Photosynthesis Reading Answers

Sep 26, 2025

Photosynthesis Reading Answers is an academic reading answers topic. Photosynthesis Reading Answers has a total of 13 IELTS questions in total. In the question set, you have to choose which paragraph contains the given statement. In the next question set, you have to state whether the statement is true, false or not given.

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Topic:

Photosynthesis

A.Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can further be released to fuel the organisms' activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water. The name photosynthesis is a compound word derived from "photo", means "light", and "synthesis," means "putting together". In most cases, oxygen is also produced as a waste product from this process. Most plants, most algae. and cyanobacteria perform photosynthesis. They are commonly called as photoautotrophs. Photosynthesis is largely responsible for producing and sustaining the oxygen content of the Earth's atmosphere and supplies all of the organic compounds and most of the energy necessary for life on Earth.

B.Photosynthesis is a process that always begins when energy from light is captivated by proteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are stored inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are implanted in the plasma membrane. In these light-dependent reactions, some energy is used to shred electrons from suitable substances, such as water, producing oxygen gas. The hydrogen freed by the splitting of water is utilised in the creation of two additional compounds that serve as short-term stores of energy, enabling its transfer to drive other reactions. These compounds are dinucleotide adenine phosphate (NADPH) and adenosine reduced nicotinamide triphosphate (ATP), the "energy currency" of cells.

C.In plants, algae and cyanobacteria. long-term energy storage in the form of sugars is formed by a following order of light-independent reactions called the Calvin cycle; some bacteria use different processes, such as the reverse Krebs cycle, to achieve the same end. In the Calvin cycle, atmospheric carbon dioxide is merged into already existing organic carbon compounds, such as ribulose bisphosphate (RuBP). Using the ATP and NADPH formed by the light-dependent reactions, the following compounds are then condensed and detached to form additional carbohydrates, such as glucose D.

D.The first photosynthetic organisms perhaps grew early in the evolutionary history of life and most likely used reducing agents such as hydrogen or hydrogen sulphide, somewhat than water, as sources of electrons. Cyanobacteria came far ahead; the surplus oxygen they produced contributed directly to the oxygenation of the Earth, which rendered the evolution of complex life possible. Today, the average rate of energy capture by photosynthesis globally is approximately 130 terawatts, which is about eight times the current power consumption of human civilization. Photosynthetic organisms also convert around 100-115 billion tons (91-104 petagrams) of carbon into biomass per year.

E.Photosynthetic organisms are photoautotrophs, which means that they can produce food directly from carbon dioxide and water using energy from light. Though not all organisms use carbon dioxide as a source of carbon atoms to carry out photosynthesis; photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants, algae, and cyanobacteria, photosynthesis produces oxygen. This is named oxygenic photosynthesis and is by far the most common kind of photosynthesis used by living organisms. Though there are some alterations between oxygenic photosynthesis in plants, algae, and cyanobacteria, the complete process is quite similar in these organisms. There are also many varieties of anoxygenic photosynthesis, used largely by certain types of bacteria, which absorb carbon dioxide but do not release oxygen.

F.Carbon dioxide is transformed into sugars in a process called carbon fixation; photosynthesis absorbs energy from sunlight to convert carbon dioxide into carbohydrates. Carbon fixation is an endothermic redox reaction. In general outline, photosynthesis is the reverse of cellular respiration: while photosynthesis is a process of reduction of carbon dioxide to carbohydrate, cellular respiration is the oxidation of carbohydrate or other nutrients to carbon dioxide. Nutrients used in cellular respiration include carbohydrates, amino acids and fatty acids. These nutrients are oxidized to generate carbon dioxide and water, and to produce chemical energy to drive the organism's metabolism. Photosynthesis and cellular respiration are different processes, as they take place through different sequences of chemical reactions and in different cellular compartments. Photosynthesis happens in two stages. In an initial stage, light-dependent reactions or light reactions capture the energy of light and use it to create the energy-storage molecules ATP and NADPH. Through the second stage, the light-independent reactions use these products to seize and decrease carbon dioxide.

G.Most organisms that use oxygenic photosynthesis use visible light for the light-dependent reactions, whereas at least three use shortwave infrared or, more precisely, far-red radiation. Some organisms service even more essential variants of photosynthesis. Some archaea use a modest method that services a pigment similar to those used for vision in animals. The bacteriorhodopsin alters its configuration in response to sunlight, acting as a proton pump. This generates a proton gradient more directly, which is then converted to chemical energy. The process does not include carbon dioxide fixation and does not produces oxygen and seems to have evolved distinctly from the more common types of photosynthesis.

Questions 28-34

Which paragraph contains the following information? Write the correct letter A-G in your answer sheet

NB, you may use any letter more than once

28. The explanation of Photosynthesis.

Answer: A

Supporting statement: Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can further be released to fuel the organisms' activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water.

Keywords: Photosynthesis, plants and other organisms, energy

Keyword Location: Para A, Lines 1-2

Explanation: Paragraph A provides a fundamental definition of photosynthesis, explaining what it is, what it does, and what it produces.

29. Organisms that produce food using light as energy.

Answer: E

Supporting statement: Photosynthetic organisms are photoautotrophs, which means that they can produce food directly from carbon dioxide and water using energy from light.

