Respiration in Plants

Introduction:

For performing routine activities, be it absorption, transport, movement, reproduction or even breathing, all living organisms need energy.
The energy needed for life processes is extracted by oxidation of some macromolecules.
In general, it is the food that acts as the fuel of the body as the body produces energy from it through cellular respiration.
Respiration is an energy releasing, catabolic process, which is enzymatically controlled and involves a sequenced breakdown of food substances inside the living cells.
Different organisms obtain food through different habits.
Through the process of photosynthesis, green plants and cyanobacteria and some other photosynthetic bacteria can produce their own food (autotrophs).
The chemoautotrophs produce food from different chemicals and hence they are autotrophs too.
Animals are heterotrophic, i.e., they obtain food from plants directly (herbivores) or indirectly (carnivores).
Saprotrophs (fungi) depend on dead and decaying matter.

Topics covered

Respiration and its types
Plant parts which helps them to respire
Glycolysis/EMP Pathway
Pentose Phosphate Pathway/ Hexose monophosphate shunt
Anaerobic respiration/Fermentation
Induction to aerobic respiration
Amphibolic pathway
Respiratory quotient

Quiz

1. This biomolecule is common to a respiration-mediated breakdown of fats, carbohydrates and proteins
A. Acetyl CoA
B. Pyruvic acid
C. fructose 1, 6-bisphosphate
D. Glucose-6-phosphate

2. This is an incorrect statement for Kreb’s cycle
A. There are three points in the cycle where NAD+ is reduced to NADH + H+
B. The cycle starts with the condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid
C. during the conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesized
D. there is one point in the cycle where FAD+ is reduced to FADH2

3. In which one of the following do the two names refer to one and the same thing ?
A. Krebs cycle and Calvin cycle
B. Tricarboxylic acid cycle and citric acid cycle
C. Citric acid cycle and Calvin cycle
D. Tricarboxylic acid cycle and urea cycle

4. The energy-releasing metabolic process in which substrate is oxidized without an external electron acceptor is called
A. photorespiration
B. aerobic respiration
C. glycolysis
D. fermentation

5. The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because
A. ADP is pumped out of the matrix into the intermembrane space
B. high energy bonds are formed in mitochondrial proteins
C. there is a change in the permeability of the inner mitochondrial membrane towards adenosine diphosphate (ADP)
D. a proton gradient forms across the inner membrane

6. The overall goal of glycolysis, Krebs cycle and the electron transport system is the formation of
A. sugars
B. ATP in small stepwise units
C. ATP in one large oxidation reaction
D. nucleic acids

7. How many ATP molecules could maximally be generated from one molecule of glucose, if the complete oxidation of one mole of glucose to CO2 and H2O yields 686 kcal and the useful chemical energy available in the high energy phosphate bond of one mole of ATP is 12 kcal?
A. 57
B. 30
C. 2
D. 1

8. During which stage in the complete oxidation of glucose is the greatest number of ATP molecules formed from ADP?
A. Electron transport chain
B. Krebs cycle
C. Glycolysis
D. Conversion of pyruvic acid to acetyl CoA

9. In alcohol fermentation
A. triose phosphate is the electron donor while pyruvic acid is the electron acceptor
B. triose phosphate is the electron donor while acetaldehyde is the electron acceptor
C. oxygen is the electron acceptor
D. there is no electron donor

10. How many ATP molecules are produced by aerobic oxidation of one molecule of glucose?
A. 38
B. 34
C. 4
D. 2