TBC 3013

INFORMATION AND COMMUNICATION TECHNOLOGY

IN BIOLOGY

SECONDARY STUDENTS’ INTERPRETATION OF

PHOTOSYNTHESIS AND PLANT NUTRITION

GROUP MEMBERS:

NAME MATRIC NUMBER

AZFATINI BT NAWI D20081032320

ZETY LIYANA BT ZAINAL ABIDIN D20081032351

SYAFIQAH BT SHAARI D20091034830

YIP SOOK HAN D20091034841

LETCURER: ASSOC PROF DR SOPIA MD YASSIN

SECONDARY STUDENTS’ INTERPRETATION OF PHOTOSYNTHESIS AND

PLANT NUTRITION

Concept of Photosynthesis and Plant Nutrition

Understanding photosynthesis, respiration and energy issues in organisms are vital for us to

understand global issue such as energy flow, food supplies and other ecological principles.

The word ‘nutrition’ can be defined as the process by which an organism obtains food which

is used to provide energy and materials for its life sustaining activities. Photosynthesis is a

production process of green plants. Photosynthesis converts light energy into the chemical

energy of sugars and other organic compounds. This process consists of a series of chemical

reactions that require carbon dioxide (CO2) and water (H2O) and store chemical energy in the

form of sugar. Plants use simple inorganic materials and build these up into complex

molecules and this is called autotrophic nutrition. Plants that manufacture organic substances

form chlorophyll from the inorganic substance taken from their external environment. Sugar

produced in photosynthesis will be used in plant respiration which produces metabolic energy

for plant’s growth and maintenance. Oxygen (O2) is the by product of photosynthesis and is

released into the atmosphere. Carbon cycle is one of the most important cycles of the earth

and allows for carbon to be recycled and reused in the photosynthesis process. Photosynthesis

will generate energy flow which is required by plants and animals to survive in the

ecosystem.

Technique

A number of methods can be used for assessing students’ misconceptions in biology

education. To carry out a research on this study, a questionnaire was designed to assess

students’ misconceptions about photosynthesis and related concepts. This study involved 88

Grade 9 students aged between 14 and 15 years from a school in the central area of Erzurum

in Turkey. All students were required to answer written questions within approximately an

hour.

The questionnaire included items designed to determine students’ idea about the importance

of photosynthesis, plant nutrition, autotrophy, oxygen release by plants, respiration in plants

and the sun’s energy.

Table 1 Correct response to questionnaire items

A- Questions

B- Percentage of correct answers

A B

1. Why is photosynthesis vital for all living organisms? 20.45

2. What is the source of weight increase in plants during their growth? 19.31

3. Why are plants called producers? 22.72

4. Is it possible for animals to survive without plants in an ecosystem? 25.00

5. What is the atmosphere, even though living organisms breath it

continuously?

59.09

6. Do plants carry out respiration all day or only during some periods

of the day?

27.27

7. How do plants benefit from the sun’s energy? 23.86

Note: Total number of students asked was n=88.

Alternative conceptions

Students often exhibit strikingly similar misconception about photosynthesis. When the first

question ‘Why is photosynthesis vital for all living organisms?’ was asked, only 18 students

understand that plant both release oxygen and produce food through the process of

photosynthesis, thus enabling the continuation of our lives. Others had incomplete and

mistaken idea about photosynthesis.

The question ‘What is the source of weight increase in plants during their growth?’ tested

students’ understanding of autotrophic feeding. Most students mentioned water and soil in

their answers and seven mentioned carbon dioxide as source of the plants’ weight. Only 17

students know that the weight increase in plants comes from organic substances, produced by

plants themselves.

The third question ‘Why plants are called producers?’ tested their knowledge about the role

of photosynthesis in the ecosystem. There are 20 students believe that plant manufacture

organic substance by photosynthesis, but about 23% of this group thought that plants are

called producers because they produce oxygen. About half of students claimed that most

plants produce fruit or vegetables, so they are called producers.

To test the students’ understanding about the concept of the food chain relationship between

plants and animals, we asked them the fourth question ‘Is it possible for animals to survive

without plants in an ecosystem?’ Most of them believed that animals need plants to survive.

Only 22 students associated this with the process of photosynthesis.

The fifth question ‘What is the reason for keeping carbon dioxide at an optimum level in the

atmosphere, even though living organisms breath it continuously?’ tested students knowledge

about the relationship between carbon cycle and photosynthesis. Approximately 62 students

have a clear understanding about the role of carbon dioxide in photosynthesis, but the

remaining 36 students did not give accurate answers to this question.

The sixth question ‘Do plants carry out respiration all day or only during some periods of the

day?’ tested students’ understanding of the plant respiration. About half of students claimed

that plants undergo respiration only during the night. Only 24 students answered correctly

that plants respire continuously during the day and night.

The last question ‘How do plants benefit from the sun’s energy?’ tested students’ knowledge

of energy flow from the sun through to plants. About 24% of students correctly claimed that

plants manufacture their own food via photosynthesis by using the sun’s energy. Others

thought that plants have to use the sun’s energy for looking healthy while some believe that

plants use the sun for keeping warm.

Bibliography

Ozay, Esra, Oztaz, Haydar. (2003). Secondary Students Interpretation of Photosynthesis and Plant Nutrition. Journal of Biological Education, v37 n2 p68-70.