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Questions and Answers
What is the primary role of photosynthetic organisms in an ecosystem?
What is the primary role of photosynthetic organisms in an ecosystem?
- Consuming other organisms to obtain energy.
- Decomposing organic material into simpler substances.
- Converting light energy into chemical energy. (correct)
- Regulating the population size of heterotrophs.
Which of the following is the most accurate description of photosynthesis?
Which of the following is the most accurate description of photosynthesis?
- The breakdown of carbohydrates, fats, and proteins to release energy.
- The process by which heterotrophs obtain energy from consuming autotrophs.
- The synthesis of complex organic molecules using light energy. (correct)
- The conversion of chemical energy into kinetic energy.
In the context of energy conversion, what type of energy transformation occurs during photosynthesis?
In the context of energy conversion, what type of energy transformation occurs during photosynthesis?
- Potential energy is converted into light energy.
- Chemical energy is converted into kinetic energy.
- Kinetic energy (sunlight) is converted into chemical energy. (correct)
- Thermal energy is converted into potential energy.
How do heterotrophs primarily obtain the energy they need to survive?
How do heterotrophs primarily obtain the energy they need to survive?
If a new pesticide drastically reduced the population of photosynthetic organisms in an ecosystem, what would be the most likely long-term consequence?
If a new pesticide drastically reduced the population of photosynthetic organisms in an ecosystem, what would be the most likely long-term consequence?
What energy source do embryos receive in greater quantities due to the presence of algae and light exposure?
What energy source do embryos receive in greater quantities due to the presence of algae and light exposure?
Which method was employed to track the transfer of nutrients from algae to amphibian embryos?
Which method was employed to track the transfer of nutrients from algae to amphibian embryos?
In a symbiotic relationship between algae and amphibian embryos, what environmental condition enhances the transfer of sugars from algae to embryos?
In a symbiotic relationship between algae and amphibian embryos, what environmental condition enhances the transfer of sugars from algae to embryos?
How might increased sugar availability affect the development rate of amphibian embryos in an algal symbiotic relationship?
How might increased sugar availability affect the development rate of amphibian embryos in an algal symbiotic relationship?
If amphibian embryos receive more sugars in the light, what might be a potential consequence if the algae in their environment are suddenly deprived of light?
If amphibian embryos receive more sugars in the light, what might be a potential consequence if the algae in their environment are suddenly deprived of light?
If a plant species lacked carotenoids, what would be the most likely observable difference in its photosynthetic capabilities?
If a plant species lacked carotenoids, what would be the most likely observable difference in its photosynthetic capabilities?
A scientist discovers a new pigment in a plant that absorbs light most efficiently at 720 nm. How would including this pigment likely affect the plant's photosynthetic activity?
A scientist discovers a new pigment in a plant that absorbs light most efficiently at 720 nm. How would including this pigment likely affect the plant's photosynthetic activity?
How might a plant adapt to maximize photosynthesis in an environment with high exposure to ultraviolet radiation?
How might a plant adapt to maximize photosynthesis in an environment with high exposure to ultraviolet radiation?
If a plant appears black, what does this indicate about its light absorption properties?
If a plant appears black, what does this indicate about its light absorption properties?
Why is only a small percentage of the sun's energy captured through photosynthesis, considering the abundance of sunlight?
Why is only a small percentage of the sun's energy captured through photosynthesis, considering the abundance of sunlight?
During the regeneration phase of the Calvin cycle, what key molecule is synthesized to ensure the cycle can continue?
During the regeneration phase of the Calvin cycle, what key molecule is synthesized to ensure the cycle can continue?
In the light reactions of photosynthesis, ATP is produced. What is the primary role of this ATP within a plant cell?
In the light reactions of photosynthesis, ATP is produced. What is the primary role of this ATP within a plant cell?
What are the three crucial inputs for the Calvin cycle to efficiently produce carbohydrates?
What are the three crucial inputs for the Calvin cycle to efficiently produce carbohydrates?
Most plant species, like the sycamore tree, utilize which carbon fixation pathway for photosynthesis?
Most plant species, like the sycamore tree, utilize which carbon fixation pathway for photosynthesis?
Which environmental condition favors C3 plants over C4 and CAM plants?
Which environmental condition favors C3 plants over C4 and CAM plants?
In C3 plants, where does the entire process of photosynthesis, including both the light-dependent and Calvin cycle reactions, occur within the leaf?
In C3 plants, where does the entire process of photosynthesis, including both the light-dependent and Calvin cycle reactions, occur within the leaf?
During hot, dry weather, plants often close their stomata to conserve water. What is a direct consequence of this closure in C3 plants?
