this presentation describes the basics of photosynthesis. it includes Significance of photosynthesis, Photosynthetic apparatus, Absorption & action spectra, Absorption & action spectra, Factors affecting photosynthesis, Photosynthetic apparatus, Position of photosynthetic pigments, Photosynthetic pigments, Functions of carotenoids, Phycobilins, Principle /Blackman’s law of limiting factors.
what is photosynthesis?-history background-photosynthetic pigmment system-light harvesting complex-photo oxidation of water-photophosphorylation and mechanism of electron transport
what is photosynthesis?-history background-photosynthetic pigmment system-light harvesting complex-photo oxidation of water-photophosphorylation and mechanism of electron transport
Photosynthesis is a very crucial process in nature and I have cleared a lot of basics concepts in this presentation. Any student in grade 11 or 12 (medical sc/biology/biotech) or a college student from science field will be able to clear his/her concepts through this ppt.
Plz do follow my Instagram page @biologistindia
In this ppt, you will learn about photosystem first of photosynthesis, with video and animation such a nice presentation. electron movement by animation, see and understand the system.
Photosynthesis (Light and Dark reaction of photosynthesis)Shekhar Tidke
Importance of photosynthesis. Light reaction of photosynthesis, Dark reaction of photosynthesis. Hill, and Blackman reaction or C3 cycle or Calvin Cycle
Photosynthesis is a oxidation reduction process in which water is oxidized and carbon dioxide is reduced to carbohydrate level, the water and oxygen being by product.
Photosynthesis is a very crucial process in nature and I have cleared a lot of basics concepts in this presentation. Any student in grade 11 or 12 (medical sc/biology/biotech) or a college student from science field will be able to clear his/her concepts through this ppt.
Plz do follow my Instagram page @biologistindia
In this ppt, you will learn about photosystem first of photosynthesis, with video and animation such a nice presentation. electron movement by animation, see and understand the system.
Photosynthesis (Light and Dark reaction of photosynthesis)Shekhar Tidke
Importance of photosynthesis. Light reaction of photosynthesis, Dark reaction of photosynthesis. Hill, and Blackman reaction or C3 cycle or Calvin Cycle
Photosynthesis is a oxidation reduction process in which water is oxidized and carbon dioxide is reduced to carbohydrate level, the water and oxygen being by product.
Photosynthesis is an inevitable process that keeps us alive.It is the main source for food and it's byproduct keeps us breathing. This ppt is the detailed explanation of photosynthesis and the components involved in it. Here you can easily understand the concept and you are able to strengthen your grip on this topic.
This was my presentation on the C4 pathway which includes the portions for 11th grade i hope it helps ppl for better understanding :)
I would like to say special Thanks to my biology teacher Mrs.Alarmelu for her outstanding support and her amazing effort in helping me to make this presentation a success
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In this ppt competitive inhibition of enzymes is fully explained with its examples. it will be helpful for all the life science students. Non Competitive inhibition , Uncompetitive inhibition & Irreversible inhibition of Enzymes have been well explained in this presentation. it will be helpful for biochemistry, botany, zoology and other life/bio sciences students. I tried to explain Allosteric enzymes, their mechanism of action, Allosteric inhibition, Feedback inhibition in this presentation so that it can be easy to understand the concept for viewers.
this presentation explain the mechanism of action of enzymes how they interact with their substrates by the two theories i.e. Lock & Key Mechanism and Induced Fit model. it also explains the active site details. In this presentation Enzyme Kinetics is explained by Michaelis–Menten equation. this also include derivation of Michaelis–Menten equation.
his video explains the different Characteristics of enzymes like specificity, efficiency, catalytic, protein and colloidal nature.
https://youtu.be/EzCSWQAv7so link for you tube video
this video describes the introduction about enzymes and nomenclature of enzymes. it explains IUB system of classification of Enzyme fully. it also explains the different classes of enzymes and enzyme commission number.
https://youtu.be/JZOx9v1V7mA you tube link for lecture
Seed dormancy is fully explained in this ppt. it includes causes ( dormancy due to hard seed coat, dormancy due to condition of embryo, dormancy due to absence of light, dormancy due to low temperature etc. ) of seed dormancy, types of seed dormancy, various methods to remove seed dormancy like impaction, stratification, scarification, exposure of seed to light
this presentation describes the concept of growth and development of plants in details. it explains different types and phases of growth. it also contain notes on growth rate that ie arithmetic & geometric. Growth curve and growth requirements are also well explained in this ppt. it also define differentiation, dedifferentiation and redifferentiation.
this presentation describes the basics of enzymology like enzyme definition, history of enzyme discovery. it also explains the IUB nomenclature of enzyme proposed by Enzyme commission
this presentation describes light phase of photosynthesis. it explains Evidences for two phases, Photosynthetic unit & Harvesting of light energy, Emerson effect &two photosystem, Hill reaction & Photolysis /photo-oxidation of water, Redox potential & mechanism of light reaction, Cyclic photophosphorylation, Non- cyclic photophosphorylation .
