Photosynthesis and the Calvin Cycle Quiz

Photolysis of water molecules ($H_2O$).

NADP⁺.

Reduction is the gain of electrons or hydrogen. In the Calvin cycle, PGA is reduced to PGAL/G3P.

<p>ATP and NADPH.</p> Signup and view all the answers

<p>It does not directly require light, but uses the ATP &amp; NADPH generated by the light-dependent reactions.</p> Signup and view all the answers

<p>It catalyzes the first step of carbon fixation, combining RuBP with $CO_2$. It is very abundant and crucial for photosynthesis.</p> Signup and view all the answers

<p>18 ATP and 12 NADPH.</p> Signup and view all the answers

<p>Two molecules of G3P from 6 rounds of the Calvin Cycle are used to form a single molecule of glucose in the cytoplasm.</p> Signup and view all the answers

<p>The promoter region is where RNA polymerase binds to initiate transcription, marking the starting point for RNA synthesis.</p> Signup and view all the answers

<p>The template strand is read by RNA polymerase to create mRNA, while the non-template strand is not directly involved but has the same sequence as the mRNA (with U instead of T).</p> Signup and view all the answers

<p>The non-template strand is called the coding strand because its sequence matches the mRNA sequence, except with T instead of U.</p> Signup and view all the answers

<p>RNA polymerase reads the template strand in the 3' to 5' direction, while the pre-mRNA strand is assembled in the 5' to 3' direction.</p> Signup and view all the answers

<p>Transcription factors are proteins that bind to DNA sequences near a gene's promoter. Their main role is regulating transcription by controlling when and how a gene is expressed.</p> Signup and view all the answers

<p>Pre-mRNA is the initial RNA transcript formed in eukaryotes, containing both exons (coding) and introns (non-coding) regions.</p> Signup and view all the answers

<p>Exons are the coding regions of a gene that remain in the final mRNA and determine the amino acid sequence of a protein. Introns are non-coding regions removed during splicing.</p> Signup and view all the answers

<p>Transcription factors bind to specific DNA sequences near a gene's promoter such as the TATA box.</p> Signup and view all the answers

<p>The early atmosphere had very little free oxygen. Photosynthesis initially evolved in anoxic conditions, using other molecules as electron donors.</p> Signup and view all the answers

<p>The electrochemical gradient stores potential energy that drives protons through ATP synthase via chemiosmosis, converting ADP to ATP.</p> Signup and view all the answers

<p>A plateau signifies that the rate of photosynthesis has reached its maximum and is no longer increasing. This indicates some other factor is now limiting the reaction rate.</p> Signup and view all the answers

<p>Light plants have a higher light saturation point and a higher photosynthetic rate, whereas shade plants have a lower light saturation point and slower rate of photosynthesis.</p> Signup and view all the answers

<p>Gross photosynthesis represents total CO₂ fixed. Net photosynthesis is the gross rate minus CO₂ used by the plant's own respiration.</p> Signup and view all the answers

<p>The cristae increase the surface area of the inner membrane, providing more space for the electron transport chain to function.</p> Signup and view all the answers

<p>Proton pump proteins actively transport protons across a membrane creating a charge and H⁺ gradient. The stored potential energy is used to power ATP synthesis.</p> Signup and view all the answers

<p>In the mitochondrial matrix, pyruvate is converted to 2C acetyl-CoA, releasing CO₂ and forming NADH.</p> Signup and view all the answers

<p>DNA replication copies the entire DNA molecule, while transcription only synthesizes specific genes into RNA.</p> Signup and view all the answers

<p>The start codon signals the beginning of translation and specifies the amino acid methionine.</p> Signup and view all the answers

<p>It means that multiple codons can encode the same amino acid, providing redundancy in the genetic code.</p> Signup and view all the answers

<p>The coding strand has the same sequence as the mRNA (with T replaced by U), while the template strand is the one used by RNA polymerase to synthesize RNA.</p> Signup and view all the answers

<p>Operons coordinate the expression of clusters of genes that function together by being transcribed into a single mRNA.</p> Signup and view all the answers

<p>Stop codons, such as UAA, UAG, and UGA, signal the end of translation and help terminate protein synthesis.</p> Signup and view all the answers

