Photosynthesis is the process by which plants, algae, and cyanobacteria use sunlight, water and carbon dioxide to produce oxygen and energy in the form of ATP and NADPH. It occurs in two stages - the light-dependent reactions in which solar energy is captured and converted to chemical energy in the form of ATP and NADPH, and the carbon fixation reactions where carbon dioxide is incorporated into organic compounds like glucose using the energy from the light reactions. The light reactions take place in the thylakoid membranes of chloroplasts and involve two photosystems that work together to produce ATP and NADPH. The carbon fixation reactions occur in the stroma and involve the Calvin cycle which uses ATP and NADPH to reduce
dark reactions in plants botany calvin cycle biosynthetic pathway photosynthesis stages of photosynthesis steps of Calvin cycle carboxylation
reduction regeneration end products of calvin cycle
Photosynthesis overview
A. Purpose
B. Location
The light vs. the “dark” reaction
Chloroplasts pigments
A. Light absorption
B. Types
Light reactions
A. Photosystems
B. Photophosphorylation
V. The light independent reaction (“dark” reaction)
A. Carbon “fixation”
B. Reduction
C. Regeneration
VI. Alternative plants
dark reactions in plants botany calvin cycle biosynthetic pathway photosynthesis stages of photosynthesis steps of Calvin cycle carboxylation
reduction regeneration end products of calvin cycle
Photosynthesis overview
A. Purpose
B. Location
The light vs. the “dark” reaction
Chloroplasts pigments
A. Light absorption
B. Types
Light reactions
A. Photosystems
B. Photophosphorylation
V. The light independent reaction (“dark” reaction)
A. Carbon “fixation”
B. Reduction
C. Regeneration
VI. Alternative plants
Recognize the importance of photosynthesis for our survival;
Identify the reactants and products of photosynthesis;
To draw the absorption and action spectrum of photosynthesis
Explain and illustrate the two phases of photosynthesis.
The origin and geological history of oxygenrita martin
Oxygen third most profusely found element in the universe Commercially, oxygen can be prepared by the process of liquefaction and fractional distillation of air and through electrolysis of water
Recognize the importance of photosynthesis for our survival;
Identify the reactants and products of photosynthesis;
To draw the absorption and action spectrum of photosynthesis
Explain and illustrate the two phases of photosynthesis.
The origin and geological history of oxygenrita martin
Oxygen third most profusely found element in the universe Commercially, oxygen can be prepared by the process of liquefaction and fractional distillation of air and through electrolysis of water
this presentation contains briefing of the chapter as per NCERT syllabus in details that contains photosynthesis process, early experiments, photosynthetic pigments,photophosphorylation, light reactions and dark reactions n factors affecting photsynthesis.
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 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.
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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.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
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!
2. 2
Photosynthesis Overview
Energy for all life on Earth ultimately comes
from photosynthesis.
6CO2 + 12H2O C6H12O6 + 6H2O + 6O2
Oxygenic photosynthesis is carried out by:
cyanobacteria, 7 groups of algae,
all land plants
3. 3
Photosynthesis Overview
Photosynthesis is divided into:
light-dependent reactions
-capture energy from sunlight
-make ATP and reduce NADP+ to NADPH
carbon fixation reactions
-use ATP and NADPH to synthesize
organic molecules from CO2
7. 7
Discovery of Photosynthesis
The work of many scientists led to the
discovery of how photosynthesis works.
Jan Baptista van Helmont (1580-1644)
Joseph Priestly (1733-1804)
Jan Ingen-Housz (1730-1799)
F. F. Blackman (1866-1947)
8. 8
Discovery of Photosynthesis
C. B. van Niel, 1930’s
-proposed a general formula:
CO2+H2A + light energy CH2O + H2O + 2A
where H2A is the electron donor
-van Niel identified water as the source of the
O2 released from photosynthesis
-Robin Hill confirmed van Niel’s proposal that
energy from the light reactions fuels carbon
fixation
9. 9
Pigments
photon: a particle of light
-acts as a discrete bundle of energy
-energy content of a photon is inversely
proportional to the wavelength of the light
photoelectric effect: removal of an electron
from a molecule by light
-occurs when photons transfer energy to
electrons
11. 11
Pigments
Pigments: molecules that absorb visible
light
Each pigment has a characteristic
absorption spectrum, the range and
efficiency of photons it is capable of
absorbing.
13. 13
Pigments
chlorophyll a – primary pigment in plants
and cyanobacteria
-absorbs violet-blue and red light
chlorophyll b – secondary pigment
absorbing light wavelengths that
chlorophyll a does not absorb
14. 14
Pigments
Structure of pigments:
porphyrin ring: complex ring structure with
alternating double and single bonds
-magnesium ion at the center of the ring
-photons excite electrons in the ring
-electrons are shuttled away from the ring
16. 16
Pigments
accessory pigments: secondary pigments
absorbing light wavelengths other than
those absorbed by chlorophyll a
-increase the range of light wavelengths that
can be used in photosynthesis
-include: chlorophyll b, carotenoids,
phycobiloproteins
-carotenoids also act as antioxidants
17. • Carotenoids
– Carbon rings linked to
chains with alternating
single and double
bonds
– Can absorb photons
with a wide range of
energies
– Also scavenge free
radicals – antioxidant
• Protective role
• Phycobiloproteins
– Important in low-light
ocean areas
17
18. 18
Photosystem Organization
A photosystem consists of
1. an antenna complex of hundreds of
accessory pigment molecules
2. a reaction center of one or more
chlorophyll a molecules
Energy of electrons is transferred through
the antenna complex to the reaction
center.
