Chlorophyll is one of a class of pigments that absorbs light energy i.pdfArrowdeepak
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Chlorophyll is one of a class of pigments that absorbs light energy in photosynthesis. Relate the
function of chlorophyll to its location. Design an experiment to investigate the influence of
sunlight on the activity of chlorophyll. Describe what information concerning the structure of
chlorophyll could be inferred from your experiment.
Solution
Answer:
1. (a) Structure of chloroplasts:
i. Double membrane encloses dense fluid stroma.
ii. Interconnected stacks of flattened membranes are present in the stroma.
iii. The flattened membranes are called thylakoids while the stacks are called grana.
iv. Chlorophyll is bound to the thylakoid membranes.
Location: Around the periphery of the cell
How chloroplast structure relates to its function:
i. Dense stacks of thylakoids efficiently absorb light.
ii. Light energy is converted into chemical energy at the thylakoid.
iii. Chemical energy used to build carbohydrate in the stroma.
(b) Experiment to investigate the the effect of sunlight on photosynthesis:
Aim of the experiment:-
To prove that chlorophyll pigment in green leaves is necessary for the plants to prepare their
carbohydrate (starch) food.
Requirements for the experiment:-
A well watered variegated leaf plant, beaker, water, Bunsen burner, mentholated spirit or
rectified spirit or ethanol, iodine solution, a white porcelain tile.
Procedure for the experiments:-
A variegated leaf plant is taken for this particular experiment to prove the necessity of
chlorophyll for photosynthesis. A variegated leaf is a leaf in which different patches of colors are
present in a Croton or Coleus or Geranium plant. The place where green patches are present in
the leaf, chlorophyll pigment is present while at the other color patches present in the leaf
contain other pigments but not chlorophyll.
Before starting the experiment to prove chlorophyll is necessary for photosynthesis an important
step has to be carried out is known as De-starching. De-starching is a step in which the starch
present in the leaves of the plant will be removed by keeping the variegated leaves plant in a dark
room or closed cup-board for about 48 hours. This step is done to ensure that previously
synthesized starch in the leaves get consumed up because photosynthesis doesn\'t occur at that
time as the plant is kept in dark place.
After De-starching step the variegated leaf plant is kept in bright sunlight for about 6 hours.
After this one of the variegated leaf is plucked out from the experimental plant. Then Iodine test
is conducted for this experimental leaf to find out whether the leaf prepared starch through
photosynthesis or not.
Steps to be followed for Iodine test:-
i. The plucked out experimental leaf is immersed in boiling water in the beaker for few minutes
so that the cells of the leaf will be killed and at the same time metabolic activities of the leaf cells
will be stopped.
ii. Now the boiled leaf is taken out from the beaker with the help of a forceps. It is then placed in
a.
Photosynthesis and the leaf - starch testSHANIQUECAREY
Â
This document contains information on photosynthesis including the: raw materials needed, conditions and products. The steps needed by science students to carry out a starch test may also be found in this document. Lastly, you will find a critical thinking question involving a variegated leaf.
Chlorophyll is one of a class of pigments that absorbs light energy i.pdfArrowdeepak
Â
Chlorophyll is one of a class of pigments that absorbs light energy in photosynthesis. Relate the
function of chlorophyll to its location. Design an experiment to investigate the influence of
sunlight on the activity of chlorophyll. Describe what information concerning the structure of
chlorophyll could be inferred from your experiment.
Solution
Answer:
1. (a) Structure of chloroplasts:
i. Double membrane encloses dense fluid stroma.
ii. Interconnected stacks of flattened membranes are present in the stroma.
iii. The flattened membranes are called thylakoids while the stacks are called grana.
iv. Chlorophyll is bound to the thylakoid membranes.
Location: Around the periphery of the cell
How chloroplast structure relates to its function:
i. Dense stacks of thylakoids efficiently absorb light.
ii. Light energy is converted into chemical energy at the thylakoid.
iii. Chemical energy used to build carbohydrate in the stroma.
(b) Experiment to investigate the the effect of sunlight on photosynthesis:
Aim of the experiment:-
To prove that chlorophyll pigment in green leaves is necessary for the plants to prepare their
carbohydrate (starch) food.