Keywords: photoautotrophs, produce food, energy from light

Keyword Location: Para E, Lines 1-2

Explanation: Paragraph E introduces the term "photoautotrophs" and defines them as organisms that "produce food directly from carbon dioxide and water using energy from light," which directly matches the question.

30. Different cycles used to store energy.

Answer: C

Supporting statement: In plants, algae and cyanobacteria. long-term energy storage in the form of sugars is formed by a following order of light-independent reactions called the Calvin cycle; some bacteria use different processes, such as the reverse Krebs cycle, to achieve the same end.

Keywords: Calvin cycle, reverse Krebs cycle

Keyword Location: Para C, Lines 2-3

Explanation: This paragraph details the Calvin cycle and mentions that some bacteria use different processes, such as the reverse Krebs cycle, to store energy in the form of sugars, thus discussing different cycles.

31. Hypothesis that photosynthetic organism took birth in the early history of life.

Answer: D

Supporting statement: The first photosynthetic organisms perhaps grew early in the evolutionary history of life and most likely used reducing agents such as hydrogen or hydrogen sulphide, somewhat than water, as sources of electrons.

Keywords: first photosynthetic organisms, early in the evolutionary history

Keyword Location: Para D, Line 1

Explanation: This paragraph directly hypothesises about the origins of photosynthetic organisms, stating they grew early in the evolutionary history of life.

32. A process responsible for conversion of carbon dioxide into sugars.

Answer: F

Supporting statement: Carbon dioxide is transformed into sugars in a process called carbon fixation; photosynthesis absorbs energy from sunlight to convert carbon dioxide into carbohydrates.

Keywords: Carbon dioxide, transformed into sugars, carbon fixation

Keyword Location: Para F, Line 1

Explanation: The first definition of carbon fixation in paragraph F is the conversion of carbon dioxide into sugars, which answers the question.

33. Different organisms using different methods for Photosynthesis.

Answer: G

Supporting statement: Some organisms service even more essential variants of photosynthesis. Some archaea use a modest method that services a pigment similar to those used for vision in animals.

Keywords: more essential variants, archaea, pigment

Keyword Location: Para G, Lines 3-4

Explanation: This paragraph explains how some organisms, like certain archaea, use different, more modest methods of photosynthesis that don't involve carbon dioxide fixation or oxygen production, differentiating them from the more common types.

34. Storage of proteins in plants and bacteria.

Answer: B

Supporting statement: In plants, these proteins are stored inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are implanted in the plasma membrane.

Keywords: proteins are stored, chloroplasts, bacteria, plasma membrane

Keyword Location: Para B, Lines 3-4

Explanation: Paragraph B describes where the light-capturing proteins are located in both plants (chloroplasts) and bacteria (plasma membrane), thus detailing their storage locations.

Questions 35-40

Do the following statements agree with the information given in the Reading Passage?

TRUE - If the statement agrees with the information

FALSE - If the statement contradicts the information

NOT GIVEN - If there is no information on this

35. Photosynthesis converts chemical energy into light energy.

Answer: FALSE

Supporting statement: Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy

Keywords: light energy, chemical energy

Keyword Location: Para A, Lines 1-2

Explanation: The passage states the opposite photosynthesis converts light energy into chemical energy, not the other way around.

36. There is evidence that the first photosynthetic organisms grew early in the evolutionary history of life.

Answer: FALSE

Keywords: photosynthetic organisms, evolutionary history

Keyword Location: Para D, Line 1

Explanation: The passage uses speculative words like perhaps and most likely, indicating that this is a hypothesis, not a proven fact supported by evidence mentioned in the text.

37. Photosynthetic organisms can produce food directly from carbon dioxide and water using energy from light.

Answer: TRUE

Supporting statement: Photosynthetic organisms are photoautotrophs, which means that they can produce food directly from carbon dioxide and water using energy from light.

Keywords: produce food, carbon dioxide and water

Keyword Location: Para E, Lines 1-2

Explanation: The text states that photosynthetic organisms use light energy to directly make food from carbon dioxide and water.

38. Carbon dioxide is altered into sugars in a process called carbon fixation.

Answer: TRUE

Supporting statement: Carbon dioxide is transformed into sugars in a process called carbon fixation

Keywords: transformed into sugars, carbon fixation

Keyword Location: Para F, Line 1

Explanation: The text explicitly states that carbon dioxide is transformed into sugar, using the word "transformed", which is a synonym for "altered."

39. Photosynthesis is the most complex reaction in the world.

Answer: NOT GIVEN

Explanation: The passage describes the process of photosynthesis but never makes a comparative claim about its complexity relative to all other reactions.

40. The bacteriorhodopsin modifies its configuration when exposed to sunlight.

Answer: TRUE

Supporting statement: The bacteriorhodopsin alters its configuration in response to sunlight, acting as a proton pump.

Keywords: bacteriorhodopsin, alters its configuration, response to sunlight

Keyword Location: Para G, Line 5

Explanation: As a synonym for "modifies its configuration when exposed to sunlight," the paragraph explicitly states that the bacteriorhodopsin "alters its configuration in response to sunlight."

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