20. 20
Photosystem Organization
At the reaction center, the energy from the
antenna complex is transferred to
chlorophyll a.
This energy causes an electron from
chlorophyll to become excited.
The excited electron is transferred from
chlorophyll a to an electron acceptor.
Water donates an electron to chlorophyll a
to replace the excited electron.
22. 22
Light-Dependent Reactions
Light-dependent reactions occur in 4 stages:
1. primary photoevent – a photon of light is
captured by a pigment molecule
2. charge separation – energy is transferred
to the reaction center; an excited electron
is transferred to an acceptor molecule
3. electron transport – electrons move
through carriers to reduce NADP+
4. chemiosmosis – produces ATP
24. 24
Light-Dependent Reactions
In sulfur bacteria, only one photosystem is
used for cyclic photophosphorylation
1. an electron joins a proton to produce
hydrogen
2. an electron is recycled to chlorophyll
-this process drives the chemiosmotic
synthesis of ATP
25. 25
Light-Dependent Reactions
In chloroplasts, two linked photosystems are
used in noncyclic photophosphorylation
1. photosystem I
-reaction center pigment (P700) with a peak
absorption at 700nm
2. photosystem II
-reaction center pigment (P680) has a peak
absorption at 680nm
26. 26
Photosystem II
• Resembles the reaction center of purple bacteria
• Core of 10 transmembrane protein subunits with
electron transfer components and two P680
chlorophyll molecules
• Reaction center differs from purple bacteria in
that it also contains four manganese atoms
– Essential for the oxidation of water
• b6-f complex
– Proton pump embedded in thylakoid membrane
27. 27
Photosystem I
• Reaction center consists of a core
transmembrane complex consisting of 12
to 14 protein subunits with two bound P700
chlorophyll molecules
• Photosystem I accepts an electron from
plastocyanin into the “hole” created by the
exit of a light-energized electron
• Passes electrons to NADP+ to form
NADPH
29. 29
Light-Dependent Reactions
Photosystem II acts first:
-accessory pigments shuttle energy to the
P680 reaction center
-excited electrons from P680 are transferred
to b6-f complex
-electron lost from P680 is replaced by an
electron released from the splitting of
water
30. 30
Light-Dependent Reactions
The b6-f complex is a series of electron
carriers.
-electron carrier molecules are embedded in
the thylakoid membrane
-protons are pumped into the thylakoid
space to form a proton gradient
31. 31
Light-Dependent Reactions
Photosystem I
-receives energy from an antenna complex
-energy is shuttled to P700 reaction center
-excited electron is transferred to a
membrane-bound electron carrier
-electrons are used to reduce NADP+ to
NADPH
-electrons lost from P700 are replaced from
the b6-f complex
32. 32
Light-Dependent Reactions
ATP is produced via chemiosmosis.
- ATP synthase is embedded in the
thylakoid membrane
-protons have accumulated in the thylakoid
space
-protons move into the stroma only through
ATP synthase
-ATP is produced from ADP + Pi
35. 35
Carbon Fixation Reactions
To build carbohydrates, cells need:
1. energy
-ATP from light-dependent reactions
2. reduction potential
-NADPH from photosystem I
36. 36
Carbon Fixation Reactions
Calvin cycle
-biochemical pathway that allows for carbon
fixation
-occurs in the stroma
-uses ATP and NADPH as energy sources
-incorporates CO2 into organic molecules
37. 37
Carbon Fixation Reactions
carbon fixation – the incorporation of CO2
into organic molecules
-occurs in the first step of the Calvin cycle
ribulose-bis-phosphate + CO2 2(PGA)
5 carbons 1 carbon 3 carbons
The reaction is catalyzed by rubisco.
39. 39
Carbon Fixation Reactions
The Calvin cycle has 3 phases:
1. carbon fixation
RuBP + CO2 2 molecules PGA
2. reduction
PGA is reduced to G3P
3. regeneration of RuBP
G3P is used to regenerate RuBP
40. 40
Carbon Fixation Reactions
Glucose is not a direct product of the Calvin
cycle.
-2 molecules of G3P leave the cycle
-each G3P contains 3 carbons
-2 G3P are used to produce 1 glucose in
reactions in the cytoplasm
41. 41
Carbon Fixation Reactions
During the Calvin cycle, energy is needed.
The energy is supplied from:
- 18 ATP molecules
- 12 NADPH molecules
42. 42
Carbon Fixation Reactions
The energy cycle:
-photosynthesis uses the products of
respiration as starting substrates
-respiration uses the products of
photosynthesis as starting substrates
45. 45
Photorespiration
Rubisco has 2 enzymatic activities:
1. carboxylation – the addition of CO2 to
RuBP
-favored under normal conditions
2. photorespiration – the oxidation of
RuBP by the addition of O2
-favored in hot conditions
CO2 and O2 compete for the active site on
RuBP.
47. 47
Photorespiration
Some plants can avoid photorespiration by
using an enzyme other than rubisco.
-PEP carboxylase
-CO2 is added to phosphoenolpyruvate
(PEP)
-a 4 carbon compound is produced
-CO2 is later released from this 4-carbon
compound and used by rubisco in the
Calvin cycle
48. 48
Photorespiration
C4 plants
-use PEP carboxylase to capture CO2
-CO2 is added to PEP in one cell type
(mesophyll cell)
-the resulting 4-carbon compound is moved
into a bundle sheath cell where the CO2 is
released and used in the Calvin cycle
51. 51
Photorespiration
CAM plants
-CO2 is captured at night when stomata are
open
-PEP carboxylase adds CO2 to PEP to
produce a 4 carbon compound
-this compound releases CO2 during the day
-CO2 is then used by rubisco in the Calvin
cycle