Requirements for the experiment:-
A well watered variegated leaf plant, beaker, water, Bunsen burner, mentholated spirit or
rectified spirit or ethanol, iodine solution, a white porcelain tile.
Procedure for the experiments:-
A variegated leaf plant is taken for this particular experiment to prove the necessity of
chlorophyll for photosynthesis. A variegated leaf is a leaf in which different patches of colors are
present in a Croton or Coleus or Geranium plant. The place where green patches are present in
the leaf, chlorophyll pigment is present while at the other color patches present in the leaf
contain other pigments but not chlorophyll.
Before starting the experiment to prove chlorophyll is necessary for photosynthesis an important
step has to be carried out is known as De-starching. De-starching is a step in which the starch
present in the leaves of the plant will be removed by keeping the variegated leaves plant in a dark
room or closed cup-board for about 48 hours. This step is done to ensure that previously
synthesized starch in the leaves get consumed up because photosynthesis doesn\'t occur at that
time as the plant is kept in dark place.
After De-starching step the variegated leaf plant is kept in bright sunlight for about 6 hours.
After this one of the variegated leaf is plucked out from the experimental plant. Then Iodine test
is conducted for this experimental leaf to find out whether the leaf prepared starch through
photosynthesis or not.
Steps to be followed for Iodine test:-
i. The plucked out experimental leaf is immersed in boiling water in the beaker for few minutes
so that the cells of the leaf will be killed and at the same time metabolic activities of the leaf cells
will be stopped.
ii. Now the boiled leaf is taken out from the beaker with the help of a forceps. It is then placed in
a.
Photosynthesis and the leaf - starch testSHANIQUECAREY
Â
This document contains information on photosynthesis including the: raw materials needed, conditions and products. The steps needed by science students to carry out a starch test may also be found in this document. Lastly, you will find a critical thinking question involving a variegated leaf.
Based on ncert and will be suitable for notes. Covers all the domains. In this PPT nutrition is covered and it also describes the structure of chloroplast which is not described in ncert. All the questions whether objective or descriptive are covered. Might be appear lengthy but is suitable for notes.
All the best đ
Photosynthesis definition states that the process exclusively takes place in the chloroplasts through photosynthetic pigments such as chlorophyll a, chlorophyll b, carotene and xanthophyll. All green plants and a few other autotrophic organisms utilize photosynthesis to synthesize nutrients by using carbon dioxide, water and sunlight. The by-product of the photosynthesis process is oxygen.Let us have a detailed look at the process, reaction and importance of photosynthesis.
What Is Photosynthesis in Biology?
The word âphotosynthesisâ is derived from the Greek words phÅs (pronounced: âfosâ) and ĪĪÎŊθÎĩĪΚĪ (pronounced: âsynthesisâ)PhÅs means âlightâ and ĪĪÎŊθÎĩĪΚĪ means, âcombining together.â This means âcombining together with the help of light.â
Photosynthesis also applies to other organisms besides green plants. These include several prokaryotes such as cyanobacteria, purple bacteria and green sulfur bacteria. These organisms exhibit photosynthesis just like green plantsThe glucose produced during photosynthesis is then used to fuel various cellular activities. The by-product of this physio-chemical process is oxygen.
Photosynthesis Reaction
A visual representation of the photosynthesis reaction
Photosynthesis is also used by algae to convert solar energy into chemical energy. Oxygen is liberated as a by-product and light is considered as a major factor to complete the process of photosynthesis.
Photosynthesis occurs when plants use light energy to convert carbon dioxide and water into glucose and oxygen. Leaves contain microscopic cellular organelles known as chloroplasts.
Each chloroplast contains a green-coloured pigment called chlorophyll. Light energy is absorbed by chlorophyll molecules whereas carbon dioxide and oxygen enter through the tiny pores of stomata located in the epidermis of leaves.
Another by-product of photosynthesis is sugars such as glucose and fructose.
These sugars are then sent to the roots, stems, leaves, fruits, flowers and seeds. In other words, these sugars are used by the plants as an energy source, which helps them to grow. These sugar molecules then combine with each other to form more complex carbohydrates like cellulose and starch. The cellulose is considered as the structural material that is used in plant cell walls.
