Introduction to respiration - class-IX

The part of the respiratory system starting with the external nostrils up to the terminal bronchioles constitutes the conducting part whereas the alveoli and their ducts form the respiratory or exchange part. During swallowing, glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the larynx.

Anaerobic respiration in yeast results in the production of ethyl alcohol, carbon dioxide and energy. $C _6H _{12}O _6 \xrightarrow[Complex]{Zymase} \underset{Ethyl , alcohol}{2C _2H _5OH} + 2CO _2 + $

• Inhaled air contains more oxygen used to create energy and less carbon dioxide.
•  Exhaled air contains more carbon dioxide produced as a waste product of energy production and less oxygen as it has been used in respiration. Gas exchange takes place by diffusion in the alveoli within the lungs.
•  As a result, the composition of inhaled and exhaled air is different.

Respiration is the process in which nutrients are converted into useful energy in a cell. It is responsible in transporting oxygen and carbon dioxide between cells and the external environment.

Respiration is a catabolic process that takes place in living organisms. In this glucose is broken down in presence of oxygen to generate ATP along with the production of water and evolution of carbon dioxide. It is an exergonic process. Thus the correct answer is option A.

The calorie was first defined to measure energy in the form of heat. These units are often used for the total amount of food energy. Nutritional requirements or intakes are expressed in calories per day. 

Glycolysis is the first step of respiration which converts the glucose molecules into two molecules of pyruvate along with the production of 8 ATP. The two pyruvate molecules produced by the glycolysis enters the Krebs cycle. Each molecule of pyruvate produces 15 ATP. So total 30 ATP is formed during the Krebs cycle. Total 38 ATP is formed during the aerobic respiration.

ATP is an Adenosine triphosphate (ribose sugar, adenine base, and three phosphate groups), where a high energy bond attaches the third phosphate group to the molecule. The highly unstable bonds break to release the inorganic phosphate to fulfill the energy required for the metabolism.

Henri Dutrochet, a French physiologist who is known for his valuable works in animal and plant physiology coined the term 'respiration'. He also discovered and named the process of osmosis (passage of solvent through a semipermeable membrane) that occurs at cellular level in both plants and animals. 

Carbon dioxide dissolves very well in water, which is actually why water breathers can eliminate CO2 efficiently across their gills. Thus, the statement that CO2 does not dissolve well in water is incorrect, meaning it is not a reason why breathing air is easier than breathing water. In fact, the high solubility of CO2 in water creates challenges for aquatic animals to maintain low internal levels without continuous ventilation.

In 1906, Haldane and Priestley discovered that respiratory reflex i.e. breath is caused by an excess of carbon dioxide in the blood and not by a lack of oxygen. They described the regulation of respiratory drive by carbon dioxide and its effects on blood hydrogen ion concentration The high ability of deoxygenated haemoglobin to bind with carbon dioxide was named as Haldane effect. Thus the correct answer is option B.

Glucose is a primary energy source for cells. Through the process of cellular respiration, glucose is oxidized to produce ATP, which powers cellular activities.

A healthy adult typically has a tidal volume of about 500 ml and a respiratory rate of 12 to 16 breaths per minute. The total volume of air inspired or expired per minute (minute ventilation) is roughly 6000 to 8000 ml.

The amount of energy and biomass in the producers of the food chain is 100%. At each successive level, the energy and biomass are lost. The organisms at each level use energy for respiration. This is called respiration loss. When producers are eaten by the herbivores, there is 20% respiratory loss as producers use about 20% of energy in the form of respiration. Similarly, when herbivores are eaten by carnivores, there is 30% respiratory loss as 30% of energy is used by herbivores. Also, about 60% of the energy is used by carnivores during respiration. Hence, respiratory loss from carnivores to decomposer is 60%. 

Phosphorus, nitrogen and sulphur do not loss due to respiration because they are not particularly involved in gaseous exchange.

The phlogiston theory is a scientific theory which states that the fire-like element is referred to phlogiston which is released during the process of combustion and explains the process of combustion and rusting which is together called as oxidation.

An alarmed rate of respiration is seen in germination of seeds. Higher respiration rate is seen in floral vegetative bud, germinating seedlings, young leaves, etc.

Germination is an aerobic process. Seeds require oxygen to perform cellular respiration, which provides the energy necessary for the embryo to grow and break through the seed coat.

As the temperature increases, the kinetic energy also increases and this increases the rate of reactions. Due to this the rate of cellular respiration also increases. So, the correct option is 'increase'.