BIOL1010- Photosynthesis (week 10)

B. Calvin cycle (light-independent)

Carbon fixation occurs in which phase? A. Light-dependent reaction B. Calvin cycle (light-independent) C. Cellular respiration D. All of these

-bigger plants -more diversity in plants -will help control the loss of diversity to climate change -would increase crop yields in areas where conventional fertilizers are not readily available -decreases the greenhouse gases in the atmosphere which helps climate change

Describe some applications for this science that will benefit humans.

(eukaryotic) they enable plants to utilize the energy in sunlight to make sugars from carbon dioxide

Determine the role of chloroplasts

A. Fertilizers

In addition to fuel production, what else might be produced using metabolically engineered bacteria? A. Fertilizers B. Bioplastics C. Medicines D. All of these

A. Light Dependent Reactions

In which of the following parts of photosynthesis is water split and oxygen released? A. Light Dependent Reactions B. Light Independent Reactions C. Calvin Cycle D. Dark Reactions E. All of these

Plasma membrane, the cytoplasm, nucleic acid, ribosomes Chloroplasts have their own ribosomes

Name the four components that all cells have [which of these are also shared by chloroplasts?].

B. H2O

The oxygen that plants release comes from which of the following compounds? A. Air B. H2O C. CO2 D. Soil E. All of the above

Chemoautotroph

they use inorganic molecules as an energy source; organism capable of synthesizing its own food using energy from inorganic molecules

Producers

trophic level that obtains its energy from sunlight, inorganic chemicals, or dead and/ or decaying organic material

Primary Consumers

trophic level that obtains its energy from the primary producers of an ecosystem

-Cyanobacteria: prokaryotes that lack membrane-bound organelles -Cyanobacteria have pigments but no chloroplasts -they are similar to chloroplasts -they are the chloroplasts for prokaryotes

Compare cyanobacteria and chloroplasts [review evidence for endosymbiosis]

-An artificial leaf would go through a process similar to photosynthesis, but it would generate energy that could be stored for later. This would provide a way to stow the energy when the sun is not shining and the air is still. -Natural photosynthesis would be using the energy right away.

Compare the efficiency of an artificial leaf to natural photosynthesis.

The Water (Hydrologic) Cycle: evaporation (water to water vapor)/ sublimation (ice to water vapor) -> condensation/ precipitation-> subsurface water flow (water flows beneath the surface) -> surface runoff/ snowmelt-> streamflow. Long term cycles: most of water/ stored in oceans, underground, ice. Short term cycles: surface water/ runoff water is how minerals are cycled from land to water. -it cools down an environment -helps climate and weather (is essential for both) The Carbon Cycle - rapid carbon exchange among living organisms: - the long-term cycling of carbon through geological processes: carbon is stored for long periods of time in reservoirs (the atmosphere, bodies of water, ocean sediment, soil, land sediments, Earth's interior)/ this is essential for the process of photosynthesis Describe how matter cycles through an ecosystem using the hydrologic and carbon cycles as examples. Discuss long term (reservoirs) and short term cycles for each and the impact of each on climate.

Describe how matter cycles through an ecosystem using the hydrologic and carbon cycles as examples. Discuss long term (reservoirs) and short term cycles for each and the impact of each on climate.

-the sun emits a broad range of electromagnetic radiation, the electromagnetic spectrum is the range of all the possible wavelengths of radiation. Light energy can be absorbed by pigments. Different kinds of pigments exist and each absorbs only certain wavelengths (colors) of visible light. Pigments reflect the color of the wavelength that they cannot absorb. Many photosynthetic organisms have a mixture of pigments; between them, the organism can absorb energy from a wider range of visible-light wavelengths; wavelengths are a form of energy, pigments absorb energy at different wavelengths

Describe the relationship between pigments, the electromagnetic spectrum and photosynthesis.

-Enzymes (are proteins), which are produced by living cells, are catalysts in biochemical reactions (like digestion). Each enzyme is specific for the substrate (a reaction that binds to an enzyme) upon which it acts. Enzymes can function to break molecular bonds, to rearrange bonds, or to form new bonds. They decrease the activation energy needed for a reaction to take place. -Changes in temperature, pH(acidity), and exposure to chemicals lead to permanent changes in the shape of the protein, leading to a loss of function or denaturation

Describe the role of an enzyme in a cell and explain how denaturation would affect its activity.

