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Life Processes - RESPIR5.3 RESPIR5.3 RESPIR5.3 RESPIR5.3 RESPIR A AAAATIONTIONTIONTIONTION

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Respiration is the process by which living organisms produce energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances.

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The first step in all types of respiration is the breakdown of glucose, a six-carbon molecule (C6H12O6C_6H_{12}O_6), into a three-carbon molecule called pyruvate (C3H4O3C_3H_4O_3). This process occurs in the cytoplasm.

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Aerobic Respiration: Takes place in the presence of oxygen in the mitochondria. It breaks down pyruvate into CO2CO_2, H2OH_2O, and releases a significant amount of energy (3838 ATP).

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Anaerobic Respiration (Fermentation): Occurs in the absence of oxygen. In yeast, pyruvate is converted into ethanol (C2H5OHC_2H_5OH) and CO2CO_2.

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Anaerobic Respiration (Muscle Cells): During vigorous exercise, when there is a lack of oxygen, pyruvate is converted into lactic acid (C3H6O3C_3H_6O_3), which can cause muscle cramps.

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ATP (Adenosine Triphosphate): Known as the energy currency of the cell. The energy released during respiration is used to synthesize ATP from ADP and inorganic phosphate.

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Human Respiratory System: Consists of the nostrils, nasal passage, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli. The trachea is supported by rings of cartilage to prevent collapse.

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Alveoli: These are balloon-like structures at the end of bronchioles that provide a maximum surface area for the exchange of gases (O2O_2 and CO2CO_2).

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Hemoglobin: The respiratory pigment in human beings which has a high affinity for oxygen, transporting it from the lungs to the tissues.

📐Formulae

C6H12O6→Cytoplasm2 Pyruvate+EnergyC_{6}H_{12}O_{6} \xrightarrow{\text{Cytoplasm}} 2\text{ Pyruvate} + \text{Energy}

Pyruvate→Presence of O2 (Mitochondria)6CO2+6H2O+38 ATP\text{Pyruvate} \xrightarrow{\text{Presence of } O_2 \text{ (Mitochondria)}} 6CO_{2} + 6H_{2}O + 38\text{ ATP}

Pyruvate→Absence of O2 (Yeast)2C2H5OH+2CO2+2 ATP\text{Pyruvate} \xrightarrow{\text{Absence of } O_2 \text{ (Yeast)}} 2C_{2}H_{5}OH + 2CO_{2} + 2\text{ ATP}

Pyruvate→Lack of O2 (Muscle Cells)2 Lactic Acid+2 ATP\text{Pyruvate} \xrightarrow{\text{Lack of } O_2 \text{ (Muscle Cells)}} 2\text{ Lactic Acid} + 2\text{ ATP}

ADP+Pi+Energy→ATPADP + P_i + \text{Energy} \rightarrow ATP

ATP→HydrolysisADP+Pi+30.5 kJ/molATP \xrightarrow{\text{Hydrolysis}} ADP + P_i + 30.5\text{ kJ/mol}

💡Examples

Problem 1:

Calculate the total energy released in kJ/mol if a cell hydrolyzes 1010 molecules of ATP.

Solution:

10×30.5 kJ/mol=305 kJ/mol10 \times 30.5\text{ kJ/mol} = 305\text{ kJ/mol}

Explanation:

Since the hydrolysis of one mole of ATP releases 30.5 kJ30.5\text{ kJ} of energy, 1010 moles will release 1010 times that amount.

Problem 2:

Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?

Solution:

The amount of dissolved oxygen in water is fairly low compared to the amount of oxygen in the air (21%21\%).

Explanation:

Because the availability of oxygen is lower in water, aquatic organisms like fish must breathe faster to get sufficient oxygen for their metabolic needs.

Problem 3:

Explain the mechanism of inhalation.

Solution:

Ribs Lift+Diaphragm Flattens→Increased Chest Cavity Volume→Decreased Pressure\text{Ribs Lift} + \text{Diaphragm Flattens} \rightarrow \text{Increased Chest Cavity Volume} \rightarrow \text{Decreased Pressure}

Explanation:

When we breathe in, we lift our ribs and flatten our diaphragm. The chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli.