof reactionatt= 40s
25. 1. Size of Solid Reactants/Total Surface Area
The smaller the size of the particle, the bigger
the total surface area.
The bigger the total surface area, the higher the
rate of reaction.
26. Experiment 1
25 cm3of 0.5 mol dm–3hydrochloric acid + calcium carbonate chips. The
carbon dioxide gas released is collected in a burrete. The volume of
the gas released is recorded in every 30s. The result is plotted in a
graph.
27. Experiment 2
25 cm3of 0.5 mol dm–3hydrochloric acid + calcium carbonate powder.
As in experiment 1, the carbon dioxide gas released is collected in a
burrete and the volume of the gas released is recorded in every 30s.
The result is plotted in the same graph in experiment 1.
28. Conclusion
• The gradient of the curve for experiment 2 is greater than the curve for
experiment 1. This indicate that the rate of reaction in experiment 2 is
higher than experiment 1.
• Conclusion: the smaller the particle size of the reactant, the bigger the
total surface area, and the bigger the total surface area, the higher the
rate of the reaction will be.
29. 2. Concentration Of
Reactants
Experiment
By measuring the time taken for the formation of sulphur
precipitate (yellow solid) when sulphuric acid, H2SO4reacts
with sodium thiosulphate(VI), Na2S2O3of different
concentration , we can investigate the effect of
concentration of the reactant on the rate of reaction.
The higher the concentration of the solution, the higher
the rate of reaction.
30. Procedure:
•50 cm3of 0.2 mol dm-3sodium thiosulphate solution + 10 cm3of 0.5 mol
dm-3sulphuric acid.
•
from view is recorded.
•The experiment is repeated by using sodium thiosulphate solution with
concentration 0.4 mol dm-3, 0.6 mol dm-3, 0.8 mol dm-3and 1.0 mol dm-3.
32. 3. Temperature Of The Reactant
Experiment
By measuring the time taken for the formation of sulphur
precipitate (yellow solid) when sulphuric acid, H2SO4reacts
with sodium thiosulphate(VI), Na2S2O3of different
temperature, we can investigate the effect of temperature
of the reactant on the rate of reaction.
Thehigherthetemperatureof the
solution,thehighertherateofreaction.
33. Procedure:
•50 cm3of 0.2 mol dm-3sodium thiosulphate solution at 30ºC + 10 cm3 of
0.5 mol dm-3sulphuric acid.
•
from view is recorded.
•The experiment is repeated by using sodium thiosulphate solution with
temperature 35ºC, 40ºC, 45ºC and 50ºC.
34. Conclusion :
• The graph for temperatureof sodium thiosulphate(VI),
Na2S2O3againsttimetakenforthesulphurprecipitatetoformed is
plotted.
• Asthetemperatureof sodiumthiosulphatesolutiondecreases, the
35. Pressure Of Gas
For reactions involve gas, the rate of reaction is affected
by the pressure of the gas.
Pressure DOES NOT affect the rate of reaction where
the reactants are in the form of solids or liquids.
The higher the pressure of the gas, the higher the rate of
reaction
The higher the pressure of the gas, the higher
the rate of reaction
36. 4. Catalyst
Catalyst
Only a small amount of catalyst is
needed to increases the rate of
reaction. An increase in the
quantity of catalyst will increase
the rate of reaction slightly
During a reaction, catalyst remains
chemically unchanged but may
undergo physical changes. For
example, catalyst may turn into
powder during the reaction
Change the rate of
reaction
Does not change the
quantity of products formed
Catalyst is a chemical substance that change the rate of
chemical reaction
Characteristics of catalyst:
It is specific in its action. It can
only catalyse a particular
reaction
38. List of Reactions and the Catalyst
Chemical Reaction Catalyst
Decomposition of hydrogen peroxide:
2H2O2 → 2H2O + O2
Manganese(IV) oxide, MnO2
Haber Process
N2 + 3H2 → 2NH3
Iron, Fe
Contact Process
2SO2 + O2 → 2SO3
Vanadium(V) oxide, V2O5
Ostwald Process
4NH3 + 5O2 → 4NO + 6H2O
Platinum, Pt
39. Factors Affecting
Catalyst
Acatalyst is a substance which can
change the rate of reaction.