<p>mRNA is synthesized in the 5' to 3' direction as RNA polymerase reads the DNA template strand in the 3' to 5' direction.</p> Signup and view all the answers

<p>A promoter is a DNA sequence where RNA polymerase binds to initiate transcription.</p> Signup and view all the answers

<p>RNA polymerase II synthesizes pre-mRNA by using a DNA template strand.</p> Signup and view all the answers

<p>Splicing removes introns from pre-mRNA and connects exons to create mature mRNA.</p> Signup and view all the answers

<p>Eukaryotic transcription occurs in the nucleus and involves RNA processing, while prokaryotic transcription occurs in the cytoplasm and is coupled with translation.</p> Signup and view all the answers

<p>Polycistronic mRNA codes for multiple proteins from a single transcript and is common in prokaryotes.</p> Signup and view all the answers

<p>The 5' cap protects mRNA from degradation and aids in ribosome binding, while the poly(A) tail stabilizes mRNA and facilitates its export to the cytoplasm.</p> Signup and view all the answers

<p>Monocistronic mRNA contains the coding sequence for a single protein.</p> Signup and view all the answers

<p>RNA polymerase II synthesizes RNA in the 5' to 3' direction.</p> Signup and view all the answers

<p>Transcription factors bind to the promoter region to initiate transcription by RNA polymerase II.</p> Signup and view all the answers

<p>Photosynthesis, which evolved before significant levels of oxygen were present, gradually released oxygen into the atmosphere, changing its composition from a reducing environment to an oxidizing one. This had a profound impact on life forms on Earth, leading to the development of oxygen-dependent organisms and the eventual emergence of complex life.</p> Signup and view all the answers

<p>As light intensity increases, the rate of photosynthesis also increases, but only up to a certain point. This point, known as the light saturation point, represents the maximum rate of photosynthesis that can be achieved, even with further increases in light intensity. Beyond this point, the rate of photosynthesis plateaus because other factors become limiting.</p> Signup and view all the answers

<p>Light plants are adapted to high light environments and thus have a higher light saturation point and a faster maximum rate of photosynthesis. Shade plants, on the other hand, are adapted to lower light intensities and have a lower light saturation point and a slower maximum rate of photosynthesis.</p> Signup and view all the answers

<p>The compensation point for photosynthesis refers to the light intensity at which the rate of photosynthesis exactly balances the rate of respiration. At this point, the net gas exchange is zero, meaning there is no net uptake or release of carbon dioxide. It represents the minimum light intensity necessary for the plant to maintain a positive carbon balance.</p> Signup and view all the answers

<p>The electron transport chain is a series of protein complexes embedded in the inner mitochondrial membrane. It functions to transfer electrons from high-energy carriers like NADH and FADH₂ down a series of redox reactions, releasing energy along the way. This energy is used to pump protons across the membrane, creating an electrochemical gradient. The flow of protons back across the membrane through ATP synthase drives the production of ATP, the cell's energy currency.</p> Signup and view all the answers

<p>Mitochondria are double-membraned organelles with an outer membrane and an inner membrane folded into cristae. The inner membrane encloses the mitochondrial matrix. The cristae increase the surface area for the electron transport chain and ATP synthase, key components of aerobic respiration. The matrix contains enzymes for the Krebs cycle, which produces electron carriers used in the ETC.</p> Signup and view all the answers

<p>Chemiosmosis is the process of using the electrochemical gradient created across the inner mitochondrial membrane by proton pumping to drive ATP synthesis. Protons accumulate in the intermembrane space, driven by the ETC. These protons then flow through the ATP synthase channel, releasing energy that is used to convert ADP to ATP. This process is essential for the efficient production of ATP during aerobic respiration.</p> Signup and view all the answers

<p>Proton pumps are proteins located in the inner mitochondrial membrane that actively transport protons (H⁺) across the membrane. These pumps are powered by the flow of electrons through the ETC. By pumping protons against their concentration gradient, they create an electrochemical gradient. The energy stored in this gradient is then used by ATP synthase to generate ATP, illustrating the critical role of proton pumps in ATP production.</p> Signup and view all the answers