Also Read: Photosynthesis in Higher plants
Where Does This Process Occur?
Chloroplasts are the sites of photosynthesis in plants and blue-green algae. All green parts of a plant, including the green stems, green leaves, and sepals â floral parts comprise of chloroplasts â green colour plastids. These cell organelles are present only in plant cells and are located within the mesophyll cells of leaves.
Factors Affecting Photosynthesis
Photosynthesis process requires several factors such as:
Light Intensity: Increased light intensity results in a higher rate of photosynthesis. On the other hand, low light intensity results in a lower rate of photosynthesis.
The concentration of CO2: Higher conce
Economization of Datura Plant Using Planttissue Cultureiosrjce
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IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Based on ncert and will be suitable for notes. Covers all the domains. In this PPT nutrition is covered and it also describes the structure of chloroplast which is not described in ncert. All the questions whether objective or descriptive are covered. Might be appear lengthy but is suitable for notes.
All the best đ
Photosynthesis definition states that the process exclusively takes place in the chloroplasts through photosynthetic pigments such as chlorophyll a, chlorophyll b, carotene and xanthophyll. All green plants and a few other autotrophic organisms utilize photosynthesis to synthesize nutrients by using carbon dioxide, water and sunlight. The by-product of the photosynthesis process is oxygen.Let us have a detailed look at the process, reaction and importance of photosynthesis.
What Is Photosynthesis in Biology?
The word âphotosynthesisâ is derived from the Greek words phÅs (pronounced: âfosâ) and ĪĪÎŊθÎĩĪΚĪ (pronounced: âsynthesisâ)PhÅs means âlightâ and ĪĪÎŊθÎĩĪΚĪ means, âcombining together.â This means âcombining together with the help of light.â
Photosynthesis also applies to other organisms besides green plants. These include several prokaryotes such as cyanobacteria, purple bacteria and green sulfur bacteria. These organisms exhibit photosynthesis just like green plantsThe glucose produced during photosynthesis is then used to fuel various cellular activities. The by-product of this physio-chemical process is oxygen.
Photosynthesis Reaction
A visual representation of the photosynthesis reaction
Photosynthesis is also used by algae to convert solar energy into chemical energy. Oxygen is liberated as a by-product and light is considered as a major factor to complete the process of photosynthesis.
Photosynthesis occurs when plants use light energy to convert carbon dioxide and water into glucose and oxygen. Leaves contain microscopic cellular organelles known as chloroplasts.
Each chloroplast contains a green-coloured pigment called chlorophyll. Light energy is absorbed by chlorophyll molecules whereas carbon dioxide and oxygen enter through the tiny pores of stomata located in the epidermis of leaves.
Another by-product of photosynthesis is sugars such as glucose and fructose.
These sugars are then sent to the roots, stems, leaves, fruits, flowers and seeds. In other words, these sugars are used by the plants as an energy source, which helps them to grow. These sugar molecules then combine with each other to form more complex carbohydrates like cellulose and starch. The cellulose is considered as the structural material that is used in plant cell walls.
Also Read: Photosynthesis in Higher plants
Where Does This Process Occur?
Chloroplasts are the sites of photosynthesis in plants and blue-green algae. All green parts of a plant, including the green stems, green leaves, and sepals â floral parts comprise of chloroplasts â green colour plastids. These cell organelles are present only in plant cells and are located within the mesophyll cells of leaves.
Factors Affecting Photosynthesis
Photosynthesis process requires several factors such as:
Light Intensity: Increased light intensity results in a higher rate of photosynthesis. On the other hand, low light intensity results in a lower rate of photosynthesis.
