Question 1

The graph shows records of temperature (light gray line) and COS1U1B12S1U1B0 (dark gray line) over the past 1,000 years. COS1U1B12S1U1B0 is recorded in parts per million (ppm).
-If you focus on the data from the mid-1900s (indicated by the arrow) through today, the graph shows that
A) there is a correlation between CO2 and temperature; when CO2 levels are high, so is temperature.
B) there is a correlation between CO2 and temperature; when CO2 levels are high, temperature is low.
C) there is no correlation between CO2 and temperature; CO2 fluctuates randomly and temperature is constant.
D) there is no correlation between CO2 and temperature; CO2 is constant and temperature fluctuates randomly.

Accepted Answer

The paragraph states that there is a correlation between CO2 and temperature and that when CO2 levels are high, so is temperature. This is shown in the graph for the mid-1900s through today.

Question 2

Which of the following best describes the transfer of energy and matter in photosynthesis?
A) Energy in sunlight directly becomes ATP molecules in photosynthesis.
B) ATP is made up of chemical energy which is transferred to sugar.
C) Energy in sunlight is transformed into chemical energy when electrons move to a more excited state.
D) Matter in ATP is transferred to sugars in photosynthesis when electrons from ATP become part of sugars.

Accepted Answer

Photosynthesis involves the transformation of light energy into chemical energy in the form of ATP and sugars. This transformation occurs through the movement of electrons from water molecules to carbon dioxide molecules, which results in the formation of ATP and sugars. The energy in sunlight is absorbed by chlorophyll molecules, which causes electrons to move to a more excited state. These excited electrons then enter an electron transport chain, where they are used to generate ATP and reduce NADP+ to NADPH. This process is known as the light-dependent reactions of photosynthesis. The ATP and NADPH molecules are then used in the light-independent reactions of photosynthesis to convert carbon dioxide into sugars.

Question 3

It has been suggested that scientists mimic photosynthesis by building artificial leaves that can respond to electricity from solar cells. The electricity could be applied to the leaves to split water into oxygen and hydrogen. The hydrogen could then be used a fuel. Which of these is the best explanation of how this mimics photosynthesis?
A) Both this proposed process and photosynthesis store solar energy as electricity for later use.
B) Both this proposed process and photosynthesis split water into hydrogen and oxygen.
C) The mimic leaves would have to be green like photosynthesizing leaves in order to respond to light.
D) Both processes convert electrical energy to light energy.

Accepted Answer

Both the proposed process and photosynthesis involve the splitting of water into hydrogen and oxygen. This is the key process that allows for the storage of solar energy as a fuel, which is the main goal of mimicking photosynthesis. Option A is incorrect because photosynthesis stores solar energy as chemical energy in the form of glucose, not electricity. Option C is incorrect because the leaves do not need to be green and do not need to respond to light, as the energy is supplied by solar cells. Option D is incorrect because photosynthesis converts light energy to chemical energy, not electrical energy.

Question 4

Which of the following is not an expected outcome of global climate change?
A) extreme weather patterns
B) lower sea levels
C) spread of tropical diseases
D) increased extinction rates

Accepted Answer

Global climate change is expected to cause extreme weather patterns, spread of tropical diseases, and increased extinction rates. However, it is not expected to result in lower sea levels. In fact, sea levels are expected to rise due to melting of polar ice caps and glaciers.

Question 5

Which of the following is the best summary of the process of photosynthesis?
A) Plants turn sunlight into sugars.
B) The majority of the mass of plant-made sugars comes from water and nutrients from the soil.
C) The majority of the mass of plant-made sugars comes from the atmosphere.
D) Plants make sugars by breaking down other organic molecules and using those components to make sugars.

Accepted Answer

The answer of Which of the following is the best...

Question 6

It has been suggested that scientists should attempt to genetically engineer a plant to have black leaves so that it would perform photosynthesis more efficiently. What is the likely reason behind this idea?
A) Black plants would heat up faster and therefore all chemical reactions including photosynthesis would operate faster.
B) A black plant would reflect all wavelengths and therefore have more energy to drive photosynthesis.
C) A black plant would absorb all wavelengths and therefore absorb more light energy that powers photosynthesis.
D) A black plant would absorb green wavelengths like most plants, but would absorb them more efficiently.

Accepted Answer

A black plant would absorb all wavelengths and therefore absorb more light energy that powers photosynthesis. This is because chlorophyll, the pigment responsible for photosynthesis, absorbs red and blue light, but reflects green light. Therefore, a black plant that absorbs all wavelengths would be able to absorb more light energy and perform photosynthesis more efficiently.