-Photons------> Energy -Carbon Dioxide-->Converted into sugars -Water (H2O)--->Electrons; Hydrogen for gradient, sugars -Pigments---> Substances that absorb light -Chlorplasts-->Contain pigments, membranes -Rubisco-->Lowers activation energy for sugar production

Describe the structures necessary for photosynthesis.

-Carbon fixation: Carbon dioxide (CO2) is "fixed: from its inorganic form into organic molecules. -the enzyme involved: RuBisCO

Describe the term, carbon fixation, and name the enzyme involved.

A photon (aka packet of light energy) travels until it reaches a molecule of chlorophyll a. The photon causes the electron in the chlorophyll to become excited. The energy given to the electron allows it to break free from an atom of the chlorophyll molecule. In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH. In a series of reactions, the stored energy in ATP and NADPH is used to generate 3-carbon sugars that ultimately become a glucose (C6H12O6) molecule. Because the carbohydrate molecule has six carbon atoms, it takes six turns of the Calvin cycle to make one carbohydrate molecule (one for each carbon dioxide molecule fixed). The bonds in ATP and NADPH are broken to release energy, re-forming ADP, a phosphate group, and NADP+. This recycling makes them available again for the light dependent reactions.

Describe the transformation of energy in photosynthesis from photons to glucose, including the energy carriers that connect light dependent and independent reactions.

(eukaryotic) they harvest energy to power the cell...they supply the energy

Determine the role of mitochondria

(prokaryotic and eukaryotic) they are essential for protein production. They receive and transmit critical information

Determine the role of ribosomes.

Gene expression in cells controls whether a gene is expressed or not; say only this amount of proteins are going to be made this way. This affects protein levels by: transcription stops when protein is not needed (more transcription= more proteins) Gene expression is how enzymes are regulated....it stops the process if you have enough

Evaluate the importance of gene expression in cells, describing how it affects protein levels [how will this affect the types of enzymes produced in specific tissues - e.g. digestive v. blood].

-equipping the system with a different metabolically altered bacterium can produce nitrogen-based fertilizer right in the soil, an approach that would increase crops yields where conventional fertilizers are not readily available

Explain how bacteria contribute to the artificial system

The First Law of Thermodynamics states that energy can neither be created or destroyed (each level must acquire energy from the trophic level below). The Second Law of Thermodynamics states that, during the transfer of energy, some energy is lost as heat (less energy is available at each higher trophic level). Energy pyramids must always be upright because of these two laws.

Explain how the first and second laws of thermodynamics are related to the flow of energy through a food web. (5)

The overall purpose of the light-dependent reactions is to convert light energy into chemical energy. This chemical energy will be used by the Calvin cycle to fuel the assembly of sugar molecules. A photon or "packet" of light energy travels until it reaches a molecule of chlorophyll a. The photon causes an electron in the chlorophyll to become "excited." The energy given to the electron allows it to break free from an atom of the chlorophyll molecule. To replace the electron in the chlorophyll, a molecule of water is split. This splitting releases an electron and results in the formation of oxygen (O2) and hydrogen ions (H+) in the thylakoid space. Water is an electron donor and the source of the oxygen that we breathe. Since there are two Hydrogen atoms in each water molecule, each time a water molecule is broken, a pair of electrons are released. When two water molecules are broken apart, two oxygen molecules are released (one from each H2O molecule and these form a chemical bond as O2. After the electron from water replaces the freed electron, chlorophyll can respond to another photon. The hydrogen ions play critical roles in the remainder of the light-dependent reactions. The oxygen molecules produced as byproducts find their way to the surrounding environment. After the photon hits the chlorophyll molecule, the electron that was held by chlorophyll is released and moves through a series of proteins inside the thylakoid membrane called the electron transport chain. As the electron passes along these proteins, energy from the electron fuels membrane pumps that actively move hydrogen ions against their concentration gradient, creating an electrochemical gradient. After the energy is used, the electron is accepted by a pigment molecule in the next photosystem. In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH.