<p>Nucleotides are the building blocks of RNA, and RNA polymerase uses them to synthesize complementary RNA strands from a DNA template.</p> Signup and view all the answers

<p>Prokaryotes do not undergo RNA processing, while eukaryotes extensively process their mRNA by adding a 5' cap, a poly-A tail, and splicing out introns.</p> Signup and view all the answers

<p>Fermentation maintains glycolysis by regenerating NAD⁺, allowing ATP production to continue in the absence of oxygen.</p> Signup and view all the answers

<p>The carbon cycle involves the conversion of CO₂ into organic molecules via photosynthesis and the release of CO₂ during respiration, thereby maintaining ecological balance.</p> Signup and view all the answers

<p>Yeast fermentation produces carbon dioxide, which makes the dough rise, and ethanol, which evaporates during baking.</p> Signup and view all the answers

<p>Eukaryotic translation occurs in both the nucleus and cytoplasm separately from transcription, while prokaryotic translation occurs simultaneously with transcription in the cytoplasm.</p> Signup and view all the answers

<p>ATP serves as an energy source that powers the synthesis of RNA during transcription and the assembly of amino acids into proteins during translation.</p> Signup and view all the answers

<p>Respiration breaks down organic molecules to release energy and produces CO₂, which is then available for photosynthesis by plants.</p> Signup and view all the answers

<p>Proteins are broken down into amino acids, which are deaminated to enter the Krebs cycle as intermediates. Fats are broken down into glycerol, which enters glycolysis, and fatty acids, which are converted to acetyl-CoA via β-oxidation. Both processes contribute to the production of ATP through aerobic respiration.</p> Signup and view all the answers

<p>Complex IV receives electrons from cytochrome c and transfers them to O₂, forming water. This process is essential for the electron transport chain, as it allows for the continuous flow of electrons, maintaining the proton gradient across the mitochondrial membrane, which is crucial for ATP synthesis.</p> Signup and view all the answers

<p>Aerobic respiration requires oxygen as the final electron acceptor, produces carbon dioxide and water as end products, and yields 32 ATP per glucose molecule. Anaerobic respiration does not require oxygen, produces either lactic acid or ethanol and carbon dioxide, and yields only 2 ATP per glucose molecule.</p> Signup and view all the answers

<p>The proton gradient established across the inner mitochondrial membrane during electron transport provides the energy for ATP synthesis. Protons flow down their concentration gradient through ATP synthase, a protein complex in the inner mitochondrial membrane, driving the rotation of its rotor and generating mechanical energy. This energy is used to convert ADP to ATP.</p> Signup and view all the answers

<p>High ATP levels inhibit key enzymes involved in respiration, slowing down the process. Conversely, high ADP levels stimulate respiration, leading to the production of more ATP. This feedback mechanism ensures that ATP production matches the cell's energy demands.</p> Signup and view all the answers

<p>Protons flow back into the stroma through ATP synthase due to the proton gradient created by the electron transport chain.</p> Signup and view all the answers

<p>Glycolysis: Substrate - glucose; Final products - pyruvate, ATP, NADH. Link Reaction: Substrate - pyruvate; Final products - acetyl-CoA, CO₂, NADH. Krebs cycle: Substrate - acetyl-CoA; Final products - CO₂, NADH, FADH₂, ATP. Electron Transport Chain: Substrate - NADH, FADH₂; Final products - ATP, H₂O.</p> Signup and view all the answers

<p>NADP⁺ serves as the ultimate electron acceptor, being reduced to NADPH during the process.</p> Signup and view all the answers

<p>Both lactic acid and alcoholic fermentation occur in the absence of oxygen. They both start with glucose and use NADH as a reducing agent. Lactic acid fermentation produces lactic acid and has a net yield of 2 ATP per glucose. Alcoholic fermentation produces ethanol and carbon dioxide, also with a net yield of 2 ATP per glucose.</p> Signup and view all the answers

<p>The three main stages are carbon fixation, reduction, and regeneration.</p> Signup and view all the answers

<p>ATP is the primary energy currency of cells. It stores energy within the bonds between its phosphate groups. When these bonds are broken by hydrolysis, energy is released, which can be used to power various cellular processes. This makes ATP ideal for transferring and storing energy within cells.</p> Signup and view all the answers

