12.1

Respiration

10 flashcards to master Respiration

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Key Concept Flip

List seven uses of energy in living organisms.

Answer Flip

Energy is used for: 1) muscle contraction (

Example: movement of limbs), 2) protein synthesis (. enzyme production), 3) cell division (. growth), 4) active transport (. nutrient uptake in roots), 5) growth (. increase in height), 6) nerve impulse transmission (. relaying sensory information), and 7) maintaining body temperature (. endothermic mammals).
Definition Flip

What is respiration?

Answer Flip

Respiration is the chemical process that releases energy from glucose. In aerobic respiration, glucose reacts with oxygen to produce carbon dioxide, water, and energy.

Example: muscle cells respire aerobically during exercise; yeast can respire anaerobically.
Definition Flip

What is the equation for aerobic respiration?

Answer Flip

Glucose + Oxygen → Carbon Dioxide + Water + Energy. This process occurs in the mitochondria of cells, such as muscle cells during physical activity.

Definition Flip

What is the equation for anaerobic respiration in muscles?

Answer Flip

Glucose → Lactic Acid + Energy. This occurs during strenuous exercise when oxygen supply is limited, leading to muscle fatigue,

Example: in a sprinter.
Definition Flip

What is the equation for anaerobic respiration in yeast?

Answer Flip

Glucose → Ethanol + Carbon Dioxide + Energy. This process is used in brewing beer (ethanol production) and baking bread (carbon dioxide makes the dough rise).

Key Concept Flip

How does temperature affect the rate of respiration in yeast?

Answer Flip

As temperature increases up to an optimum, the rate of respiration in yeast increases due to increased enzyme activity. Above the optimum temperature, the enzymes denature and the rate decreases.

Example: at very high temperatures, yeast will no longer ferment sugar.
Definition Flip

What is oxygen debt?

Answer Flip

Oxygen debt is the amount of oxygen needed to oxidize the lactic acid that builds up during anaerobic respiration. After intense exercise, deep breathing helps repay the oxygen debt. The liver converts lactic acid back to glucose.

Key Concept Flip

What is the role of enzymes in respiration?

Answer Flip

Enzymes are biological catalysts that speed up the rate of respiration. Different enzymes are involved in each step of both aerobic and anaerobic respiration.

Example: enzymes are used to break down glucose into pyruvate.
Key Concept Flip

Explain how muscle contraction requires energy from respiration.

Answer Flip

Muscle contraction is an active process that requires ATP (adenosine triphosphate), which is produced during respiration. The energy from ATP is used to power the sliding of actin and myosin filaments within muscle cells. For instance, moving your arm uses ATP from respiration in the arm muscles.

Key Concept Flip

Describe how a respirometer can be used to measure the rate of respiration.

Answer Flip

A respirometer measures oxygen consumption by an organism. It typically involves a sealed container with the organism, a means to absorb carbon dioxide (

Example: soda lime), and a manometer to measure the decrease in volume due to oxygen uptake. The rate of respiration is calculated based on the oxygen consumed over time.

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11.1 Gas exchange in humans 12.2 Aerobic respiration

Key Questions: Respiration

What is respiration?

Respiration is the chemical process that releases energy from glucose. In aerobic respiration, glucose reacts with oxygen to produce carbon dioxide, water, and energy.

Example: muscle cells respire aerobically during exercise; yeast can respire anaerobically.
What is the equation for aerobic respiration?

Glucose + Oxygen → Carbon Dioxide + Water + Energy. This process occurs in the mitochondria of cells, such as muscle cells during physical activity.

What is the equation for anaerobic respiration in muscles?

Glucose → Lactic Acid + Energy. This occurs during strenuous exercise when oxygen supply is limited, leading to muscle fatigue,

Example: in a sprinter.
What is the equation for anaerobic respiration in yeast?

Glucose → Ethanol + Carbon Dioxide + Energy. This process is used in brewing beer (ethanol production) and baking bread (carbon dioxide makes the dough rise).

What is oxygen debt?

Oxygen debt is the amount of oxygen needed to oxidize the lactic acid that builds up during anaerobic respiration. After intense exercise, deep breathing helps repay the oxygen debt. The liver converts lactic acid back to glucose.

About Respiration (12.1)

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

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