Question 7

Put the following steps of the light reactions in the correct order: 1. Light excites an electron from photosystem I. 2) Light excites an electron from photosystem II. 3) Electrons reduce NADP⁺ to NADPH. 4) Electrons pass through an electron transport chain, which generates a H+ gradient used to make ATP. A) 1, 2, 3, 4 B) 1, 4, 2, 3 C) 2, 4, 1, 3 D) 2, 3, 1, 4

Accepted Answer

The light reactions begin with photosystem II which excites an electron, then the electron passes through an electron transport chain generating a H+ gradient used to make ATP. Next, light excites an electron from photosystem I, and the excited electron reduces NADP+ to NADPH. Therefore, the correct order is 2, 4, 1, 3, which corresponds to choice C.

Question 8

You want to use radioactively labeled oxygen to trace carbon fixation in a plant. You should incorporate the radioactively labeled oxygen into A) O₂. B) CO₂. C) H₂O. D) C₆H₁₂O₆.

Accepted Answer

Radioactively labeled oxygen should be incorporated into CO2 because during the process of carbon fixation in plants, CO2 is chemically combined with H2O to produce glucose (C6H12O6) and O2. Therefore, by incorporating the radioactively labeled oxygen into CO2, we can trace the movement of carbon dioxide as it is fixed into glucose during the Calvin cycle.

Question 9

Many of the regions of the world where hunger is prevalent are also regions with hot and dry climates. What types of agricultural crops would you suggest that these regions attempt to grow? A) C₃ plants, such as wheat and rice B) C₃ plants and C₄ plants, such as corn and sugarcane C) C₃ plants and CAM plants, such as prickly pear and pineapple D) C₄ plants and CAM plants

Accepted Answer

C₄ plants and CAM plants are more efficient in hot and dry climates due to their ability to minimize water loss and maximize photosynthesis under such conditions.

Question 10

What likely caused the slight increase of mean poison ivy biomass in the control plots? A) random experimental error B) an increase in atmospheric CO₂ levels C) There were more poison ivy plants in the control plots to begin with.

Accepted Answer

The answer of What likely caused the slight increase of...

Question 11

Which of these can be concluded from the figure below? A) In some years of the study the mean poison ivy biomass decreased to the level it was at the beginning of the study. B) There were more elevated CO₂ plots than control plots. C) Not all of the increase in mean poison ivy biomass can be attributed to the CO₂ that the researcher added. D) Poison ivy in the experimental plots was more toxic than that in the control plots.

Accepted Answer

The figure shows the increase in mean poison ivy biomass over time for both control and elevated CO2 plots. The data suggests that the increase in mean poison ivy biomass cannot be entirely attributed to the added CO2 as there is a similar increase in the control plots. Therefore, option C is the best choice. Option A is incorrect because the figure does not show any decrease in mean poison ivy biomass over time. Option B is incorrect because the figure does not indicate the number of elevated CO2 plots. Option D is incorrect because there is no mention of toxicity in the figure or the accompanying text.

Question 12

Red algae are found in relatively deep water. In order for light to penetrate to these depths, it must be high in energy. Which wavelengths of light would you expect red algae to use?
A) red
B) yellow
C) green
D) blue

Accepted Answer

Blue light has the highest energy and is able to penetrate deeper into water than other wavelengths of visible light. Therefore, it is likely that red algae would use blue light for photosynthesis.

Question 13

Chlorophyll is located in ________, which are found in ________, which are concentrated in ________.
A) thylakoids; chloroplasts; mesophyll
B) chloroplasts; thylakoids; mesophyll
C) mesophyll; chloroplasts; thylakoids
D) mesophyll; thylakoids; chloroplasts

Accepted Answer

Chlorophyll is located in thylakoids, which are membrane-bound compartments inside chloroplasts. Chloroplasts are found in the mesophyll cells of leaves, which is the primary site of photosynthesis in plants.

Question 14

In this drawing of a chloroplast, which structure represents the thylakoid membrane? 
A) structure A
B) structure B
C) structure C
D) structure D

Accepted Answer

The answer of In this drawing of a chloroplast, which...

Question 15

Atrazine is a widely used herbicide that binds to a protein in photosystem II, ultimately causing a breakdown in electron transport. Atrazine would first inhibit the production of A) NADPH. B) G3P. C) ATP. D) O₂.

Accepted Answer

The answer of Atrazine is a widely used herbicide that...

Question 16

According to this figure, how do hydrogen ions make their way from the stroma to the thylakoid interior? 
A) through photosystem I
B) through an electron transport chain molecule
C) through the ATP synthase
D) directly through the phospholipids of the thylakoid membrane

Accepted Answer

The answer of According to this figure, how do hydrogen...

