NST1502
ASSIGNMENT 4
DUE DATE: 2 OCTOBER 2025
,NST1502 PORTFOLIO ASSIGNMENT FOUR (4) [PORTFOLIO]
DUE 2 OCTOBER 2025
QUESTION 1
1.1 Define Kinetic energy
Kinetic energy is the energy an object has due to its motion. Any moving object, such
as a rolling ball, falling water, or a driving car, possesses kinetic energy.
1.2 Explain how energy is transferred in an ecosystem
Energy in an ecosystem originates from the sun. Plants (producers) absorb sunlight
during photosynthesis to make glucose. Herbivores obtain this energy by eating plants,
and carnivores by eating herbivores. At each trophic level, energy is transferred in the
form of food but a large amount is lost as heat, movement, and waste.
1.3 What is the main purpose of photosynthesis in plants?
The main purpose of photosynthesis is to use sunlight, carbon dioxide, and water to
produce glucose (food) and release oxygen. This process provides energy-rich
compounds that fuel plant growth and sustain life in ecosystems.
1.4 What is cellular respiration?
Cellular respiration is the process by which organisms break down glucose in the
presence of oxygen to release usable energy, carbon dioxide, and water. It is the
opposite of photosynthesis and takes place in the mitochondria.
, 1.5 Compare aerobic and anaerobic respiration.
1.5 Compare aerobic and anaerobic respiration
Aspect Aerobic Anaerobic
Respiration Respiration
Oxygen Requires Does not require
requirement oxygen oxygen
Location Mitochondria Cytoplasm
ATP yield Produces Produces only 2 ATP
~36–38 ATP per glucose
per glucose
By-products Carbon Lactic acid (animals)
dioxide and or ethanol + CO₂
water (plants/yeast)
1.6 What is the role of ATP in cellular processes?
ATP (Adenosine Triphosphate) is the energy currency of the cell. It provides immediate
energy for processes such as muscle contraction, active transport, cell division, and
synthesis of biomolecules.
1.7 Explain how ATP is synthesized in the mitochondria
ATP is synthesized in the mitochondria through cellular respiration:
Glucose is broken down during glycolysis into pyruvate.
In the Krebs cycle, pyruvate is further broken down, producing NADH and FADH₂.
ASSIGNMENT 4
DUE DATE: 2 OCTOBER 2025
,NST1502 PORTFOLIO ASSIGNMENT FOUR (4) [PORTFOLIO]
DUE 2 OCTOBER 2025
QUESTION 1
1.1 Define Kinetic energy
Kinetic energy is the energy an object has due to its motion. Any moving object, such
as a rolling ball, falling water, or a driving car, possesses kinetic energy.
1.2 Explain how energy is transferred in an ecosystem
Energy in an ecosystem originates from the sun. Plants (producers) absorb sunlight
during photosynthesis to make glucose. Herbivores obtain this energy by eating plants,
and carnivores by eating herbivores. At each trophic level, energy is transferred in the
form of food but a large amount is lost as heat, movement, and waste.
1.3 What is the main purpose of photosynthesis in plants?
The main purpose of photosynthesis is to use sunlight, carbon dioxide, and water to
produce glucose (food) and release oxygen. This process provides energy-rich
compounds that fuel plant growth and sustain life in ecosystems.
1.4 What is cellular respiration?
Cellular respiration is the process by which organisms break down glucose in the
presence of oxygen to release usable energy, carbon dioxide, and water. It is the
opposite of photosynthesis and takes place in the mitochondria.
, 1.5 Compare aerobic and anaerobic respiration.
1.5 Compare aerobic and anaerobic respiration
Aspect Aerobic Anaerobic
Respiration Respiration
Oxygen Requires Does not require
requirement oxygen oxygen
Location Mitochondria Cytoplasm
ATP yield Produces Produces only 2 ATP
~36–38 ATP per glucose
per glucose
By-products Carbon Lactic acid (animals)
dioxide and or ethanol + CO₂
water (plants/yeast)
1.6 What is the role of ATP in cellular processes?
ATP (Adenosine Triphosphate) is the energy currency of the cell. It provides immediate
energy for processes such as muscle contraction, active transport, cell division, and
synthesis of biomolecules.
1.7 Explain how ATP is synthesized in the mitochondria
ATP is synthesized in the mitochondria through cellular respiration:
Glucose is broken down during glycolysis into pyruvate.
In the Krebs cycle, pyruvate is further broken down, producing NADH and FADH₂.