<p>RuBP combines with CO₂ during carbon fixation, producing 3-phosphoglycerate (PGA).</p> Signup and view all the answers

<p>PGA is reduced to glyceraldehyde-3-phosphate (G3P) using ATP and NADPH.</p> Signup and view all the answers

<p>2 molecules of G3P are produced from 6 CO₂.</p> Signup and view all the answers

<p>The net equation is: $6CO₂ + 18ATP + 12NADPH \rightarrow C₆H₁₂O₆ + 18ADP + 18Pi + 12NADP^+$.</p> Signup and view all the answers

<p>RuBisCO catalyzes the first step of carbon fixation and is the most abundant enzyme on Earth.</p> Signup and view all the answers

<p>They occur in the thylakoid membrane.</p> Signup and view all the answers

<p>Photolysis provides electrons for PSII and produces oxygen.</p> Signup and view all the answers

<p>Cyclic photophosphorylation produces only ATP, while non-cyclic produces ATP, NADPH, and O₂.</p> Signup and view all the answers

<p>Electron energy is initially high, decreases in the electron transport chain, and then increases again in PSI.</p> Signup and view all the answers

<p>The Calvin cycle does not require darkness; it operates independently of light.</p> Signup and view all the answers

<p>Chlorophyll absorbs light energy but cannot transfer it, resulting in energy release as light.</p> Signup and view all the answers

<p>The equation is 2H₂O + light + PSII -&gt; 4H⁺ + 4e⁻ + O₂.</p> Signup and view all the answers

<p>The products are ATP, NADPH, and O₂.</p> Signup and view all the answers

<p>Stop codons like UAA, UAG, and UGA signal the termination of translation and recruit release factors to release the newly synthesized protein.</p> Signup and view all the answers

<p>Degenerate codons refer to the phenomenon where multiple codons can code for the same amino acid, providing a genetic buffer against mutations.</p> Signup and view all the answers

<p>Coding strands have the same sequence as mRNA (with T replaced by U), while non-coding strands serve as templates for RNA synthesis.</p> Signup and view all the answers

<p>The promoter is a DNA sequence where RNA polymerase binds to initiate transcription of a gene.</p> Signup and view all the answers

<p>mRNA is synthesized in the 5' to 3' direction by RNA polymerase, which reads the DNA template in the 3' to 5' direction.</p> Signup and view all the answers

<p>Operons are clusters of genes that are transcribed together into a single mRNA, allowing for coordinated expression of related genes.</p> Signup and view all the answers

<p>During oxidative phosphorylation, the electron transport chain uses the energy from electrons to pump protons across the inner mitochondrial membrane, establishing a proton gradient. This electrochemical gradient drives the rotation of the F₁F₀-ATP synthase, a molecular motor that uses the proton flow to catalyze ATP synthesis from ADP and inorganic phosphate (Pi).</p> Signup and view all the answers

<p>Respiration is aerobic and utilizes oxygen as the final electron acceptor, yielding significantly more ATP (around 38 molecules per glucose) than fermentation. Fermentation, on the other hand, is anaerobic and uses organic molecules as the final electron acceptor, yielding only 2 ATP molecules per glucose. Fermentation occurs when oxygen is scarce or absent, allowing glycolysis to continue and a small amount of ATP to be produced.</p> Signup and view all the answers

<p>Photosynthesis removes carbon dioxide (CO₂) from the atmosphere and incorporates it into organic molecules. Respiration breaks down these organic molecules, releasing CO₂ back into the atmosphere. Fermentation also produces CO₂ as a byproduct and can contribute to the overall carbon cycle. These interconnected processes maintain a dynamic equilibrium of carbon in the environment.</p> Signup and view all the answers

<p>Nucleotide monomers are the building blocks of RNA, which serves as the intermediary between DNA and protein synthesis. During transcription, RNA polymerase uses nucleotides to create a complementary RNA copy of a DNA template. In translation, mRNA carries the genetic code to ribosomes, where tRNA molecules, also composed of nucleotides, bring specific amino acids based on codon recognition, constructing the polypeptide chain.</p> Signup and view all the answers

