Respiration and Exercise Quiz 27 March 2024

Study Notes

Fermentation in yeast cells produces ethanol and carbon dioxide, used in making bread and alcoholic drinks.
The word equation for fermentation is: Glucose → ethanol + carbon dioxide.

Plants and algae make their own food through photosynthesis.
Almost all life on Earth depends on photosynthetic organisms.
Light provides the energy needed for photosynthesis.
Water and carbon dioxide are the reactants required for photosynthesis.
Plants produce carbohydrates in their leaves through photosynthesis and gain mineral nutrients and water from the soil via their roots.
The products of photosynthesis are oxygen and glucose.
The word equation for photosynthesis is: carbon dioxide + water → glucose + oxygen.
Photosynthesis maintains levels of oxygen in the atmosphere.

Leaves are the primary site of photosynthesis in plants.
Chloroplasts in plant cells contain a green pigment called chlorophyll, which uses the energy in light for photosynthesis.
Leaves have adaptations to carry out photosynthesis effectively, including:
- Epidermis: thin and transparent to allow more light to pass through.
- Palisade mesophyll: site of photosynthesis, containing many chloroplasts to absorb maximum sunlight.
- Spongy mesophyll: contains many air spaces to increase surface area and allow carbon dioxide and oxygen to diffuse easily.

Respiration is a chemical reaction that gives out heat (exothermic).
All living things respire.
Respiration is carried out in all cells continuously.
The purpose of respiration is to release energy for organisms to use.
Living things need energy for movement, keeping warm, and for other chemical reactions to build molecules.
The word equation for aerobic respiration is: Glucose + oxygen → carbon dioxide + water.

During exercise, cells require a greater rate of respiration to provide more energy for movement.
Heart rate, breathing rate, and breathing volume all increase during exercise to meet the increased demand for reactants during respiration.

Anaerobic means 'without oxygen'.
Anaerobic respiration takes place without oxygen and releases less energy than aerobic respiration.
During intense exercise, if there is not enough oxygen, anaerobic respiration takes place.
Aerobic respiration uses oxygen and releases more energy than anaerobic respiration.
Anaerobic respiration in muscle cells causes a build-up of lactic acid, resulting in an oxygen debt.
The word equation for anaerobic respiration is: Glucose → lactic acid (in animal muscles).