This presentation describes the nutrient uptake in plants. it explains the passive and active uptake of nutrient uptake. which are further explained as diffusion, facilitated diffusion, carrier proteins, channel proteins, ion exchange & contact exchange.
this presentation describes the various types of minerals, their roles, deficiency symptoms. this presentation also describe the criteria of essentially of the minerals.
DPD, Water potential, Plasmolyses & ImbibitionSunita Sangwan
This presentation explains DPD (diffusion pressure deficit), Plasmolyses and Imbibition in details. this also include the numericals related to Water potential. difference between DPD & water potential.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
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3. What is Photosynthesis ?
Photo – light synthesis = to join
is the single most important process on earth on which depends
the existence of human beings and almost all other living
organisms.
Photosynthesis process by which photosynthetic organisms
convert light energy into chemical energy in the form of reducing
power (NADPH)and ATP and use these chemicals to drive
carbon dioxide fixation and reduction to produce sugars.
The overall reaction of oxygen in photosynthesis can be
represented as -
5. CO2
• Through stomata by
respiration
Hydrogen
Donor
• By photolysis of
water
Light
• Radient energy consist of
discrete energy particles or
units called photon.
• Energy contained in one
photon is called quantum
and measured in Einstein.
RAW Materials for
Photosynthesis
6. •Out of total radiation output from sun
(1360Wm-1/sqm) only 900Wm-1/sqm reaches
to the earth surface.
•Plant receive about 400-500Wm-1/sqm PAR
(photosynthetically Active Radiations) from
sun.
•out of which 80% is absorbed by leaves but
only 10% is used for photosynthesis.
•Rest of them are changed in heat, used in
transpiration or re-emitted as fluorescence.
10. Four pyrrole rings joined together by methane
bridges with magnesium at its nucleus.
Side chains are attached to the pyrrole rings
which are variable in different chlorophylls.
Phytol tail consist of an alcohol phytol of 20 C
atoms bounded to the 4th pyrrole ring by ester
linkage.
In chl b formyl (-CHO) on ring II instead of CH3
In chl c phytol chain is absent
In chl d (-O-CHO) group replaces (-CH=CH2) on
ring I
11. Carotenoids
Carotenes
α- carotenes
Found in all higher plants
β- carotenes
Found in algae & many higher
plants
γ- carotenes
Found in green photosynthetic
bacteria
Xanthophylls
Lutein, zeaxanthin,
cryptoxanthin, flavoxanthin,
violoxanthin
Carotenes are unsaturated hydrocarbons, build up of isoprene units
with general formula C40H56.
Carotenes consist of an open chain of conjugated double bond
system ending on both sides with an ‘ionone ring’.
12. Functions of carotenoids
Prevent chlorophyll molecule from photo oxidation.
Absorption spectra is from 425 nm – 490 nm which I s different
from chlorophyll. Hence these are known as supplementary light
harvesters.
Absorb & transfer light to chlorophylls
β- carotenes are the precursor of vitamin A in animals
Make flower & fruit attractive by providing red & orange colour
to them.
13. Phycobilins
Mainly found in blue green algae, red algae.
Absorb short wavelength of light (below
500nm), due to short wavelength they penetrates
deep in to the sea where red algae grow.
It consist of open conjugated system of 4-pyrrole
ring.
It lacks Mg++ & phytol chain.
Three types of phycobilins are:
i. Phycocyanin- blue colored
ii. Allophycocyanin- blue colored
iii. Phycoerythrin- red colored
Phytochrome is also an example of
biliproteins
14. Absorption Spectra
The set of wavelengths absorbed by a pigment is its absorption
spectrum. The absorption spectrum of chlorophylls includes
wavelengths of blue and orange-red light, as is indicated by their
peaks around 450-475 nm and around 650-675 nm.
As a note, chlorophyll a absorbs slightly different wavelengths
than chlorophyll b.
Chlorophyll a, gives absorption peaks at 430 nm and 662 nm,
while Chlorophyll b gives peaks at 453 nm and 642 nm. The
different side groups in the two chlorophylls ‘tune’ the absorption
spectrum to slightly different wavelengths.
16. Action Spectra
An action spectrum is a graph of the rate
of biological effectiveness plotted against wavelength of light. ...
For example, chlorophyll is much more efficient at using the red
and blue regions than the green region of the light spectrum to
carry out photosynthesis.
17. Action Spectrum compared with an absorption spectrum.
The absorption spectrum is measured by plotting a response to light such as oxygen
evolution, as a function of wavelength.
If the pigment used to obtain the absorption spectrum is same as those that cause the
response, the absorption & action spectrum will match.