<p>Prokaryotic protein synthesis occurs in the cytoplasm, with transcription and translation coupled, meaning both processes happen simultaneously. Eukaryotic protein synthesis, however, is divided into transcription in the nucleus and translation in the cytoplasm. Prokaryotes have polycistronic mRNA carrying multiple genes, while eukaryotes have monocistronic mRNA carrying only one gene. Additionally, eukaryotic mRNA undergoes extensive processing before translation, including 5' capping, poly-A tail addition, and splicing of introns. Ribosomes are also differently sized in prokaryotes (70S) and eukaryotes (80S), reflecting differences in the ribosomal subunits.</p> Signup and view all the answers

<p>In prokaryotes, the Shine-Dalgarno sequence is a short ribosomal binding site located upstream of the start codon. It serves as a recognition site for the small ribosomal subunit, initiating translation. In eukaryotes, the 5’ cap, a modified guanine nucleotide at the beginning of mRNA, performs a similar role, directing the ribosome to the mRNA for translation initiation.</p> Signup and view all the answers

<p>Fermentation plays a crucial role in the production of various food items. Yeast fermentation is central to bread making, where CO₂ production causes dough to rise, and ethanol evaporates during baking. Wine and beer production rely on yeast fermentation of sugars into ethanol and CO₂. In dairy products, lactic acid bacteria ferment lactose into lactic acid, contributing to the characteristic tangy flavor of yogurt and promoting milk curdling during cheese production.</p> Signup and view all the answers

<p>Gene expression regulation is essential for maintaining cellular function and ensuring the proper production of proteins. This regulation ensures that genes are only expressed when needed, preventing unnecessary protein synthesis and conserving cellular resources. It also allows cells to respond to environmental cues and adapt to changing conditions.</p> Signup and view all the answers

Explains how ATP is produced in chloroplasts via proton gradient and ATP synthase.

Process where light energy splits water to release protons for ATP production.

Calvin cycle processes that use ATP and NADPH to fix CO₂ into organic compounds.

Gain of electrons/hydrogen, as PGA is converted into G3P using ATP and NADPH.

RuBP, PGA, G3P, and enzymes like RuBisCO work together to fix carbon and produce glucose.

Enzyme that catalyzes the first step of carbon fixation by combining CO₂ and RuBP.

6CO₂ + 18ATP + 12NADPH + 12H⁺ -> C₆H₁₂O₆ + 18ADP + 18Pi + 12NADP⁺.

Glucose is synthesized from Calvin cycle products, primarily G3P molecules.

Factors that affect the rate of photosynthesis, including light intensity, CO₂ concentration, temperature, and water availability.

When multiple factors control a process, the rate is determined by the factor closest to its minimum value.

The light intensity at which the rate of photosynthesis equals the rate of respiration, resulting in net gas exchange of zero.

Gross rate: total CO₂ fixed during photosynthesis; Net rate: gross photosynthesis minus CO₂ used in respiration.

Outer membrane allows small molecules through, inner membrane houses the ETC and ATP synthase, cristae increase surface area, matrix contains Krebs cycle enzymes.

Proteins that actively transport protons across a membrane, creating a charge difference and H⁺ concentration gradient.

1. Glycolysis: glucose to pyruvate in cytoplasm. 2. Link Reaction: pyruvate to acetyl-CoA in matrix. 3. Krebs Cycle: oxidizes acetyl-CoA, produces NADH, FADH₂, ATP. 4. ETC: drives ATP synthesis using donated electrons.

A series of proteins in the inner mitochondrial membrane that transfer electrons and drive proton pumps for ATP synthesis.

Process where rotation generates ~3 ATP molecules via F₁ subunit changes.

Yeast and bacteria convert sugars into byproducts like CO₂ and alcohol.

Process converting CO₂ and sunlight into organic molecules and O₂.

The process where DNA is copied into mRNA by RNA polymerase.

Occurs in cytoplasm with polycistronic mRNA; coupled transcription and translation.

Occurs in nucleus and cytoplasm; monocistronic mRNA; separate transcription and translation.

In eukaryotes, involves 5' cap, poly-A tail, and splicing of introns.