The concentration of CO2: Higher conce
Economization of Datura Plant Using Planttissue Cultureiosrjce
Â
IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
MATATAG CURRICULUM: ASSESSING THE READINESS OF ELEM. PUBLIC SCHOOL TEACHERS I...NelTorrente
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In this research, it concludes that while the readiness of teachers in Caloocan City to implement the MATATAG Curriculum is generally positive, targeted efforts in professional development, resource distribution, support networks, and comprehensive preparation can address the existing gaps and ensure successful curriculum implementation.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
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Letâs explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
Delivering Micro-Credentials in Technical and Vocational Education and TrainingAG2 Design
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Explore how micro-credentials are transforming Technical and Vocational Education and Training (TVET) with this comprehensive slide deck. Discover what micro-credentials are, their importance in TVET, the advantages they offer, and the insights from industry experts. Additionally, learn about the top software applications available for creating and managing micro-credentials. This presentation also includes valuable resources and a discussion on the future of these specialised certifications.
For more detailed information on delivering micro-credentials in TVET, visit this https://tvettrainer.com/delivering-micro-credentials-in-tvet/
2. Learning
objectives
âĸ You should know:
īļ How plants make
carbohydrates by
photosynthesis
īļ The structure of leaves
īļ How plants use the glucose
they produce in photosynthesis
īļ How to carry out investigations
into photosynthesis
īļ The factors that affect the rate
of photosynthesis
īļ Why plants need nitrate and
magnesium ions 2
3. Uses of glucose in the plant
ī One of the first carbohydrates to be made in photosynthesis is glucose.
3
1. Used for energy
âĸ Energy may be released from glucose in the leaf.
âĸ All cells need energy, which they obtain by the process of respiration.
âĸ Some of the glucose which a leaf makes will be broken down by
respiration, to release energy.
4. Uses of glucose in the plant
2. Stored as starch
âĸ Glucose is a simple sugar. It is soluble in water, and quite a reactive
substance. Therefore, it is not a very good storage molecule:
a) First, being reactive, it might get involved in chemical reactions where
it is not wanted.
b) Secondly, it would dissolve in the water in and around the plant cells,
and might be lost from the cell.
c) Thirdly, when dissolved, it would increase the concentration of the
solution in the cell, which could cause damage.
âĸ Thus, the glucose is converted into starch to be stored.
âĸ Starch is a polysaccharide, made of many glucose molecules joined
together. Being such a large molecule, it is not very reactive, and not very
soluble.
âĸ Starch can be made into granules which can be easily stored inside the
chloroplasts. 4
5. Uses of glucose in the plant
3. Used to make proteins and other organic substances
âĸ The plant can use glucose as a starting point for making all the other
organic substances it needs- sucrose, cellulose, fats and oils.
âĸ Plants can also use glucose to make amino acids, which can be built
into proteins.
īŧAir is 78% nitrogen- it is useless to plants because it is very
unreactive.
īŧPlants have to be supplied with nitrogen in a more reactive form,
usually as nitrate ions (NO3
-).
īŧPlants absorb nitrate ions from the soil, through their root hairs, by
diffusion and active transport.
īŧThe nitrate ions combine with glucose to make amino acids. The
amino acids are then strung together to form protein molecules.
5
6. Uses of glucose in the plant
3. Used to make proteins and other organic substances
âĸ Plants need nitrogen and magnesium to make chlorophyll.
īŧ Magnesium is obtained from the soil
âĸ Farmers often add extra mineral ions to the soil in which their crops are
growing, to make sure that they do not run short of these essential
substances.
6
7. Uses of glucose in the plant
4. Changed to sucrose for transport
âĸ A molecule has to be small and soluble to be transported easily.
īŧGlucose is small, soluble but it is also rather reactive.
7
âĸ The sucrose may later be turned back into
glucose again:
i. to be broken down to release energy
ii. turned into starch and stored
iii. used to make other substances which are
needed for growth.
īŧIt is therefore converted to the complex
sugar sucrose to be transported.
īŧ Sucrose dissolves in the sap in the
phloem vessels, and can be distributed to
whichever parts of the plant need them.
8. Testing leaves for starch
ī Iodine solution is used to test for starch.
ī A blue-black colour shows that starch is present.
8
ī If you put iodine solution onto a leaf which
contains starch, it will not immediately turn
black:
âĸ The iodine solution cannot get through
the cell membranes to reach the starch
inside the chloroplast in the cells and
react with it.
âĸ The green colour of the leaf and the
brown iodine solution can look black
together.