In the example shown here, the action spectrum for oxygen evolution matches the
absorption spectrum of intact chloroplast quite well, indicating that light absorption by
chlorophylls mediates oxygen evolution.
Discrepancies are found in the region of carotenoid absorption, from 450 to 550 nm,
indicating that energy transfer from carotenoids to chlorophylls is not as effective as
energy transfer between chlorophylls.
18. External Factors affecting photosynthesis
External Factors
affecting
photosynthesis
Light
Carbon
dioxide
Temperature
Water
Oxygen
Minerals
Air Pollutants
19. Principle /Blackman’s law of limiting factors
Optimum value of a factor is never constant. It depends upon the
magnitude of other factors
In such cases it is found that a factor called limiting factor is
holding the balance. A limiting factor is defined as a factor which
is deficient to such an extent that increase in its magnitude
directly increases the rate of the process.
The effect of limiting factors was studied by Blackman in 1905.
He formulated the principle of limiting factors which states that
when a process is conditioned as to its rapidity by a number of
separate factors, the rate of the process is limited by the pace of
the slowest factor. In other words the rate of a physiological
process is limited at a given time by one and only one factor
which is deficient.
22. Light Intensity
At low light intensities, the rate of
photosynthesis is directly proportional to the
light intensity.
Because as more light becomes available, more
chlorophyll molecules can absorb light so more
electrons are excited leading to photolysis and
photophosphorylation.
More ATP and NADPH are produced so the
light-independent reactions can occur at a higher
rate so more product is produced.
Eventually a maximum rate is reached and so
increasing light intensity has no effect so the
graph levels off.
This can be because all available chlorophyll
molecules are absorbing light or some other
factor is now the limiting factor.
23. Temperature
When light is not a limiting factor (i.e. high light
intensities), increasing the temperature increases
the rate of photosynthesis.
Above the optimum temperature, any further
increase causes the rate to decrease rapidly.
Because the Calvin Cycle is enzyme controlled,
when the temperature increases both enzymes and
substrates gain kinetic energy, so more collisions
occur, so more enzyme substrate complexes form,
so more product forms.
When the temperature exceeds the optimum, the
enzymes will denature and the specific shape of the
active site will change and no longer be
complementary to the substrate so fewer enzyme-
substrate complexes can form.
24. CO2
At low CO2 levels an increase in
concentration causes a directly
proportional increase in the rate of
photosynthesis.
A maximum rate is eventually reached
and further increase has no effect and so
the graph levels off.
This is because atmospheric CO2 levels
are lower than the optimum value so
when concentration is increased more
CO2 is absorbed so more product is
made.
Eventually, there is no more RuBP
available to absorb anymore CO2 so
25. Oxygen
Oxygen has been shown to inhibit photosynthesis in C3 plants
while C4 plants show little effect. It is suggested that C4 plants
have photorespiration and high O2 stimulates it.
The rate of photosynthesis increases by 30-50% when the
concentration of oxygen in air is reduced from 20% to 0.5% and
CO2, light and temperature are not the limiting factors.
Oxygen is inhibitory to photosynthesis because it would favour a
more rapid respiratory rate utilizing common intermediates, thus
reducing photosynthesis.
Secondly, oxygen may compete with CO2 and hydrogen becomes
reduced in place of CO2.
Thirdly, O2 destroys the excited (triplet) state of chlorophyll and
thus inhibits photosynthesis.
26. Water: Water is an essential raw material in carbon assimilation.
Less than 1% of the water absorbed by a plant is used in
photosynthesis. The decrease in water contents of the soil from field
capacity to the permanent wilting point results in the decreased
photosynthesis.
Mineral elements: As discussed earlier, several minerals are
essential for plant growth. These include Mg, Fe, Cu, CI, Mn, P and are
closely associated with reactions of photosynthesis.
Air Pollutants: Gaseous and metallic pollutants decrease
photosynthetic activity. These include ozone, SO2, oxidants, hydrogen
fluorides, etc.
Chemical Compounds: Compounds like HCN, H2S, etc. when
present even in small quantities, depress the rate of photosynthesis by
inhibiting enzymes. In addition chloroform, ether etc., also stop
27. Internal factors affecting photosynthesis
Anatomy
Chlorophyll
Protoplasmic factor
Accumulation of end products
Age of leaf
Demand
Hormones
28. You tube video links for these topics
https://www.youtube.com/watch?v=oAH6IfQfZh4
photosynthesis - Introduction
https://youtu.be/CrDEallsToo Photosynthesis part-2 Absorption
& action spectra
Please like and subscribe the channel so that it will be helpful
for maximum number of students
29. References
Taiz, L. and Zeiger, E. (2010) Plant Physiology. 5th Edition,
Sinauer Associates, Inc., Sunderland.
Hopkins, W.G. and Hüner, N.P. (2004) Introduction to Plant
Physiology. 3rd Edition, John Wiley & Sons, Inc, Hoboken.