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Photosynthesis produces glucose and carbon monoxide as by-products.
Photosynthesis produces glucose and carbon monoxide as by-products.
False
Chlorophyll is essential for the process of photosynthesis.
Chlorophyll is essential for the process of photosynthesis.
True
Destarching involves exposing a plant to light for 24 hours to increase starch levels.
Destarching involves exposing a plant to light for 24 hours to increase starch levels.
False
Starch can be tested in leaves to confirm the occurrence of photosynthesis.
Starch can be tested in leaves to confirm the occurrence of photosynthesis.
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Leaves are considered non-essential for photosynthesis in plants.
Leaves are considered non-essential for photosynthesis in plants.
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The leaf blade's broad and flat structure helps to maximize the area exposed to sunlight.
The leaf blade's broad and flat structure helps to maximize the area exposed to sunlight.
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The midrib of a leaf does not play a role in transporting materials essential for photosynthesis.
The midrib of a leaf does not play a role in transporting materials essential for photosynthesis.
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The palisade mesophyll cells are located at the lower part of a leaf.
The palisade mesophyll cells are located at the lower part of a leaf.
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Thin leaf structures allow light and carbon dioxide to reach the photosynthetic cells easily.
Thin leaf structures allow light and carbon dioxide to reach the photosynthetic cells easily.
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The extensive network of veins in a leaf ensures efficient transport of materials.
The extensive network of veins in a leaf ensures efficient transport of materials.
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The spongy mesophyll allows gases to diffuse freely inside the leaf.
The spongy mesophyll allows gases to diffuse freely inside the leaf.
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The upper epidermis of dicotyledonous plants contains more stomata than the lower epidermis.
The upper epidermis of dicotyledonous plants contains more stomata than the lower epidermis.
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Guard cells control the passage of nutrients into the leaf.
Guard cells control the passage of nutrients into the leaf.
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The cuticle helps in reducing water loss from the leaf.
The cuticle helps in reducing water loss from the leaf.
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Chloroplasts are the organelles responsible for respiration in plant cells.
Chloroplasts are the organelles responsible for respiration in plant cells.
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The cells in the spongy mesophyll are tightly packed to enhance gas exchange.
The cells in the spongy mesophyll are tightly packed to enhance gas exchange.
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The lower epidermis has stomata to facilitate gas exchange.
The lower epidermis has stomata to facilitate gas exchange.
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Chloroplasts are located in the upper epidermis for optimal light absorption.
Chloroplasts are located in the upper epidermis for optimal light absorption.
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Glucose can be converted into starch for energy storage.
Glucose can be converted into starch for energy storage.
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Intermediate compounds of photosynthesis cannot be synthesized into fatty acids.
Intermediate compounds of photosynthesis cannot be synthesized into fatty acids.
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When light intensity is the limiting factor, decreasing light intensity will increase the rate of photosynthesis.
When light intensity is the limiting factor, decreasing light intensity will increase the rate of photosynthesis.
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Carbon dioxide concentration affects the rate of photosynthesis even when it is not a limiting factor.
Carbon dioxide concentration affects the rate of photosynthesis even when it is not a limiting factor.
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The limiting factor in photosynthesis is the resource that is in the highest supply.
The limiting factor in photosynthesis is the resource that is in the highest supply.
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The grana in chloroplasts help in the efficient transport of photosynthetic products.
The grana in chloroplasts help in the efficient transport of photosynthetic products.
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Thylakoids are responsible for catalyzing reactions in the Calvin cycle.
Thylakoids are responsible for catalyzing reactions in the Calvin cycle.
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The stroma is a jelly-like fluid within the chloroplasts that stores starch grains.
The stroma is a jelly-like fluid within the chloroplasts that stores starch grains.
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Photosynthesis occurs only in the light-dependent reactions.
Photosynthesis occurs only in the light-dependent reactions.
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Chlorophyll molecules in the thylakoids absorb light energy during photosynthesis.
Chlorophyll molecules in the thylakoids absorb light energy during photosynthesis.
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The stacked structure of thylakoids increases surface area for chlorophyll.
The stacked structure of thylakoids increases surface area for chlorophyll.
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The inner membrane of the chloroplast is where the Calvin cycle occurs.
The inner membrane of the chloroplast is where the Calvin cycle occurs.
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Starch grains are a type of product formed during the light-dependent reactions.
Starch grains are a type of product formed during the light-dependent reactions.
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The light energy used in photosynthesis is exclusively for synthesize ATP and NADPH.
The light energy used in photosynthesis is exclusively for synthesize ATP and NADPH.
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The Calvin cycle occurs in the stroma of chloroplasts.
The Calvin cycle occurs in the stroma of chloroplasts.
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NADP is produced as a by-product during the photochemical reactions in photosynthesis.
NADP is produced as a by-product during the photochemical reactions in photosynthesis.
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Triose phosphate molecules are directly converted into oxygen during photosynthesis.