During hot, dry weather, plants often close their stomata to conserve water. What is a direct consequence of this closure in C3 plants?
How does the buildup of oxygen within the leaf of a C3 plant during stomatal closure affect the photosynthetic process?
How does the buildup of oxygen within the leaf of a C3 plant during stomatal closure affect the photosynthetic process?
What is the primary difference between carbon fixation in C4 and CAM plants?
What is the primary difference between carbon fixation in C4 and CAM plants?
In CAM plants, why does carbon dioxide fixation occur at night?
In CAM plants, why does carbon dioxide fixation occur at night?
What role does malate play in both C4 and CAM plants?
What role does malate play in both C4 and CAM plants?
A plant is discovered with the following characteristics: it thrives in hot, arid conditions, opens its stomata primarily at night, and stores carbon dioxide in a 4-carbon compound. This plant is most likely:
A plant is discovered with the following characteristics: it thrives in hot, arid conditions, opens its stomata primarily at night, and stores carbon dioxide in a 4-carbon compound. This plant is most likely:
If algae within salamander embryos' jelly coats perform photosynthesis, what is the most direct benefit to the salamander embryos?
If algae within salamander embryos' jelly coats perform photosynthesis, what is the most direct benefit to the salamander embryos?
Consider salamander embryos with algae-filled jelly coats. If the surrounding water becomes heavily polluted, reducing light penetration, what is the most likely initial effect on the symbiotic relationship?
Consider salamander embryos with algae-filled jelly coats. If the surrounding water becomes heavily polluted, reducing light penetration, what is the most likely initial effect on the symbiotic relationship?
What is one potential evolutionary advantage of salamander embryos forming a symbiotic relationship with algae?
What is one potential evolutionary advantage of salamander embryos forming a symbiotic relationship with algae?
In the salamander-algae symbiosis, the algae live within the jelly coat of the salamander embryos. Which of the following is the most plausible benefit the algae receive from this relationship?
In the salamander-algae symbiosis, the algae live within the jelly coat of the salamander embryos. Which of the following is the most plausible benefit the algae receive from this relationship?
In C4 plants, what is the primary reason for spatially separating the light-dependent and carbon-fixing reactions?
In C4 plants, what is the primary reason for spatially separating the light-dependent and carbon-fixing reactions?
Which of the following is a key characteristic that distinguishes CAM plants from C3 and C4 plants?
Which of the following is a key characteristic that distinguishes CAM plants from C3 and C4 plants?
A plant is found in a hot, arid environment. It opens its stomata only at night to minimize water loss. Which carbon fixation pathway is this plant MOST likely using?
A plant is found in a hot, arid environment. It opens its stomata only at night to minimize water loss. Which carbon fixation pathway is this plant MOST likely using?
What is the role of Rubisco in C3 photosynthesis, and where does this process primarily occur?
What is the role of Rubisco in C3 photosynthesis, and where does this process primarily occur?
Why is photorespiration considered an inefficient process for plants, and how do C4 and CAM plants minimize it?
Why is photorespiration considered an inefficient process for plants, and how do C4 and CAM plants minimize it?
How does the initial carbon fixation differ between C3 and C4 plants, and what enzyme is responsible for the initial carbon fixation in C4 plants?
How does the initial carbon fixation differ between C3 and C4 plants, and what enzyme is responsible for the initial carbon fixation in C4 plants?
In which type of environment would a C3 plant MOST likely thrive compared to C4 and CAM plants?
In which type of environment would a C3 plant MOST likely thrive compared to C4 and CAM plants?
If a plant species normally using the C3 pathway were genetically modified to express PEP carboxylase in its mesophyll cells, similar to C4 plants, what potential outcome might be observed under hot, dry conditions?
If a plant species normally using the C3 pathway were genetically modified to express PEP carboxylase in its mesophyll cells, similar to C4 plants, what potential outcome might be observed under hot, dry conditions?
Flashcards
Photosynthesis
Photosynthesis
Conversion of sunlight (kinetic energy) into chemical energy (potential energy) by covalently bonding atoms.
Autotroph (Producers)
Autotroph (Producers)
Organisms that produce their own food through photosynthesis, forming the base of ecosystems.
Heterotroph (Consumers)
Heterotroph (Consumers)
Organisms (animals and fungi) that consume producers or other consumers for energy.
Photosynthesis Importance
Photosynthesis Importance
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Synthesis Definition
Synthesis Definition
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What is an Embryo?
What is an Embryo?
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What are Algae?
What are Algae?
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What are Radioactive labels?
What are Radioactive labels?
