Unit 7: Energy

Flashcards summarizing key concepts from Unit 7: Energy, covering photosynthesis, chemosynthesis, and respiration.

What is photosynthesis?

A two-stage process where energy from light is harvested by pigments and transferred to organic compounds.

Where does photosynthesis take place?

In chloroplasts.

What are the two stages of photosynthesis?

Light-dependent stage and light-independent stage (Calvin cycle).

What is the effect of light intensity on the rate of photosynthesis?

Higher light intensity leads to a faster rate of photosynthesis.

What is the equation for photosynthesis?

6CO2 + 6H2O light → chlorophyll C6H12O6 + 6O2.

What is the definition of wavelength in the context of light?

The distance between one crest of a wave and the next.

What are chloroplast pigments and their roles?

Chlorophyll a is the primary pigment for photosynthesis, while accessory pigments absorb light of different wavelengths and transfer energy to chlorophyll a.

Define the euphotic zone in marine environments.

The sunlight zone where high light penetration allows producers to photosynthesize effectively, up to 200m in clear water.

What is the role of rubisco in the light-independent stage of photosynthesis?

Rubisco combines CO2 with RuBP to initiate the Calvin cycle.

Explain chemosynthesis. How do bacteria utilize it?

Chemosynthesis is the fixation of carbon using energy from inorganic chemicals, producing organic substances like glucose.

Describe the relationship between Riftia and Endoriftia.

A mutualistic symbiosis where Endoriftia live within Riftia, providing glucose while Riftia offers a habitat and protection.

What are the waste products of aerobic respiration?

Carbon dioxide and water.

How much ATP is produced by anaerobic respiration?

It produces only 2 ATP molecules per glucose molecule.

What distinguishes the absorption spectrum from the action spectrum?

The absorption spectrum shows the wavelengths absorbed by pigments, while the action spectrum shows the rate of photosynthesis at different light intensities.

What is a limiting factor in photosynthesis?

Any factor in short supply that restricts the rate of photosynthesis, such as light intensity, temperature, and CO2 concentration.

What is the difference between the euphotic, disphotic, and aphotic zones?

Euphotic has sufficient light for photosynthesis, disphotic has low light and no producers, and aphotic has no light penetration.

What happens if hydrothermal vents stop releasing mineral ions?

The food web in the deep-sea ecosystem collapses and the ecosystem disappears.

Discuss the role of light in the process of photosynthesis.

Light provides the essential energy for the photochemical reactions in photosynthesis, enabling the conversion of carbon dioxide and water into glucose and oxygen.

Identify and explain the main products of photosynthesis and their significance.

The main products of photosynthesis are glucose, which serves as an energy source for the plant and other organisms, and oxygen, which is released as a byproduct and is crucial for aerobic respiration.

What is the function of the Calvin cycle in photosynthesis, and how does it relate to light-dependent reactions?

The function of the Calvin cycle is to utilize ATP and NADPH generated in the light-dependent reactions to fix carbon dioxide into organic compounds, primarily glucose.

Evaluate the various factors that can limit the rate of photosynthesis in marine environments.

Factors limiting photosynthesis include light intensity, which affects the rate of photochemical reactions; carbon dioxide concentration, which is necessary for the Calvin cycle; temperature, which influences enzyme activity; and water availability, crucial for the overall process.

Examine the types of organisms that perform photosynthesis and their ecological roles in marine ecosystems.

Photosynthetic organisms such as phytoplankton, macroalgae, and seagrasses play vital roles in marine ecosystems by producing oxygen and serving as the base of the food web.

Explain the significance of wavelength in photosynthesis for different pigments.

Different pigments in chloroplasts absorb light at specific wavelengths, allowing for more efficient light capture across the visible spectrum and enhancing the rate of photosynthesis.

How does light penetration vary in marine environments, and what implications does this have for photosynthetic organisms?

Light penetration decreases with depth in the ocean, affecting the distribution of photosynthetic organisms such as phytoplankton, which are primarily found in the euphotic zone where sufficient light is available.

Describe the light-dependent reactions of photosynthesis, including their location and main outputs.

