Photosynthesis has two phases - the light reaction which uses energy from sunlight to produce ATP and NADPH in the thylakoid membrane, and the dark reaction (Calvin cycle) which uses these products to fix carbon and produce glucose. The Calvin cycle fixes carbon dioxide into a three-carbon molecule (G3P) in three turns of the cycle requiring 6 molecules of CO2, 6 NADPH, 9 ATP, and producing one G3P molecule. Some plants like maize use the C4 pathway to concentrate carbon dioxide around RuBisCO and prevent photorespiration. CAM plants open their stomata at night to fix carbon dioxide into malic acid then release it for the Calvin cycle in
Understanding the Basis of Photosynthesis.Light reaction, Carbon Fixation, Calvin Cycle C4 Plants and CAM plants.
Adapted from and copyright @ Plant Physiology, 3rd edby Lincoln Taiz and Eduardo Zeiger
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.
Photophosphorylation/Photosynthesis/Light reactionM. Adnan Qadar
This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors.
References
1. Taiz & Zeiger
2. Salisbury author
This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors.
Understanding the Basis of Photosynthesis.Light reaction, Carbon Fixation, Calvin Cycle C4 Plants and CAM plants.
Adapted from and copyright @ Plant Physiology, 3rd edby Lincoln Taiz and Eduardo Zeiger
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.
Photophosphorylation/Photosynthesis/Light reactionM. Adnan Qadar
This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors.
References
1. Taiz & Zeiger
2. Salisbury author
This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors. This ppt contain an easy understanding guide for teachers and students. All the contents are reviewed and edited by senior professors.
photosynthesis Presentation on AgricultureFayzanKhan10
photosynthesis, the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.
What are rubisco and RuBP And what do they do Briefly list 4 simil.pdfforecastfashions
What are rubisco and RuBP? And what do they do? Briefly list 4 similarities in how ATP is
made in mitochondria and in chloroplasts. A. How does the second law of thermodynamics
explain why diffusion occurs across a membrane? B. Describe how oxidative phosphorylation,
substrate-level phosphorylation, and photo phosphorylation differ in the way ATP is made.
Solution
RuBisCO , is an enzyme Which is used in the Calvin cycle for catalyzing the first step of carbon
fixation, a process by which the atoms of atmospheric carbon dioxide are made available to
organisms in the form of energy-rich molecules such as sucrose. RuBisCO catalyzes either the
carboxylation or oxygenation of ribulose-1,5-bisphosphate (also known as RuBP) with carbon
dioxide or oxygen.
Ribulose-1,5-bisphosphate (RuBP) is an important 5-carbon intermediate in the Calvin cycle
taking place during photosynthesis. It is the substrate, which is used by the enzyme to fix CO2 to
create a highly unstable 6 Carbon PO4 which decays into two molecules of glycerate 3-
phosphate.
In both i.e. Mitochindria as well as in Chloroplast ATP synthesis takes place via a proton
gradient-
Both have ATP synthatases
Both have Electron Transport Chains
Both have 70s ribosomes.
The second law is a trend towards the randimization or increasing entropy. When the
concentration of a substance on both sides of a membrane are equal, the distribution is more
random than when they are unequal. Diffusion of a substance to a region, where it is initially less
concentrated increases entropy, making it energetically favourable (SPONTANEOUS) process.
-Substrate level phosphorylation occurs in the cytoplasm during Glycolysis and Mitochondria
during Krebs cycle.
-2ATP/GTP are produced by conversion of ADP or GDP
OXIDATIVE PHOSPHORYLATION
-Occurs in Mitochondria
Occurs during respiration
pigment systems are not involved
ATP is produced from ADP and iP
Molecular O2 is required for terminal oxidation.
PHOTOPHOSPHORYLATION
Occurs during photosynthesis inside the chloroplasts.
Pigment systemt I & II are involved
Sunlight is the external source of energy
Molecular Oxygen is not required.
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.
(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.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
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 .
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 increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
3. content
Calvin Cycle
Hatch and Slack Cycle (C4
cycle)
Structure of chloroplast
What is Photosynthesis
Cam cycle
Reference
4. What is Photosynthesis
It is a process in which energy from sunlight is transformed into chemical
energy that is stored in carbohydrates and other organic molecules.
Two phase of photosynthesis.
1) Light reaction or light dependent phase.
- The reaction occurs in thylakoids.