9. Testing leaves for starch
ī Therefore, before testing a leaf for starch, you must break down the cell
membranes, and get rid of the green colour (chlorophyll) as below:
9
1. Take a leaf from a healthy plant, and drop it
into boiling water in a water bath. Leave for
about 30 s. Turn off the Bunsen flame.
2. Remove the leaf, and drop it into a tube of
alcohol in the water bath. Leave it until all the
chlorophyll has come out of the leaf.
3. Remove the brittle leaf from the alcohol and
dip it into hot water again to soften it.
4. Spread the leaf on a white tile, and cover it
with iodine solution. A blue-black colour shows
that the leaf contains starch.
10. Experimental controls
ī In each investigation, the plant is given everything it needs, except
for one substance.
ī Another plant is used at the same time. This is a control. The control
is given everything it needs, including the substance being tested for.
Sometimes the control is a leaf, or even a part of a leaf, from the
experimental plant. The important thing is that the control has all the
substances it needs, while the experimental plant - or leaf - is lacking
one substance.
ī Both plants (or leaves) are then treated in exactly the same way. Any
differences between them at the end of the investigation, therefore,
must be because of the substance being tested.
ī At the end of the investigation, test a leaf from your experimental
plant and one from your control to see if they have made starch. By
comparing them, you can find out which substances are necessary
for photosynthesis. 10
11. Destarching plants
ī It is very important that the leaves you are testing should not
have any starch in them at the beginning of the investigation. If
they did, and you found that the leaves contained starch at the
end of the investigation, you could not be sure that they had
been photosynthesising. The starch might have been made
before the investigation began.
ī So, before doing any of these investigations, you must destarch
the plants. The easiest way to do this is to leave them in a dark
cupboard for at least 24 hours .
ī The plants cannot photosynthesise while they are in the
cupboard because there is no light. So they use up their stores
of starch. To be certain that they are thoroughly destarched, test
a leaf for starch before you begin. 11
12. 1. Take a plant, growing in a pot. Leave it
in a cupboard for a few days, to
destarch it.
12
To see if light is needed for photosynthesis
2. Test one of its leaves for starch, to check that it does not contain any.
3. Using a folded piece of black paper or aluminium foil, a little larger than a
leaf, cut out a shape. Fasten the paper or foil over both sides of a leaf on
your plant, making sure that the edges are held firmly together. Donât
take the leaf off the plant!
4. Leave the plant near a warm, sunny window for a few days.
5. Remove the cover from the leaf, and test the leaf for starch.
Safety precautions:
âĸ Wear eye protection if available.
âĸ Take care with the boiling water.
âĸ Alcohol is very flammable. Turn out your Bunsen flame
before putting the tube of alcohol into the hot water.
âĸ Use forceps to handle the leaf.
13. To see if chlorophyll is needed for photosynthesis
1. Destarch a plant with variegated (green and white)
leaves. Then leave your plant in a warm, sunny spot for
a few days.
2. Test one of the leaves for starch.
13
Results:
Only the parts that were
previously green turn
blue-black when
stained with iodine. The
parts that were white
were stained brown.
14. 1. Water two destarched potted plants and enclose
their shoots in polythene bags.
2. In one pot place a dish of soda-lime
to absorb the carbon dioxide from the air (the
experiment).
3. In the other place a dish of sodium
hydrogen carbonate solution
to produce carbon dioxide (the control).
4. Place both plants in the light for several hours
and then test a leaf from each for starch.
14
To see if carbon dioxide is needed for photosynthesis
Results:
The leaf that had no carbon dioxide remains brown when stained with iodine.
The one from the polythene bag containing carbon dioxide turns blue-black when
stained with iodine.
15. To show that oxygen is produced in photosynthesis
1. Place an inverted funnel over some aquatic plant in a beaker of
water.
2. Fill a test tube with water and place it upside-down over the funnel
stem.
15
3. Leave the apparatus near a warm, sunny
window for a few days.
4. Carefully remove the test tube from the top of
the funnel, allowing the water to run out, but not
allowing the gas to escape.
5. Insert a glowing splint carefully into the gas
in the test tube. If it bursts into flame, then the
gas is oxygen.