Light-Dependent Reactions explanation from the reading

After the energy from the sun is converted and packaged into ATP and NADPH, the cell has the fuel needed to build food in the form of carbohydrate molecules. The carbohydrate molecules made will have a backbone of carbon atoms. Where does the carbon come from? The carbon atoms used to build carbohydrate molecules comes from carbon dioxide (CO2). The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form carbohydrate molecules. In plants, carbon dioxide (CO2) enters the chloroplast through the stomata and diffuses into the stroma of the chloroplast—the site of the Calvin cycle reactions where sugar is synthesized. The reactions are named after the scientist who discovered them, and reference the fact that the reactions function as a cycle. The Calvin cycle reactions occur with the assistance of an enzyme abbreviated as RuBisCO. RuBisCO catalyzes a reaction between CO2 and the molecule ribulose bisphosphate (RuBP) which forms a six-carbon compound that is immediately converted into two three-carbon compounds. This process is called carbon fixation, because CO2 is "fixed" from its inorganic form into organic molecules. In a series of reactions (Figure 5.15), the stored energy in ATP and NADPH is used to generate 3-carbon sugars that ultimately become a glucose (C6H12O6) molecule. Because the carbohydrate molecule has six carbon atoms, it takes six turns of the Calvin cycle to make one carbohydrate molecule (one for each carbon dioxide molecule fixed). The bonds in ATP and NADPH are broken to release energy, re-forming ADP, a phosphate group, and NADP+. This recycling makes them available again for the light dependent reactions. In summary, it takes six turns of the Calvin cycle to fix six carbon atoms from CO2. These six turns require energy input from 12 ATP molecules and 12 NADPH molecules in the reduction step and 6 ATP molecules in the regeneration step.

Light-Independent Reactions (Calvin Cycle) explanation from the reading

Coral: primary consumer Zooxanthellae: primary producer (photoautotroph) Sea star: secondary consumer

Name the trophic position of each of these: coral, zooxanthellae, sea star [know which of these is a photoautotroph]

A plant exchanges gases for photosynthesis through stomata in leaves. If it is dry, stomata close to prevent water loss

On a hot, dry day, plants close their stomata to conserve water. What impact will this have on photosynthesis?

A. Light dependent Reactions

Oxygen is released during which stage of photosynthesis? A. Light dependent Reactions B. Calvin Cycle (light-independent) C. Both D. Neither

I believe that this technology will be beneficial with climate change occurring because it will allow plants to get the sources that they need to survive.

Predict the effects of this technology on mitigating climate change.

B. H2O

The oxygen that plants release comes from which of the following compounds? A. Air B. H2O C. CO2 D. Soil E. All of the above

False

True/False: Artificial leaves release high amounts of CO2 into the air.

ATP and NADPH

What are the energy carriers, formed in the light-dependent reactions of photosynthesis and used in the Calvin cycle?

-Inputs: CO2, ATP, NADPH -Outputs: Sugars, C6H12O6, ADP, NADP+

What are the inputs and the outputs to Light-Independent Reactions (Calvin Cycle)?

-Inputs: photons of light, (H2O) water -Outputs: O2, ATP and NADPH

What are the inputs and the outputs to the Light-dependent reactions?

C. Glucose

What energy-rich compound is produced as a result of the Calvin Cycle (light-independent reactions)? A. ATP B. RuBisCo C. Glucose D. All of these

-Light-dependent reactions: *Pigments absorb energy and an electron gets energized *An electron from water replaces the "bounced" electron *When the water gets split, O2 is released *Converts light energy to chemical energy *forms ATP and NADPH *releases an electron from chlorophyll then it moves through proteins to create an electrochemical gradient *Light energy comes in the form of photons *water provides electrons *Photosynthesis uses light energy to form high energy chemical compounds

What is Light-Dependent reactions?

-Light-independent reactions (Calvin Cycle): *Calvin Cycle-->Carbohydrates from Carbon Dioxide *Chloroplast is where it occurs *regenerates the ADP and NADP+ for use in the light-dependent reactions *forms carbohydrate molecules *uses Rubisco *High energy compounds produced in first part are used to make sugars from H2O and CO2 *Sugars store energy and can be converted to other compounds

What is Light-Independent Reactions (Calvin Cycle)?

B. energize an electron

What is the energy of a photon first used to do in photosynthesis? A. split a water molecule B. energize an electron C. produce ATP D. synthesize glucose

C. Metabolically engineered bacteria are used to produce fuels.

What is the role of bacteria in the artificial leaf system? A. Bacteria must be kept out of the system so that they do not cause shortages. B. Bacteria will not grow in the lab but researchers are seeking ways to incorporate them. C. Metabolically engineered bacteria are used to produce fuels. D. All of these

A. Metabolically engineered bacteria are used to produce fuels and fertilizers.

What is the role of bacteria in the artificial leaf system? A. Metabolically engineered bacteria are used to produce fuels and fertilizers. B. Bacteria must be kept out of the system so that they do not cause shortages. C. Bacteria will not grow in the lab but researchers are seeking ways to incorporate them.