Triose phosphate molecules are directly converted into oxygen during photosynthesis.
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ATP and NADPH produced in photochemical reactions are necessary for the reduction of 3-C compounds in the Calvin cycle.
ATP and NADPH produced in photochemical reactions are necessary for the reduction of 3-C compounds in the Calvin cycle.
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The process of photophosphorylation refers to the production of glucose from carbon compounds.
The process of photophosphorylation refers to the production of glucose from carbon compounds.
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Calvin cycle and photochemical reactions are independent of each other.
Calvin cycle and photochemical reactions are independent of each other.
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Glucose is formed directly from ATP in the Calvin cycle.
Glucose is formed directly from ATP in the Calvin cycle.
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Study Notes
Photosynthesis Overview
- Photosynthesis is the process where complex organic molecules are made from simple inorganic molecules using light energy.
- The word equation for photosynthesis is: carbon dioxide + water → glucose + oxygen (light energy captured by chlorophyll)
- Photosynthesis is crucial for: sustaining plant life, providing food for most organisms, and maintaining the balance of oxygen and carbon dioxide in the atmosphere
Requirements for Photosynthesis
- The presence of starch in leaves can be tested using an iodine test and is evidence of photosynthesis.
- Destarching leaves (removing starch) by keeping them in the dark for 24 hours before an investigation ensures any detected starch was produced during the investigation.
- Chlorophyll, light, carbon dioxide, and water are necessary for photosynthesis
Site of Photosynthesis (Leaves)
- Leaves are the primary photosynthetic organs in plants.
- Leaf structure is adapted for efficient photosynthesis.
- Leaf blade: broad and flat to maximize surface area for light absorption, thin for efficient CO2 access
- Midrib: contains vascular bundles (xylem and phloem) that transport water and minerals to the leaf, and carbohydrates from the leaf respectively.
- Network of veins: branches into an extensive network to support the leaf, maximizing the area exposed to sunlight and ensure efficient transport
- Palisade mesophyll: located at the top of the leaf, packed closely with numerous chloroplast in the cells for maximum light absorption.
- Spongy mesophyll: cells are loosely packed, filled with air spaces, maximizing gas diffusion within the leaf.
- Upper and lower epidermis: containing numerous stomata bordered by guard cells to regulate gas exchange and water loss.
- Cuticle: the upper epidermis layer is often covered by a waxy cuticle to reduce water loss.
Chloroplasts (Organelles)
- Chloroplasts are organelles where photosynthesis occurs in plant cells.
- Chloroplast structure is adapted for efficient photosynthesis:
- Thylakoid: stacked into grana, providing large surface area for chlorophyll packing.
- Grana: interconnected to efficiently transport photosynthetic products within the chloroplast
- Stroma: jelly-like fluid, containing enzymes that catalyze reactions for the Calvin cycle. It also contain starch grains.
The Process of Photosynthesis (Two Stages)
-
Photochemical reactions (light-dependent):
- Occur in the thylakoids of chloroplasts
- Chlorophyll absorbs light, excites electrons to higher energy levels
- As electrons move along the electron transport chain, energy is released, used for ATP synthesis
- Water is split into hydrogen and oxygen (photolysis); hydrogen is accepted by NADP to form NADPH.
- Oxygen is released or utilized for respiration.
-
Calvin cycle (light-independent):
- Occurs in the stroma of chloroplasts
- Carbon dioxide combines with a 5-carbon acceptor molecule to produce a 3-carbon compound
- The 3-carbon compound is reduced (gaining energy) to form triose phosphate using energy from ATP and hydrogen from NADPH.
- Most triose phosphate is used to regenerate the 5-carbon acceptor molecule, requiring energy from ATP.
Interdependence
- Photochemical reactions (light-dependent) produce ATP and NADPH used by the Calvin cycle.
- The Calvin cycle (light-independent) regenerates ADP and NADP to be reused by the photochemical reactions.
Photosynthetic Products
- Triose phosphate is produced by the Calvin cycle → synthesized into glucose
- Glucose used for respiration or converted to other carbohydrates (starch for storage, sucrose for transport, cellulose for cell walls).
Intermediate Compounds
- Intermediate compounds in photosynthesis are formed into glycerol, fatty acids, making lipids.
- Intermediate compounds in photosynthesis can create amino acids using minerals and then to proteins.
Factors Affecting Photosynthesis
- The rate of photosynthesis is affected by environmental factors.
- The factor in the shortest supply (limited) is the limiting factor.
- Light intensity: higher intensity, higher rate as more energy is available for photochemical reactions.
- Carbon dioxide concentration: Higher concentration, higher rate of photosynthesis because more carbon dioxide is available for carbon fixation in the Calvin cycle.
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Description
This quiz covers the essential processes of photosynthesis, including the conversion of light energy into chemical energy, the requirements for the process, and the significance of leaves as the primary site of photosynthesis. Test your understanding of key concepts like the photosynthesis equation and the importance of chlorophyll.
