The document discusses the photoelectric effect and its characteristics. It can be summarized as follows:
1) The photoelectric effect occurs only when the frequency of incident radiation is greater than or equal to the threshold frequency, which is different for different metals.
2) The maximum kinetic energy of emitted photoelectrons depends on the frequency of incident radiation and is independent of intensity.
3) The rate of photoelectric emission, and thus the photoelectric current, is directly proportional to the intensity of incident radiation for a frequency greater than the threshold.
Understand the the phenomenon of Photoelectric effect with the help of virtual lab and also learn about the conditions required for this phenomenon.
Plot the graph between the observed quantities during performing this experiment.
And calculate the value of Planck's Constant ,work function and cut-off frequency with the help of Graph.
Understand the the phenomenon of Photoelectric effect with the help of virtual lab and also learn about the conditions required for this phenomenon.
Plot the graph between the observed quantities during performing this experiment.
And calculate the value of Planck's Constant ,work function and cut-off frequency with the help of Graph.
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.
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.
(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.
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.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
3. DUAL NATURE OF RADIATION
Effect of and I on stopping potential
Variation in
stopping potential
When constant
And I varying
When varying
And I constant
4. DUAL NATURE OF RADIATION
ip
0
V
VS3
VS2
VS1
Now, let us see the graph
of stopping potential vs
photoelectric current ip
Let intensity be constant,
let frequency
be varying, 0,
As frequency increases
K.E. also increases
As kinetic energy
increases stopping potential
also increases.
But the saturation
current will be same for all
stopping potentials.
Because no. of photons
are same, no. of electrons
emitted will be same.
the saturation current
will be same
We will see the effect of
frequency on stopping
potential
Saturation Current
Effect of and I on stopping potential
5. DUAL NATURE OF RADIATION
ip
0
VS
Saturation current
V
I3
I2
I1
Let us see the graph between
stopping potential &
photoelectric current ip
We will see the effect
of intensity on stopping
potential
Let frequency be
constant, be varying i.e.
intensity no. of photons
be varying
If no. of photons
increases, the no. of
electrons emitted will
also increase.
If no. of electrons
increases, photoelectric
current will also
increase.
But KEmax will be
constant because
is constant.
Therefore, for
different saturation
currents stopping potential
will be same.
Effect of and I on stopping potential
6. DUAL NATURE OF RADIATION
1. For different saturation currents stopping potential will be ……
a) increasing
b)
c) same
d) changes
decreasing
7. DUAL NATURE OF RADIATION
2. If the number of photo electrons increases the photoelectric current…
a) increases
b)
c) remains constant
d) none of these
decreases
9. DUAL NATURE OF RADIATION
CONSTRUCTION OF PHOTOELECTRIC CELL
It consists of a
semi cylindrical photosensitive
metal plate E (emitter)
E
PHOTOELECTRIC CELL
10. DUAL NATURE OF RADIATION
C
It consists of a wire loop C
(collector)
CONSTRUCTION OF PHOTOELECTRIC CELL
E
11. DUAL NATURE OF RADIATION
Both emitter and collector are
supported in an evacuated glass
tube is quartz Bulb
E C
CONSTRUCTION OF PHOTOELECTRIC CELL
12. DUAL NATURE OF RADIATION
It is connected to the external
circuit having a battery and
a micro ammeter (mA)
E C
mA
+
–
Battery
+
–
CONSTRUCTION OF PHOTOELECTRIC CELL
Photo sensitive plate E
Collector plate C
Glass Tube
13. DUAL NATURE OF RADIATION
When light of suitable
wavelength (l) l < l 0 falls
on the emitter E
E C
mA
+
–
Battery +
–
WORKING
Photo sensitive plate E
Collector plate C
Glass Tube
Photoelectrons are
emitted
These photoelectrons
are attracted towards
collector (C).
As the electrons get
collected by collector (C)
small photoelectric current ip is
induced.
ip
This photoelectric
current is recorded by
micro ammeter (mA)
If the intensity of incident
radiation is increased, the rate
of photoelectric current
emission increases.
As rate of photoelectric
emission increases current also
increases
Therefore, current is directly
proportional to the intensity
of incident light.
14. DUAL NATURE OF RADIATION
WORKING
Photo sensitive plate E
Collector plate C
Glass Tube
E C
mA
+
–
Battery
+
–
ip
Now, connect any
electrical device to this
photocell.
Due to the photoelectric
current the device will be in
working condition.
Electrical Device
The photoelectric cell
is a device which converts
light energy into electrical
energy
15. DUAL NATURE OF RADIATION
The rate of photo electric emission is directly
proportional to the intensity of incident
radiation.
APPLICATIONS OF PHOTO-CELL
Exposure Meter :
PRINCIPLE :
It is a device used along with a camera to find the correct time of
exposure for having a good photograph.
1)
2)
16. DUAL NATURE OF RADIATION
1) In this application, a photoelectric cell is used to activate
relay mechanism.
APPLICATIONS OF PHOTO-CELL
Burglar Alarm :
Photoelectric effect is instantaneous
PRINCIPLE :
2) The light from an infrared lamp falls on the photosensitive surface of
photoelectric cell .
3) The infrared beam is invisible and when some one crosses the beam, the light is
cut-off and photoelectric current stops.
4) This operates the relay circuit and starts ringing the bell.
17. DUAL NATURE OF RADIATION
2) The photoelectric current varies according to the intensity of light
transmitted by the amplified sound track.
3) The varying current is amplified and fed to the loudspeaker.
4) The loudspeaker reproduces the sound which is recorded on the sound track.
