Question 18
NECO_MODEL_QUESTIONS_VOL1
•
2021
•
ENGLISH_LANGUAGE
•
objective
Explain the process of photosynthesis in a paragraph of about 120 words. Your explanation should use appropriate scientific terminology, describe the main stages, and show logical sequencing from light absorption to glucose formation.
Answer Options
A.
Photosynthesis takes place in the mitochondria of plant cells and involves a single stage called the light‑independent reaction. Sunlight is absorbed by chlorophyll, which directly converts carbon dioxide into glucose without producing oxygen. The energy captured is stored as ATP in the cytosol, and the glucose molecules are synthesized in the thylakoid lumen.
Correct Answer
B.
Photosynthesis occurs in the chloroplasts of plant cells and consists of two linked stages: the light‑dependent reactions and the Calvin‑Benson cycle. First, chlorophyll pigments absorb sunlight, exciting electrons that travel through the thylakoid membrane, producing ATP and NADPH while splitting water molecules to release oxygen. In the second stage, the ATP and NADPH generated are used in the stroma to fix carbon dioxide through a series of reactions known as the Calvin‑Benson cycle. Carbon atoms are gradually reduced and combined to form glucose, which serves as an energy source for the plant. Thus, light energy is transformed into chemical energy stored in glucose, with oxygen as a by‑product.
C.
Photosynthesis is carried out in the cell wall where chlorophyll pigments capture sunlight and immediately form glucose molecules. The process does not involve any electron transport chain, and oxygen is a waste product released during the Calvin‑Benson cycle rather than during water splitting.
D.
In photosynthesis, the light‑dependent reactions occur after the Calvin‑Benson cycle. First, carbon dioxide is fixed in the stroma to produce 3‑phosphoglycerate, and then water is split in the thylakoid membranes to release oxygen and generate ATP. The ATP and NADPH produced are then used to break down glucose for energy.
Correct Answer
B
Correct Option:
Photosynthesis occurs in the chloroplasts of plant cells and consists of two linked stages: the light‑dependent reactions and the Calvin‑Benson cycle. First, chlorophyll pigments absorb sunlight, exciting electrons that travel through the thylakoid membrane, producing ATP and NADPH while splitting water molecules to release oxygen. In the second stage, the ATP and NADPH generated are used in the stroma to fix carbon dioxide through a series of reactions known as the Calvin‑Benson cycle. Carbon atoms are gradually reduced and combined to form glucose, which serves as an energy source for the plant. Thus, light energy is transformed into chemical energy stored in glucose, with oxygen as a by‑product.
About This Question
This is
Neco Model Questions Vol1
2021
English Language
Question 18.
It is one of the
objective
questions from the
2021
Neco Model Questions Vol1
English Language
examination.
Difficulty level:
Hard
.