Basic Agricultural Concepts 2 - JSS1 Agricultural science Past Questions and Answers - page 2
In photosynthesis, what is the role of water?
It serves as a structural component in leaves.
It provides energy for the process.
It donates electrons to replace those lost in sunlight absorption.
It absorbs carbon dioxide from the atmosphere.
Which of the following is a direct byproduct of the photosynthesis process?
Carbon dioxide
Oxygen
Nitrogen
Hydrogen
How does photosynthesis contribute to the energy needs of plants?
By extracting energy from the soil
By converting sunlight into chemical energy stored in glucose
By absorbing energy from the atmosphere
By releasing energy during respiration
What role does carbon dioxide play in the photosynthesis process?
Providing energy for the process
Serving as a structural component in leaves
Donating electrons to chlorophyll
Supplying carbon for the formation of glucose
How does photosynthesis contribute to the growth of plants in terms of biomass?
By reducing biomass through energy consumption
By increasing water absorption
By converting sunlight into chemical energy stored in plant tissues
By enhancing root development
Explain the process of photosynthesis in plants, detailing the role of sunlight, chlorophyll, and the exchange of gases.
Photosynthesis is the process by which plants convert light energy into chemical energy, stored in the form of glucose. It takes place in the chloroplasts of plant cells, primarily in the leaves. Sunlight is captured by chlorophyll, a green pigment in chloroplasts, initiating the process. During the light-dependent reactions, sunlight energises electrons in chlorophyll, leading to the splitting of water molecules. Oxygen is released as a byproduct. The energised electrons move through the electron transport chain, creating energy-rich molecules. In the light-independent reactions (Calvin cycle), carbon dioxide is assimilated, and using the energy from the light-dependent reactions, glucose is synthesised. This glucose serves as a source of energy for the plant's metabolic processes.
Discuss the importance of photosynthesis for plant growth, emphasising its role in providing energy and contributing to biomass.
Photosynthesis is crucial for plant growth as it provides the primary source of energy for metabolic processes and contributes to biomass accumulation. During photosynthesis, plants convert sunlight into chemical energy stored in glucose. This glucose serves as a fuel for respiration, powering various physiological functions, including nutrient absorption, cell division, and synthesis of complex molecules. Additionally, the oxygen released during photosynthesis supports aerobic respiration in plants and other organisms. The process contributes to biomass by converting light energy into chemical energy stored in plant tissues, enabling the growth and development of plant structures.
Discuss the environmental factors that can limit the rate of photosynthesis in plants.
Several environmental factors can limit the rate of photosynthesis in plants. Insufficient water can lead to water stress, impairing the transport of nutrients and the availability of water for the photosynthesis process. Low carbon dioxide levels, often occurring in closed environments or during specific times of the day, can hinder the Calvin cycle, reducing the overall efficiency of photosynthesis. Extreme temperatures, both high and low, can affect the enzymes involved in the process.
Examine the importance of photosynthesis in the broader ecosystem, highlighting how it contributes to the release of oxygen and the production of food for other organisms.
Photosynthesis plays a vital role in the broader ecosystem by releasing oxygen into the atmosphere and producing food for other organisms. The oxygen released during photosynthesis supports aerobic respiration in plants, animals, and microorganisms. Additionally, the glucose produced serves as a primary energy source for various organisms in the food chain. Herbivores consume plants, carnivores consume herbivores, and decomposers break down organic matter.