Ch 14Respiration — Class 11 Botany, concept-first.

Try sitting beneath a tree after dark and you may notice the air feels a little harder to breathe - at night, with no sunlight to drive photosynthesis, plants only take in oxygen and give out carbon d…

Plants and animals form a complementary, self-sustaining loop of gas exchange in the biosphere. During photosynthesis, plants absorb carbon dioxide through their stomata and release oxygen as a by-pro…

The term 'respiration' was coined by Pepys (1966). At its core, respiration is the biological oxidation of food substances - carbohydrates, proteins and fats - a process that consumes oxygen and relea…

The term 'respiration' was coined by Pepys (1966, as recorded in the textbook) to describe the biological oxidation of food substances -- carbohydrates, proteins and fats -- inside living cells, a pro…

At dawn and dusk, when sunlight is too weak to drive photosynthesis at full speed, a plant reaches a moment where the rate of CO2 released by respiration is exactly matched by the rate of CO2 being fi…

Respiration exists, ultimately, to generate ATP (Adenosine Triphosphate), the molecule Karl Lohmann first discovered in 1929.

Much of respiration's energy is captured not directly as ATP but first as reduced electron-carrier coenzymes, chiefly NAD+ (Nicotinamide Adenine Dinucleotide, oxidised form) and FAD (Flavin Adenine Di…

Based on whether molecular oxygen is used, respiration is classified into two broad types: aerobic respiration, which requires oxygen, and anaerobic respiration, which does not.

Aerobic respiration is respiration that proceeds only in the presence of oxygen, and it completely oxidises food materials -- carbohydrates, fats and proteins -- all the way down to carbon dioxide and…

In the complete absence of molecular oxygen, glucose cannot be broken down completely -- instead it is only incompletely degraded, most commonly into either ethyl alcohol or lactic acid, and the proce…

Aerobic respiration is best understood as four connected stages, each named for its principal chemical transformation and each occurring in a specific part of the cell: (1) glycolysis converts glucose…

Glycolysis (Greek: glykos = glucose, lysis = splitting) is a linear sequence of ten enzyme-catalysed reactions that splits one six-carbon glucose molecule into two molecules of three-carbon pyruvic ac…

The two molecules of pyruvate produced by glycolysis in the cytosol must first cross into the mitochondrial matrix before aerobic respiration can continue.

The two molecules of acetyl CoA generated by the link reaction now enter the Krebs cycle, named for its discoverer, the German biochemist Sir Hans Adolf Krebs, who worked it out in 1937 and later won…

Glycolysis, the link reaction and the Krebs cycle between them generate a large pool of reduced coenzymes -- and -- and it is the electron transport chain (ETC), located on the folded cristae of the i…

The Respiratory Quotient (RQ), or respiratory ratio, is the ratio of the volume of carbon dioxide released to the volume of oxygen consumed during respiration, and because different respiratory substr…

Anaerobic respiration is fundamentally less efficient than aerobic respiration because it never completely oxidises the respiratory substrate: only a limited number of ATP molecules are generated per…

Some organisms can respire even in the total absence of oxygen through a process called fermentation, of which three types exist: alcoholic fermentation, lactic acid fermentation and mixed acid fermen…

The rate at which a plant or tissue respires is not constant; it responds continuously to conditions both inside the organism and in its environment.

Not all of a plant cell's glucose is broken down by glycolysis -- roughly two-thirds is processed that way, while the remaining third is oxidised through a parallel route called the pentose phosphate…

These questions test whether you can apply the chapter's core ideas rather than simply recall them: computing ATP yields for pyruvate, cytosolic NADH and sucrose oxidation; identifying the biochemical…

Sample papers and previous-year board questions for this subject.