Page 20 - Focus PT3 2020 Science ( BI Version )

Science PT3 Chapter 2 Cell as the Basic Unit of Life
The Differences between Cellular Respiration and Photosynthesis

1. Cellular respiration and
photosynthesis are opposite
processes that complement each
other in the environment. Form Form

2. Photosynthesis by green plants 1
produces food (glucose) for other Light energy
organisms and releases oxygen absorbed Photosynthesis occurs
into the atmosphere. in the chloroplast of
plant cells
3. The oxygen and glucose produced
are used by other organisms for
cellular respiration to obtain
energy. Glucose Chloroplast Carbon dioxide
+
+
4. Cellular respiration releases carbon Oxygen Water
dioxide which is used by green
plants to carry out photosynthesis,
and this cycle continues.
5. Therefore, both processes of
photosynthesis and cellular Mitochondrion Cellular respiration occurs
respiration are important and in the mitochondrion of
complement each other for Energy is released living cells of all organisms
ATP
(a) the survival of living things.
(b) maintaining the balance of
oxygen and carbon dioxide in
the atmosphere. Figure 2.23 Relationship between photosynthesis and
cellular respiration
Table 2.1 Differences between cellular respiration and
photosynthesis Formative Practice 2.2

Cellular respiration Photosynthesis 1. Why do we test for the presence
of starch to determine if
Occurs in all the plant cells photosynthesis has occurred?
Occurs in all the living cells. that contain chlorophyll. 2. Based on the diagram below,
answer the following questions.
Process of breaking down Process of making food (a) What are processes X and Y?
food (glucose). (glucose). (b) What are the purposes of
processes X and Y?
Takes place in mitochondria. Takes place in chloroplasts. (c) Which process also occurs in
animal cells?
Carbon dioxide and water are Carbon dioxide and water Process X
released. are used. Carbon dioxide (day)
Oxygen
Light
Oxygen is used. Oxygen is released. Carbohydrates
Water
Occurs all the time (day and Occurs only in the presence Energy
night). of light.
Oxygen Process Y
Energy is released during the Light energy is absorbed to Water Carbon dioxide (day and night)
breakdown of food. make food.

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