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What is Photosynthesis?
What is Photosynthesis?
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Algae and Embryo Relationship
Algae and Embryo Relationship
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Electromagnetic Spectrum
Electromagnetic Spectrum
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Chlorophyll a
Chlorophyll a
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Light-Capturing Pigments
Light-Capturing Pigments
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Melanin
Melanin
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Photosynthesis and Absorbed Light
Photosynthesis and Absorbed Light
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C3 Plants
C3 Plants
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C4 Plants
C4 Plants
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CAM Plants
CAM Plants
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C3 Example
C3 Example
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C3 Location
C3 Location
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Where do C4 plants thrive?
Where do C4 plants thrive?
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What conditions do C4 plants adapt to?
What conditions do C4 plants adapt to?
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What environment do CAM plants Live in?
What environment do CAM plants Live in?
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Glucose's Role
Glucose's Role
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RuBP Regeneration
RuBP Regeneration
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ATP Use in Light Reactions
ATP Use in Light Reactions
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CO2, ATP, & NADPH Roles
CO2, ATP, & NADPH Roles
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C3, C4, CAM Plants
C3, C4, CAM Plants
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C3 Plants' Environment
C3 Plants' Environment
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C4 & CAM Plants' Environment
C4 & CAM Plants' Environment
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C3 Photosynthesis
C3 Photosynthesis
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Mesophyll Cell (C4)
Mesophyll Cell (C4)
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Bundle-Sheath Cell (C4)
Bundle-Sheath Cell (C4)
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Nocturnal CO2 Intake
Nocturnal CO2 Intake
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Vacuole (CAM)
Vacuole (CAM)
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Chloroplast (CAM)
Chloroplast (CAM)
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Algal-Embryo Symbiosis
Algal-Embryo Symbiosis
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Study Notes
- Biologists consider photosynthesis to be the most important metabolic process on Earth
- Photosynthesis is the process of converting sunlight (kinetic energy) into chemical energy (covalent bond, potential stored energy) in plants
- Photosynthetic organisms can be producers (autotrophs)
- The basis of every ecosystem on Earth
- Photo means light; synthesis means storing energy by covalently bonding atoms together and forming carbohydrates, fats, and protein
- Heterotrophs are consumers that eat producers (animals and fungi)
- Examples of photosynthetic organisms include algae, plants, protists, and some bacteria
- Photosynthesis requires sunlight
- Oxygen is a byproduct of photosynthesis
- Photosynthesis is considered an oxidation-reduction (redox) process
- Photosynthetic organisms require sunlight, carbon-dioxide (CO2), and water to make their own sugar molecules
- As sugar is formed during photosynthesis, oxygen gas is released into the air
Sunlight
- Powers photosynthesis
- Oxygen is a byproduct
- Photosynthesis is an oxidation-reduction (redox) process
- Sunlight is a component for photosynthetic organisms to make their own molecules of sugar
- Includes sunlight, carbon dioxide (CO2), and water
- Oxygen gas is released into the air as sugar is formed during photosynthesis
- Photosynthesis is evolutionarily advantageous because it allows organisms to produce oxygen
- Photosynthesis means organisms can make their own food, make food for heterotrophs, and use carbon dioxide
- Sunlight emits energy in waves as light kinetic energy
- Visible light is one part of the sun's energy
- Photon's wavelength is the distance it moves during a complete vibration; measured in nanometers
- Shorter a photon's wavelength, the more energy it contains, the more damaging it is to DNA
- Portion of sun's spectrum that reaches earth's surface is between 400 - 750 nanometers
- Main components of sunlight are Gamma rays, X-rays, and Ultraviolet radiation = damage DNA
- Only about 1% of the sun's energy is used for photosynthesis
Chlorophyll
- Captures pigment molecules
- The main photosynthetic pigment in plants, algae, and cyanobacteria
- Pigments in plants specialize in absorbing energy from different wavelengths of light
- Photosynthesis can only use absorbed light
- Reflected light is what you see with your eyes and is not absorbed by a plant's existing chlorophyll