C. Light strikes a chlorophyll molecule.

What occurs in the light-dependent reactions? A. Carbohydrates are made from carbon dioxide. B. Carbohydrates are broken down C. Light strikes a chlorophyll molecule. D. All of these

Chlorophyll is a pigment that all photosynthetic organisms contain and is which humans see as the common green color associated with plants (absorbs in the violet and red wavelengths and reflects green)

What pigment is used in plant photosynthesis?

A. ATP and NADPH

What products of the light reactions of photosynthesis are used in the Calvin cycle? A. ATP and NADPH B. Carbon dioxide and water C. ADP and NADP+ D. Glucose and oxygen E. All of these

C. chlorophyll

Which molecule absorbs the energy of a photon in photosynthesis? A. ATP B. glucose C. chlorophyll D. water

Pigments

Which of the following are molecules in plants that absorb some wavelengths of light and reflect others?

C. Photoautotroph

Which of the following convert the energy of sunlight to chemical compounds? A. Heterotroph B. Chemoautotroph C. Photoautotroph D. All of these

C. CO2 is converted into sugars

Which of the following occurs during the Calvin cycle (light-independent reactions)? A. Cellular respiration B. Water is converted into hydrogen and oxygen C. CO2 is converted into sugars D. Nothing occurs; the plant rests in the dark E. All of these

A. Carbon dioxide can be recycled by the artificial leaf after combustion to produce more fuel.

Which of these describes the effect of artificial leaves on greenhouse gases? A. Carbon dioxide can be recycled by the artificial leaf after combustion to produce more fuel. B. Artificial leaves would cause greater emission of CO2 into the air. C. The development of artificial leaves would have no effect on greenhouse gases.

B. Artificial system make more efficient use of light energy than plants.

Which of these describes the efficiency of energy use in artificial photosynthesis? A. Absence of chlorophyll reduces the efficiency of energy use in artificial systems. B. Artificial system make more efficient use of light energy than plants. C. Plants and artificial systems are equivalent in their energy efficiency.

A. RuBisCo

Which of these is a catalyst that lowers the activation energy of carbon fixation in photosynthesis? A. RuBisCo B. Chlorophyll C. ATP D. All of these

Rubisco

Which of these is an enzyme involved in carbon fixation through photosynthesis?

D. No Carbon is being returned to fossil fuels in the C cycle.

Which of these is true of fossil fuels? A. There is no Carbon compound being released. B. The energy from fossil fuels goes into the ocean C. The amount of carbon stored in fossil fuels is greater than ocean reservoirs D. No Carbon is being returned to fossil fuels in the C cycle.

D. In chloroplasts, pigments absorb light of certain wavelengths and shuttle the light energy to the chlorophyll a molecules in the center where electrons get excited.

Which of these statements about pigments is correct? A. When sunlight hits the pigments in chloroplasts, carbon dioxide is split and converted to sugars. B. All of the pigments in chloroplasts absorbs energy at every wavelength of light, exciting electrons and starting a chain reaction to pass energy along. C. Pigments in the chloroplast absorb light photons and act as enzymes to drive the conversion of carbon dioxide to oxygen. D. In chloroplasts, pigments absorb light of certain wavelengths and shuttle the light energy to the chlorophyll a molecules in the center where electrons get excited.

A. the conversion of CO2 to an organic compound

Which statement correctly describes carbon fixation? A. the conversion of CO2 to an organic compound B. the use of RUBISCO to form 3-PGA C. the production of carbohydrate molecules from G3P D. the formation of RuBP from G3P molecules E. the use of ATP and NADPH to reduce CO2

6CO2+12H2O+Energy--light enzymes-->C6H12O6+6O2+6H2O

Write the balanced formula for photosynthesis from your text.

Heterotrophs

consume food

Photoautotroph

harness the solar energy of the sun by converting it to chemical energy in the form of ATP (and NADP); they use sunlight as an energy source

Trophic level

indicates the position of a group of organisms within a food chain and describes how those organisms acquire energy and act as a source of energy for others

Biomass

is the total mass, in a unit area at the time of measurement, of living or previously living organisms within a trophic level

Autotrophs

make their own food

Net primary productivity (NPP)

the energy that remains in the primary producers after accounting for the organisms' respiration and heat loss

Biogeochemical cycle

the recycling of inorganic matter between living organisms and their environment; cycling of mineral nutrients through ecosystems and through the non-living world

Secondary Consumers

usually a carnivore that eats primary consumers