19.1

Energy flow

10 flashcards to master Energy flow

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Definition Flip

What is the principal source of energy input to biological systems?

Answer Flip

The Sun is the primary source of energy for nearly all biological systems on Earth. Plants capture this light energy and convert it into chemical energy via photosynthesis, which then fuels ecosystems.

Definition Flip

What form of energy is captured by plants during photosynthesis?

Answer Flip

Plants capture light energy from the Sun during photosynthesis. This light energy is converted into chemical energy stored in glucose.

Example: a maize plant in a field converts sunlight into glucose, providing energy for its growth and, ultimately, food for humans and animals.
Definition Flip

What type of energy is stored in the glucose produced during photosynthesis?

Answer Flip

Glucose stores chemical energy. This chemical energy is released during respiration to power cellular activities.

Example: glucose is broken down in root cells to provide energy for active transport of mineral ions from the soil.
Key Concept Flip

How does energy flow from plants to other organisms in an ecosystem?

Answer Flip

Energy flows from plants to other organisms when herbivores consume plants. For instance, a caterpillar eats a leaf, obtaining the chemical energy stored in the plant's tissues. This energy is then used by the caterpillar for growth and movement.

Key Concept Flip

What process releases the chemical energy stored in glucose within organisms?

Answer Flip

Cellular respiration releases the chemical energy stored in glucose. This process occurs in both plants and animals.

Example: muscle cells use respiration to convert glucose into energy for muscle contraction.
Key Concept Flip

In what form is energy eventually transferred to the environment?

Answer Flip

Energy is eventually transferred to the environment as heat.

Example: when animals respire, some energy is lost as heat due to the inefficiency of metabolic processes, warming the surrounding environment.
Key Concept Flip

Explain how energy is transferred from the sun to a lion.

Answer Flip

Energy from the sun is captured by plants during photosynthesis and stored as chemical energy. A zebra eats the plant, transferring the chemical energy to the zebra. A lion then eats the zebra, transferring the chemical energy up the food chain to the lion.

Key Concept Flip

Describe the role of decomposers in energy transfer.

Answer Flip

Decomposers like fungi and bacteria break down dead organisms and waste products, releasing nutrients back into the environment. While they gain energy from this process, a significant portion is lost as heat during decomposition.

Key Concept Flip

Why is energy transfer between trophic levels inefficient?

Answer Flip

Energy transfer is inefficient because organisms use energy for their own metabolic processes (respiration, movement), and some energy is lost as heat to the environment at each trophic level. Only a small portion of energy consumed is converted into new biomass.

Definition Flip

What is a food web?

Answer Flip

A food web is a complex network of interconnected food chains within an ecosystem. It represents the flow of energy and nutrients between different organisms. An example is how grass is eaten by rabbits, and rabbits are eaten by foxes.

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18.3 Selection 19.2 Food chains and food webs

Key Questions: Energy flow

What is the principal source of energy input to biological systems?

The Sun is the primary source of energy for nearly all biological systems on Earth. Plants capture this light energy and convert it into chemical energy via photosynthesis, which then fuels ecosystems.

What form of energy is captured by plants during photosynthesis?

Plants capture light energy from the Sun during photosynthesis. This light energy is converted into chemical energy stored in glucose.

Example: a maize plant in a field converts sunlight into glucose, providing energy for its growth and, ultimately, food for humans and animals.
What type of energy is stored in the glucose produced during photosynthesis?

Glucose stores chemical energy. This chemical energy is released during respiration to power cellular activities.

Example: glucose is broken down in root cells to provide energy for active transport of mineral ions from the soil.
What is a food web?

A food web is a complex network of interconnected food chains within an ecosystem. It represents the flow of energy and nutrients between different organisms. An example is how grass is eaten by rabbits, and rabbits are eaten by foxes.

About Energy flow (19.1)

These 10 flashcards cover everything you need to know about Energy flow for your Cambridge IGCSE Biology (0610) exam. Each card is designed based on the official syllabus requirements.

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