- Plant pigments do not absorb green light, therefore green light is reflected
- Carotenoids reflect longer wavelengths of light, so they appear red, orange, or yellow
- Accessory pigments are always present in plants, but are masked by chlorophyll
- Chlorophyll a: Most abundant and green
- Chlorophyll b & Carotenoids: Accessory pigments; energy-capturing pigment molecules
- Anthocyanins: Protect leaves from damage by UV radiation
Chloroplast
- Contains Chlorophyll = light-harvesting pigments; Chlorophyll is embedded in the thylakoid membrane
- Gas exhange occurs at leaf pores called stomata (s. Stoma – mouth)
- Stroma is the fluid part within the double membrane of chloroplasts; sugars are made in the stroma
- Photosynthesis takes place in mesophyll cells
- Light and carbon reactions of photosynthesis:
- Occur in the chloroplasts
- Light reactions occur in the thylakoid membranes
- Carbon reactions occur in the stroma
Photosystems
- Photosynthesis occurs in photosystems
- A photosystem is a large complex protein in the thylakoid membrane
- Contains a pigment molecule in chloroplasts called chlorophyll that absorbs light and generates O2 during the light reactions of photosynthesis
- A photosystem consists of antenna pigments and a reaction center that contains chlorophyll
Light Reactions
- 1st Stage of Photosynthesis
- Occur in thylakoid membranes
- Light reactions begin photosynthesis
- Water + Light energy is captured by pigment molecules and converted to chemical energy (ATP/NADPH)
- ADP and NADP are electron carrier molecules
- ATP and NADPH are produced to carry stored energy
- Oxygen gas (O2) is formed as a byproduct
- Require ATP Synthase – to moves H+ from ATP into Stroma, using Facilitated diffusion
- Movement is kinetic energy, which covalently bonds ADP to P to make ATP
- Process called Chemiosmotic phosphorylation -> makes ATP
- Electrons arrive at the photosystem (PSI); when light hits PSI, chlorophyll transfers light energy to the electrons
- Electrons move to a second electron transport chain
- Electrons reduce NADP+ to NADPH
- Herbicides stop light Rxn
- example: Roundup/Glyphosate inhibits an enzyme/aa synthesis
Carbon Reactions
- 2nd Stage of Photosynthesis (Calvin Cycle) Produce primarily glucose (as well as starch, cellulose and sucrose)
- Occur in the stroma
- Requires Rubisco Enzyme
- ATP and NADPH produced during light reactions carry the stored chemical energy derived from sunlight
- ATP and NADPH power carbon reactions; Energy (ATP/NADPH) is used to produce sugar
- Occurs in 3 steps
- Carbon Fixation - chloroplast absorbs CO2 and chemically bonds it onto a molecule of RuBP producing an unstable six-carbon organic molecule
- PGAL synthesis: Small organic molecules are formed, and ATP/NADPH from light reactions is converted to PGAL which are building blocks for glucose, aa, and triglyceride
- Regeneration of RuBP: leftovers are turned into an organic molecule
- The C3 pathway is used by all plants to make glucose
- The light reactions produce ATP ,which the plant cell uses to fuel carbon fixation
- CO2 combines with (phosphorylated 5-carbon sugar) RuBP (Ribulose BisPhosphate) in the Calvin reactions
- The reaction is catalyzed by the RUBISCO enzyme (ribulose bisphosphate carboxylase oxygenase), the most abundant protein/enzyme on earth
- The resulting unstable 6-carbon compound breaks down into two molecules of 3-PhosphoGlyceric Acid (PGA)
- PGA molecules are phosphorylated (by ATP) and are reduced (by NADPH) to form PhosphoGlycerAldehyde (PGAL)
- PGS serves as the starting material for the synthesis of glucose, and fructose - Glucose and fructose make the disaccharide sucrose, which travels in solution to other parts of the plant (e.g., fruit, roots) - Glucose is the monomer that is used in the synthesis of polysaccharides starch & cellulose
- RuBP is regenerated from the PGAL leftover molecules
Carbon Fixation
- Plants use variants to fix carbon depending on their environmental adaptations C3, C4, and CAM each do photosynthesis, using different pathways
- C3 plants: Do well in cool/moist weather such as a sycamore tree; Calvin cycle done in the mesophyll which takes in carbon dioxide with Rubisco to produce sugar. All of the photosynthesis occurs in mesophyll cells at once
- C4 plants (Crassulacean Acid Metabolism): are adapted to hot, dry weather such as cactus. light and carbon reactions occur at different times; carbon reactions occur out of the mesophyll to avoid too much oxygen
- Light and carbon reactions occur in different cells
- Carbon reactions (away from oxygen to avoid photorespiration) take place in two types of cells
- Mesophyll
- Bundle Sheath
- CAM metabolism: divide labor between temp sites like in cactus -All reactions for photosynthesis occur in mesophyll cells -Carbon reactions at night to prevent photorespiration. -Used by desert plants like cacti
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Description
Photosynthesis is the conversion of light energy into chemical energy by plants. Photosynthetic organisms are the base of every ecosystem and require sunlight, carbon dioxide, and water to produce sugar molecules, releasing oxygen as a byproduct.
