Internal Respiration

Our body is made up of billions of microscopic cells. Within each cell are smaller structures known as organelles, many of which can only be seen using an electron microscope.

Mitochondria are the organelles in which cellular respiration takes place. Oxygen and glucose enter the cell from the blood capillaries and move through the cytoplasm to the mitochondria where they are used in cellular respiration. Cellular respiration is a series of chemical reactions assisted by enzymes. These chemical reactions release energy from glucose.

In case of aerobic respiration there occur complete oxidation of food yielding carbon dioxide, water and energy in the presence of oxygen is called aerobic respiration. This respiration starts in the cytoplasm (glycolysis) and continues in the mitochondria (Kreb's cycle) of the cell. The products of this reaction include: ATP, carbon dioxide and water.

The number of molecules of ATP formed by each glucose molecule during aerobic respiration is 38. Hence, the energy made available is much greater than in the case of anaerobic respiration.

In the process, energy is produced. This energy is used to drive cellular processes that are endothermic (processes that absorb energy). steps take place during aerobic respiration are:

In Cytoplasm (Glycolysis) :-

$Glucose:(6;Carbon)xrightarrow[In;Cytoplasm]{Glycolysis}Pyruvic ;Acid; (3;Carbon)$

In Mitochondria (Kreb cycle ) :-

$Pyruvic: Acidxrightarrow[In;mitochondria;presence;of;oxygen]{Krebs;Cycle} CO_2+H_2O+38ATP$

While the reactions of respiration are taking place in the mitochondria , chemical reactions to produce proteins are occurring on the surface of structures called ribosomes. At the ribosomes, amino acids from the protein you have digested are reassembled into proteins your body can use. Enzymes and hormones are proteins, as are parts of cell membranes and muscle fibres.

Sample Questions

(More Questions for each concept available in Login)

Question : 1

The starting process of respiration that takes place in the cytoplasm is called as ________________
A. Glycolysis	B. Kreb cycle	C. External respiration	D. None of the above
Right Option : A
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Question : 2

Cellular respiration takes place in which of the following cell organelle ?
A. Mitochondria	B. Plastid	C. Nucleus	D. Chloroplast
Right Option : A
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Question : 3

The process of complete oxidation of food material in the presence of oxygen gas is called as ______________
A. Aerobic respiration	B. Anaerobic respiration	C. Oxidative respiration	D. None of the above
Right Option : A
View Explanation