Prokaryotes use Shine-Dalgarno; eukaryotes use a 5' cap for ribosome binding.

Enzyme synthesizing pre-mRNA using a DNA template.

Process of removing introns and connecting exons in pre-mRNA.

Begins when transcription factors bind to the promoter region.

RNA polymerase adds nucleotides to growing RNA strand.

Ends when RNA polymerase hits a termination signal.

Occurs in the nucleus; mRNA processing required.

Occurs in the cytoplasm; transcription and translation are coupled.

Polycistronic mRNA codes for multiple proteins; monocistronic for one.

The process in which RNA is synthesized from a DNA template in eukaryotes, consisting of initiation, elongation, and termination.

A segment of DNA that includes the promoter, coding sequence, and terminator that is transcribed into RNA.

The DNA strand that RNA polymerase reads to synthesize RNA; it is complementary to the mRNA.

The opposite DNA strand that has a sequence identical to the mRNA, except it contains thymine instead of uracil.

Proteins that bind to DNA near a gene's promoter and regulate the transcription process by aiding RNA polymerase.

The initial RNA transcript containing both exons and introns, which undergoes processing to become mature mRNA.

Exons are coding segments that stay in RNA, while introns are non-coding segments removed during processing.

During transcription, RNA polymerase reads the template strand in the 3' to 5' direction and synthesizes RNA in the 5' to 3' direction.

The process of copying an entire DNA molecule to produce two identical strands.

The process in which mRNA is used to synthesize proteins using ribosomes.

A sequence of three nucleotides on mRNA that specifies an amino acid during protein synthesis.

A specific codon (AUG) that signals the start of translation and codes for methionine.

Codons (UAA, UAG, UGA) that signal the termination of translation without encoding amino acids.

A DNA sequence where RNA polymerase binds to initiate transcription.

Light-independent phase where ATP and NADPH fix CO₂ into glucose in the stroma.

Process where light splits H₂O to release electrons, protons, and O₂ for photosynthesis.

Light-dependent process where electrons cycle back to PSI, producing only ATP.

Process where electrons flow from H₂O to NADP⁺, producing ATP, O₂, and NADPH.

High-energy electron carrier formed from NADP⁺ during light reactions to support the Calvin cycle.

The photolysis of water in light-dependent reactions that generates O₂, protons, and electrons.

A difference in proton concentration across a membrane that drives ATP production.

A channel protein that synthesizes ATP as protons flow back into the stroma.

The process of converting CO₂ into organic compounds during the Calvin cycle.

Glyceraldehyde-3-phosphate, a molecule produced in the Calvin cycle that helps form glucose.

Process where RuBisCO combines with O₂ instead of CO₂, decreasing photosynthesis efficiency.

Factors that affect photosynthesis include light intensity, CO₂ concentration, temperature, and water availability.

Light plants have higher saturation points than shade plants, affecting their photosynthetic rates.

The total amount of CO₂ fixed during photosynthesis before accounting for respiration.

The gross photosynthesis rate minus the CO₂ consumed in respiration.

Transfers electrons to power proton pumps, facilitating ATP synthesis through chemiosmosis in mitochondria.

Outer membrane allows small molecules through; inner membrane houses ETC; cristae increase surface area.

Part of ATP synthase that catalyzes ATP production during rotation.

Yeast converts sugars into ethanol and CO₂ during fermentation.

Breaks down organic molecules to produce energy and release CO₂.

Cycle involving CO₂ incorporation into organic molecules and its release through respiration.

Cytochrome c oxidase that transfers electrons to O₂, forming H₂O.

The process converting glucose into pyruvate, producing ATP and NADH.

A series of reactions that produce CO₂, NADH, FADH₂, and ATP from acetyl-CoA.

Respiration that requires oxygen and produces 32 ATP per glucose molecule.

Respiration that does not use oxygen, yielding only 2 ATP per glucose molecule.

Conversion of pyruvate to acetyl-CoA, producing CO₂ and NADH.

Process that converts pyruvate into lactic acid or ethanol without oxygen.

Multiple codons can encode the same amino acid, providing a buffer against mutations.

Clusters of genes in prokaryotes that are transcribed into a single mRNA, allowing coordinated expression.