APPLICATIONS OF PHOTO-CELL
1) Light from a powerful lamp passes through the
sound track at the edge of the film and falls on
photosensitive surface of photoelectric cell .
Sound reproduction from motion pictures :
18. DUAL NATURE OF RADIATION
1. The photoelectric cell works on the principle of...
a) Raman effect
b)
c) both of these
d) none of these
photoelectric effect
19. DUAL NATURE OF RADIATION
2. In a photocell, increasing the intensity of incident light increases...
a) stopping potential
b)
c) max. kinetic energy
d) none of these
photoelectric current
20. DUAL NATURE OF RADIATION
3. The photocell is used to convert....
a) electric energy to light energy
b)
c) both of these
d) none of these
light energy to electric energy
22. DUAL NATURE OF RADIATION
Photo-electric emission occurs from the surface of a metal only
when the incident radiation has a frequency greater than or equal to
a certain minimum frequency (0) called the threshold frequency.
Characteristics of the Photoelectric Effect
The threshold frequency is different for different materials.
A)
B)
It follows that for photoelectric emission to occur, the wavelength
of incident radiation must be less than or equal to l0 (i.e. greater
than or equal to 0).
C)
0 l l0
The wavelength (l0)
corresponding to the threshold
frequency (0) is called the
threshold wavelength.
l0 =
0
c
23. DUAL NATURE OF RADIATION
The number of electrons emitted per second from a given surface is
directly proportional to the intensity of incident radiation and 0.
The maximum kinetic energy of photo-electrons increases with
the increase in the frequency of incident radiation.
Photoelectric effect is an instantaneous process. There is no time lag.
D)
Characteristics of the Photoelectric Effect
E)
F)
Kinetic Energy does not depend upon the intensity of incident
radiation.
G)
24. DUAL NATURE OF RADIATION
Failure of Wave Theory to explain Photo – Electric effect
i) According to wave theory, the kinetic energy of the photoelectrons
depend on the intensity of the incident radiation, and increases with
increase in intensity.
ii) But according to photoelectric effect the K.E depends on
frequency and not on the intensity.
A)
B) The wave theory also fails to explain the instantaneous nature of
photo-emission.
25. DUAL NATURE OF RADIATION
1. Threshold frequency is different for ……..metals.
a) different
b)
c) independent
d) none of these
same
26. DUAL NATURE OF RADIATION
2. Kinetic Energy is independent of...
a) frequency
b)
c) wavelength
d) none of these
intensity
28. DUAL NATURE OF RADIATION
(2) e V0 = h–W0
The Einstein photoelectric equations are
(1) K.E.max = h–W0
mv2 = h –W0
i.e.
1
2
max
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTO ELECTRIC EQUATION
29. DUAL NATURE OF RADIATION
Characteristics of photoelectric effect are :
For photo emission to take place, the incident light energy must
have frequency 0 if it < 0 then photo emission will not take
place.
(1)
For a given photosensitive material and of incident light. ( 0 ) ,
ip I.
(2)
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTOELECTRIC EQUATION
30. DUAL NATURE OF RADIATION
For a given frequency ( 0 ), the maximum kinetic energy
linearly increases with increase in frequency , it is independent of
intensity.
(3)
The photoelectric effect is an instantaneous process and there is
no time lag.
(4)
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTO ELECTRIC EQUATION
31. DUAL NATURE OF RADIATION
According to Einstein's photoelectric equation
Energy of photon = Photoelectric + K.E.max
Work function
=
h W0 + K.E.max
E = W0 = h0
at = 0
h = h0 + K.E.max
h – K.E.max
h0 =
h K.E.max
(–0 ) =
If = 0
EXPLANATION OF CHARACTERISTICS OF PHOTOELECTRIC
EFFECT WITH EINSTEIN’S PHOTOELECTRIC EQUATION
K.E.max = 0
32. DUAL NATURE OF RADIATION
When < 0
K.E. becomes –ve
h ( – 0) K. E.max
According to Einstein's photo electric equation
And all know that K.E
cannot be negative
When 0 K.E. has some
positive value
=
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTO ELECTRIC EQUATION
When < 0
no photo emission takes place
When 0
photoemission takes place
with some positive value of kinetic energy
33. DUAL NATURE OF RADIATION
According to Einstein's equation we come to the conclusion that
1) When = 0 the photoelectrons are emitted without kinetic energy
2) When < 0 the photoelectrons are not emitted
3) When >0 the photoelectrons are emitted with some kinetic energy
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTO ELECTRIC EQUATION
34. DUAL NATURE OF RADIATION
h ( – 0) K.E.max
According to Einstein's photo electric equation
= As the I the no. of photons
striking the metal plate
As the no. of photons , the
photoelectric current ip
This explains that ip with
in intensity
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTO ELECTRIC EQUATION
Here ‘I’ represents intensity
of incident radiation.
35. DUAL NATURE OF RADIATION
h ( – 0)
The photoelectric effect is instantaneous
and there is no time lag
According to Einstein's photo electric equation
= Emission of photoelectrons is
a result of collision between
electrons and photons.
EXPLANATION OF CHARACTERISTICS OF PHOTO ELECTRIC
EFFECT WITH EINSTEIN’S PHOTO ELECTRIC EQUATION
W0
36. DUAL NATURE OF RADIATION
1. If < 0 , will photoelectrons be emitted...
a) yes
b)
c) may be
d) none of these
no
37. DUAL NATURE OF RADIATION
2. An increase in intensity of beam will _____ the photoelectric current.
a) increase
b)
c) no change
d) none of these
decrease
38. DUAL NATURE OF RADIATION
4. Maximum K.E of emitted photoelectrons depends upon...
a) frequency
b)
c) wavelength
d) none of these
intensity