There are 2 types of catalyst:
• Positive catalyst – Increase the rate of
reaction.
• Negative catalyst – Reduce the rate of
reaction.
42. Application of Catalysts in Industry
a) Haber Process (Produces Ammonia)
• In the Haber process, a mixture of nitrogen and hydrogen in
the ratio 1:3 is conducted through the powdered iron as
catalyst at a temperature of 450°- 550°C and a pressure of 200
-300 atmospheres.
Powdered iron is used as the catalyst to raise the rate of
reaction.
Also, the reaction is conducted at high temperature to increase
the rate of reaction.
•
•
43.
44.
45. 1.3 Collision Theory
The collision theory states
that:
•
•
• The particles of the reacting
need to touch to enable bond
formation or breaking to
happen.
Collisions of particles of a
reacting substance need to
achieve a certain minimum
energy (Activation Energy) in
order to produce a reaction.
Particles that collide also need
to have the correct orientation
of collision.
46. According to collision theory, atoms, ions, and molecules
can react to form products when they collide with one
another, provided that the colliding particles have
enough kinetic energy.
Effective Collision
Ineffective Collision
47. Activation Energy
• The minimum energy that the reactants particles must achieve at
the time of collision in order for a chemical reaction to take
place.
• The value of the activation energy is different for different
reactions.
• A reaction with high activation energy occurs slowly whereas a
reaction with a low activation energy occurs fast.
48. Energy Profile Diagram
In this diagram, the activation energy is shown by the difference in
energy between the peak of the graph and the level of the energy
of the reacting substance.
Exothermic Reaction Endothermic Reaction
49. Factors Affecting Rate Of
Reaction - Explanation By
Collision Theory
Total Surface Area of Reactants
• When the size of the solid substance that reacts is smaller, its total
surface area exposed becomes larger.
• This causes the collisions frequency between the reactants increases.
• As a result, the frequency of effective collisions also increases and
hence increases the rate of reaction.
50. Presence of Catalyst
• When a positive catalyst is used in a reaction, the catalyst
prepares an alternative path with lower activation energy for the
reaction.
• As a result, the frequency of effective collisions increases and
hence increases the rate of reaction.
51. Concentration
• Solution with higher concentration has more particles per unit
volume in the solution.
• As a result, the collisions frequency between the reactants
increases.
• Consequently, the frequency of effective collisions also
increases and hence the rate of reaction increases.
52. Temperature
•
• When the temperature of a reaction increases, the particles of
the reacting substances move faster.
This causes the collisions frequency between the reactants
increases.
• As a result, the frequency of effective collisions also increases
and hence increases the rate of reaction.
53. Pressure of Gas
•
•
• For a reaction that involves a gas, when pressure increases,
the particles of gas are compressed to fill the spaces which are
small. This makes the number of particles of gas per unit of
volume to increase.
This causes the collisions frequency between the reactants
increases.
As a result, the frequency of effective collisions also increases
and hence increases the rate of reaction
54. 1.4 Scientific Knowledge
to Enhance
Quality of Life
1. Keeping food in a refrigerator
• If food is kept in the fridge, the food will keep longer
because the low temperature will slow down the
rate of the chemical reaction which destroys food.
2. Cooking food in a pressure cooker
•
• In a pressure cooker, the high pressure causes the
water in the cooker to boil at a temperature of more
than 100°C.
At a higher temperature, the time for the food to get
cooked is decreased.
55. 3. Cooking Food in Small Pieces
Vegetable oil is an organic compound that is not
saturated and exists in liquid state at room
temperature.
Vegetable oil can be changed to margarine through
the process of hydrogenation using nickel as catalyst
at a temperature of 180°C
• Food in the shape of big pieces has a surface area
per volume which is small, so the heat takes a longer
time to reach the inside of the food. So, to cook
faster, the food needs to be cut into smaller pieces.
4. Making Margarine
•
56. 5. Burning of Coal
• Coal contains the element carbon.
• A big piece of coal takes a long time to burn because the total
surface area that is touched by the fire is small.
• The rate of burning pieces of coal which are small is higher
because the total surface area is bigger. With this, it provides a
lot of heat energy in a short period of time.