- The products are ATP and NADPH.
2) Dark reaction or light independent phase
- The reaction occur in stroma.
- Product are Trioses, Tetroses, Pentoses, Hexoses & Heptose.
5. Structure of Chloroplast
It is Double membrane contains thylakoids sacs.
Chlorophyll, the green pigment within chloroplast gives Green
color of leaves.
Chloroplast also contains stroma, a dense interior fluid.
Ultrastructure of chloroplast
Electron microscopic studies reveals that chloroplast is composed
of following two parts:-
1) Limiting membrane
2) Stroma
8. Overview
The Calvin cycle is part of photosynthesis, which occurs in two stages. In
the first stage, chemical reactions use energy from light to produce ATP
and NADPH. In the second stage (Calvin cycle or dark reactions), carbon
dioxide and water are converted into organic molecules, such as glucose.
Although the Calvin cycle may be called the "dark reactions," these
reactions don't actually occur in the dark or during nighttime. The
reactions require reduced NADP, which comes from a light-dependent
reaction.
9. What is Calvin cycle
Calvin cycle is a set of light independent redox reactions
that occur during photosynthesis and carbon fixation to
convert carbon dioxide into the sugar glucose. These
reactions occur in the stroma of the chloroplast, which is
the fluid-filled region between the thylakoid membrane
and inner membrane of the organelle. Here is a look at
the redox reactions that occur during the Calvin cycle
10. The Calvin cycle consists of:
Carbon fixation - Carbon dioxide (CO2) is reacted to produce
glyceraldehyde 3-phosphate (G3P). The enzyme RuBisCO catalyzes the
carboxylation of a 5-carbon compound to make a 6-carbon compound
that splits in half to form two 3-phosphoglycerate (3-PGA) molecules.
The enzyme phosphoglycerate kinase catalyzes phosphorylation of 3-
PGA to form 1,3-biphosphoglycerate (1,3BPGA).
Reduction reactions - The enzyme glyceraldehyde 3-phosphate
dehydrogenase catalyzes reduction of 1,3BPGA by NADPH.
Ribulose 1,5-bisphosphate (RuBP) regeneration - At the end of the
regeneration, the net gain of the set of reactions is one G3P molecule
per 3 carbon dioxide molecules
11. Calvin Cycle Chemical Equation
The overall chemical equation for the Calvin cycle is:
3 CO2 + 6 NADPH + 5 H2O + 9 ATP → glyceraldehyde-3-phosphate (G3P) +
2 H+ + 6 NADP+ + 9 ADP + 8 Pi (Pi = inorganic phosphate)
Six runs of the cycle are required to produce one glucose molecule.
Surplus G3P produced by the reactions can be used to form a variety of
carbohydrates, depending on the needs of the plant.
12. Three turns of the Calvin cycle are needed to make one G3P
molecule that can exit the cycle and go towards making glucose.
Let’s summarize the quantities of key molecules that enter and
exit the Calvin cycle as one net G3P is made. In three turns of the
Calvin cycle:
Summary of Calvin cycle reactants and products
13. Hatch and Slack Cycle (C4 cycle)
C4 pathway- It also involves carbon fixation to synthesize 4- carbon
compound oxaloacetic acid, C4 pathway occurs only in some plants to
prevent loss of energy by photorespiration.
In the C4 cycle, the first stable compound is 4- Carbon compound,
namely Oxaloacetic acid (OAA). Hence it is called C4 cycle. The
primary CO2 acceptor is Phosphoenole pyruvic acid (PEP). It is a
process of CO2 fixation. CO2 fixation is fast and more efficient. This
pathway was worked out by Hatch and Slack in 1966. Hence the C4
cycle is also called as Hatch- Slack cycle.
Fixation of one molecule of CO2 requires 5 ATP and 3 NADH.
C4 cycle occurs in plants like maize, sorghum etc
14. Kranz anatomy
The special structure of leaves in C4
PLANTS (e.g. maize) where the tissue
equivalent to the spongy mesophyll
cells is clustered in a ring around the
leaf veins, outside the bundle-sheath
cells. (The term ‘Kranz’ means wreath
or ring in German). The bundle-sheath
cells contain large CHLOROPLASTS
whereas the spongy mesophyll cells
have few if any chloroplasts, unlike
their counterparts in C3 plants (see
MESOPHYLL).
15.
16.
17. Steps of C4 pathway
Carboxylation:It takes place in the chloroplast of mesophyll cells.