Question 17

Put the following steps of the Calvin cycle in the correct order: 1. carbon fixation
2) regeneration of RuBP
3) release of G3P
4) reduction
A) 1, 2, 3, 4
B) 1, 3, 4, 2
C) 1, 4, 3, 2
D) 4, 1, 2, 3

Accepted Answer

The Calvin cycle proceeds as follows: carbon fixation (1), where CO2 is attached to RuBP; reduction (4), where ATP and NADPH from the light-dependent reactions are used to reduce 3-PGA into G3P; release of G3P (3), where some G3P leaves the cycle to be used in the synthesis of glucose and other compounds; and finally, regeneration of RuBP (2), allowing the cycle to continue.

Question 18

The graph shows records of temperature (light gray line) and COS1U1B12S1U1B0 (dark gray line) over the past 1,000 years. COS1U1B12S1U1B0 is recorded in parts per million (ppm). -Currently, atmospheric CO₂ levels are approximately 400 ppm. The annual mean growth rate in CO₂ is about 2 ppm/year. Assuming this trend continues, what would you predict the CO₂ level to be in 100 years? A) 100 ppm B) 200 ppm C) 600 ppm D) 1,000 ppm

Accepted Answer

If the annual mean growth rate in CO2 is about 2 ppm/year, then in 100 years, the CO2 level would increase by 200 ppm (2 ppm/year x 100 years), resulting in a total of 600 ppm (400 ppm + 200 ppm). Therefore, the best choice is C.

Question 19

It has been suggested that global warming could be halted by fertilizing the oceans to increase the growth of algae. How might this affect the greenhouse effect? A) Algal photosynthesis would use up more CO₂, which traps heat. B) Algal photosynthesis would produce more O₂, which blocks light. C) Algal photosynthesis would be inhibited by the addition of fertilizer. D) Algae photosynthesis would use heat in place of photons.

Accepted Answer

Algal photosynthesis consumes carbon dioxide, one of the main greenhouse gases, during photosynthesis. By increasing the growth of algae, more carbon dioxide would be consumed, reducing the amount of this gas in the atmosphere and potentially slowing the greenhouse effect.

Question 20

Purple sulfur bacteria are organisms capable of photosynthesis. They get their name, in part, because they use H₂S (hydrogen sulfide) instead of water during the light reactions. In what form would you expect to find sulfur (S) as a result of photosynthesis in these bacteria? A) S₂ B) SO₂ C) CS₂ D) C₆H₁₂S₆

Accepted Answer

Purple sulfur bacteria oxidize hydrogen sulfide (HS) to elemental sulfur (S) during photosynthesis, which is then deposited as granules inside or outside their cells.

Quiz 7: Photosynthesis: Using Light to Make Food

The graph shows records of temperature (light gray line) and CO₂ (dark gray line) over the past 1,000 years. CO₂ is recorded in parts per million (ppm) . -If you focus on the data from the mid-1900s (indicated by the arrow) through today, the graph shows that

Which of the following best describes the transfer of energy and matter in photosynthesis?

Which of the following is not an expected outcome of global climate change?

Which of the following is the best summary of the process of photosynthesis?

It has been suggested that scientists should attempt to genetically engineer a plant to have black leaves so that it would perform photosynthesis more efficiently. What is the likely reason behind this idea?

You want to use radioactively labeled oxygen to trace carbon fixation in a plant. You should incorporate the radioactively labeled oxygen into

Many of the regions of the world where hunger is prevalent are also regions with hot and dry climates. What types of agricultural crops would you suggest that these regions attempt to grow?

What likely caused the slight increase of mean poison ivy biomass in the control plots?

Which of these can be concluded from the figure below?

Red algae are found in relatively deep water. In order for light to penetrate to these depths, it must be high in energy. Which wavelengths of light would you expect red algae to use?

Chlorophyll is located in , which are found in , which are concentrated in .

In this drawing of a chloroplast, which structure represents the thylakoid membrane?

Atrazine is a widely used herbicide that binds to a protein in photosystem II, ultimately causing a breakdown in electron transport. Atrazine would first inhibit the production of

According to this figure, how do hydrogen ions make their way from the stroma to the thylakoid interior?

Put the following steps of the Calvin cycle in the correct order: 1. carbon fixation 2) regeneration of RuBP 3) release of G3P 4) reduction

It has been suggested that global warming could be halted by fertilizing the oceans to increase the growth of algae. How might this affect the greenhouse effect?

Purple sulfur bacteria are organisms capable of photosynthesis. They get their name, in part, because they use H₂S (hydrogen sulfide) instead of water during the light reactions. In what form would you expect to find sulfur (S) as a result of photosynthesis in these bacteria?