Light-dependent reactions occur in the thylakoid membranes of chloroplasts, converting light energy into chemical energy in the form of ATP and NADPH, while producing oxygen as a byproduct.

Discuss the role of ATP and NADPH in the light-independent reactions (Calvin cycle).

ATP and NADPH generated during the light-dependent reactions provide the energy and reducing power necessary for the Calvin cycle to convert carbon dioxide into glucose.

What environmental factors can affect the wavelengths of light available for photosynthesis in aquatic ecosystems?

Factors include water clarity, dissolved organic matter, and phytoplankton populations, which can absorb and scatter light, thus altering the wavelengths that penetrate to different depths.

Outline the steps involved in the Calvin cycle and identify the key enzyme involved.

The Calvin cycle involves carbon fixation, reduction, and regeneration of RuBP, with rubisco being the key enzyme that catalyzes the initial reaction between CO2 and RuBP.

Examine the process of cellular respiration and its relationship to photosynthesis.

Cellular respiration occurs in all living organisms and involves the breakdown of glucose to produce ATP; it complements photosynthesis by utilizing oxygen and organic compounds produced during photosynthesis.

Contrast the mechanisms of aerobic and anaerobic respiration, and state their ATP yield.

Aerobic respiration requires oxygen and yields approximately 36-38 ATP per glucose molecule, while anaerobic respiration occurs without oxygen and typically yields only 2 ATP.

What is chemosynthesis, and how do organisms that utilize this process differ from photosynthetic organisms?

Chemosynthesis is the process by which certain bacteria convert inorganic chemicals into organic substances using energy from chemical reactions, in contrast to photosynthetic organisms that use solar energy.

Analyze the mutualistic relationship between Riftia and Endoriftia, detailing the benefits to both organisms.

Endoriftia bacteria provide glucose produced via chemosynthesis for Riftia, while Riftia offers a protected habitat and access to inorganic nutrients from hydrothermal vents.

Describe how the anatomy of Riftia supports its symbiotic relationship with Endoriftia.

Riftia has specialized tissues known as trophosome that house Endoriftia bacteria, providing a suitable environment for bacterial growth and nutrient exchange.

What are the ecological implications of the relationship between Riftia and Endoriftia in hydrothermal vent ecosystems?

Their mutualistic relationship supports the entire food web in hydrothermal vent ecosystems, as it enables primary production in an environment devoid of sunlight.

Discuss the factors that influence light availability for photosynthesis in different ocean layers.

Factors include water depth, turbidity, and the presence of phytoplankton and other suspended particles that can absorb or scatter light.

What are the adaptations of plants found in the euphotic zone that enhance photosynthesis?

Plants in the euphotic zone may have specialized chlorophyll variants and structures that optimize light absorption and reduce light saturation damage.

Explain how light-dependent reactions contribute to the growth of marine autotrophs.

The ATP and NADPH generated in the light-dependent reactions provide the energy and reducing power necessary for autotrophs to synthesize organic compounds during the Calvin cycle.

How does the limitation of light intensity affect photosynthetic rates in deep-sea environments?

In deep-sea environments, low light availability restricts the growth and productivity of photosynthetic organisms, potentially leading to lower biodiversity.

Analyze the role of rubisco in influencing the efficiency of photosynthesis under varying environmental conditions.

Rubisco has varying efficiencies based on environmental CO2 levels and temperature, impacting the rate of carbon fixation in the Calvin cycle.

What adaptations do marine photosynthetic organisms possess to cope with variable light conditions in their habitats?

These adaptations may include changes in pigmentation, the ability to adjust leaf morphology, or the regulation of photosynthetic rates in response to light fluctuations.

Explain the process of energy transfer in chemosynthesis and its dependencies on external conditions.

Chemosynthesis depends on the availability of inorganic molecules and suitable conditions (like pressure and temperature) at hydrothermal vents for bacterial survival and growth.

In what ways can the loss of hydrothermal vents impact the mutualistic relationship between Riftia and Endoriftia?

The loss of hydrothermal vents removes the nutrient source for Endoriftia, endangering the Riftia population as they rely on these bacteria for glucose and energy