Photosynthesis I
What is photosynthesis?
Photosynthesis is the process by which green plants use energy from sunlight to make glucose food.
What is a limiting factor in the context of photosynthesis?
A limiting factor is a raw material or condition, that when in shortage, slows down the rate of a reaction.
What is an ecosystem?
An ecosystem is a community of living organisms interacting with their environment.
What is a food chain?
A linear sequence of organisms showing how food/energy is transferred from one to the next, starting with a producer and ending with a top predator.
What is a food web?
A complex network of interconnected food chains, showing multiple feeding relationships within an ecosystem.
What is the word equation for photosynthesis? Include conditions.
Carbon dioxide + Water → Glucose + Oxygen (in the presence of sunlight and chlorophyll).
Which of the graphs (plots) show how light intensity and carbon dioxide concentration affect the rate of photosynthesis?
[Shown from a ppt]
Answer: B
What are the two types of ecosystems? Provide examples.
Terrestrial: Forests, grasslands, deserts, tundra.
Aquatic: Oceans, lakes, rivers, wetlands.
Construct a food chain using the following organism.
grass, small bird, hawk, caterpillar
grass → caterpillar → small bird → hawk
Construct two food chains from the projected food web.
State the sites (organ, cell, organelle/cell structure) of photosynthesis, starting from the main organ to the organelle.
Organ: leaf
Cell: palisade mesophyll
Organelle: chloroplast
Which of the graphs (plots) shows how temperature affects the rate of photosynthesis?
[Shown from a ppt]
Answer: A
What are the two main components of an ecosystem? Describe them.
Abiotic Factors: Nonliving components like temperature, water, sunlight, soil, and air.
Biotic Factors: Living components like plants, animals, fungi, and microorganisms.
Identify the trophic level and status of the 4th organism in the food chain:
algae → small fish → larger fish → crane → hawk
Trophic level: 4
Status: Tertiary consumer
Construct a food web from the following food chains.
Food Chain 1:
Grass → Mouse → Snake → Hawk
Food Chain 2:
Grass → Insect → Frog → Snake → Hawk
- Grass is the primary producer.
- Mouse, Insect, and Frog are primary consumers.
- Snake is a secondary consumer that preys on Mouse and Frog.
- Hawk is a tertiary consumer that preys on Snake.
What are the raw materials of photosynthesis? How are they obtained? Include plant structures and mechanisms/processes.
Raw Materials
Carbon dioxide: Obtained through stomata
Water: Absorbed through roots and transported via xylem
Plant Structures
Carbon dioxide: stomata from the atmosphere
Water: root and xylem vessels
Mechanisms/Processes
Carbon dioxide: diffusion
Water: osmosis, capillarity, transpiration pull, root pressure
How do light intensity and carbon dioxide concentration affect the rate of photosynthesis?
As light intensity increases, the rate of photosynthesis also increases, until a certain point where it levels off (saturation point). If light intensity is too low, photosynthesis slows down. If it is too high, it can damage the chlorophyll and hinder the process.
Increased CO2 concentration boosts the rate of photosynthesis until other factors become limiting. Without enough CO2, the process cannot proceed at maximum efficiency, even if light and temperature are optimal.
What is the role of solar energy in photosynthesis?
To split water and make ATP energy.
How does temperature affect the rate of photosynthesis?
Temperature influences the enzymes responsible for photosynthesis. Higher temperatures accelerate enzyme activity, up to an optimal point. If the temperature is too high, enzymes can denature, and if it is too low, enzyme activity slows down, both reducing the efficiency of photosynthesis.