Bioenergetics

Why is respiration essential for living things?

All living organisms need energy for life processes, provided by cellular respiration.

Where does respiration occur in plants and animals?

Respiration takes place in the mitochondria of cells.

What is the word equation for aerobic respiration?

Glucose + Oxygen → Carbon Dioxide + Water + Energy

What are the reactants and waste products of aerobic cellular respiration?

Reactants: Glucose and Oxygen; Waste Products: Carbon Dioxide and Water.

Why is respiration important for living organisms?

It provides energy for essential life processes.

How can we prove that respiration produces carbon dioxide?

By using a chemical test for carbon dioxide.

What is the chemical test for carbon dioxide, and what is a positive result?

Test: Limewater; Result: Changes from clear to milky/cloudy.

Why is a control important in an experiment?

A control ensures that the results are due to the variable being tested.

How do humans obtain the reactants for respiration and excrete the products?

Through the gas exchange system.

Name the organs of the gas exchange system.

Nose, trachea, bronchi, lungs, alveoli.

What is the function of the organs in the gas exchange system?

To deliver oxygen to the blood and remove carbon dioxide.

How is the structure of the gas exchange organs related to their function?

They have large surface areas, thin walls, and are close to blood vessels to enable efficient gas exchange.

What is breathing?

The mechanical movement of gases into and out of the lungs involving muscles.

Name the muscles involved in breathing.

Diaphragm and intercostal muscles.

What is the role of muscles in breathing?

They contract and relax to change the volume of the chest, moving air in and out.

How is cellular respiration different from breathing?

Cellular respiration is a chemical process in cells to produce energy, while breathing is the physical movement of air into and out of the lungs.

Describe the structure of the alveoli in the lungs.

Thin walls, close to capillaries, large surface area.

What happens at the alveoli during gas exchange?

Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli.

How do plants achieve nutrition?

Plants are producers that use photosynthesis to make their own food.

Describe the process of photosynthesis in words.

Plants use sunlight, carbon dioxide, and water to produce glucose and oxygen.

What is the word equation for photosynthesis?

Carbon Dioxide + Water + Sunlight → Glucose + Oxygen

What is the role of chloroplasts in photosynthesis?

Chloroplasts contain chlorophyll, which captures sunlight for photosynthesis.

How do plants use the glucose made in photosynthesis?

For building materials (biomass) and as fuel for cellular respiration.

What is the leaf’s role in photosynthesis?

The leaf is the organ of photosynthesis.

How is a leaf adapted for photosynthesis?

Large surface area, thin structure, chlorophyll for capturing sunlight, and stomata for gas exchange.

What are the limitations of stomata?

Stomata can lead to water loss.

How can we prove that glucose is made in photosynthesis?

By showing that starch, which is made of glucose, is present in leaves.

What is starch made of?

Long chains of glucose molecules joined together.

Why do plants store carbohydrates as starch?

Starch is compact and insoluble, making it easier to store.

How can we prove that oxygen is a product of photosynthesis?

By collecting oxygen released by a water plant and testing it.

What is the chemical test for oxygen, and what is the result?

Test: A glowing splint; Result: The splint relights in oxygen.

Why is a water plant used for this experiment?

It releases visible bubbles of oxygen during photosynthesis.

What are the word equations for respiration and photosynthesis?

Respiration: Glucose + Oxygen → Carbon Dioxide + Water + Energy; Photosynthesis: Carbon Dioxide + Water + Sunlight → Glucose + Oxygen.

When and why do plants perform respiration and photosynthesis?

Photosynthesis: During the day to produce glucose; Respiration: All the time to use glucose for energy.

How is biomass transferred through food chains?

Biomass is passed to organisms in the chain, and some of it is used as fuel for cellular respiration.