Phosphoenol pyruvate (PEP), a 3 carbon compound picks up CO2 and
changes into 4 C- Oxaloacetate in the presence of water. This reaction is
catalyzed by the enzyme, PEP Carboxylase. PEP
+ CO2+H2O -------- oxaloacetate (4C) + H3PO4 (PEP carboxylase)
Breakdown:Oxaloacetate breaks down readily into 4 C- Malate and
Aspartate in the presence of the enzymes, transaminase and Malate
dehydrogenase. Oxaloacetate
(4C) ------- Aspartate (4C) +Malate (4C) (Transaminase, Malate
dehydrogenase). These
compounds diffuse from the mesophyll cells into sheath cells.
Next->
18. Splitting: In the sheath cells Malate and Aspartate split enzymatically
to yield free CO2 and 3C- pyruvate. The CO2 is used in Calvin cycle in
the sheath cells.
Malate --------------- CO2 + Pyruvate (Decarboxylation)
Phosphorylation:The pyruvate molecule is transferred to chloroplasts
of mesophyll cells, where it is phosphorylated to regenerate PEP in
the presence of ATP. This reaction is catalyzed by pyruvate
phosphokinase and the phosphoenol pyruvate is regenerated.
Pyruvate + ATP+ Pi --------------- PEP + AMP + Pyrophosphate (Pyruvate
phosphokinase)
19. Significance of C4 cycle
Fixation of CARBON dioxide is more efficient in C4 cycle than C3 cycle
because of following reasons
1) production in C4 plant 2-3 times grater than C3 plant.
2)C4 plant can be photosynthesize even in the presence of low
concentration of carbon dioxide.
3)
20. Cam cycle
Introduction and definition:-It occurs mostly in succulent plants
which grow under semi-arid conditions. The fixation of CO2 only at
night because the stomata is open only at these plants observe CO2
and convert into mallic acid.
At day time the decarboxylation of malic acid take place and CO2 is
released and used in C3 cycle.
It was first seen in crassulacea family e.g. Bryophyllum sedum and
kalanchoe and hence it is also called Crassulacean Acid Metabolism
21. The mechanism or cycle is reported on following families:
1) Dicotyledenous family:- Crassulacea, Azoaceae, Asclepiadaceae,
Caryophyllaeae,Chenopodium compositae, Canvolvulaceae,
Euphorpiaceae etc.
2) Monocotoledenous family:- Liliaceae, orchidaceae etc
3) Pteridophytes:- Polypediaceae.
22. 1) The stomata is remain closed at day and open at night.
2) CO2 fixation takes place in chlorophyll containing cell of leaves and stem
during night and malic acid synthesis take place.
3) malic acid is formed during night and stored in large vacuoles.
4) Decarboxylation of malic acid and converted into starch by C3 cycle.
5) the level of malate (malic) acid is increased and the level of gluecan
because decrease at night and vice versa.
6) Transpiration rate is low as well as parenchymatous cell are larger and
vacuolated.
7) function of vacuoles as a site of accumulation of organic acid.
8) They posses high level of gaseous exchanges and xerophytic characters.
Characteristics feature of CAM cycle:-
23.
24.
25. Mechanism of CAM cycle:-
CAM cycle take place in two parts:-
1) Acidification. 2) Deacidification
Acidification:- It takes please in following steps:-
1) Carbohydrates are converted into PEP (phosphenol pyruvic acid) through
glycosis.
2) The CO2 combines with PEP Erin the presence of phosphenol-Carboxylase
(PEP-C) enzyme to produce oxalicacetic acid (OAA)
26. 3) The OAA is now reduced to malate in the presence of mallate
dehydogenase enzyme and form NADPH+ ----> NADPH + H+
Deacidification:- the carboxylation of malic acid into pyruvic acid and
CO2 in presence of light called Deacidification.
During day time malic acid is stored in vacuoles is diffused into cytoplast
and become Decarboxylated to produce pyrivic acid and carbon dioxide in
the presence of NADP malic acid.
One molecules of NADP is also reduced in this reaction.
27. 1) the CAM cycle is found in dry habitat plant due to sunken stomata.
2) Stomata in CAM plant remain closed in day time but photosynthesis
take place in the process of Deacidification.
3) As CAM plant are able to fix CO2 in dark, they survive longer with CO2
uptakes.
Significance of CAM cycle:-
